Measurement properties of patient-reported outcome measures for sexual health in the general population: a systematic review following the COSMIN 2.0 guidelines.

This systematic review, encompassing 27 studies, examines a total of 27 scales for assessing sexual health across different domains; the recommendations derived from this analysis are summarized in Table 5 . Sexual health: The study [ 31 ] assessed male sexual health. Although its recommendation grade is B, we recommend the MSHQ for this purpose. Although both the SHIMA and FSWB scales for assessing women’s sexual health are rated as Grade C, the FSWB demonstrates superior methodological quality and measurement properties across multiple domains. Therefore, we recommend the FSWB scale. The SHLS scale, which focuses on sexual health awareness between sexual partners, has received an A-level recommendation and is therefore recommended for this assessment. Sexual function: Among the four studies [ 27 , 32 , 44 , 50 ] that evaluate male sexual function, three [ 27 , 44 , 50 ] received a recommendation grade of B. The scale used in study [ 32 ] is the IIEF, developed by experts from 12 countries. It has been translated into multiple languages, is widely used, and is often considered the ‘gold standard’ for assessing male sexual function. According to the COSMIN 2.0 evaluation [ 19 ], it has an A recommendation level. Therefore, we recommend the IIEF scale for assessing male sexual function. For female sexual function, we recommend the FSFI scale, which received a grade A and is considered the ‘gold standard’. This recommendation is made in the context of six evaluated studies [ 34 , 38 , 40 , 44 , 50 , 51 ], among which studies [ 34 , 38 , 44 , 50 ] received Grade B, and study [ 51 ] received Grade C. Sexual pleasure: Sexual pleasure is defined as the physical and/or psychological satisfaction and enjoyment derived from solitary or shared erotic experiences, including thoughts, dreams and autoeroticism [ 52 ]. Two studies [ 41 ] and [ 48 ] were used to assess sexual pleasure. Both studies included male and female participants; however, study [ 48 ] received a Grade B recommendation due to its “-” rating for content validity. In contrast, study [ 41 ] was superior to [ 48 ] in terms of methodology, measurement properties, and the dimensions used to assess sexual pleasure. Therefore, we recommend using ASPI to assess sexual pleasure. Sex addiction: Sex addiction, also called hypersexuality or compulsive sexual behavior, refers to an uncontrolled frequency of sexual behavior, associated with compelling and irresistible craving, and which persists despite the subject’s experience of negative consequences and suffering, psychically or physically. It may be continuous or episodic [ 53 ]. Two scales for assessing sexual addiction were identified: one from Study [ 45 ] and the BYSAS from Study [ 46 ]. Both studies involved male and female participants and received a Grade B. However, the BYSAS demonstrated superior methodological quality and measurement properties across more aspects. Therefore, we recommend the BYSAS scale. Genital appearance: Studies [ 25 ] and [ 36 ] evaluated the appearance of male and female genitalia, respectively. Currently, no patient-reported outcome measure (PROM) has achieved a Grade A recommendation for this purpose. Although both studies received a Grade B, in accordance with COSMIN 2.0 guidelines [ 19 ], we recommend the MGSIS for male and the FGSIS for female genital appearance assessment. The development of higher-quality instruments in the future is warranted. Quality of Sexual Life: The QSE and NSSS are instruments used to assess the quality of sexual life in both men and women. The NSSS has a recommendation grade of A. The MSQ scale is used to assess sexual life satisfaction in men but has a recommendation grade of C. Additionally, relevant domains are included as subscales within other instruments (e.g., QSF, SHIMA, SaRDS). Therefore, we recommend the NSSS for the assessment of quality of sexual life. Sexual Violence: Study [ 42 ], which is the only one in this systematic review to evaluate sexual violence between intimate partners and is rated as a Grade A scale, introduces the IPSVS. As such, we recommend the IPSVS for assessing violent behaviors during sexual activities between intimate partners. Ejaculation function: Two studies [ 28 , 29 ] address male ejaculatory function, using the MSHQ-EjD (focusing on ejaculation function) and the PEDT (focusing on ejaculation time), respectively; both scales have a recommendation grade of B. Our systematic review of major databases revealed that most existing research focuses on male erectile function, highlighting a significant gap in the availability of scales for assessing male ejaculatory function. Based on the recommendation grades, we recommend the SSASM [ 26 ] for male sexual arousal and the FSDQ [ 35 ] for female sexual desire. Specific results are presented in Table 5 . Table 5 Quality of evidence and recommendations of the scale Questionnaire Content validity Structural validity Internal consistency Reliability Criterion validity Hypotheses testing for construct validity Responsiveness Recommendation M E M E M E M E M E M E M E ASPI + M + H + H NR NR NR NR + H NR NR A IPSVS + M - H + H NR NR NR NR NR NR NR NR A SHLS + M - H + H + H - H + H NR NR A SFEQ - M + H NR NR + M + H NR NR ? H B CSBD-19 - M - H + H NR NR + H + H NR NR B BYSAS - M - H + H NR NR - H + H NR NR B SaRDS + M - H + H NR NR ? H + H NR NR A SPS - M + H + H NR NR + H + H NR NR B QSE - M - M + H NR NR NR NR + M ? H B NSSS + M - H + H + M ? H ? L NR NR A QSF - M - H + H NR NR NR NR + H NR NR B MGSIS - M - H + H - M - H + H NR NR B SSASM + M - M + H - L + H + H NR NR A EMAS-SFQ - M + H + H - L - H + H ? H B MSHQ-EjD - M + M + H + M - H + H NR NR B PEDT + M - H + H + H NR NR NR NR NR NR B MSQ - M - M - H NR NR + H NR NR NR NR C MSHQ + M - M + H - L + H + H NR NR B IIEF + M - H + H - H + H + H ? H A SHIMA + M - H - H + H NR NR + H NR NR C SFQ28 - M - H + H + M + H + M NR NR B FSDQ + M - H + H NR NR + H + M NR NR B FGSIS - M - M + H NR NR - H NR NR NR NR B FSWB - M - M + H + H - H + M NR NR C FSFI-6 - M NR NR ? H + M + H + H NR NR B SFQ + M - M - H - H ? H + H ? H C FSFI + M - M + H + H - H + M NR NR A Notes: M  = Rating the measurement properties; E = Level of evidence; “+”=sufficient; “-”=indeterminate; “?”=insufficient; NR = Not Reported; A/B/C = Scale recommendation level; H = High; M  = Moderate; L = Low; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale;SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Quality of evidence and recommendations of the scale Notes: M  = Rating the measurement properties; E = Level of evidence; “+”=sufficient; “-”=indeterminate; “?”=insufficient; NR = Not Reported; A/B/C = Scale recommendation level; H = High; M  = Moderate; L = Low; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale;SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function

The 27 scales did not provide evidence for all ten COSMIN measurement properties [ 22 ]. Our evaluation focused on the following properties, for which data were available: content validity, structural validity, internal consistency, test-retest reliability, criterion validity, hypotheses testing for construct validity, and responsiveness. The methodological quality of scale development was also assessed. Detailed results are presented in Tables 3 , 4 , and 5 . Table 3 details the methodological quality of the development and content validity of the included Patient-Reported Outcome Measures (PROMs), while Table 4 summarizes the results of their measurement properties. The results are presented in this sequence. In the concept generation phase, all 27 studies were found to have a clear conceptual basis. Regarding sample size in the survey phase, all studies received an ‘V’ rating. For 14 studies [ 26 , 29 – 33 , 35 , 37 , 40 , 41 , 43 , 47 , 49 , 51 ], although the overall methodological quality could not be rated as ‘V’, they provided sufficiently detailed descriptions of the development process. The remaining 13 studies relied solely on survey methods for concept elicitation, without supplementary interviews. Although 7 studies [ 27 , 32 , 39 – 41 , 43 , 51 ] included a pilot study, none explicitly reported whether issues related to scale comprehensibility were addressed based on the pilot findings. It is noteworthy that two studies from Iran [ 33 , 43 ] explicitly stated that data saturation was reached, obtaining more ‘V’s in the project evaluation of the Box1 [ 22 ] domain. Since the scale development did not involve measurement properties, we refrain from making further statements. The evaluation of content validity involves gathering feedback from both patients and experts on the instrument’s relevance, comprehensiveness, and comprehensibility. Nineteen studies [ 25 – 27 , 29 , 31 – 33 , 35 , 37 , 39 – 44 , 47 , 49 – 51 ] addressed content validity. However, only three [ 40 , 42 , 43 ] collected feedback from both patients and experts on the tools’ relevance, comprehensiveness, and comprehensibility. Despite this, their evaluations were still rated ‘D’ (Doubtful) due to several methodological shortcomings: an insufficient number of participants in qualitative studies, a lack of clarity on whether data were analyzed independently, and unclear data processing methods. Eleven studies [ 26 , 29 , 31 – 33 , 35 , 40 – 43 , 47 ] assessed patients’ understanding of the items during the survey, and the measurement properties of these studies were rated as “+”. Eight studies [ 28 , 30 , 34 , 36 , 38 , 45 , 46 , 48 ] did not conduct interviews or surveys with experts and patients to evaluate the content validity of the scales. Among them, study [ 33 ] received an ‘A’ rating for its process of collecting feedback from patients and experts on the comprehensibility of the scale. The methodological quality of the remaining studies was rated as ‘Doubtful’ for various reasons. Although studies [ 27 , 39 ] and [ 51 ] did not directly assess patient comprehension, they conducted pilot studies. Based on this, the content validity of these scales was rated positively (“+”). For detailed results, see Tables 3 and 4 . Table 3 Methodological quality of patient-reported outcome measure (PROM) development and content validity Questionnaire PROM development Content validity (Concept elicitation study) (Pilot study) (Patient consultation) (Expert consultation) Relevance Comprehensiveness Comprehensibility Relevance Comprehensiveness Comprehensibility ASPI D D D D D D NR D IPSVS D NR D D D D D D SHLS D D D D D D D D SFEQ D NR D NR NR D NR NR CSBD-19 D NR NR NR NR NR NR NR BYSAS D NR NR NR NR NR NR NR SaRDS D NR D D D NR NR NR SPS D NR NR NR NR NR NR NR QSE D NR NR NR NR D D NR NSSS D D NR NR NR D NR NR QSF D NR D D NR NR NR NR MGSIS D NR NR NR NR NR D D SSASM D NR D D D NR NR NR EMAS-SFQ D D NR NR NR NR NR NR MSHQ-EjD D NR NR NR NR NR NR NR PEDT D NR D NR D D D D MSQ D NR NR NR NR NR NR NR MSHQ D NR NR NR D D NR NR IIEF D D NR NR D D D D SHIMA A NR A NR A NR A A SFQ28 D NR NR NR NR NR NR NR FSDQ D NR NR NR D D NR D FGSIS D NR NR NR NR NR NR NR FSWB D NR A A NR NR NR NR FSFI-6 D NR NR NR NR NR NR NR SFQ D D NR NR NR D NR D FSFI D D D D D D D D Notes: V = Very Good; A = Adequate; D = Doubtful;I = Inadequate; NR = Not Reported; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Methodological quality of patient-reported outcome measure (PROM) development and content validity Notes: V = Very Good; A = Adequate; D = Doubtful;I = Inadequate; NR = Not Reported; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function For the assessment of structural validity, ten studies [ 25 , 29 , 32 – 34 , 41 , 43 , 44 , 46 , 47 ] applied both confirmatory factor analysis (CFA) and exploratory factor analysis (EFA). According to the criteria for structural validity, one study [ 29 ] was rated ‘A’, because its sample size was five to seven times the number of items. The remaining studies were rated ‘V’. Six studies [ 27 , 35 , 39 , 42 , 45 , 50 ] used exploratory factor analysis only and received an ‘A’ rating. Nine studies [ 26 , 28 , 30 , 31 , 36 , 37 , 40 , 49 , 51 ] employed principal component analysis (PCA) and were rated ‘D’. Study [ 40 ] did not report on structural validity. Although structural validity was reported in these studies, the majority failed to meet the criterion that “Maximum 10% of the items have factor loadings ≥ 0.30 on multiple factors” resulting in an ‘indeterminate’ rating for this measurement property. Regarding internal consistency, with the exception of study [ 44 ], the remaining 26 studies all reported this property and calculated Cronbach’s alpha. Their methodological quality was rated ‘V’. These studies provided at least low-quality evidence for structural validity, and with Cronbach’s alpha ≥ 0.70, their measurement properties were rated’+’. However, three studies [ 30 , 33 , 51 ] received a’-’ rating as their subscale Cronbach’s alpha < 0.7. Study [ 38 ] was rated ‘?’ due to its failure to report structural validity. Sixteen studies [ 25 – 29 , 31 – 34 , 37 – 40 , 43 , 44 , 51 ] assessed the reliability (test-retest reliability) of their respective instruments. Study [ 31 ] had a retest interval of less than 7 days, while studies [ 26 , 27 ] changed the testing conditions from face-to-face survey to telephone survey. The methodological quality of these three studies was rated ‘I’. Among the studies, six [ 25 – 27 , 31 , 32 , 51 ] reported either an Intraclass Correlation Coefficient (ICC) or Pearson correlation coefficient of <0.7, and consequently, their measurement properties were rated’-’. Five studies [ 29 , 33 , 42 , 49 , 50 ] did not report on criterion validity. Among the remaining studies that did, most used instruments that were not the “gold standard” as comparators, however, since they reported the measurement properties of the comparator instruments, their methodological quality was rated ‘V’ (Very Good) according to the COSMIN Risk of Bias checklist version 3.0 [ 22 ]. Eight studies [ 25 , 27 , 28 , 36 , 37 , 40 , 43 , 46 ] received a’-’ rating for their measurement properties because their correlation with the “gold standard” was  0.70. Regarding hypotheses testing for construct validity, the evaluation primarily focused on convergent and discriminant validity. Twenty studies [ 25 – 28 , 31 , 32 , 34 , 35 , 37 – 41 , 43 , 44 , 46 – 49 , 51 ] reported both convergent and discriminant validity. Study [ 45 ] reported only convergent validity, while studies [ 25 ] and [ 33 ] reported only discriminant validity. Three studies [ 30 , 36 , 42 ] did not report any hypotheses testing content. For convergent validity, five studies [ 34 , 35 , 37 , 40 , 49 ] received a ‘D’ methodological quality rating because the comparator instruments they used lacked comprehensive quality assessment. Study [ 39 ] was rated ‘I’ in methodological quality as it failed to provide any measurement properties of the comparator instrument. In contrast, all studies assessing discriminant validity provided detailed descriptions of subgroup characteristics and between-group differences, consequently receiving a ‘V’ methodological quality rating. Since the results from all studies were consistent with their pre-specified hypotheses, their measurement properties were rated’+’. Five studies [ 27 , 32 , 44 , 49 , 51 ] reported on the responsiveness of their scales. Studies [ 49 ] and [ 51 ] assessed responsiveness by comparing different groups, studies [ 32 ] and [ 44 ] compared changes before and after an intervention, and study [ 27 ] evaluated responsiveness by tracking changes in testosterone levels. These studies employed robust designs and appropriate statistical methods, thus receiving a ‘V’ rating for methodological quality. However, because they failed to provide clear results regarding responsiveness, their measurement properties were rated ‘?’. Table 4 Methodological quality evaluation levels Questionnaire Structural validity Internal consistency Reliability Criterion validity Hypotheses testing for construct validity Responsiveness ASPI V V NR NR V NR IPSVS A V NR NR NR NR SHLS V V V V V NR SFEQ V NR D V V V CSBD-19 A V NR V V NR BYSAS V V NR V V NR SaRDS V V NR V V NR SPS V V NR V V NR QSE D V NR NR D V NSSS A V D V I NR QSF A V NR NR NR NR MGSIS V V D V V NR SSASM D V I V V NR EMAS-SFQ A V I V V V MSHQ-EjD D V D V V NR PEDT V V A NR V NR MSQ D V NR V NR NR MSHQ D V I V V NR IIEF V V A V V V SHIMA V V A NR V NR SFQ28 V V D V D NR FSDQ A V NR V D NR FGSIS D V NR V NR NR FSWB D V A V D NR FSFI-6 NR V D V V NR SFQ D V A V V V FSFI D V V V D NR Notes: V = Very Good;A = Adequate; D = Doubtful;I = Inadequate; NR = Not Reported; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool;SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Methodological quality evaluation levels Notes: V = Very Good;A = Adequate; D = Doubtful;I = Inadequate; NR = Not Reported; ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool;SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Following the updated methodology for grading evidence in quantitative systematic reviews, the quality of evidence concerning measurement properties was not downgraded for inconsistency. Inconsistency refers to disagreements between the results of different studies when assessing the same measurement property of the same instrument [ 23 ]. Consequently, we considered downgrading based solely on three domains: risk of bias, imprecision, and indirectness. The resulting levels of evidence and corresponding recommendations are presented in Table 5 . Risk of Bias: The methodological quality of content validity for these 27 scales was rated as doubtful in certain items, indicating a potential risk of bias. Consequently, the level of evidence for their content validity was downgraded by one level. The evidence level for structural validity in study [ 40 ] was downgraded by one level due to an insufficient sample size, which was less than five times the number of items [ 19 ]. For internal consistency, with the exception of study [ 44 ] which did not report this property, all other studies employed rigorous methods and reported Cronbach’s alpha, resulting in a ‘H’ evidence grade. However, three studies [ 26 , 27 , 31 ] received an ‘I’ rating on methodological quality for reliability, leading to a two-level downgrade in their reliability evidence. Additionally, eight studies [ 25 , 28 , 34 , 38 , 39 , 41 , 44 , 48 ] were rated doubtful in methodological quality, resulting in a one-level downgrade of their evidence. The methodological quality of criterion validity was rated as doubtful for ten studies [ 26 , 28 , 30 , 31 , 36 , 37 , 40 , 41 , 49 , 51 ], leading to a one-level downgrade in the evidence level for the criterion validity of these nine scales. For the remaining studies that reported criterion validity, the methodological quality was rated ‘V’, with no risk of bias identified. In hypotheses testing, five studies [ 34 , 35 , 37 , 40 , 49 ] received a ‘D’ rating in methodological quality, resulting in a one-level downgrade of their evidence level. Study [ 39 ] was rated ‘I’ in methodological quality, leading to a two-level downgrade of its evidence level. For responsiveness, five studies [ 34 , 35 , 37 , 40 , 47 ] were rated ‘V’ in methodological quality. Consequently, no risk of bias was identified for these five scales. Inaccuracy and indirectness: All 27 studies had sample sizes exceeding 100, and the populations, constructs, and contexts examined during scale development aligned with their intended applications. Consequently, neither factor necessitated a downgrade in the quality of evidence.

Based on the retrieval principles recommended by COSMIN [ 24 ], systematic searches of five databases (PubMed, Embase, Web of Science, Cochrane Library, and CNKI) identified a total of 10,973 records. After removing duplicates and conducting an initial screening of titles and abstracts, a total of 208 potentially relevant articles were selected. Following full-text review, 27 studies met the inclusion criteria and were ultimately included in the analysis. The detailed study selection process is illustrated in Fig. 1 . Fig. 1 Preferred reporting items for systematic review and Meta-analysis flow chart Preferred reporting items for systematic review and Meta-analysis flow chart These 27 studies, published between 1997 and 2025, each described the development or validation of a distinct self-report scale and encompassed research from 22 countries, reflecting sustained global interest in sexual health. Analysis of the scales’ target populations revealed considerable diversity. Eight studies focused specifically on men [ 25 – 32 ], addressing aspects such as erectile function, ejaculatory function, sexual health, sexual quality of life, and genital appearance. Eight studies focused on women [ 33 – 40 ], addressing sexual function, sexual health, sexual desire, and genital appearance. Another eleven studies examined couples or partners [ 41 – 51 ], covering aspects such as sexual function, health, pleasure, quality of life, violence, and distress. Analysis of the age ranges of the 27 included scales showed that although some scales measure the same construct, their target age groups often differ. For instance, while both the 28-item version of the SFQ (SFQ28) and the Female Sexual Function Index (FSFI) assess female sexual function, the SFQ28 is specifically targeted at middle-aged women (around 45 years old), whereas the FSFI was developed for a broader adult age range. This specificity therefore makes the SFQ28 a more precise tool for that particular demographic. Our review includes scales originating from diverse contexts: developed countries (e.g., the IIEF and FSFI both from US/Multi-National Cooperation), developing countries (e.g., the The Male Sexual Quotient, MSQ from Brazil), and societies with relatively conservative sexual cultures (e.g., the Sexual Health Literacy Scale, SHLS from Iran). For specific results, see Table 1 (Ordered by Target Population and Year of Publication). Table 1 Characteristics of included studies Study Questionnaire Suitable crowd Country Study population Age, year Borgmann et al. 2025 [ 41 ] ASPI Male/Female Netherlands/Switzerland Adults >18 Laura et al. 2024 [ 42 ] IPSVS Male/Female Australia Intimate partner >18 Kazhal et al. 2023 [ 43 ] SHLS Male/Female Iran Iranian adults / Kirstin et al. 2022 [ 44 ] SFEQ Male/Female UK Adults >18 Beáta et al. 2020 [ 45 ] CSBD-19 Male/Female America/Hungary/Germany Adults >18 Cecilie et al. 2018 [ 46 ] BYSAS Male/Female Norway Norwegian adults 35.8 ±(13.3) Rebecca et al. 2018 [ 47 ] SaRDS Male/Female Australia Intimate partner >18 Pascoal et al. 2016 [ 48 ] SPS Male/Female America/Portugal Adults >18 Stephanie et al. 2013 [ 49 ] QSE Male/Female America American adults 18–60 Aleksandar et al. 2010 [ 50 ] NSSS Male/Female Croatia/America Croatian adults/American adults 18–55 Lothar et al. 2005 [ 51 ] QSF Male/Female Germany German adults 45–70 Debby et al. 2013 [ 25 ] MGSIS Male America Men 18–60 Stanley et al. 2011 [ 26 ] SSASM Male America Men 21–70 Daryl et al. 2008 [ 27 ] EMAS-SFQ Male Italy/Belgium/Poland/Sweden/UK/Spain/Hungary/Estonia Aging men 40–79 Raymond et al. 2007 [ 28 ] MSHQ-EjD Male America Men 30–94 Tara et al. 2007 [ 29 ] PEDT Male America/Germany/Spain/Australia/France Men 18–65 Carmita et al. 2007 [ 30 ] MSQ Male Brazil Men 18–72 Raymond et al. 2004 [ 31 ] MSHQ Male America Men >50 Rosen et al. 1997 [ 32 ] IIEF Male UK/America/Australia/Netherlands/Denmark/France/Italy/Finland/Germany/Norway/Spain/Sweden Men >55 Sedigheh et al. 2022 [ 33 ] SHIMA Female Iran Iranian women 40–65 Tara et al. 2012 [ 34 ] SFQ28 Female America/Germany/Spain American women/German women/Spanish women 42–48 Denisa et al. 2011 [ 35 ] FSDQ Female Australia Australian women >18 Debra et al. 2010 [ 36 ] FGSIS Female America Women 18–40 Raymond et al. 2009 [ 37 ] FSWB Female America American women 21–72 Andrea et al. 2009 [ 38 ] FSFI-6 Female Italy Italian women >18 Frances et al. 2002 [ 39 ] SFQ Female UK/America/Australia/Netherlands/Denmark/France/Italy Women 19–65 Rosen et al. 2000 [ 40 ] FSFI Female America American women 21–69 Notes: ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Characteristics of included studies Notes: ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale; FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Table 2 provides an overview of the 27 scales evaluated in this review, detailing their target constructs, sample characteristics, number of items, domain structure, and scoring systems. There is substantial variation among these scales in their length and complexity. Specifically, the number of items varies widely, ranging from as few as 3 items to 106 items. These scales can be roughly categorized into three types based on their length and intended use: ultra-short scales containing 3 items (e.g., Sexual Pleasure Scale, SPS [ 48 ]) and 6 items (e.g., 6-Item Version of the Female Sexual Function Index, FSFI-6 [ 38 ] and Premature Ejaculation Diagnostic Tool, PEDT [ 29 ]), designed to provide maximum efficiency for clinical screening, though they may sacrifice content breadth; medium-length scales (e.g., IIEF [ 32 ] and FSFI [ 40 ]), which strike a balance between providing multidimensional information and maintaining good feasibility, suitable for most clinical surveys; and the 106-item Sexual Health Literacy Scale (SHLS) [ 43 ], which, while offering unparalleled detail, may affect data collection due to the heavy burden on respondents. This review identifies a multidimensional conceptual framework constructed from the conceptual domains of the 27 included sexual health scales. The conceptual areas covered by these scales can be categorized into several core dimensions: physiological function, psychological experience, relational interaction, and socio-cultural aspects. Although significant overlap exists across scales, each instrument possesses unique features, reflecting the diverse conceptualizations of sexual health by their developers. Within the dimension of physiological function, several scales target different phases of the sexual response cycle. While scales like the IIEF, FSFI, Sexual Function Questionnaire (SFQ) [ 39 ], and SFQ28 [ 34 ] comprehensively assess core sexual function domains (e.g., desire, arousal, orgasm), others target specific dysfunctions: the IIEF and Male Sexual Health Questionnaire (MSHQ) [ 31 ] focus on erectile function, and the Four-Item Version of Male Sexual Health Questionnaire (MSHQ-EjD) [ 28 ] and PEDT [ 29 ] on ejaculatory function. Notably, scales vary in their approach to measuring similar functions. For instance, the QSF [ 51 ] assesses both the individual’s and the partner’s perspectives, whereas the European Male Ageing Study Sexual Function Questionnaire (EMAS-SFQ) [ 27 ] incorporates items on masturbation and associated distress. An examination of the psychological experience dimensions uncovers considerable complexity. Beyond commonly assessed constructs such as satisfaction (e.g., New Sexual Satisfaction Scale, NSSS [ 50 ] and Male Sexual Quotient, MSQ [ 30 ]) and self-confidence (Sexual Function Evaluation Questionnaire, SFEQ [ 44 ]), these scales also measure more nuanced psychological phenomena. Sexual Pleasure Scale (SPS) [ 48 ] and Amsterdam Sexual Pleasure Inventory (ASPI) [ 41 ] each have their own strengths in their approaches to measuring sexual pleasure. The SPS, as a concise scale, focuses specifically on the immediate sensations experienced during sexual activity, and its extreme brevity offers unique value for large-scale surveys and clinical screenings. In contrast, the ASPI is more sophisticated, encompassing multiple dimensions such as cognitive, emotional, physical, and interpersonal aspects. This allows it to delve deeply into the complex structure and individual differences of sexual pleasure, providing richer information for theoretical testing and targeted interventions. The Compulsive Sexual Behavior Disorder Scale (CSBD-19) [ 45 ] and Bergen–Yale Sex Addiction Scale (BYSAS) [ 46 ] target addiction-related psychological mechanisms; the Sexual and Relationship Distress Scale (SaRDS) [ 47 ] encompasses diverse psychological factors, including anxiety, guilt, and body image; and the Male Genital Self-Image Scale (MGSIS) [ 25 ] and Female Genital Self-Image Scale (FGSIS) [ 36 ] are dedicated to evaluating genital self-image and associated emotions. At the relational level, scales such as the Subjective Sexual Arousal Scale for Men (SSASM) [ 26 ], Sexual Health Scale for Middle-Aged Married Women (SHIMA) [ 33 ], and MSQ [ 30 ] focus on partner communication, synchrony, and relationship quality. The NSSS specifically addresses the critical dimension of ‘emotional connection and intimacy, whereas the Sexual Function Evaluation Questionnaire (SFEQ) [ 44 ] and SaRDS [ 47 ] evaluate the influence of relationships on sexual health from positive and negative standpoints, respectively. A notable development is the expansion into the socio-cultural dimension. For instance, the SHLS [ 43 ] introduces the concept of sexual health literacy, covering six specific areas such as information acquisition and socio-cultural barriers. The SHIMA [ 33 ] further broadens this scope by incorporating service accessibility and sexual autonomy, thereby significantly expanding the framework of traditional sexual health measurement. A notable observation is the varied operationalization of core concepts across scales. ‘Sexual desire,’ for example, is an independent domain in scales like the IIEF [ 32 ], Sexual Health Literacy Scale (FSDQ) [ 35 ], and SFQ28 [ 34 ], with the FSDQ [ 35 ] making a further distinction between partner-oriented and solitary desire. Meanwhile, ‘satisfaction’ is framed as personal confidence in the MSQ [ 30 ], as emotional connection in the NSSS [ 50 ], and encompasses both intercourse and overall satisfaction in the IIEF [ 32 ]. The overlap and complementarity of systems in this field are not simply repetitions; rather, they reflect the refined operationalization of sexual health constructs at different scales based on their specific theoretical foundations and applicable contexts. Table 2 Characteristics of the included scales Questionnaire Construct Participants, n Number of Items Domain Response Options Completion Time ASPI Sexual Pleasure 1080 57 4 domains: Hedonic, Interpersonal, Intrapersonal, General 6-point Likert scale, 1–6 per item Unknown IPSVS Sexual Violence 1026 20 3 domains: Dominance and Humiliation, Emotional Coercion, Aggressive Indifference Unknown 30 min SHLS Sexual Health Literacy 650 106 6 domains: Sexual skills, Individual socio-cultural barriers, Sexual vulnerability, Resources to access sexual information, Understanding and application, Capacity and motivation 5-point Likert scale, 1–5 per item Unknown SFEQ Sexual Function 486 16 4 domains: problem distress, partner relationship, sex life, sexual confidence Unknown Unknown CSBD-19 Sex Addiction 9325 19 5 domains: control, salience, relapse, dissatisfaction, negative consequences Unknown 30 min BYSAS Sex Addiction 23533 6 1 domains: Sex Addiction 5-point Likert scale, 0–4 per item Unknown SaRDS Sexual and Relationship Distress 1381 30 14 domains:anxiety, conflict, initiation,guilt, infidelity, security, predictability, communication, body image, physical affection, hopelessness, self-esteem, normalness,and relationship quality 7-point Likert scale, 0–6 per item 17 min SPS Sexual Pleasure 279 3 1 domains: Sex Pleasure 7-point Likert scale, 1–7 per item <1 min QSE Sexual Experience 2056 8 1 domains: Quality of Sexual Experience 7-point Likert scale, 1–7 per item Unknown NSSS Sexual Satisfaction 388 20 5 domains: sexual sensations, sexual presence and awareness, sexual exchange, emotional connection and closeness, sexual activity 6-point Likert scale, 1–6 per item Unknown QSF Sexual Function 738 40 4 domains: psycho-somatic quality of life, sexual activity, sexual (dys)function-self-reflection, sexual (dys)function-partner’s view 6-point Likert scale, 0–5 per item <10 min MGSIS Genital Self-Image 1047 7 4 domains: size, appearance, sexual function, embarrassment/pride 4-point Likert scale, 1–4 per item Unknown SSASM Subjective Male Sexual Arousal 304 20 5 domains: sexual performance, mental satisfaction, sexual assertiveness, partner communication, partner relationship 7-point Likert scale, 1–7 per item Unknown EMAS-SFQ Sexual Function 1685 16 4 domains: overall sexual function, masturbation, sexual functioning-related distress, change in sexual functioning 5-point Likert scale, 0–4 per item Unknown MSHQ-EjD Ejaculation function 8333 4 4 domains: force, volume, frequency, delay of ejaculation 6-point Likert scale, 0–5 per item Unknown PEDT Premature Ejaculation 993 5 1 domains: Premature Ejaculation 5-point Likert scale, 0–4 per item Unknown MSQ Sexual satisfaction 612 20 3 domains: performance, confidence/satisfaction, partner synchronization 6-point Likert scale, 0–5 per item average 11 min MSHQ Sexual Health 249 25 3 domains: Erection, Ejaculation, Satisfaction Unknown Unknown IIEF Sexual Function 336 15 5 domains: erectile function, orgasmic function, sexual desire, intercourse satisfaction, overall satisfaction EF:0 (or 1)-5; OF:0–5; SD:1–5; IS:0–5; OS:1–5 <15 min SHIMA Sexual Health 427 34 6 domains: Couple sexual interaction, Couple relationship quality, Couple sexual function, Access to sexual health services, Sexual agency, Sexual concerns Unknown Unknown SFQ-28 Sexual Function 639 28 8 domains: Desire, Arousal (sensation), Arousal (lubrication), Arousal (cognitive), Orgasm, Pain, Enjoyment, Partner Unknown Unknown FSDQ Sexual Desire 741 50 6 domains: Dyadic desire, Solitary desire, Resistance, Positive relationship, Sexual self-image, Concern 6-point Likert scale, 1–6 per item 30 min FGSIS Genital Self-Image 1937 11 4 domains: smell/taste, appearance, sexual function, shame/pride 4-point Likert scale, 1–4 per item 10-20 min FSWB Sexual Health 443 17 5 domains: interpersonal, cognitive–emotional, physical arousal, orgasm-satisfaction, external lubrication Unknown Unknown FSFI-6 Sexual Function 200 6 1 domains: Female Sexual Function 6-point Likert scale, 0–5 per item <3 min SFQ Sexual Function 1781 24 7 domains: Desire, Enjoyment, Arousal-sensation, Arousal-lubrication, Orgasm, Pain, Enjoyment, Partner Desire: score range 5–31; Arousal-sensation: score range 4–20; arousal-lubrication: score range 2–10; orgasm :score range 3–15; enjoyment: score range 6–30; pain: score range 2–15; partner relationship: score range2–10 Unknown FSFI Sexual Function 259 19 6 domains: Desire, Arousal, Lubrication, Orgasm, Satisfaction, Pain 5-point Likert scale, 1–5 f or Desire; 6-point Likert scale for Arousal, Lubrication, Orgasm, Pain; 5or6-point Likert scale, 0 (or 1)– 5 for Satisfaction Unknown Notes: ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale;FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function Characteristics of the included scales Sexual Violence Sexual Health Literacy 6 domains: Sexual skills, Individual socio-cultural barriers, Sexual vulnerability, Resources to access sexual information, Understanding and application, Capacity and motivation 5-point Likert scale, 1–5 per item Sexual and Relationship Distress 7-point Likert scale, 0–6 per item Sexual Experience 7-point Likert scale, 1–7 per item 6-point Likert scale, 1–6 per item 6-point Likert scale, 0–5 per item 6-point Likert scale, 0–5 per item Sexual Function Sexual Desire 6-point Likert scale, 1–6 per item 6-point Likert scale, 0–5 per item Sexual Function Notes: ASPI = Amsterdam Sexual Pleasure Inventory; IPSVS = Intimate partner sexual violence scale; SHLS = Sexual Health Literacy Scale; BYSAS = Bergen–Yale Sex Addiction Scale; SaRDS = Sexual and Relationship Distress Scale; SPS = Sexual Pleasure Scale; NSSS = New Sexual Satisfaction Scale; QSE = Quality of Sexual Experience scale; FSFI-6 = 6-Item Version of the Female Sexual Function Index; FSFI = Female Sexual Function Index; SFQ28 = 28-Item Version of Sexual Function Questionnaire; SHIMA = Sexual Health Scale for Middle-Aged Married Women; FSWB = Female Sexual Well-Being Scale;FSDQ = Female Sexual Desire Questionnaire; SFQ = Sexual Function Questionnaire; IIEF = The international index of erectile function; MSHQ = Male Sexual Health Questionnaire; SSASM = Subjective Sexual Arousal Scale for Men; MSQ = Male Sexual Quotient; MGSIS = Male Genital Self-Image Scale; FGSIS = Female Genital Self-Image Scale; MSHQ-EjD = Four-Item Version of Male Sexual Health Questionnaire; PEDT = Premature Ejaculation Diagnostic Tool; SFEQ = Sexual Function Evaluation Questionnaire; EMAS–SFQ = European Male Ageing Study Sexual Function Questionnaire; CSBD-19 = Compulsive Sexual Behavior Disorder Scale; QSF = Scale for Quality of Sexual Function

This systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) - COSMIN (Consensus-based Standards for the Selection of Health Measurement Instruments) 2024 guidelines for outcome measurement tools, and was reported following these standards [ 20 ]. This review has been prospectively registered in PROSPERO (Registration number: CRD420251132830. Following the COSMIN guideline for search strategies, all the authors collectively discussed and formulated a search strategy based on three core concepts: ‘sexual health’, ‘general population’, and ‘Patient-Reported Outcome Measures (PROMs)’. These search terms were constructed based on the filters recommended by COSMIN and the MeSH vocabulary. According to the unified search strategy, and under the oversight and review of Baojun Ju (Professor of Andrology and a clinician with over 25 years of clinical experience), Yihan Shang and Quan Yuan independently searched five databases (PubMed, Cochrane, Web of Science, Embase, and CNKI) from database inception to March 14, 2025 and cross-checked the results, using both keyword and free-text search methods. The search strategy utilized three distinct sets of terms, with terms within each set combined using the Boolean operator ‘OR’ [ 1 ]: ‘sexual health’, ‘sexual function’, ‘sexual pleasure’ ‘sexual quality of life’, ‘sexual experience’ [ 2 ]; ‘adults’ [ 3 ]; ‘questionnaire’, ‘survey’, ‘instrument’, ‘scale’. The three sets were then combined with the ‘AND’ operator. Additionally, we hand-searched the reference lists of included studies to identify potentially relevant articles and conducted searches using related Chinese keywords. The complete search strategies for all databases are available in Appendix S1. Inclusion Criteria: (1) Participants were the general adult population aged 18 years or older; (2) The study utilized a patient-reported outcome measure (PROM) for assessing sexual health; (3) The study evaluated at least one psychometric property of the PROM; (4) The PROM was self-completed by participants to assess their own sexual health. Exclusion criteria: (1) Study subjects have diseases other than sexual dysfunction. Note that sexual dysfunction is defined as a group of clinical syndromes characterized by persistent or recurrent significant difficulties experienced by an individual during one or more phases of the sexual response cycle—including desire, arousal, orgasm, and resolution—which cause significant personal distress or interpersonal impairment [ 21 ]; (2) In clinical studies, the scales are only used as measurement tools; (3) Scales that have undergone language translation for cross-cultural research; (4) Secondary studies (reviews, systematic reviews); (5) Study subjects belong to sexual minority groups (e.g., LGBTQ+ groups); (6) Duplicate publications. Yihan Shang and Quan Yuan, who are clinical doctors with over five years of clinical experience, received consistency training prior to the formal screening and evaluation to ensure assessment reliability. They underwent a standardized training session on the COSMIN Risk of Bias checklist and criteria for good measurement properties prior to the formal screening and evaluation. This training included independent rating of sample studies followed by discussion to resolve discrepancies, ensuring a common understanding and application of the COSMIN guidelines. They then independently performed the quality assessment according to the COSMIN Guideline for Systematic Reviews of Patient-Reported Outcome Measures (version 2.0) [ 19 ]. Using the COSMIN Risk of Bias Checklist (version 3.0) [ 22 ] and the COSMIN Criteria for Good Measurement Properties (version 2.0) [ 19 ], they evaluated the measurement properties of the included scales and the methodological quality of the studies. The results were subsequently cross-checked. Any discrepancies encountered were resolved through consultation with the third researcher (Yihang Shen, a clinician with over five years of clinical experience who received the same training as Yihan Shang and Quan Yuan) to ensure the consistency and reliability of the final ratings. Methodological quality was assessed using the COSMIN Risk of Bias Checklist (version 3.0) [ 22 ]. This checklist comprises ten domains (Boxes 1–10): PROM development, content validity, structural validity, internal consistency, cross-cultural validity/measurement invariance, reliability, measurement error, criterion validity, hypotheses testing for construct validity and responsiveness. A four-point rating system (“Very Good”, “Adequate”, “Doubtful” or “Inadequate”) was used to evaluate the risk of bias for each item, with an additional “Not Applicable” option. The “worst-score-counts” principle was applied to determine the overall quality rating for each measurement property within a study [ 22 ]. The measurement properties of each scale were assessed separately. It is important to note that although the checklist covers ten measurement properties, only the measurement properties reported in each study were evaluated. The measurement properties of the scales reported in the included studies were evaluated according to the COSMIN Guideline for Systematic Reviews of Patient-Reported Outcome Measures (version 2.0) [ 19 ]. This assessment covered the aforementioned nine domains (Boxes 2–10), while Box 1 (PROM development) was excluded. For each property, the evidence was rated as “sufficient” (+), “insufficient” (-), or “indeterminate” (?). The findings from each study were compared against the COSMIN criteria for good measurement properties to determine their reliability, thereby facilitating clear conclusions and recommendations. The overall quality of evidence was assessed using a modified Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach (High, Moderate, Low, and Very Low) [ 23 ]. This method initially assumes that the evidence is of high quality. If risks of bias, inconsistency, imprecision, or indirectness are identified in the evidence, it will then be systematically downgraded based on these four criteria. The GRADE system was not applied to measurement properties with an overall “indeterminate” rating [ 19 ]. Any discrepancies in assessment were resolved through consultation with a third reviewer. Based on the COSMIN Guideline for Systematic Reviews of Patient-Reported Outcome Measures (version 2.0) [ 19 ], the included scales were categorized into three classes according to their measurement properties and the overall quality of evidence: (A) Category A: scales demonstrating sufficient content validity with any level of evidence, plus at least low-quality evidence for sufficient internal consistency; (B) Category B: scales not meeting the criteria for Category A or C; (C) Category C: scales with high-quality evidence indicating insufficient measurement properties. When multiple Category A instruments were identified, they were further compared based on measurement quality, feasibility, and interpretability to select the most appropriate tool. If all available instruments fell into Category B, the most promising tool was selected according to content validity, with recommendations provided for further refinement. In cases where only Category C instruments were available, priority was given to those demonstrating at least low-quality evidence for sufficient content validity, and an agenda for further validation studies was proposed.

This study represents the first systematic evaluation of Patient-Reported Outcome Measures (PROMs) for assessing sexual health in the general adult population, conducted in accordance with the COSMIN 2.0 standards. It identified and synthesized PROMs designed to assess sexual health in this population and, based on methodological quality and measurement properties, recommended the most appropriate instruments. Importantly, this review revealed fundamental methodological limitations in existing tools and identified significant structural gaps in the field of sexual health assessment, thereby providing directions for future research aimed at establishing a more balanced and comprehensive sexual health evaluation framework.

In this study, we rigorously applied the COSMIN 2.0 guidelines [ 19 ] to evaluate the methodological quality, measurement properties, and overall quality of evidence of 27 PROMs. This study had two primary objectives. The first was to identify questionnaires suitable for assessing sexual health in the general adult population. Following established inclusion and exclusion criteria, we performed a literature search across five databases, which yielded 27 original studies. Each study detailed the development process and measurement properties of a unique scale. Consequently, we identified 27 distinct PROMs capable of assessing sexual health across different dimensions. The study’s second objective aimed to determine the questionnaires exhibiting the most favorable measurement characteristics, thereby enabling a more comprehensive evaluation of sexual health in the general adult population. The criteria for which are detailed in the scale recommendation section. Our study found that these PROMs frequently exhibit methodological flaws in their development, which largely accounts for the generally poor quality of evidence supporting them. The scales we evaluated demonstrate substantial limitations in their content validity. According to the COSMIN standards, a high-quality assessment of this property calls for the systematic integration of feedback from both patients and experts throughout the development process. Notably, content validity—encompassing relevance, comprehensiveness, and comprehensibility—is the most critical measurement property [ 54 ]. However, we found that most studies lacked methodological rigor. Firstly, during item generation, they often relied exclusively on literature reviews and expert consultation. Moreover, they frequently failed to document whether developers had systematically queried experts to confirm that the scale’s content accurately reflected the intended construct, was comprehensive, and was understandable. A common methodological flaw is that developers systematically neglect to consult patients about the scales. We argue that items generated without this essential step are inherently limited in their ability to represent the complex feelings of the target population. Secondly, PROM development procedures are often irregular. A critical omission is that few scales are piloted after initial item development and then field-tested in a separate, independent population, as required by standard practice. Thirdly, many studies inadequately documented data transcription, analytical methods, and whether data saturation was achieved. Despite the SHLS [ 43 ] and FSFI [ 40 ] scales receiving a ‘D’ rating for the methodological quality of their content validity, they were notable for comprehensively soliciting input from both patients and experts. For future PROM development, we recommend strict adherence to COSMIN 2.0 guidelines [ 19 ], with complete documentation of all steps—from sample characteristics and data collection to analysis—to guarantee transparency and reproducibility. For reliability, it refers to the consistency of repeated measurement results. In Study [ 31 ], the measurement interval was under one week, while Studies [ 26 , 27 ] were conducted under inconsistent contextual conditions, which compromised reliability. Future research designs should therefore ensure stable measurement contexts and adequate intervals. Furthermore, none of the studies reported on cross-cultural validity or measurement error. Although scales such as the IIEF, NSSS, SFQ, CSBD-19, and EMAS-SFQ have been translated into multiple languages, they lack formal cross-cultural validation. Patient completion time was reported in only a minority of studies [ 30 , 32 , 35 , 36 , 38 , 42 , 45 , 47 , 48 , 50 ]. The time required to complete the scales is crucial for the practical feasibility of these tools, and therefore, such data should be routinely collected in future work. Neglecting measurement error makes it impossible to determine the accuracy of these tools. The failure to report responsiveness data in most studies means their sensitivity cannot be determined, which ultimately restricts the practical value of these instruments. It is imperative that future research prioritizes assessing these measurement properties as per the COSMIN guidelines [ 19 ], thereby strengthening the scientific rigor and generalizability of these instruments. Overall, while the PROMs included in this systematic review cover multiple aspects of sexual health constructs, the number of scales addressing each specific aspect is limited, and there remain gaps in certain specific domains. This limits the options for scale recommendation, but also highlights directions for the future development of measurement tools. First, in sexual health research, culture, the level of economic development, and social openness significantly influence the development, validation, and application of measurement scales. From the perspective of the geographic origins of scale development, the number of scales originating from developed countries (such as the United States and European nations) exceeds that from developing countries (such as Brazil and Iran). Although certain scales have become gold standards (e.g., IIEF, FSFI), when selecting sexual health measurement tools, it is essential to consider the specific cultural context of their intended research or clinical setting. Particularly in regions with relatively conservative sexual attitudes, employing locally developed or rigorously culturally adapted tools can generally yield more valid and reliable data than directly applying international “standard” measures. This also suggests that future efforts should focus on developing scales suitable for diverse economic conditions and cultural backgrounds. Second, upon careful examination of the development and content of these instruments, marked gender differences are evident in the tools assessing sexual health. The evaluation of male sexual health, particularly erectile function, has coalesced into a relatively unified and well-established measurement framework centered on the IIEF. In contrast, the assessment of female sexual health presents greater complexity and fragmentation. Although the FSFI excels within the functional domain, female sexual health more comprehensively encompasses psychosocial, emotional, relational, and sociocultural factors (e.g., body image, sexual self-confidence, relational power dynamics, sequelae of sexual violence). Currently, a comprehensive, integrative tool with a Grade A recommendation capable of assessing the psychosocial dimensions of female sexual health is still lacking. For instance, existing instruments for issues related to female sexual desire (FSDQ, Grade B) or for the relational sexual health of middle-aged women (SHIMA, Grade C) possess measurement properties that warrant significant improvement. This delineates a key focus for future research: to develop or refine PROMs that better capture the multidimensionality of female sexual health, particularly its psychosocial determinants—such as those underlying hypoactive sexual desire, anxiety that co-occurs with sexual pain, and the influence of relational power dynamics on sexuality—as well as the quality of subjective experience. Third, the current landscape of sexual health Patient-Reported Outcome Measures (PROMs) demonstrates a pronounced structural imbalance. In male health, for instance, the availability of high-quality, specialized tools for assessing ejaculatory function (e.g., MSHQ-EjD and PEDT) is far more limited compared to those for erectile function (e.g., IIEF). This structural bias within the measurement toolkit directly leads to two critical limitations: firstly, it prevents this review from issuing Grade A recommendations for these under-researched domains; secondly, it reveals significant gaps in the current sexual health assessment framework, which likely results in an underestimation of the corresponding disease burden. Moreover, the vast majority of existing scales for assessing sexual health were developed and validated primarily within a heterosexual, monogamous framework. At present, there is a severe shortage of high-quality scales specifically designed or validated for sexual minority populations (e.g., LGBTQ+ individuals). Similarly, scales tailored for people with multiple partners are virtually nonexistent. Future research should focus on developing or culturally/contextually adapting sexual health assessment tools to encompass diverse sexual orientations, gender identities, and relationship structures, thereby ensuring equitable and accurate sexual health assessments for all. Consequently, the future development of high-quality PROMs targeting these neglected areas is not merely an exercise in expanding the available instruments, but a crucial step toward rectifying a systemic cognitive bias and constructing a truly comprehensive assessment paradigm. As with any systematic review, the findings of this study are influenced by the limitations inherent to the included studies. Moreover, although this review strictly adhered to the COSMIN 2.0 guidelines [ 19 ], several limitations must be acknowledged. First, we excluded studies involving sexual minority populations. The rationale for this exclusion is that instruments specifically designed for minority groups (e.g., LGBTQ+ individuals) often incorporate unique psychosocial stress factors (e.g., minority stress) or considerations for specific physiological contexts. The psychometric properties of such instruments may not be directly comparable to those developed for the general population, thereby significantly compromising comparability. To ensure the scientific rigor and precision of this review, we believe these instruments warrant dedicated investigation. Future research is urgently needed to focus on the validation of measurement tools tailored for sexual minority populations. Second, although we searched five major databases and conducted supplementary searches, we may still have missed some studies. This is because we did not search databases in languages other than Chinese and English, which may have affected the comprehensiveness of our findings. Third, our scope was restricted to self-reported instruments, excluding scales designed for partner assessment. Fourth, although we strictly adhered to the COSMIN 2.0 guidelines [ 19 ], the analysis and evaluation processes involve a degree of inherent subjectivity. To mitigate this, we ensured six researchers participated in the process and conducted cross-checks to maximize consistency.

In 1975, the World Health Organization (WHO) first introduced the concept of sexual health in a technical report, defining it as “the integration of the physical, emotional, intellectual, and social aspects of sexuality, which is directed toward enriching and enhancing personality, communication, and love.” [ 1 ]. The definition was further revised in 2002 and has been in use ever since. Sexual health refers to a state of physical, emotional, psychological, and social well-being in relation to sexuality; it is not merely the absence of disease, dysfunction, or infirmity. Sexual health requires not only a positive and respectful approach to sexuality and sexual relationships but also the ability to enjoy pleasurable and safe sex, free of coercion, discrimination, and violence. To achieve and maintain sexual health, the sexual rights of all individuals must be respected, protected, and fulfilled. A comprehensive view of sexual health encompasses not only the absence of organic diseases in the reproductive system but also psychological and sociological dimensions, including levels of distress, satisfaction, pleasure, and the importance of consent. Organic diseases refer to diseases that are caused by observable and detectable anatomical abnormalities or physiological and biochemical dysfunctions, such as erectile dysfunction due to vascular insufficiency or sexual pain associated with endometriosis [ 2 , 3 ]. Sexual health is an integral component of overall health and is significantly positively correlated with both general and health-related quality of life [ 4 ]. However, conditions related to sexual health are widespread. Epidemiological studies across different countries (e.g., America, Australia, Germany, Turkey, Sweden) indicate, for example, that the prevalence of erectile dysfunction among men ranges from 20% to 50% [ 5 – 7 ], while approximately 40% to 50% of women report experiencing some form of sexual distress or sexual pain. (Sexual distress refers to significant subjective suffering, anxiety, distress, and negative impacts caused by issues related to an individual’s sexual function, sexual experiences, sexual relationships, or sexual orientation. Sexual pain refers to any unpleasant or painful sensory and emotional experience that occurs in the genital, pelvic, or other related areas during sexual activity, including foreplay, intercourse, attempts at penetration, or masturbation. It is a symptom, not a final diagnosis.) [ 8 – 10 ]. These issues are not only critical health concerns but also exert multidimensional negative impacts on individuals’ psychological well-being and social relationships. Notably, erectile dysfunction in men may be associated with cardiovascular disease, diabetes, and neurological disorders [ 11 , 12 ]. Furthermore, entrenched gender inequalities often place women in a disadvantaged position regarding sexual attitudes and autonomy, rendering them more vulnerable to violence during sexual activities [ 13 – 15 ]. However, when it comes to topics related to sexuality, only a minority of individuals are willing to openly express their concerns, and clinicians frequently overlook sexual health issues during clinical consultations [ 16 ]. Unlike singular metrics such as blood glucose or blood pressure, sexual health is not a single-dimensional indicator. Instead, it constitutes a holistic concept encompassing physical, emotional, psychological, and social dimensions. Due to significant individual variation and strong subjective dependence, it is inherently challenging to measure objectively [ 17 ]. The introduction of PROMs has provided researchers with valuable tools to quantify dimensions of sexual health, thereby offering a means to objectively capture individuals’ subjective experiences. The use of such scales dates back to the 1940s when sexologist Dr. Alfred Kinsey developed the Kinsey Scale to describe an individual’s position on a continuum of sexual orientation, ranging from exclusively heterosexual to exclusively homosexual [ 18 ]. New scales continue to emerge to assess sexual health from different dimensions, though their methodological rigor, comprehensiveness of psychometric validation, and overall quality vary considerably. To date, no systematic review has evaluated the methodological quality and psychometric properties of PROMs for sexual health in the general population; this gap hinders the advancement of evidence-based clinical practice. Therefore, this systematic review aims to identify the available PROMs for assessing sexual health in the general adult population, and evaluate and compare their measurement properties to determine which PROMs currently demonstrate the most robust evidence. This study uses the latest version of the ‘COSMIN Guideline for Systematic Reviews of Patient-Reported Outcome Measures’ (version 2.0, published in 2024) and its accompanying tools, published by the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) initiative, as a guiding framework [ 19 ]. It critically reviews the methodological quality and measurement properties of sexual health measurement tools for the general population, analyzes problems in the scale development process, and formulates recommendations. The aim is to provide evidence for promoting the clinical application of such scales and to offer a reference for the proper selection of scales in clinical practice.

Below is the link to the electronic supplementary material. Supplementary Material 1 Supplementary Material 1