Diagnosing Appendicitis with Precision: A Comparative Analysis of Modified Alvarado and RIPASA Scoring Systems in a Northern Divisional Hospital of Bangladesh

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This study aimed to evaluate the diagnostic efficacy of the Modified Alvarado Scoring System 37 (MASS) and the Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) scoring system , assessing their 38 sensitivity, specificity, positive predictive value (PPV), ne gative predictive value (NPV), and overall 39 accuracy. 40

A cross -sectional analysis was conducted at the Department of General Surgery, Rajshahi 41 Medical College Hospital, Bangladesh, from September to December 2020. The study included 138 42 purposively selected individuals aged 13 years and above, suspected of acute appendicitis. Data were 43 collected through structured interviews, detailing socio -demographic characteristics, medical history, 44 clinical examinations, and specific laboratory tests (CBC, Urin e RE). Histopathology reports from post -45 operative cases were used as the gold standard for diagnosis. MASS and RIPASA scores, derived from their 46 respective criteria, were analyzed using STATA. 47

Participants had a mean age of 26.2 years, with male s constituting 55.0% of the sample. The 48 MASS scoring system reported a sensitivity of 79.8%, specificity of 57.9%, PPV of 92.2%, NPV of 31.4%, 49 and an overall diagnostic accuracy of 76.8%. In contrast, the RIPASA scoring system demonstrated a 50 sensitivity of 96.6%, specificity of 73.7%, PPV of 95.8%, NPV of 77.8%, and a diagnostic accuracy of 93.5%. 51 ROC AUC analysis yielded values of 0.6886 for MASS and 0.8516 for RIPASA, indicating a statistically 52 significant difference (p<0.05). 53

The findings h ighlight the superior clinical utility of the RIPASA scoring system over MASS, 54 particularly in settings with limited access to advanced diagnostic facilities. Adopting the RIPASA scoring 55 system could significantly enhance the diagnosis of acute appendiciti s, suggesting its potential for 56 improving clinical outcomes in similar healthcare environments. 57

Acute appendicitis, MASS, RIPASA, Diagnostic Performance, Bangladesh 58 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 3

59 Acute appendicitis is a prevalent surgical emergency that demands prompt and accurate diagnosis for 60 optimal patient management.[1] However, the diagnostic challenge of acute appendicitis is compounded 61 by atypical symptoms in approximately 50% of cases and the potential for other conditions to mimic its 62 signs and symptoms.[2] Medical history, clinical examination, and laboratory investigations are critical to 63 the diagnostic process. Despite the availability of diagnostic aids such as abdominal Ultrasonography, 64 Computerized Tomography, Laparoscopy, Magnetic Resonance I maging, and Computer -Aided Barium 65 Enema, their utility is limited by the need for expertise and associated high costs.[3] In peripheral districts, 66 limited access to these diagnostic facilities further complicates the accurate diagnosis of acute 67 appendicitis, underscoring the need for accurate and timely diagnosis to facilitate appropriate patient 68 management and optimize clinical outcome.[4] 69 To aid in the diagnosis of acute appendicitis, various scoring systems have been developed to improve 70 diagnostic accuracy and reduce unnecessary surgical interventions .[5] The Alvarado scoring system, 71 introduced in 1986 and later refined as the Modified Alvarado Scoring System (MASS) in 1994 ,[6], [7] 72 assigns scores based on clinical signs, symptoms, and laborator y findings associated with acute 73 appendicitis. It has been extensively studied and validated across different populations, demonstrating 74 reasonable accuracy in diagnosing appendicitis. Conversely, the Raja Isteri Pengiran Anak Saleha 75 Appendicitis (RIPASA) scoring system, developed by Chong et al. in 2010,[2] is tailored specifically for the 76 Asian population. It includes clinical, laboratory, and imaging findings alongside demographic 77 characteristics, offering promising results in diagnostic accuracy and p otential advantages over other 78 scoring systems.[8], [9] 79 Despite the widespread application of both scoring systems, a consensus on their comparative 80 performance in various clinical settings, especially in resource -limited environments like peripheral 81 district hospitals, remains elusive .[10] Moreover, research directly comparing the Modified Alvarado 82 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 4 (MASS) and RIPASA Scoring Systems within the context of Bangladesh's peripheral medical facilities is 83 scarce. Therefore, this study aims to conduct a thorough analysis of both scoring systems' diagnostic 84 performance, assessing their sensitivity, specificit y, positive predictive value (PPV), negative predictive 85 value (NPV), and overall accuracy. The insights gained from this research are expected to contribute to 86 minimizing negative appendectomies, particularly in peripheral hospital settings.[11] The outcomes of this 87 study may have important implications for clinical practice, guiding the selection and implementation of 88 the most suitable scoring system for the accurate and efficient diagnosis of acute appendicitis in similar 89 healthcare environments. 90 Methodology 91 Study design, setting and sampling 92 This cross-sectional study was conducted at the Department of General Surgery, Rajshahi Medical College 93 Hospital, Bangladesh, from September to December 2020. A total of 173 patients suspected of acute 94 appendicitis were initially considered for the study (Supplementary figure 1 ). However, 35 patients 95 (20.2%) were excluded due to unavailable histopathology reports (n=17), conservative treatment (n=12), 96 and urogenital causes identified through ultrasonography (n=6). After these exclusions, the final sample 97 size was 138 patients. Additional exclusions were applied to patients with a prior history of RIF pain, those 98 who developed RIF pain after being admitted for another reason, or those with generalized peritonitis, 99 septic shock, or pregnancy. 100 Data collection 101 Data on suspected acute appendicitis patients were collected through investigator -led interviews in the 102 admission unit.[12] Informed consent was obtained prior to 15 to 20 -minute sessions, which covered 103 demographic, and medical history details. Clinical examination data were recorded at admission or 104 retrieved from post -operative files. Routine laboratory investigations (CBC, Urine RME) and 105 histopathology reports of post-operative cases were collected for further analysis. Surgical decisions were 106 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 5 made by the attending surgeons. A ward round the following morning facilitated the completion of 107 pending information and enrollment of new cases. Data collection utilized a pre -tested, semi-structured 108 questionnaire available in both English and Bangla. 109 Index case 110 In this study, the Modified Alvarado Scoring System (MASS) and the Raja Isteri Pengiran Anak Saleha 111 Appendicitis (RIPASA) scoring system were used as the index tests to predict acute appendicitis. The MASS 112 score was calculated based on seven standard clinical and laboratory parameters, while the RIPASA score 113 utilized 14 parameters, including an additional criterion for patients holding a Foreign National Record of 114 Identity Card (NRIC), as outlined in Supplementary Tables 1 and 2 , respectively. To minimize bias in 115 surgical decision-making, neither scoring system was calculated during the data collection phase. Instead, 116 the total scores were categorized post -hoc using a cut -off threshold of 7 for MASS and 7.5 for RIPASA, 117 with scores above these thresholds indicating a high likelihood of appendicitis. 118 Gold standard 119 In this study, histopathology served as the operational gold standard for confirming acute appendicitis of 120 the post-operative cases. It ensured a definitive and accurate assessment of the condition, providing a 121 detailed understanding of the underlying pathological changes . Consistent with findings from the 122 literature, where histopathology has been widely acknowledged as the gold standard for confirming acute 123 appendicitis,[9], [13], [14], [15], [16] post-operative specimens' histopathological analysis was considered 124 the benchmark for confirming cas es of acute appendicitis and distinguishing them from normal or non -125 appendicitis cases. 126 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 6 Quality control 127 The study implemented extensive quality control measures, including pre -piloting of the questionnaire 128 and daily review of completed forms for consistenc y and completeness. Laboratory data and 129 histopathological reports were verified against patient identifiers to ensure accuracy. The research 130 adhered strictly to its planned timeline and budget. 131 Minimization of bias 132 Several steps were taken to minimize potential sources of bias. To reduce selection bias, participants were 133 purposively selected, though this may limit the generalizability of the findings. Recall bias was addressed 134 by ensuring that data were collected thr ough structured interviews conducted shortly after admission, 135 reducing the reliance on long -term memory. Observer bias was minimized by using consistent clinical 136 examination protocols across all surgeons. Additionally, neither the Modified Alvarado nor the RIPASA 137 scores were calculated during data collection to prevent decision-making bias in surgical procedures. 138 Statistical analysis 139 Descriptive statistics were used to summarize the socio -demographic and clinical characteristics of the 140 participants. The diagnostic performance of the Modified Alvarado Scoring System (MASS) and the Raja 141 Isteri Pengiran Anak Saleha Appendicitis (RIPASA) scoring system was assessed by calculating their 142 sensitivity, specificity, positive predictive value (PPV), negative predictiv e value (NPV), and overall 143 diagnostic accuracy, using histopathological findings as the reference standard. 144 Receiver Operating Characteristic (ROC) curves were generated for both scoring systems by systematically 145 varying the classification thresholds. The Area Under the ROC Curve (AUC) was determined to evaluate 146 each system's discriminative capability in diagnosing appendicitis. Statistical associations between 147 categorical variables were assessed using the chi -square (χ2) test. All p -values were two -tailed, with 148 statistical significance set at p<0.05. Statistical analyses were performed using STATA 17, with findings 149 presented in tables and graphs. 150 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 7 Ethical consideration 151 Ethical approval for this study was granted by the Institutional Review Board (IRB) of Ra jshahi Medical 152 College Hospital (Ref: RMC/IRB/2019/20 -011/54, Date: 04 Aug 2020). Detailed information about the 153 study's objectives, procedures, potential risks, and benefits was provided to participants before obtaining 154 informed consent. For illiterate participants, thumbprints were collected in lieu of signatures, witnessed 155 and co-signed. Participants were assured of their right to withdraw from the study at any time without 156 affecting their medical care. The research was conducted in strict adherence to t he Helsinki Declaration, 157 ensuring the confidentiality and privacy of all participants. Results from medical examinations were 158 distributed and explained to participants, who were then given the opportunity to discuss their reports 159 with the researcher and receive appropriate guidance as needed. 160

161 The demographic characteristics, symptoms, signs, and pathological findings of the 138 participants are 162 presented in Table 1. The median age was 22 years (IQR: 17, 35), with 55.0% being male . A majority 163 (60.1%) resided in rural areas. Among symptoms, anorexia and nausea or vomiting were prevalent in 164 76.1% and 90.6% of cases, respectively. Notably, all participants exhibited right iliac fossa (RIF) pain, with 165 86.2% reporting pain extending from the umbilicus to the RIF. The duration of pain was less than 48 hours 166 in 67.4% of cases. Clinical signs showed 47.9% had a febrile temperature, and RIF tenderness was present 167 in all cases. Rovsing's sign was positive in 58.0%, while muscle guarding and rebound tenderness we re 168 observed in 79.0% and 86.2% of participants, respectively. Pathological findings revealed positive urine 169 analysis in 35.5% and leukocytosis in 88.4% of cases. 170 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 8 Table 1: Characteristics of the participants (n=138) 171 Variables Sub-category n (%) Demographic characteristics Age, median (IQR), year* 22 (17, 35) Gender Male 76 (55.0) Residence Urban 55 (39.9) Rural 83 (60.1) Clinical characteristics Symptoms Anorexia Yes 105 (76.1) Nausea/ vomiting Yes 125 (90.6) RIF pain Yes 138 (100) Umbilicus to RIF pain Yes 119 (86.2) Pain duration <48 hours 93 (67.4) Signs Temperature Febrile 66 (47.9) RIF tenderness Yes 138 (100) Rovsing’s sign Yes 80 (58.0) Muscle guard Yes 109 (79.0) Rebound tenderness Yes 119 (86.2) Pathological findings Urine analysis Positive findings 49 (35.5) WBC count Leukocytosis 122 (88.4) *Continuous non-normally distributed variables 172 Table 2 details the distribution of diagnostic tool scores in relation to histopathological diagnosis. For the 173 MASS, scores ≥7 indicated appendicitis, with 95 out of 103 cases confirmed histopathologically, and 8 174 classified as other conditions. For scores <7, 24 out of 35 were confirmed as appendicitis. The RIPASA 175 utilized a cutoff ≥7.5, with 115 out of 120 cases confirmed for appendicitis, and 5 as other conditions. 176 Scores <7.5 resulted in 4 out of 18 cases confirmed as appendicitis. Both scoring models showed significant 177 associations with histopathological outcomes (p<0.001). 178 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 9 Table 2: Diagnostic tool scores by histopathological outcome (gold standard) 179 Diagnostic tool score Histopathological diagnosis Total P value Acute Appendicitis Other than appendicitis MASS ≥7 95 8 103 <7 24 11 35 Total 119 19 138 p<0.001 RIPASA ≥7.5 115 5 120 <7.5 4 14 18 Total 119 19 138 p<0.001 180 Furthermore, table 3 presents a comprehensive comparison of the diagnostic performance between the 181 MASS and the RIPASA scoring system. This study identified noteworthy differences in sensitivity, 182 specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy 183 between the two scoring systems. The MASS system dem onstrated a sensitivity of 79.8% (95% CI: 71.5 -184 86.6) and specificity of 57.9% (95% CI: 33.5-79.7), with a PPV of 92.2% (95% CI: 85.3-96.6) and an NPV of 185 31.4% (95% CI: 16.9-49.3), leading to a diagnostic accuracy of 76.8% (95% CI: 68.9 -83.6). In contrast, the 186 RIPASA score outperformed MASS with a sensitivity of 96.6% (95% CI: 91.6-99.1), specificity of 73.7% (95% 187 CI: 48.8-90.9), a PPV of 95.8% (95% CI: 90.5 -98.6), and an NPV of 77.8% (95% CI: 52.4 -93.6), culminating 188 in a diagnostic accuracy of 93.5% (95% CI: 88.0-97.0). 189 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 10 Table 3: Comparison of diagnostic performance between MASS and RIPASA tool 190 Parameter MASS RIPASA Estimate (95% C) Estimate (95% C) Sensitivity 79.8 (71.5-86.6) 96.6 (91.6-99.1) Specificity 57.9 (33.5-79.7) 73.7 (48.8-90.9) Positive predictive value 92.2 (85.3-96.6) 95.8 (90.5-98.6) Negative predictive value 31.4 (16.9-49.3) 77.8 (52.4-93.6) Diagnostic accuracy 76.8 (68.9-83.6) 93.5 (88.0-97.0) 191 In the presented ROC AUC analysis (Fig 1), this study further assessed the diagnostic performance of the 192 MASS and RIPASA scoring systems for acute appendicitis. The ROC (Receiver Operating Characteristic ) 193 AUC (Area Under the Curve) serves as a critical metric for evaluating the discriminatory capabilities of 194 these systems. Notably, the MASS scoring system exhibited a ROC AUC of 0.6886 (95% CI: 0.5690-0.8083), 195 reflecting its fair capacity to distinguish between patients with and without acute appendicitis. In contrast, 196 the RIPASA scoring system demonstrated a signific antly higher ROC AUC of 0.8516 (95% CI: 0.7486 -197 0.9546), evidencing superior discrimination between acute appendicitis and other conditions. The 198 significant difference in performance (p<0.05) highlights RIPASA's enhanced diagnostic accuracy in the 199 studied population. 200 Fig 1: ROC-AUC plots for the MASS and RIPASA score model 201 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 11

202 This study compared the diagnostic performance of the Modified Alvarado Scoring System (MASS) and 203 the RIPASA scoring system for acute appendicitis in a peripheral district me dical college hospital in 204 Rajshahi, Bangladesh. Our analysis provides insights into their utility and limitations, offering a valuable 205 perspective on their application in a specific demographic. 206 The demographic and clinical profile of our patient cohort, with a mean age of 26.2 years, is reflective of 207 the global epidemiology of acute appendicitis, which predominantly affects individuals in this age 208 group,[17] underscoring the relevance of our findings. The male predominance (55.0%) in our study 209 corroborates the literature indicating a higher incidence of acute appendicitis among males .[18] 210 Symptoms such as anorexia, nausea/vomiting, and the classic presentation of right iliac fossa (RIF) pain, 211 alongside Rovsing's sign, muscle guarding, and rebo und tenderness, align with the established clinical 212 manifestation of acute appendicitis.[19] 213 In evaluating the diagnostic scores against histopathological diagnosis as the gold standard, both the 214 MASS and RIPASA scoring systems demonstrated notable sensitivity and specificity in distinguishing acute 215 appendicitis from other conditions. The MASS system exhibited a sensitivity of 79.8%, correctly identifying 216 a significant proportion of true positive cases, and a specificity of 57.9% for accurately discerni ng non-217 appendicitis cases. Comparing our study with previous research in Asian populations, the MASS model 218 demonstrated a higher sensitivity of 79.8% compared to Al -Hashemy et al. (53.8%) ,[15] Jang et al. 219 (50.6%),[20] and Chong et al. (68.3%) [9] but was close to Naeem et al. (83.3%) ,[16] and Shuaib et al. 220 (82.8%).[21]. However, its specificity in our study (57.9%) was lower than reported in Al -Hashemy et al. 221 (80%),[15] Jang et al. (94.5%), [20] and Chong et al. (87.9%), [9] but higher than Naeem et al. ( 41%),[16] 222 and similar as Shuaib et al. (56%).[21] 223 Conversely, the RIPASA score with a sensitivity of 96.6% and specificity of 73.7% performed consistently 224 high across other studies . Our study reported a sensitivity of 96.6%, aligning closely with Singla et al. 225 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 12 (95.6%),[8] Chong et al. (98%)[9] and Shuaib et al. (94.5%).[21] However, RIPASA's specificity in our study 226 (73.7%) was slightly lower than reported in Singla et al. (80%),[8] Chong et al. (81.3%),[9] and Shuaib et al. 227 (88%).[21] 228 The higher sensitivity (96.6%) of the RIPASA score compared to the MASS system (79.8%) highlights its 229 enhanced ability to correctly identify individuals with acute appendicitis. The specifi city of the RIPASA 230 score (73.7%), although higher than that of MASS (57.9%), suggests there is potential for further 231 refinement in distinguishing non -appendicitis cases. The diagnostic advantage of the RIPASA scoring 232 system in our study carries important clinical implications. Its elevated sensitivity indicates effectiveness 233 in identifying acute appendicitis, potentially reducing the incidence of unnecessary surgeries in false -234 negative scenarios. The commendable specificity and positive predictive value also underscore its clinical 235 utility. Moreover, both scoring systems showed reasonably high positive predictive values (PPV), with 236 RIPASA marginally outperforming MASS. The notably higher negative predictive value (NPV) of RIPASA 237 (77.8%) compared to MASS (31. 4%) suggests that RIPASA is more dependable in ruling out appendicitis 238 when the test result is negative. These outcomes collectively highlight the enhanced diagnostic accuracy 239 of the RIPASA scoring system (93.5%) over the diagnostic accuracy of MASS (76.8%). 240 The Receiver Operating Characteristic (ROC) AUC analysis highlights the diagnostic advantage of the 241 RIPASA scoring system over the Modified Alvarado Scoring System (MASS). Specifically, RIPASA's ROC AUC 242 is 23.7% higher than that of MASS, reflecting a statistically significant improvement in discriminatory 243 capability (p < 0.05). This finding aligns with previous studies showing that the RIPASA scoring system 244 provides superior diagnostic accuracy compared to MASS.[13], [14], [21], [22], [23] 245 This study has several strengths. It directly compares two widely used appendicitis scoring systems, the 246 Modified Alvarado and RIPASA scores, providing valuable insights in a resource -limited setting. To our 247 knowledge, this is the first study in Bangladesh to conduct such a comparison, utilizing histopathology as 248 the diagnostic benchmark to ensure reliable confirmation of appendicitis cases. Additionally, the study's 249 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 13 focus on a low-resource environment enhances its relevance to similar settings. However, the st udy has 250 some limitations. While twenty percent of the initially eligible patients were excluded from the final 251 analysis, these exclusions were necessary to maintain diagnostic consistency and accuracy, which could 252 limit the generalizability of the findings to cases without histopathology or those treated conservatively. 253 The study was conducted in a single hospital, which also limits its generalizability. Variability in clinical 254 assessments by different attending surgeons could result in observer bias. 255

256 This study provides valuable insights into the diagnostic performance of the Modified Alvarado and 257 RIPASA scoring systems for acute appendicitis in a specific population. The RIPASA scoring system 258 exhibited superior diagnostic performance across several metrics, including sensitivity, specificity, positive 259 and negative predictive values, overall diagnostic accuracy, and the AUC, when compared to the MASS 260 system. These results enrich the ongoing discourse on diagnostic strategies for acute appendicit is, 261 highlighting the RIPASA scoring system's value in similar healthcare settings where access to advanced 262 diagnostic resources may be limited. 263 Future research endeavors should focus on validating these findings in diverse populations and settings. 264 Additionally, prospective studies could explore the integration of advanced imaging modalities and 265 biomarkers to enhance diagnostic accuracy further and can develop a new scoring model which is more 266 appropriate for the local context . Comparative analyses with other scoring systems and clinical decision 267 support tools would contribute to a more comprehensive understanding of the optimal approach to acute 268 appendicitis diagnosis. 269 Acknowledgments: This paper utilized data from Master’s thesis of Nafisa conducted by the Rajshahi 270 Medical College & Hospital, Rajshahi, Bangladesh under the Bangabandhu Sheikh Mujib Medical 271 University (BSMMU), Bangladesh. We extend our sincere gratitude to the participants and the faculty 272 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 14 members of the Department of General Surgery, Pathology, and Biochemistry at Rajshahi Medical College 273 & Hospital, Rajshahi, Bangladesh, for their invaluable contributions to this study. 274 Author Contributions: Nafisa, Shahid, Baharul, and Monower conceptualized and designed the study. 275 Nafisa led the study implementation, with data collection conducted by Nafisa, Momena, and Tanvir. 276 Nafisa prepared the initial manuscript draft, while Monower performed the statistical analyses and 277 interpreted the results. Nafisa and Monower jointly contributed to the interpretation of findings and the 278 literature review. Baharul supervised the thesis work. 279 Conflict of Interest: The authors declare no conflicts of interest related to this research. 280 Funding: This research received no specific grant from any fundin g agency in the public, commercial, or 281 not-for-profit sectors. 282 Data availability statement: The data supporting the findings of this study are openly available in Zenodo 283 at https://doi.org/10.5281/zenodo.14043746, under the citation: Naz, N. (2024). A Comparative Study of 284 RIPASA and Modified Alvarado Scoring System for the Diagnosis of Acute Appendicitis [Data set]. Access 285 to the dataset requires prior permission from the corresponding author for reuse. 286 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 15

287 [1] M. F. Ditillo, J. D. Dziura, and R. Rabinovici, “Is it safe to delay appendectomy in adults with acute 288 appendicitis?,” Ann Surg, vol. 244, no. 5, pp. 656–660, Nov. 2006, doi: 289 10.1097/01.sla.0000231726.53487.dd. 290 [2] Chong C F, M I W Adi, Thien A, and Suyoi A, “Development of the RIPASA score: a new 291 appendicitis scoring system for the diagnosis of acute appendicitis.,” Singapore Med J, vol. 51, no. 292 3, pp. 220–225, 2010. 293 [3] Delibegovic Samir, “Acute Appendicitis: Diagnosis and Treatment, with Special Attention to a 294 Laparoscopic Approach,” Emerg Med (Los Angel), vol. 05, no. 03, 2015, doi: 10.4172/2165-295 7548.1000255. 296 [4] R. R. Gorter et al., “Diagnosis and management of acute appendicitis. EAES consensus 297 development conference 2015,” Surg Endosc, vol. 30, no. 11, pp. 4668–4690, Nov. 2016, doi: 298 10.1007/s00464-016-5245-7. 299 [5] M. Korkut, C. Bedel, Y. Karancı, A. Avcı, and M. Duyan, “Accuracy of Alvarado, Eskelinen, 300 Ohmann, RIPASA and Tzanakis Scores in Diagnosis of Acute Appendicitis; a Cross-sectional 301 Study,” Archives of Academic EmergencyMedicine, vol. 8, no. 1, p. e20, Mar. 2020. 302 [6] Alvarado A, “A Practical Score for the Early Diagnosis of Acute Appendicitis,” Ann Emerg Med, vol. 303 15, no. 5, pp. 557–564, 1986, doi: 10.1016/s0196-0644(86)80993-3. 304 [7] E. S. Kanumba, J. B. Mabula, P. Rambau, and P. L. Chalya, “Modified Alvarado Scoring System as a 305 diagnostic tool for Acute Appendicitis at Bugando Medical Centre, Mwanza, Tanzania,” BMC Surg, 306 vol. 11, 2011, doi: 10.1186/1471-2482-11-4. 307 [8] A. Singla, S. Singla, M. Singh, and D. Singla, “A comparison between modified Alvarado score and 308 RIPASA score in the diagnosis of acute appendicitis,” Updates Surg, vol. 68, no. 4, pp. 351–355, 309 Dec. 2016, doi: 10.1007/s13304-016-0381-0. 310 [9] C. F. 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Narayanan, “RIPASA and air scoring systems are superior to 347 alvarado scoring in acute appendicitis: Diagnostic accuracy study,” Annals of Medicine and 348 Surgery, vol. 59, pp. 138–142, Nov. 2020, doi: 10.1016/j.amsu.2020.09.029. 349 350 351 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint 17 Supporting information 352 Supplementary figure 1: Flow diagram of participants 353 Supplementary tables 1: Modified Alvarado Scoring System (MASS) 354 Supplementary tables 2: Score distribution of RIPASA score system 355 . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint . CC-BY-NC-ND 4.0 International licenseIt is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted November 7, 2024. ; https://doi.org/10.1101/2024.11.06.24316874doi: medRxiv preprint