{"paper_id":"57bfc333-7f13-46fa-a265-ff87b70eb89e","body_text":"BioMed Central\nPage 1 of 7\n(page number not for citation purposes)\nBMC Public Health\nOpen AccessResearch article\nWHO systematic review of prevalence of chronic pelvic pain: a \nneglected reproductive health morbidity\nPallavi Latthe*1, Manish Latthe2, Lale Say3, Metin Gülmezoglu3 and \nKhalid S Khan4\nAddress: 1Birmingham Women's Healthcare NHS Trust, Birmingham, UK, 2Tower Hill Medical Centre, Great Barr, Birmingham, 3UNDP/UNFPA/\nWHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive \nHealth and Research, World Health Organization, Geneva, Switzerland and 4Academic Department of Obstetrics & Gynaecology, University of \nBirmingham, Birmingham, UK\nEmail: Pallavi Latthe* - pallavi.latthe@bwhct.nhs.uk; Manish Latthe - manish@latthe.freeserve.co.uk; Lale Say - sayl@who.int; \nMetin Gülmezoglu - gulmezoglum@who.int; Khalid S Khan - k.s.khan@bham.ac.uk\n* Corresponding author    \nAbstract\nBackground: Health care planning for chronic pelvic pain (CPP), an important cause of morbidity\namongst women is hampered due to  lack of clear collated summaries of its basic epidemiological\ndata. We systematically reviewed worldwide literature on the prevalence of different types of CPP\nto assess the geographical distribution of data, and to explore sources of variation in its estimates.\nMethods: We identified data available from Medlin e (1966 to 2004), Embase (1980 to 2004),\nPsycINFO (1887 to 2003), LILACS (1982 to 2004), Science Citation index, CINAHL (January 1980\nto 2004) and hand searching of reference lists. Two reviewers extracted data independently, using\na piloted form, on participants' characteristics, study quality and rates of CPP. We considered a\nstudy to be of high quality (valid) if had at least three of the following features: prospective design,\nvalidated measurement tool, adequate sampling method, sample size estimation and response rate\n>80%. We performed both univariate and multiv ariate meta-reg ression analysis  to explore\nheterogeneity of results across studies.\nResults: There were 178 studies (459975 participants) in 148 articles. Of these, 106 studies were\n(124259 participants) on dysmenorrhoea, 54 (35973 participants) on dyspareunia and 18 (301756\nparticipants) on noncyclical pain. There were only 19/95 (20%) less developed and 1/45 (2.2%) least\ndeveloped countries with relevant  data in contrast to 22/43 (51.2%) developed countries. Meta-\nregression analysis showed that rates of pain varied according to study quality features. There were\n40 (22.5%) high quality studies with represen tative samples. Amongst them, the rate of\ndysmenorrhoea was 16.8 to 81%, that of dyspareunia was 8 to 21.8%, and that for noncyclical pain\nwas 2.1 to 24%.\nConclusion: There were few valid population based estimates of disease burden due to CPP from\nless developed countries. The variation in rates of CPP worldwide was due to variable study quality.\nWhere valid data were available, a high disease burden of all types of pelvic pain was found.\nPublished: 06 July 2006\nBMC Public Health 2006, 6:177 doi:10.1186/1471-2458-6-177\nReceived: 12 September 2005\nAccepted: 06 July 2006\nThis article is available from: http://www.biomedcentral.com/1471-2458/6/177\n© 2006 Latthe et al; licensee BioMed Central Ltd.\nThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), \nwhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.\n\nBMC Public Health 2006, 6:177 http://www.biomedcen tral.com/1471-2458/6/177\nPage 2 of 7\n(page number not for citation purposes)\nBackground\nChronic pelvic pain (CPP) is a debilitating condition\namong women with a major impact on health-related\nquality of life, work productivity and health care utilisa-\ntion. It is the single most common indication for referral\nto women's health services accounting for 20% of all out-\npatient appointments in secondary care [1]. This leads to\na substantial burden on limited health care resources. For\nexample, $881.5 million are spent per year on its outpa-\ntient management in the USA [2] and an estimated £158\nmillion are spent annually on the management of this\ncondition in the UK National Health Service [3].\nValid information about the true extent of CPP is an\nessential consideration in resource allocation and health\ncare planning. In addition, these basic epidemiological\ndata are necessary to monitor trends of the disease burden\nas well as to inform design of other research in this condi-\ntion, like genetic and environmental epidemiology to\nassess aetiology, qualitative studies to establish well being\nand overall quality of life, and studies aimed at the devel-\nopment of new treatment strategies [4]. The epidemiolog-\nical features of CPP have been generously reported in the\nworldwide literature. The majority of the studies are lim-\nited by small sample size and hence their estimates are\nimprecise. The need to summarise these data have gener-\nally received scant attention [5].\nA systematic literature review was performed to ascertain:\nthe prevalence rates of CPP according to the type of pain;\nits geographical distribution; its variation within sub-\ngroups defined by age and development status of the\ncountry of origin; and the effect of study quality and rep-\nresentativeness on the rates.\nMethods\nOur systematic review followed a protocol developed\nusing widely recommended methodology [6,7] and com-\nplied with the MOOSE statement [8].\nData sources\nWe searched general bibliographic databases: Medline\n(1966–2004), Embase (1980–2004) and PSYCHINFO\n(1887–2004). We also searched specialist computer data-\nbases: LILACS (Literatura Latinoamericana y del Caribe en\nCiencias de la Salud 1982 to 2004), CINAHL (January\n1980 to 2004) and SCISEARCH (1974–2004). Our search\nterm combination for electronic databases was as follows:\nMeSH headings, text words and word variants for \"pelvic\npain\" or \"dysmenorrhoea\" or \"dyspareunia\" or \"low\nabdominal pain\" were combined using Boolean operator\nand with terms like \"prevalence\" or \"community survey\"\nor \"incidence\". These were combined with terms repre-\nsenting relevant study designs e.g. cross-section, survey\netc. according to recent recommendations [9] for search-\ning and the search was restricted to human and female.\nWe also hand searched the bibliographies of all relevant\nreviews and primary studies to identify cited articles not\ncaptured by electronic searches. The search did not have\nany language restrictions. We also attempted to contact\nauthors from indexed electronic abstracts on theses for\ndata.\nStudy selection\nStudies on CPP were selected using the following prede-\nfined criteria:\nParticipants\nNon-pregnant women without cancer participating in sur-\nveys about rates of CPP. Women with or without known\nendometriosis or irritable bowel syndrome were to be\nincluded\nOutcome\nThere is lack of consensus on the definition of CPP in the\npublished literature [10]. We used a definition based on\nduration and nature of pain (constant or intermittent,\ncyclical or noncyclical pain, that persisted for 3 months or\nmore [11]) and included three types: cyclical pain during\nmenstruation (dysmenorrhoea), deep dyspareunia and\nnoncyclical pelvic pain. Studies were included in the\nabsence of information on duration of pain as long as it\nwas explicit that cases of acute pain were excluded.\nThere is a debate about the definition of CPP as recurrent\npain such as that associated with isolated dysmenorrhoea\nand dyspareunia is often considered biologically distinct\nfrom chronic pain, however many women have overlap-\nping symptoms. For our review, CPP may be regarded as a\ncomposite of chronic and recurrent pelvic pain.\nStudy design\nCross sectional studies that reported the prevalence of\nCPP.\nData extraction and quality assessment\nTwo reviewers (PML, ML) extracted data independently,\nusing a piloted form, on participants' characteristics, study\nquality and rates of CPP. Data on studies not published in\nEnglish were extracted by people with a medical back-\nground with command of the relevant language. In some\nstudies the existence of multiple symptoms amongst indi-\nviduals could not be evaluated separately due to the struc-\nture of their questionnaires and their manner of reporting,\nso these were excluded. Two of the datasets in the system-\natic review of dysmenorrhoea prevalence were extracted\nfrom the abstracts of theses were when the full copies\ncould not be obtained [12,13].\n\nBMC Public Health 2006, 6:177 http://www.biomedcen tral.com/1471-2458/6/177\nPage 3 of 7\n(page number not for citation purposes)\nThe methodological quality of all selected papers was\nassessed to evaluate internal validity using the following\nattributes [6]: (a) Study design to determine if CPP assess-\nment had been performed prospectively to minimise\nrecall bias; (b) Adequacy of sampling by assessing\nwhether recruitment of participants was random or con-\nsecutive or a convenience sample; (c) Sufficiently high\nresponse rate (>80%); (d) Use of a validated measure-\nment tool to ascertain CPP [14] as this ensures that partic-\nipants' responses are a true representation of the\nunderlying condition; (e) Sample size calculation so as to\nascertain prevalence reliably. It was considered 'adequate'\nif the studies had mentioned that sample size was calcu-\nlated and 'inadequate' if this was not done or not men-\ntioned explicitly. The studies were classified into high and\nlow quality groups based on compliance with 3/5 quality\ncriteria or more. Representativeness of the sample for gen-\neral population (source of sample) was considered sepa-\nrately to methodological quality as this relates to external\nvalidity. This distinction is important because internally\nvalid studies of women attending hospitals or for private\nhealth care checks may not be biased but they are less use-\nful due to sampling of non-generalisable population\ngroups.\nNumerators and denominators were extracted or esti-\nmated from each study for computing rates and confi-\ndence intervals (CI). In most studies, prevalence\nmeasured how many women had CPP at a single point in\ntime, i.e. point prevalence [14]. Period prevalence, based\non the number of women developing CPP during a\ndefined period of time, was reported only in a few studies.\nData synthesis\nFor each study, we computed prevalence rates and their\n95% CI according to the three different types of CPP.\nRates of the different CPP were mapped to depict the var-\niation in prevalence by country of origin. Heterogeneity\nwas explored in the log rates of CPP graphically using for-\nest plots of point estimates of rates and their 95% CI and\nstatistically using Cochrane Q and I2, a statistic that quan-\ntifies the degree of inconsistency across studies in a meta-\nanalysis on a scale ranging from 0–100% [15,16]. In\nreviews with high degree of inconsistency meta-analysis is\nnot recommended. Meta-regression explored if inconsist-\nency in results across individual studies could be\nexplained by variations in countries' development status,\nparticipants' age, representativeness of the sample and\nmethodological quality of the included studies [17]. For\ndevelopment status we used the United Nations classifica-\ntion (developed, less developed and least developed) for\ncountries. Study quality was assessed separately for indi-\nvidual items and scores. We performed both univariate\nand multivariate meta-regression analysis. We did not\npool results even from high quality representative studies\ndue to the statistically significant heterogeneity in this\nsubgroup of high quality representative studies. We how-\never, have reported the rate ranges for representative stud-\nies [18]. Publication and related biases were examined for\nby plotting log rates versus their corresponding variances\nin a funnel plot. Funnel asymmetry was tested by Begg's\ntest [19].\nResults\nThe electronic search yielded a total of 1226 citations (fig-\nure 1). On examination of titles and abstracts, 225 were\nfound to be potentially relevant and their full papers were\nobtained. The reference lists of these revealed 32 further\ncitations. After reviewing these, 109 papers were excluded\n(see additional file 3). The remaining 148 papers (see\nadditional file 2 for a complete list of included articles)\nmet the inclusion criteria, which provided data on\n459972 participants. 30 studies overlapped and reported\nmore than one outcome or more than one group of pop-\nulation. There is very little data (1/148 papers) available\nfrom the least developed countries. 22/43 developed\ncountries had published data on prevalence of CPP in\ncontrast to 19/95 less developed and 1/46 least developed\nStudy selection for systematic review on prevalence of chronic pelvic painFigure 1\nStudy selection for systematic review on prevalence of \nchronic pelvic pain.\nTotal citations identified from electronic searches 1226\nPapers retrieved for detailed evaluation: 225\n1001 Citations excluded after screening abstract\nPapers excluded: 109\nNo/ Insufficient /unclear data 5 \nNot a primary data source 19\nNot on prevalence of pelvic pain 50\nDuplicate data 9\nUnobtainable 3\nStudy performed in : pregnant/postnatal women 8\n: cancer 4 \n: other specified disorders 7\n: case-control study/case report  4\nPrimary papers included in systematic review: 148\n178 studies (some papers  report more than one outcome/study):  \n106 – dysmenorrhea\n54 - dyspareunia \n18 -noncyclical CPP \nSearching of reference lists: 32\n\nBMC Public Health 2006, 6:177 http://www.biomedcen tral.com/1471-2458/6/177\nPage 4 of 7\n(page number not for citation purposes)\ncountries (P < 0.0001) [the denominator is the number of\ndeveloped, less developed and least developed countries\nin the world according to UN country classification].\nStudy quality assessment (figure 2) revealed deficiencies\nin many areas of methodology: Two (1.2%) studies met\nall five high quality criteria, 13 (7.1%) met 4/5 criteria\nand 40 (22.5%) met three or more criteria.\nThe details of studies included in the systematic review on\nprevalence of dysmenorrhoea, dyspareunia and noncycli-\ncal pelvic pain are given in table 1, 2 and 3 respectively\n(additional file 1). The data on prevalence of CPP in\nincluded studies is summarised in figures 3, 4. Epimaps in\nFigure 3 depict the available data by countries, on world-\nwide prevalence of different types of chronic pelvic pain\nby percentage.\nDysmenorrhoea\nThe prevalence rates ranged from 1.7% [2] to 97% [20] in\n106 studies including 125249 women. Prevalence rates\nfor cyclical pelvic pain in the UK reported were between\n45% (12% reporting severe dysmenorrhoea) [21] to 97%\n[20] (14% severe) for any dysmenorrhoea in community\nbased studies and between 41–62% in hospital based\nstudies [22-24]. In other European countries it was similar\n[25,26]. The lowest prevalence was reported in Bulgaria\n(8.8%) in women hospitalised with adnexitis between the\nages of 19–41 years and the highest was in Finland (94%)\nin girls aged 10–20 years [27]. In 20 high quality studies\nwith representative samples, the rate of dysmenorrhoea\nwas reported between 16.8 [28] to 81% [29]. There was\nsubstantial heterogeneity in forest plots and I2 statistic was\n98% (figure 4). The funnel plot for dysmenorrhoea was\nasymmetrical (Begg's test P = 0.02; figure 5a) but not for\nrepresentative studies (P = 0.333). Metaregression (Table\n4) showed validated measurement tool to be a significant\nfactor to explain heterogeneity but not study quality score,\nrepresentativeness, age < 25 years or development status\nof the country (developed versus less developed versus\nleast developed).\nPrevalence of different types of chronic pelvic painFigure 4\nPrevalence of different types of chronic pelvic pain.\nQuality of studies included in systematic review on preva-lence of chronic pelvic painFigure 2\nQuality of studies included in systematic review on \nprevalence of chronic pelvic pain. (Data presented as \n100% stacked bars; figures in the stacks represent number of \nstudies).\nEpimaps of worldwide prevalence of chronic pelvic painFigure 3\nEpimaps of worldwide prevalence of chronic pelvic pain.\nDysm\nenorrhea\nDyspareunia\nNoncyclicalpelvicpain\n\nBMC Public Health 2006, 6:177 http://www.biomedcen tral.com/1471-2458/6/177\nPage 5 of 7\n(page number not for citation purposes)\nDyspareunia\nThe prevalence rates ranged from 1.3% [30] to 45.7% [31]\nin 54 studies including 35973 women. The rates of dys-\npareunia varied from 1.1% in Sweden [32] to 45% [31] in\nUS studies. In 18 high quality studies with representative\nsamples, the rate range of dyspareunia was reported to be\n8 [33] to 21.1 [34]% Studies were markedly heterogene-\nous (I2 = 97.9%) and the funnel plot for dyspareunia was\nasymmetrical (Begg's test P = 0.001; figure 5b) but not in\nrepresentative studies (P = 0.227). The representativeness\nof sample provided the main explanation for heterogene-\nity that was statistically significant in meta-regression\nanalysis (table 4) but age under 60 was not (P = 0.15).\nNon-cyclical pelvic pain\nThe prevalence rates ranged from 4.0% [35] to 43.4% [36]\nin 18 studies including 299740 women. Two recent stud-\nies stated a 3 month prevalence of 15% in women aged\n18–50 years in the USA [2] and 24% in ages between 12–\n70 in the UK [37]. In less developed countries in South\nEast Asia the prevalence rates varied from 5.2% in India,\n8.8% in Pakistan to 43.2% in Thailand [36]. Amongst the\n3 high quality studies with representative samples, the\nrate range of noncyclical pain was 2.1 [37] to 24 [29]% as\nreported from the primary studies. There was heterogene-\nity across studies (I 2 = 99%). Metaregression (table 4)\nrevealed that prospective design, adequate sampling strat-\negy and sample size estimation tended to describe lower\nprevalence of noncyclical pelvic pain though none of\nthese were significant (table 4). The funnel plot for non-\ncyclical pelvic pain was asymmetrical (Begg's test P =\n0.048; figure 5c) but not for representative studies (Begg's\ntest P = 0.88).\nDiscussion\nThis is the first systematic review of the worldwide preva-\nlence of CPP. The variation in rates of CPP worldwide was\nexplained by variable study quality. The number of popu-\nlation-based studies yielding estimates of burden of CPP\nfrom less developed countries was low. High quality liter-\nature comprising representative samples revealed a high\nburden of disease for all types of pelvic pain, however,\nthere remained heterogeneity in these subgroup of stud-\nies.\nWe believe that the findings of our study are valid as our\nreview methodology was rigorous. A prospective review\nprotocol was used and a concerted effort made to identify\nall the available evidence without language restriction. We\nmade concerted efforts to report this systematic review as\nsuggested by the MOOSE consensus statement [8]. Both\nthe methodology and the rates of CPP varied among the\nincluded primary studies and we explored the reasons for\nvariations comprehensively. This review represents the\nbest available evidence on the estimates of the prevalence\nof CPP at the time of writing and rate ranges from high\nquality studies of representative samples provide the best\ninformation available for targeting services at women suf-\nfering from pelvic pain.\nThe variation in geographical distribution may be related\nto study characteristics, study quality, age groups included\nand definitions used rather than intrinsic differences\nbetween the prevalence of CPP between the different pop-\nulations. Other plausible explanations might be differ-\nences in the prevalence of sexually transmitted infections,\nFunnel plots of the three types of pelvic pain prevalence stud-iesFigure 5\nFunnel plots of the three types of pelvic pain preva-\nlence studies. [a – dysmenorrhoea; b – dyspareunia; c – \nnoncyclical pelvic pain]\nBegg's funnel plot with pseudo 95% confidence limits\nlogr\ns.e. of:logr\n0 .2 .4\n-4\n-3\n-2\n-1\n0logr\ns.e. of:logr\n0 .5 1\n-6\n-4\n-2\n0\n2logr\ns.e. of:logr\n0 .5 1\n-6\n-4\n-2\n0\n2\nDysmenorrhoea-5 a\nDyspareunia-5 b\nNoncyclical pelvic pain-5 c\n\nBMC Public Health 2006, 6:177 http://www.biomedcen tral.com/1471-2458/6/177\nPage 6 of 7\n(page number not for citation purposes)\navailability of medical and other resources or cultural dif-\nferences. Although we have included studies from 1924\nonwards, majority of the studies are from 1980 onwards.\nThe population demographics are unlikely to have under-\ngone major changes over this period, making the studies\nrelevant to current populations' Nevertheless, one has to\nbear in mind the changes in patterns of smoking, sexually\ntransmitted infections and contraception during this time\nand their consequences for pelvic pain [38]. Substantial\ndifferences in and even complete absence of definitions,\ntogether with differences in age ranges of the populations\nstudied also complicate the interpretation of our findings.\nOne study noted the overlaps among different pain disor-\nders (irritable bowel syndrome, interstitial cystitis etc)\n[39], A better understanding of the epidemiology of these\ndisorders would facilitate our understanding of somato-\nsensory disorders in general. We explored for heterogene-\nity using sophisticated technique of metaregression. We\nfound that validated measurement tool, representative-\nness and high quality were the variables that were statisti-\ncally significant (P < 0.05) for dysmenorrhoea,\ndyspareunia and noncyclical pelvic pain respectively. In\nthe meta-regression for countries classification, there are\nso few least developed countries that the power is very\nlow. Also, it is worth pointing out that there is a potential\nrisk of aggregation bias when age is used as a variable in\nmeta-regression.\nThe information on the rates of dysmenorrhoea, dyspare-\nunia have implication for provision of services to policy-\nmakers in terms of provision of improved access for these\nwomen to health care resources as well as the develop-\nment of appropriate treatment protocols. Future epidemi-\nological studies should ideally be prospective, with\nexplicit definitions of the outcome and representative of\nthe general population. Close attention must be paid to\nstudy design and to the use the validated measurement\ntools for validity and comparability of the results across\nstudies and regions. Such efforts will need funding agen-\ncies to be willing to support broader and more systems\noriented approach [40].\nConclusion\nThere were few valid population based estimates of dis-\nease burden due to CPP from less developed countries.\nThe variation in rates of CPP worldwide was due to varia-\nble study quality. Where valid data were available, a high\ndisease burden of all types of pelvic pain was found.\nFunding source\nWorld Health Organization\nCompeting interests\nThe author(s) declare that they have no competing inter-\nests.\nAuthors' contributions\nDr. P Latthe: Conception, design, search, study selection,\ndata extraction, data synthesis, writing the manuscript\nDr. M Latthe: Data extraction, tables\nDr L Say, Dr AM Gülmezoglu: Revising the manuscript,\nfigures\nProf. KS Khan: Conception, design, data synthesis, writing\nand revising the manuscript\nAdditional material\nAcknowledgements\nMary Publicover, Librarian, Birmingham Women's HealthCare Trust for \nher help with the searches; Luciano Mignini, Sam Pretlove, H. Kuntz, \nTomoo Shaktari and Stefka Ritchie for translation of foreign language man-\nuscripts; Daniel Wojdyal for producing the Epimaps\nReferences\n1. Howard FM: The role of laparoscopy in chronic pelvic pain:\npromise and pitfalls.  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Rudan I, Lawn J, Cousens S, Rowe AK, Boschi-Pinto C, Tomaskovic L,\nMendoza W, Lanata CF, Roca-Feltrer A, Carneiro I, Schellenberg JA,\nPolasek O, Weber M, Bryce J, Morris SS, Black RE, Campbell H: Gaps\nin policy-relevant information on burden of disease in chil-\ndren: a systematic review.  Lancet 2005, 365:2031-2040.\nPre-publication history\nThe pre-publication history for this paper can be accessed\nhere:\nhttp://www.biomedcentral.com/1471-2458/6/177/pre\npub","source_license":"CC0","license_restricted":false}