Alberta Heritage Foundation for Medical Research Diagnostic tests for vaginosis/vaginitis Christa Harstall and Paula Corabian October 1998 HTA12 Diagnostic tests for vaginosis/vaginitis Christa Harstall and Paula Corabian October 1998 © Copyight Alberta Heritage Foundation for Medical Research, 1998 This Health Technology Assessment Report has been prepared on the basis of available information of which the Foundation is aware from public literature and expert opinion, and attempts to be current to the date of publication. The report has been externally reviewed. Additional information and comments relative to the Report are welcome, and should be sent to: Director, Health Technology Assessment Alberta Heritage Foundation for Medical Research 3125 Manulife Place, 10180 - 101 Street Edmonton Alberta T5J 3S4 CANADA Tel: 403-423-5727, Fax: 403-429-3509 This study is based, in part, on data provided by Alberta Health. The interpretation of the data in the report is that of the authors and does not necessarily represent the views of the Government of Alberta. ISBN 1-896956-15-7 Alberta's health technology assessment program has been established under the Health Research Collaboration Agreement between the Alberta Heritage Foundation for Medical Research and the Alberta Health Ministry. Acknowledgements The Alberta Heritage Foundation for Medical Research is most grateful to the following persons for their comments on the draft report and for provision of information. The views expressed in the final report are those of the Foundation. Dr. Jane Ballantine, Section of General Practice, Calgary Dr. Deirdre L. Church, Microbiology, Calgary Laboratory Services, Calgary Dr. Nestor N. Demianczuk, Royal Alexandra Hospital, Edmonton Dr. Maire A. Duggan, Calgary Laboratory Services, Calgary Dr. Patrick Gibb, Microbiology, Calgary Laboratory Services, Calgary Dr. Devidas Menon, Institute of Pharmaco-Economics, Edmonton Dr. Miriam Orleans, University of Colorado, Denver Dr. Robert P. Rennie, University of Alberta Hospital, Edmonton Dr. S. Nanette Schuurmans, Women’s Health Program, Edmonton Dr. Jack D. Sorbel, Harper Hospital, Detroit Contents Summary ........................................................................................................................................ 1 Introduction ................................................................................................................................... 2 Diagnostic tests .............................................................................................................................. 3 Practice patterns in Alberta ......................................................................................................... 3 Bacterial vaginosis ........................................................................................................................ 4 Candidiasis .................................................................................................................................... 6 Trichomoniasis .............................................................................................................................. 8 Studies of accuracy ....................................................................................................................... 9 Conclusions .................................................................................................................................. 11 References .................................................................................................................................... 29 Tables of publications on diagnosis of vaginosis/vaginitis Abbreviations .............................................................................................................................. 13 Table 1: Studies of accuracy for diagnosis of vaginitis/vaginosis ............................... 14 Table 2: Reviews on diagnosis of vaginitis/vaginosis ................................................... 21 Appendix A: Methodology ..................................................................................................... 23 Appendix B: Alberta Health Care Insurance Plan Physician Payment Administrative Database ................................................................ 26 Prevalence data Table 3: Estimated age adjusted physician contact prevalence, 1996/97 .................... 27 Table 4: Estimated age adjusted physician contact prevalence, 1997/98 .................... 27 Table 5: Prevalence rate for the total population ............................................................ 27 Data on costs and specialities Table 6: Physician payments, 1996/97 and 1997/98 ...................................................... 28 Table 7: Services provided by speciality .......................................................................... 28 Summary The importance of accurate, reproducible and rapid laboratory methods to diagnose the cause of vaginitis symptoms has increased as recent data suggest an association between bacterial vaginosis, candidiasis and trichomoniasis, and obstetrical and gynecological complications. These are diagnostically complex diseases and in some incidences more than one disease state may be present. Currently, the diagnosis of the cause of vaginitis symptoms requires both the assessment of clinical symptoms (vaginal discharge, odour, appearance, discomfort) and the performance of diagnostic tests (pH, microscopic evaluation, whiff test, occasionally cultures). There is a need for scientific evidence to establish a causal relation or association of bacterial vaginitis, candidiasis and trichomoniasis with such serious gynecological and obstetrical conditions as late onset miscarriage, preterm birth, postabortal pelvic inflammatory disease, post caesarian section endometritis and HIV. Without this information, it is difficult to set the acceptable limits of sensitivity and specificity for diagnostic tests. The primary studies of accuracy included in this assessment are of fairly poor methodological quality and design. Moreover, the scientific evidence to date suggests relatively poor diagnostic performance. The accuracy of the clinical criteria used for the diagnosis of these three disease states also needs to be re-evaluated. Most of the published studies located are from researchers in the United States and other countries. Guidelines based on existing evidence should take into account that the results from these studies are not generalizable to the situation in Alberta since the practice patterns seem to be very different. For the fiscal year 1997/98 in Alberta, 16,473 women of childbearing age had a confirmed diagnosis of either one or a combination of bacterial vaginosis, candidiasis and trichomoniasis. Females between the ages of 21 to 25 years are the population at highest risk. There seem to be some promising tests on the horizon but these are expensive techniques requiring specialized skills. Antibody and DNA based techniques have the potential to increase accuracy and decrease the time taken for laboratory identification. Further work is needed on their cost effectiveness in routine application. 1 Introduction This report has been prepared following a request from the provincial Clinical Practice Guidelines Program for information on the accuracy of diagnostic tests for the detection of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and trichomoniasis in females of reproductive age. The intention of this document is to provide background and scientific evidence for the potential development of a provincial guideline. The focus of the report is the diagnosis of vaginitis, an inflammation of the vagina, and vaginosis, an imbalance in the normal flora of the vagina without inflammation. Specifically, this assessment looks at the analytical performance (sensitivity, specificity, positive and negative predictive values) of the current or new diagnostic tests for BV, VVC and trichomoniasis. The methodology used for the literature review is outlined in Appendix A. Vaginal infections are frequently the cause of distress and discomfort in adult women. The American College of Obstetricians and Gynecologists and others have noted that symptoms of vaginitis are the most common gynecologic problem seen by obstetricians/gynecologists and physicians providing primary care (19,30,49) . Vaginal discharge was listed among the top 25 reasons for physician consultation (19). The vaginal ecosystem is a complex biosphere composed of a great variety of microorganisms; these interact in various ways to maintain a balanced or healthy state. The ecosystem is in a constant state of flux and its equilibrium is constantly challenged by both endogenous and exogenous factors (16) . Factors that may alter the delicate equilibrium are the following: antibiotics, hormones, contraceptive preparations (oral and topical), douches, sexual intercourse, presence of foreign bodies such as IUDs, alterations in immune status, sexually transmitted diseases, stress and change in partners (21,49) . The concept of an unbalanced versus a diseased vaginal ecosystem needs be understood by both the patient and the physician. Diseases of the vagina which may cause an abnormal vaginal discharge may fall into one of three categories: infectious, allergic and neoplastic; whereas an unbalanced ecosystem, referred to as vaginosis, reflects a disturbance which has caused an alteration in the vaginal microflora (16) . It is common for the terms vaginitis and vaginosis to