|
|
Vol. 55, No. 4, April 2009, pp.376 - 377 Copyright © 2009 by The College of Family Physicians of Canada
Does a water-based lubricant affect Pap smear and cervical microbiology results?Michal Pawlik, MD CCFPPractises family medicine in New Westminister, BC
Frank J. Martin, MD MClSc MEd FCFP
Griffith WF, Stuart GS, Gluck Kl, Heartwell SF. Vaginal speculum lubrication and its effects on cervical cytology and microbiology. Contraception 2005;72(1):60–4. Research question Does water-based lubricant affect results of Papanicolaou smears and detection of sexually transmitted infections? Type of article and design This was a randomized, single-blind, controlled trial. Relevance to family physicians Vaginal speculum examination is routinely performed by most family physicians, most commonly to obtain a Pap smear or to test for sexually transmitted infections, mainly Chlamydia trachomatis and Neisseria gonorrhoeae. The most common reason cited by women for not having routine speculum examination is pain during the examination.1 Whether or not lubrication will decrease discomfort during the speculum examination has never been tested, but several women have indicated to one of the authors (M.P.) that speculum examinations with lubrication are more comfortable. However, although lubrication might make the speculum examination more comfortable, most family physicians are reluctant to use lubrication because they have been told that it alters cytology and microbiology results.2–4 Overview of study and outcomes The study was performed at the University of Texas Southwestern Medical Center at Dallas Maple Plaza Womens Health Center between July 2003 and February 2004. The clinic is 1 of 8 federally funded university family-planning clinics, servicing a homogenous, reproductive-aged, and predominantly low-socioeconomic Hispanic patient population. Patient demographic information and laboratory results were received in monthly aggregates without patient identification information. All patients undergoing Pap smear or endocervical DNA probe assay for C trachomatis and N gonorrhoeae were included in the study; therefore, repeat clinical visits by individual patients could occur. No exclusion criteria were listed in the article. The study was exempt from the universitys Institutional Ethics Review Board. The authors did not state whether or not patients were informed that the trial was taking place and if they could decline participation. The 8 months of the study period were randomized into equal numbers of control and experimental months. During the experimental months, all patients undergoing vaginal speculum examinations had the speculum lubricated with water-soluble gel lubricant. During the control months, water-moistened vaginal speculums were used. Pap smears were performed with Ayre spatulas followed by cytobrush, and the cells were applied to single glass slides, fixed with isopropyl alcohol, and allowed to air dry. Patients tested for C trachomatis and N gonorrhoeae were tested using DNA probe assay. Both cytopathology and microbiology laboratories were blinded to lubricant use. The expertise of the clinicians (nurse practitioners, residents, medical students, and nursing students supervised by faculty) was consistent during the study period. The study compared the number of unsatisfactory cytology results and the number of C trachomatis infections detected between water-lubricant (control) and gel-lubricant (experimental) months. Because of the small number of N gonorrhoeae infections detected, statistical comparisons could not be calculated.
The Results The total number of clinic visits during the trial period was 9500 (4901 during the experimental months and 4599 during the control months). No difference in demographic characteristics between the control and experimental groups was demonstrated. The total number of Pap smears collected was 3460 (1828 in the experimental months and 1632 in the control months). Results of 20 (1.1%) Pap smears were unsatisfactory during the experimental months and 24 (1.5%) were unsatisfactory during the control months (OR 0.74, 95% confidence interval [CI] 0.41 to 1.35). This statistically insignificant result is consistent with those of other experiments.5,6 A total of 5535 combination microbial DNA probe assays for endocervical C trachomatis and N gonorrhoeae infections were collected (2909 during experimental months and 2626 during control months). During experimental months, 44 (1.5%) assays returned positive results for C trachomatis; during control months, 38 (1.5%) assays returned positive results for C trachomatis (OR 1.05, 95% CI 0.67 to 1.62). Because there were only 3 positive results for N gonorrhea in the control months and 0 in the experimental months, statistical calculations for N gonorrhea DNA probe assays could not be made. Analysis of methodology This study was a well-conducted randomized trial in a federally funded family-planning facility. The study participants included all patients who presented for Pap tests or DNA probe assays for C trachomatis or N gonorrhoeae. Although there were various service providers—including nurse practitioners, residents, medical students, and nursing students overseen by faculty—which might have resulted in inconsistent sampling techniques, distribution of service provider expertise did not change by month during the study period. Monthly randomization of lubricant or nonlubricant assignment for speculum insertion was chosen over individual patient randomization and permitted the inclusion of all patients. The study sampling method, therefore, could not account for repeat testing during the study period by individuals. Repeat testing of the same patient would not likely affect test results unless the Pap test and DNA probe swabs could not be obtained successfully from the individual. Because the rates of unsatisfactory tests were no different in each group, repeat testing did not appear to be a factor. Both the Pap smear and DNA probe assay laboratories were blinded to the monthly randomization assignment, and the study revealed no differences in the test results during the intervention and nonintervention months, with an OR of 0.74 for unsatisfactory cervical cytology and an OR of 1.05 for C trachomatis detection. The results for N gonorrhoeae could not be compared because of the low incidence rate of the infection in the sample population. Application to clinical practice The mix of disciplines and varying expertise among service providers did not indicate a significant change in satisfactory or unsatisfactory results during the monthly randomization assignment, which suggests that results would likely be similar in most physician offices. Although the single study site and patient characteristics could affect the generalizability of results, use of water-based gel lubricant or water-moistened vaginal speculum and the effect on test results is consistent with other Pap testing studies,5,6 which show no increase in unsatisfactory results. This study addressed concerns raised by Amies et al6 about the effects of water-based gel lubricants on sexually transmitted infection test results and found no significant difference in the detection of C trachomatis infections. The effect of water-based gel lubricant on the detection of N gonorrhea could not be studied because the incident rate in this population did not provide sufficient cases for analysis.
Footnotes Competing interests: None declared References
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||