Pap smear screening in an urban STD clinic. Yield of screening and predictors of abnormalities.

BACKGROUND

Pap smear screening studies in STD clinics have reported high rates of squamous intraepithelial lesions (SIL); however, there are limited data on levels of unsatisfactory smears of characteristics associated with cytologic abnormalities.

GOAL

To assess the yield to Pap smear screening in an STD clinic and to evaluate the rates of and risk factors for atypia, low-grade SIL (LSIL), and high-grade SIL (HSIL).

STUDY DESIGN

A chart review of the clinic records of women undergoing Pap smear screening between 1991 and 1994 was conducted. Results were assessed from two different screening protocols, the first using a Dacron swab to obtain the endocervical sample and the second using a cytobrush.

RESULTS

Of 2034 Pap smears, 1313 (64.6%) were negative, 202 (9.9%) were unsatisfactory, 257 (12.6%) were atypical, 211 (10.4%) had LSIL, and 51 (2.5%) had HSIL. With the change to the cytobrush protocol, the rate of unsatisfactory smears decreased from 14.4% to 3% (p < 0.001), atypia increased from 10% to 16.7% (p < 0.001), and HSIL rose from 1.7% to 3.7% (p < 0.001). By multivariate analysis, atypia was associated with genital warts (odds ratio (OR) 1.53, 95% confidence interval (CI): 1.16-2.02); LSIL with younger age (p < 0.001, for trend), black race (OR 1.51, 95% CI: 1.08-2.10), genital warts (OR 1.81, 95% CI: 1.33-2.47), and an abnormal appearance of the cervix on examination (OR 2.49, 95% CI: 1.85-3.35); and HSIL with a previous abnormal Pap smear (OR 2.48, 95% CI: 1.08-2.10). Overall, abnormality rates were significantly higher in adolescents (35.5%) than older women (21.7%) (p < 0.01).

CONCLUSIONS

Obtaining satisfactory Pap smears among women undergoing screening in an STD clinic is feasible and cytologic abnormalities are common. These results continue to support the need for Pap smear screening in STD clinics, but the high rates in adolescents, a group in whom the natural history of cytologic abnormalities has not been well-defined, raise questions about the need to develop age-appropriate screening and management strategies.