Cost Effectiveness of Routine Screening for Gonorrhea and Chlamydia When Obtaining Pap Smears in Urban Adolescents

Abstract

<h3>Background</h3> Most adolescent females are tested for gonorrhea and chlamydia during any pelvic exam. We hypothesized that empirically obtaining these tests at time of routine Pap Smear is not cost effective because the prevalence of gonorrhea and chlamydia in the subset population is low. <h3>Methods</h3> A retrospective chart analysis of 576 adolescent females obtaining Pap Smears in an urban adolescent medicine clinic from 7/96–6/97 was conducted. All patients received a gonorrhea culture and chlamydia DNA probe at the time of Pap Smear. Culture costs were detennined and cost estimates were made for complications of untreated gonorrhea and chlamydia based on our hospitals' one year average charge for pelvic inflammatory disease admissions and published literature for ectopic pregnancy and infertility¹. Cost-benefit analysis was constructed making use of odds ratios for risk factors predictive of presence and absence of a sexually transmitted disease (STD). <h3>Results</h3> 453 charts of 576 PAP smear visits were reviewed. Incidence of gonorrhea was 5.1%(27/406), chlamydia was 6.8% (36/530), and either of the two STD's was 9.7% (52/532). 53% (24/45) of patients with positive cultures were treated at time of patient visit prior to knowledge of culture results. Independent predictors of chlamydia. gonorrhea, either, and no STD are as follows: [()=odds ratios, (*)>1000]Either STDChlamydiaGonorrheaNo STDadmits sex intercourse(*)admits sex intercourse(*)admits sex intercourse(*)admits sex initiation (*)treated at visit (6.7)treated at visit (4.2)treated at visit (10.5)not treated at visit (6.6)PE vaginal discharge (2.7)trich on wet prep (5.3)PE cervix friable (3.6)PE no vag discharge(2.7)PE cervix friable (2.2)PE vaginal discharge (3.5)no friable cervix (2.2)>5 WBC wet prep (2.3)no trich on wet prep(3.2)(all odds ratios have p<0.05)<5 WBC wet prep(2.3) If 5 of the 6 above predictors of no STD existed. the incidence of gonorrhea was 1.3% (1/80) representing 17% of the tested population and the incidence of chlamydia was 2.5% (2/80). Using $30 as the cost of a culture (hospital charge) and Washington's $2114 estimate of direct costs for PID and PID associated ectopic pregnancies and infertility (compared with our hospital's average charge for PID in 1997 of $2100), cost savings of not obtaining cultures exist if the incidence of an STD is less than 1.4% in the subpopulation studied. <h3>Conclusions</h3> In 17% of our patients. the absence of predictors of a STD made omitting gonorrhea cultures marginally cost effective. However. this was not true of routine chlamydia diagnostic testing. Continued studies of diverse populations are necessary to bener establish cost effectiveness of these tests and of routine Pap Smears. In most adolescent populations. such testing will still be indicated.