This presentation is part of: Oral Concurrent Session B - Public Health 2
DOES LEAD-TIME FROM INFECTION TO PID DEVELOPMENT MATTER IN CHOOSING AN STD SCREENING INTERVAL? A COST-EFFECTIVENESS ANALYSIS
Kenneth J. Smith, MD, University of Pittsburgh, Section of Decision Sciences and Clinical Systems Modeling, Pittsburgh, PA, Robert L Cook, MD, MPH, University of Pittsburgh, Center for Research on Health Care, Pittsburgh, PA, and Mark S. Roberts, MD, MPP, University of Pittsburgh, Section of Decision Sciences and Clinical Systems Managment, Pittsburgh, PA.
Purpose: Pelvic inflammatory disease (PID) is a major cause of disability among young women. As a preventive measure, most experts recommend screening for sexually transmitted disease (STD) every 12 months, while some argue for 6 month screening in higher risk women. However the lead-time from STD acquisition to PID development is unknown and its influence on screening interval impact and cost-effectiveness is unclear. Methods: Using a Markov decision model, we estimated the incremental cost/QALY gained by chlamydia and gonorrhea screening every 6 or 12 months compared to no screening. Our base case analysis examined high-risk young women over a 2-year time horizon (25% infection risk [70% asymptomatic], 5% PID risk with 12 month screening, and 25% PID complication risk based on population-based data) using peaked PID risk distributions for lead-times from 1-12 months. Lower risk women and differing PID risk distributions were examined in sensitivity analyses. Other risk, cost, and utility data were obtained from the literature. Results: Compared to no screening, 12 month screening is cost saving for lead-times of 9-12 months and costs $2100 [8 mo] to $34,300 [1 mo] per QALY gained at shorter lead-times. Compared to 12 month screening, 6-month screening costs less than $47,000/QALY for PID lead-times from 1-12 months (range $15,100 [7 mo lead-time] to $46,700 [1 mo]), while decreasing PID cases 14.4% [1 mo] to 60.6% [12 mo]. When the incidence of infection decreases to 5%/yr, costs/QALY for 6 month compared to 12 month screening are > $75,000 for all lead-times (range $75,800 to $129,200). Other PID risk distributions showed similar relative insensitivity to PID lead-time. Conclusion: Based on our analysis, uncertainty about the lead-time between infection and PID development or the PID risk distribution is not a significant factor in choosing a screening interval: the baseline infection rate is most important. Screening for chlamydia and gonorrhea every 6 months is economically reasonable in high-risk women, but expensive in lower risk groups.
