Understanding sexual activity defined in the HEDIS measure of screening young women for Chlamydia trachomatis

Periodic screening of sexually active young women for Chlamydia trachomatis is widely recommended and is now monitored in the Health Plan Employer Data and Information Set (HEDIS). Because little is known about how well the HEDIS measure identifies sexually active women eligible for screening, rates of sexual activity as defined by the measure's specifications were compared with those derived from self-reported sexual behavior and use of sexual health services among privately insured women.

Using the 1996 MarketScan claims data for privately insured women aged 15-25 years, a measure of sexual activity based on the HEDIS specifications for sexual activity was calculated, that is, claims for Pap tests and pelvic examinations, contraceptive services, pregnancy-related service, and screening and treatment for sexually transmitted diseases.

For privately insured women 15-25 years of age, the sexual activity rate was estimated to be 27% based on the HEDIS algorithm using the MarketScan claims data and 60% based on self-reported sexual behavior or 62% based on self-reported use of sexual health services using the 1995 National Survey of Family Growth (NSFG) data.

Among young, privately insured women, use of claims specified by HEDIS classifies a smaller proportion of young women as sexually active than does use of self-reported survey data on sexual behavior or use of sexual health services. If HEDIS continues to rely on claims data because it is easier or less costly to collect and analyze than survey data, users of this performance measure should be aware that it may underestimate the number of women who are eligible for this screening benefit.