Screening for Chlamydia trachomatis in women 15 to 29 years of age: a cost-effectiveness analysis.

BACKGROUND

Clinical guidelines have traditionally advised annual Chlamydia trachomatis screening for women younger than 25 years of age.

OBJECTIVE

To assess the cost-effectiveness of recently proposed strategies for chlamydia screening.

DESIGN

State transition simulation model; cost-effectiveness analysis.

DATA SOURCES

Published literature.

TARGET POPULATION

Sexually active U.S. women 15 to 29 years of age.

TIME HORIZON

Lifetime.

PERSPECTIVE

Modified societal.

INTERVENTIONS

Four strategies targeted to 3 specific age groups (15 to 19 years, 15 to 24 years, and 15 to 29 years): 1) no screening, 2) annual screening for all women, 3) annual screening followed by 1 repeated test within 3 to 6 months after a positive test result, and 4) annual screening followed by selective semiannual screening for women with a history of infection.

OUTCOME MEASURES

Clinical events (for example, pelvic inflammatory disease, chronic pelvic pain, ectopic pregnancy, and infertility), lifetime costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS: Annual screening in women 15 to 29 years of age followed by semiannual screening for those with a history of infection was the most effective and cost-effective strategy. It consistently had an incremental cost-effectiveness ratio less than 25,000 dollars per quality-adjusted life-year (QALY) compared with the next most effective strategy. When the indirect transmission effects of a 10-year screening program on the probability of infection in uninfected women (that is, per-susceptible rate of infection) were considered, all strategies became more cost-effective.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the annual incidence of chlamydia, probability of persistent infection, screening test costs, and costs of treating long-term complications. Each variable was associated with threshold values beyond which screening became cost-saving. In probabilistic analysis, annual screening in women 15 to 29 years of age followed by semiannual screening for those with a history of infection had an incremental cost-effectiveness ratio less than 50,000 dollars per QALY in 99% of simulations.

LIMITATIONS

Uncertainty about the natural history of chlamydial infection and consideration of only the indirect transmission effects of C. trachomatis screening.

CONCLUSIONS

Annual C. trachomatis screening for all women 15 to 29 years of age and selective targeting of those with a history of infection for semiannual screening is very cost-effective compared with other well-accepted clinical interventions.