The valuation of outcomes for the temporary and chronic health states associated with Chlamydia trachomatis infection
Background: Eliciting health-state utility values (HSUVs) for some diseases is complicated by the mix of associated temporary (THSs) and chronic health states (CHSs). This study uses one such disease, chlamydia infection, to explore the challenges. The objectives were to: 1) Define a set of health-state descriptions related to chlamydia and 2) Derive HSUVs for these health states (both temporary and chronic). Methods: HSUVs were elicited for seven health states (five THSs and two CHSs) depicting the symptoms of chlamydia, developed using evidence from the literature and clinical experts. The chained time trade-off (TTO) and visual analogue scale (VAS) were applied to THSs while conventional TTO was applied to the CHSs. Ectopic pregnancy was used as the anchor for the chained TTO approach. The study sampled from three different population groups and the survey was administered face-to-face. Results: One hundred participants were assessed with an interview completion rate of 100%. Mean TTO utilities were consistently higher than VAS scores. The aggregated mean chained TTO results for the THS ranged from 0.46 (SD, 0.24) for ectopic pregnancy, to 0.77 (SD 0.21) for cervicitis. Conclusions: Chained TTO was shown to be feasible in this population and the resulting HSUVs could have implications for economic evaluations for chlamydia prevention and control. Methodological challenges included the development of health-state descriptions, the selection, and the duration of appropriate anchor state.