Impact of expedited partner therapy (EPT) implementation on chlamydia incidence in the USA

Abstract

Objectives: The diagnosis and treatment of Chlamydia trachomatis infection is important in preventing persistent or recurrent infection. Expedited partner therapy (EPT) is the favoured and supported method for STI treatment of the Centers for Disease Control and Prevention when the provider cannot be assured that all recent sexual partner(s) will seek therapy. EPT is legally permissible in 38 states and is endorsed by healthcare organisations to decrease the rates of chlamydia and gonorrhoea infection. Our study investigated the impact of EPT legal status (permissible, potentially allowable or prohibited) on C. trachomatis infection rates for each state.

Methods: Our ecological study modelled the number of reported chlamydia cases from 2000 to 2013 as a function of year, legal status and the interaction between year and legality. We used a negative binomial regression model that included state fixed effects (including the District of Columbia) to account for both the repeated measures per state and state-specific characteristics that could not be measured for inclusion in this study. The lagged number of C. trachomatis cases was included as a covariate and each state's total population for a given year was included in the model as an exposure parameter. States were designated Y (EPT permissible), N (EPT prohibited) and M (EPT potentially allowable), and the legal status of each state could vary over time.

Results: Each legal category saw an increase in the incidence rate of C. trachomatis infection, but on average, the incidence rate for states with prohibitive EPT legislation grew significantly faster over time compared with the rate for the states where EPT was permissible. The average increase in predicted incidence rates per year for states with Y, N and M legal status were 14.1 (95% CI (12.0 to 16.2)), 17.5 (95% CI (15.9 to 19.2)) and 16.8 (95% CI (15.0 to 18.6)) cases per 100 000 persons per year, respectively, when controlling for state-specific effects.

Conclusions: Our model suggests that a lack of EPT legislation is associated with an increase in STI rates. States with potentially allowable EPT legislation as of 2013 (n=8) should consider permitting EPT as a component of a multipronged strategy for treatment of sexual partners to prevent C. trachomatis infection.

Keywords: CHLAMYDIA INFECTION; REPRODUCTIVE HEALTH; SEXUAL HEALTH; TREATMENT.