The cost-effectiveness of opportunistic chlamydia screening in England

Abstract

Objective/Background: The National Chlamydia Screening Programme (NCSP) is being implemented in England. This study aims to estimate the cost-effectiveness of a) the NCSP strategy (annual screening offer to men and women aged under 25 years) and b) alternative screening strategies.

Methods: A stochastic, individual-based, dynamic sexual network model was combined with a cost-effectiveness model to estimate the complications and associated costs of chlamydial infection. The model was constructed and parameterised from the perspective of the National Health Service (England), including the direct costs of infection, complications and screening. Unit costs were derived from standard data sources and published studies. The average and incremental cost-effectiveness ratio (cost per major outcome averted or QALY gained) of chlamydia screening strategies targeting women and/or men of different age groups was estimated. Sensitivity analyses were done to explore model uncertainty.

Results: All screening strategies modelled are likely to cost the NHS money and improve health. If PID progression is less than 10% then screening at any level is unlikely to be cost-effective. However, if PID progression is 10% or higher the NCSP strategy compared to no screening appears to be cost effective. The incremental cost-effectiveness analysis suggests that screening men and women aged under 20 years to be the most beneficial strategy that falls below accepted thresholds. There is a high degree of uncertainty in the findings.

Conclusions: Offering an annual screening test to men and women aged under 20 years may be the most cost-effective strategy (i.e. under accepted thresholds) if PID progression is 10% or higher.