Cost-effectiveness of e-cigarettes for smoking cessation at homeless support centres: SCeTCH cRCT

While smoking is common among those experiencing homelessness, the effectiveness of an e-cigarette intervention to reduce smoking in this population is unclear.

To determine the cost-effectiveness of providing an e-cigarette for smoking cessation in homeless support centres compared to usual care.

A multicentre two-arm cluster randomised controlled trial, with data collection time points at baseline, 4, 12 and 24 weeks post baseline.

Adults (aged 18+) who smoked daily and accessed 32 homeless support centres across six areas of Great Britain received either e-cigarette intervention (n = 239 in 16 centres) or usual care (n = 236 in 16 centres) by centre (cluster) randomisation.

The intervention was the provision of an e-cigarette starter kit plus 4 weeks' supply of e-liquids. The usual care comprised very brief advice for smoking cessation and signposting to local Stop Smoking Services.

The total costs included costs of intervention/usual care, costs of smoking cessation outside of the trial and costs of general healthcare services use over 24 weeks. Quality-adjusted life-years were derived from EuroQol-5 Dimensions, five-level version administered at each data collection point. An incremental cost-effectiveness ratio was calculated for 24 weeks using the difference between groups in total costs and quality-adjusted life-years, with cost-effectiveness acceptability curve constructed based on bootstrap to examine uncertainty. A long-term model was employed to project a lifetime incremental cost-effectiveness ratio with probabilistic sensitivity analysis to examine uncertainty.

The analysis over 24 weeks was based on research team records and data collected via self-reported questionnaires. Unit costs for valuation were extracted from published secondary sources. The parameters of the long-term model were based on the 24-week results and published secondary sources.

Mean intervention costs were estimated at £92 [standard error (SE) £0] per participant and mean usual care costs at £50 (SE £0) per participant. Mean total costs per participant were estimated at £3859 (SE £441) in the e-cigarette group and £2716 (SE £386) in the usual care group. Mean quality-adjusted life-years were estimated at 0.303 (SE 0.008) in the e-cigarette group and 0.295 (SE 0.010) in the usual care group. Adjusting for baseline covariates and respective baseline values, e-cigarette group were £1267 (95% confidence interval £600 to £1938) more costly and yielded 0.007 (95% confidence interval -0.017 to 0.027) more quality-adjusted life-years than usual care. The incremental cost-effectiveness ratio was calculated at £181,000 per quality-adjusted life-year gain, with probability of intervention being cost-effective between the incremental cost-effectiveness ratio thresholds of £20,000-30,000 per quality-adjusted life-year gain at 0.9-3.5%. The lifetime model projected the incremental cost-effectiveness ratio at £38,360 per quality-adjusted life-year gained, with the probability of intervention being cost-effective between £20,000 and £30,000 from 47.6% to 49.6%.

The imbalance in missing data led to some uncertainty in the results, and healthcare costs recorded in the trial may not reflect the health needs of this population.

Providing e-cigarettes for smoking cessation in homeless support centres was more costly than usual care, but the small increase in quality-adjusted life-years was not significant.

Future work should aim to maximise quit rates while being cost-effective and therefore implementable.

This article presents independent research funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme as award number NIHR132158.