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

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

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

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

Setting and participants
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.

Intervention
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.

Main outcome measures
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.

Data sources
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.

Results
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%.

Limitations
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.

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

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