The cost-effectiveness of primary care referral to a UK commercial weight loss programme.

Primary care referral to commercial weight loss programmes that follow best practice is included in current UK guidance on the management of adult obesity. This study investigated whether such a programme was cost-effective compared with usual care. A decision-analytical Markov model was developed to estimate the lifetime costs and benefits of the referral programme compared with usual care and enable a cost-utility analysis. The model cohort transited between body mass index classifications and type 2 diabetes, stroke and myocardial infarction (MI) with risk, cost and effect parameter values taken from published literature. The cost per incremental quality-adjusted life year (QALY) was calculated. Extensive deterministic and scenario sensitivity analyses and probabilistic sensitivity analyses (PSA) were conducted. At 12 months, the incremental cost-effectiveness ratio was £6906, indicating that programme referral was cost-effective. Over a lifetime, referral to the commercial programme was dominant as it led to a cost saving of £924 and conferred incremental benefit (0.22 QALY) over usual care. Model simulations estimated lower lifetime rates of type 2 diabetes, stroke and MI as a result of the weight loss achieved. The results were robust to extensive sensitivity analyses. The PSA indicated that programme referral had a 68% chance of being cost-effective at a willingness to pay per incremental QALY threshold of £20,000. Referral to the programme dominated usual care, being both cheaper and more effective. These results compare favourably with economic evaluations of other obesity interventions and add to a growing evidence base on the cost-effectiveness of commercial weight loss providers and practices.