Cost effectiveness of primary care referral to a commercial provider for weight loss treatment, relative to standard care: a modelled lifetime analysis

BACKGROUND: Because of the high prevalence of overweight and obesity, there is a need to identify cost-effective approaches for weight loss in primary care and community settings. OBJECTIVE: To evaluate the long-term cost effectiveness of a commercial weight loss programme (Weight Watchers) (CP) compared with standard care (SC), as defined by national guidelines. METHODS: A Markov model was developed to calculate the incremental cost-effectiveness ratio (ICER), expressed as the cost per quality-adjusted life year (QALY) over the lifetime. The probabilities and quality-of-life utilities of outcomes were extrapolated from trial data using estimates from the published literature. A health sector perspective was adopted. RESULTS: Over a patient's lifetime, the CP resulted in an incremental cost saving of AUD 70 per patient, and an incremental 0.03 QALYs gained per patient. As such, the CP was found to be the dominant treatment, being more effective and less costly than SC (95% confidence interval: dominant to 6225 per QALY). Despite the CP delaying the onset of diabetes by similar to 10 months, there was no significant difference in the incidence of type 2 diabetes, with the CP achieving < 0.1% fewer cases than SC over the lifetime. CONCLUSION: The modelled results suggest that referral to community-based interventions may provide a highly cost-effective approach for those at high risk of weight-related comorbidities.