Utility values for childhood obesity interventions: a systematic review and meta-analysis of the evidence for use in economic evaluation.

Rigorous estimates of preference-based utilities are important inputs into economic evaluations of childhood obesity interventions, yet no published review currently exists examining utility by weight status in paediatric populations. A comprehensive systematic literature review and meta-analysis was therefore undertaken, pooling data on preference-based health state utilities by weight status in children using a random-effects model. Tests for heterogeneity were performed, and publication bias was assessed. Of 3,434 potentially relevant studies identified, 11 met our eligibility criteria. Estimates of Cohen's d statistic suggested a small effect of weight status on preference-based utilities. Mean utility values were estimated as 0.85 (95% uncertainty interval [UI] 0.84-0.87), 0.83 (95% UI 0.81-0.85), 0.82 (95% UI 0.79-0.84) and 0.83 (95% UI 0.80-0.86) for healthy weight, overweight, obese and overweight/obese states, respectively. Meta-analysis of studies reporting utility values for both healthy weight and overweight/obese participants found a statistically significant weighted mean difference (0.015, 95% UI 0.003-0.026). A small but statistically significant difference was also estimated between healthy weight and overweight participants (0.011, 95% UI 0.004-0.018). Study findings suggest that paediatric-specific benefits of obesity interventions may not be well reflected by available utility measures, potentially underestimating cost-effectiveness if weight loss in childhood/adolescence improves health or well-being.

Pharmaceutical utilisation and costs before and after bariatric surgery.

OBJECTIVE: To determine whether pharmaceutical utilisation and costs change after bariatric surgery. SUBJECTS: Total population of Australians receiving Medicare-subsidised laparoscopic adjustable gastric banding (LAGB) in 2007 (n=9542). DESIGN: Computerised data linkage with Medicare, Australia's universal tax-funded health insurance scheme. Pharmaceuticals relating to obesity-related disease and postsurgical management were assigned to therapeutic categories and analysed. The mean annual numbers of pharmaceutical prescriptions for each category were compared over the 4-year period from the year before LAGB (2006) to 2 years after LAGB (2009) using utilisation incidence rate ratios (IRRs). RESULTS: The population was mainly female (77.7%) and age was normally distributed with the majority (60.7%) of subjects aged between 35-54 years. Utilisation rates decreased significantly after LAGB in the following therapeutic categories: diabetes (IRR 0.51, IRR 95% CI 0.50-0.53, mean annual cost differences per person $30), cardiovascular (0.81, 0.80-0.82, $29), psychiatric (0.95, 0.93-0.97, $13), rheumatic and inflammatory disorders (0.51, 0.49-0.53, $10) and asthma (0.78, 0.75-0.81, $9). In contrast, significantly greater utilisation was observed in the pain (1.28, 1.23-1.32, $12), gastrointestinal tract disorder (1.04, 1.02-1.07, $5) and anaemia/vitamins (2.34, 2.01-2.73, $4) therapeutic categories. When the defined categories were combined, a net reduction in pharmaceutical utilisation was observed, from 10.5 to 9.6 pharmaceuticals prescribed per person/year, and costs decreased from $AUD517 to $AUD435 per year in 2009 prices. CONCLUSION: Relative to the year before LAGB, overall pharmaceutical utilisation was reduced in the 2 years after the year of LAGB surgery, demonstrating that bariatric surgery can lead to reductions in pharmaceutical utilisation in the 'real world' setting. The greatest absolute cost reductions were observed in the therapies to treat diabetes and cardiovascular disease.