Purpose: Obesity has a high cost to individuals and society; it is estimated that $166 billion in annual health care costs are directly attributable to obesity. In this post hoc analysis, the estimated cost change associated with each unit difference in body-mass index (BMI) and potential savings that could be achieved via weight loss with phentermine and topiramate extended-release (PHEN/TPM ER) were evaluated.
Methods: Data were extracted from the Phase 3, 56-week CONQUER study, which randomized (2:1:2 ratio) obese and overweight subjects (BMI ≥27 to ≤45 kg/m2) with ≥2 weight-related comorbidities to lifestyle modifications plus placebo, PHEN 7.5 mg/TPM ER 46 mg (7.5/46), or PHEN 15 mg/TPM ER 92 mg (15/92). Mean change in BMI in the overall population and change in BMI when stratified by baseline BMI (kg/m2): overweight (BMI <30), obesity Class I (BMI 30-34.9), Class II (BMI 35-39.9), or Class III (BMI ≥40) were assessed at 56 weeks in responders to treatment (≥3% weight loss at week 12). These changes were then compared to the medical and pharmacy costs associated with each BMI unit (Table).
Results: Overall baseline BMI was 36.6 kg/m2 (SD ±4.5). At week 56, significantly greater decreases in BMI were experienced with 7.5/46 (n=321) and 15/92 (n=747) vs placebo (n=636) (P<.0001; Table). Applying the medical and pharmacy cost-change estimates, overall annual costs per subjects in this overweight/obese population could be reduced by up to $1095 in the 7.5/46 group and $1175 in the 15/92 group. For the Class I obese group, annual cost could decrease $968 and $1020, for the 2 doses, respectively. Compared with individuals with Class I obesity at baseline, the cost decrease was 16% greater for those with baseline Class II obesity and 28% greater for Class III obesity for the 7.5/46 group, and 15% and 48% greater for those with baseline Class II and Class III obesity, respectively, in the 15/92 group (Table).
Conclusions: Across all baseline BMI categories, PHEN/TPM ER induced greater weight loss than did placebo. Across all groups, the potential for medical and pharmacy cost savings were greatest in those with higher baseline BMI levels, highlighting the potential opportunity for health care cost offsets for overweight and obese individuals with PHEN/TPM ER–assisted weight loss.
