Economic impact of moderate weight loss in patients with Type 2 diabetes: the Fremantle Diabetes Study.

AIM: To assess the change in the cost of diabetes medication attributable to moderate weight loss in patients with Type 2 diabetes.
METHODS: Longitudinal data collected annually from 590 patients participating in the observational, community-based Fremantle Diabetes Study were examined to determine whether moderate weight loss (≥ 5% of initial body weight) was independently associated with diabetes medication cost during 4 years' follow-up.
RESULTS: Overall, the weight of the cohort decreased significantly during 4.3 ± 0.4 years' follow-up by 1.3 ± 6.2 kg (-1.4 ± 7.9% baseline body weight; trend P < 0.001). Moderate weight loss was achieved by 31%. HbA(1c) improved significantly in the group with moderate weight loss compared with the group without moderate weight loss [-4 ± 16 mmol/mol (-0.3 ± 1.5%) vs. 0 ± 17 mmol/mol (0.0 ± 1.5%), P = 0.015]. Mean (bias-corrected 95% confidence intervals) diabetes medication costs were $A820 ($A744-907) during follow-up. As the cost distribution was highly right-skewed and contained zeros, it was square root (√) transformed before multiple linear regression analysis. The most parsimonious model of baseline associates of √(diabetes medication cost) included glycaemic control, diabetes treatment, diabetes duration, BMI, systolic blood pressure, serum HDL cholesterol (negative), taking lipid-lowering medication and age (negative) (adjusted R(2) = 73.6%). After adjusting for these variables, √(diabetes medication cost) was negatively associated with moderate weight loss (P = 0.026). After entering average values for the cohort into the model, the cost of diabetes medications between baseline and fourth review for an average patient with no weight loss was $A752 compared with $A652 for a patient who attained moderate weight loss, a saving of $A100 (-13.3%). DISCUSSION: These data highlight the economic and clinical benefits of moderate weight loss in Type 2 diabetes.