Impact of lifestyle intervention and metformin on health-related quality of life: the diabetes prevention program randomized trial.

BACKGROUND: Adults at high risk for diabetes may have reduced health-related quality of life (HRQoL). OBJECTIVE: To assess changes in HRQoL after interventions aimed at diabetes risk reduction. DESIGN, SETTING, AND PARTICIPANTS: A randomized clinical trial, the Diabetes Prevention Program, was conducted in 27 centers in the United States, in 3,234 non-diabetic persons with elevated fasting and post-load plasma glucose, mean age 51 years, mean BMI 34 Kg/m(2); 68 % women, and 45 % members of minority groups. INTERVENTIONS: Intensive lifestyle (ILS) program with the goals of at least 7 % weight loss and 150 min of physical activity per week, metformin (MET) 850 mg twice daily, or placebo (PLB). MEASUREMENTS: HRQoL using the 36-Item Short-Form (SF-36) health survey to evaluate health utility index (SF-6D), physical component summaries (PCS) and mental component summaries (MCS). A minimally important difference (MID) was met when the mean of HRQoL scores between groups differed by at least 3 %. RESULTS: After a mean follow-up of 3.2 years, there were significant improvements in the SF-6D (+0.008, p=0.04) and PCS (+1.57, p<0.0001) scores in ILS but not in MET participants (+0.002 and +0.15, respectively, p=0.6) compared to the PLB group. ILS participants showed improvements in general health (+3.2, p<0.001), physical function (+3.6, p<0.001), bodily pain (+1.9, p=0.01), and vitality (+2.1, p=0.01) domain scores. Treatment effects remained significant after adjusting sequentially for baseline demographic factors, and for medical and psychological comorbidities. Increased physical activity and weight reduction mediated these ILS treatment effects. Participants who experienced weight gain had significant worsening on the same HRQoL specific domains when compared to those that had treatment-related (ILS or MET) weight loss. No benefits with ILS or MET were observed in the MCS score. CONCLUSION: Overweight/obese adults at high risk for diabetes show small improvement in most physical HRQoL and vitality scores through the weight loss and increased physical activity achieved with an ILS intervention.