Lifestyle Intervention Beneficial for Overweight and Obese Type 2 Diabetics

Summary

The multicenter Look AHEAD study [Action for Health in Diabetes; NCT0017953] is a randomized controlled clinical trial that showed that overweight and clinically obese people with type 2 diabetes mellitus who received an intensive lifestyle intervention had statistically significant better health-related quality of life compared with controls.

  • Obesity
  • Prevention & Screening
  • Diabetes Mellitus
  • Diabetes & Endocrinology Clinical Trials
  • Obesity
  • Prevention & Screening
  • Diabetes Mellitus
  • Diabetes & Endocrinology Clinical Trials
  • Endocrinology
  • Diabetes & Metabolic Syndrome

The multicenter Look AHEAD study [Action for Health in Diabetes; NCT0017953] is a randomized controlled clinical trial that showed that overweight and clinically obese people with type 2 diabetes mellitus who received an intensive lifestyle intervention (ILI) had statistically significant better health-related quality of life compared with controls. The findings of the present analysis were presented by Ping Zhang, PhD, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

The 5145 participants were randomly assigned to ILI (n = 2570) or diabetes support and education (DSE; n = 2575). The intervention included a calorie goal of 1200 to 1800 kcal/day, with < 30% from fat and > 15% from protein, with use of meal-replacement products, and with at least 175 minutes of moderate-intensity physical activity per week. DSE was a more traditional approach, involving support and education. The primary objective of the main trial was to compare the long-term effects on cardiovascular morbidity and mortality, while this analysis assessed the impact on quality of life as measured by health utility scores (HUSs). Effects were measured directly with a feeling thermometer (FT) and indirectly with the Health Utility Index 2 and 3 (HUI-2 and HUI-3) and the SF-6D. The FT is an established measurement based on an imaginary scale of 0 to 100, with 0 being the worst health imaginable and 100 the best with respect to the respondent's view of his or her health on that day. The SF-6D is a classification for describing health as derived from 11 items of the SF-36 questionnaire. These instruments allowed the assessment of a variety of physical, cognitive, emotional, and social well-being. The study enrolled participants from 2001 to 2004. The median follow-up was 9.67 years, and the intervention was stopped in September 2012. HUI-2, HUI-3, and SF-6D data were collected every 6 months for the first 4 years and annually thereafter, with FT data collected every 6 months throughout follow-up. Analyses of the HUSs were on an intention-to-treat basis and included differences in the mean scores overall and at the time of each data collection. Covariates included clinic site, baseline HUS, and year. Significance was indicated by p< .05.

The participants were well matched at baseline for sex, age, body mass index, duration of diabetes, prevalence of insulin use, A1C (glucose) level, and history of cardiovascular disease (CVD; p> .06 for each parameter). The completion rate for the assessments was good, ranging from ∼ 78% to 93% depending on the assessment tool (Table 1).

Table 1.

Average Completion Rates of Study Assessments, %

The HUI-2 and HUI-3 tools did not indicate a difference between the ILI and DSE arms, but a significant difference was found for ILI with the SF-6D and FT tools (Table 2). Significant differences favoring ILI were based on the mean SF-6D scores (overall difference, −0.010; 95% CI, −0.014 to −0.006; p< .001) and the mean FT scores (overall difference, −0.021; 95% CI, −0.026 to −0.016; p< .001).

Table 2.

Mean Differences in Mean Health Utility Score Over the Study Period Between DSE and ILI by Measurement Tool

Subgroup analyses according to age, body mass index, sex, race and ethnicity, and presence or absence of CVD at baseline revealed no significant differences in mean HUSs across subgroups between the ILI and DSE approaches based on any measurement tool. Comparison of data obtained at each time point during the follow-up revealed a higher HUS for the ILI group only at Months 12 and 18 for HUI-2 scores and Months 6 and 12 for HUI-3 scores. However, SF-6D scores were always higher for the ILI group and were nearly always significantly different (ie, not at 0 and 5 years; p< .05 for all). FT scores were always significantly higher for the ILI group (p< .05 for all). HUI-2, HUI-3, and SF-6D values for all study participants tended to diminish with time, while FT values plateaued in the latter two thirds of follow-up.

Limitations included missing data not included in the analysis, potential reporting biases, and preferential weighting of HUSs that may not have been representative of the US population. The researchers concluded that an ILI is effective in improving quality of life. This estimated improvement will be used to assess the cost-effectiveness of this strategy.

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