Consistent with the goal of improving metabolic control and preventing complications of Type II diabetes is the need for patients to attain and maintain normal body weight. Eighty to ninety percent of persons with Type II diabetes are obese and promoting weight loss in these individuals is one of the most important, yet difficult goals to accomplish. Weight reduction has been shown to enhance insulin sensitivity and improve glucose control.The purpose of this study is to: 1) examine strategies - behavior therapies, exercise, diet, and/or a combination of strategies - used for promoting and maintaining weight loss in persons with Type II diabetes and 2) determine which variables - age, degree of obesity, gender, ethnicity, socioeconomic status, compliance, research design, quality, date of publication - might affect the degree of weight loss. Also, interventions for fostering long-term weight loss/prevention of weight regain and potential interactional effects of biological and behavioral factors on weight loss will be explored. Results of previous research have been inconclusive; therefore, meta-analysis will be used to synthesize studies of weight loss in Type II diabetes in an effort to resolve conflicts in the data. A rigorous literature search will be conducted to locate published and unpublished studies on weight loss interventions in Type II diabetes. Information will be extracted from primary studies and entered onto code sheets which have been developed and tested in previous meta- analyses conducted by the investigator. Research quality and validity and reliability of instruments will be assessed. Effect sizes for each weight loss strategy will be calculated for each study and adjusted for sample size, precision estimation, direction of effect, and pretest differences. Homogeneity analyses will be conducted on groups of effect sizes categorized under weight loss strategies in order to determine homogeneity and also to compute weighted mean effect sizes for each homogeneous group. Hedges and Olkin's analogue to the analysis of variance for effect sizes will be calculated to determine if there are differences between intervention types. A weighted least squares analysis will be performed to test the impact of weight loss strategies and subject/study variables on weight loss outcomes, including long-term weight loss maintenance. Expected outcomes of this study are:1) a clearer description of effective weight loss strategies in diabetes; 2) information on subject/study characteristics which influence effectiveness in promoting and maintaining ideal body weight in obese persons with diabetes; and 3) a new reliable and valid instrument to measure research quality.
| Brown, S A; Upchurch, S; Anding, R et al. (1996) Promoting weight loss in type II diabetes. Diabetes Care 19:613-24 |
