Enhancing Adherence in Type 2 Diabetes: The ENHANCE Study

This randomized study, the ENHANCE Study (Enhancing Adherence to Diabetes Self-Management) will test a behavioral intervention, based on social cognitive theory (SCT), to improve regimen adherence in three different groups of people with type 2 diabetes; (1) HbA1c < 8% and no concurrent chronic renal insufficiency, (2) HbA1c>8% and no chronic renal insufficiency, and (3) those with evidence of chronic renal insufficiency regardless of glucose control.

The primary aims of this study are to:

• . Determine whether the intervention improves behavioral adherence to the diabetes self-management regimen including: 1.a. dietary adherence, as measured by self-report using dietary recalls and the Nutrient Data System, 1.b. physical activity as measured by the CHAMPS Physical Activity Questionnaire as well as pedometer readings, and 1.c. adherence to capillary glucose self-monitoring as assessed by the FreeStyle monitor.
• . Determine whether the intervention improves clinical outcome measures including: 2.a. glycosylated hemoglobin levels (HbA1c), 2.b. weight loss, 2.c. anthropometrics.
• . Explore the extent to which self-efficacy is a mediator of adherence.
• . Explore the extent to which the effectiveness of the intervention varies with respect to glycemic control and nephrovascular complications at baseline.
• . Explore the impact of a variety of covariates (medications, depression, social support, severity of disease, and general health and sociodemographic characteristics, clinic from which they were recruited, health literacy, and trust in research) on the effectiveness of the intervention.

Hypothesis #1 is that intervention group participants will perform better than attention control group participants on various measures of adherence to the diabetes management regimen. Primary behavioral adherence variables will be dietary intake, and physical activity. Hypothesis #2 is that intervention group participants will have lower HbA1c levels than attention control group participants.

The 6-month intervention includes group classes, held weekly during months 1&2, biweekly during months 3&4, and monthly during month 5&6. Classes focus on building a sense of mastery over the diabetes regimen and features the use of PDA-base dietary self-monitoring. Intervention group participants are compared to an attention care group, that receives monthly contacts. Measurements are made at baseline, 3, and 6 months.

Inclusion criteria

Study subjects will include those with: type 2 diabetes mellitus defined according to the 1997 ADA criteria and age of 18 years or greater. We will sample from three different patient populations: (1) 96 individuals who have HbA1c < 8%, and no evidence of chronic renal insufficiency (a serum creatinine <1.3mg/dl for women and <1.5mg/dl for men). (2) 96 individuals with HbA1c > 8%, and no evidence of chronic renal insufficiency, and (3) 96 individuals with evidence of chronic renal insufficiency (a serum creatinine >1.3mg/dl for women and >1.5mg/dl for men, but who have not yet progressed to dialysis), regardless of HbA1c level.

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Exclusion criteria

Exclusion criteria were selected to enhance safety and ability to complete the study protocol. They include: (1) history of hypoglycemic coma/seizure within the last 12 months, (2) hypoglycemia requiring 3rd party assistance within the last 3 months, (3) history consistent with type 1 diabetes, (4) unwillingness to do capillary blood testing using the FreeStyle monitor, (5) unwillingness or inability to participate in scheduled group classes or individual counseling sessions, (7) subjects currently on renal dialysis, (8) any factors likely to preclude adherence to the study protocol including dementia, alcohol or substance abuse, plan to move within the next 8 months, lack of support from the subject's primary health care provider (i.e. PCP is aware of significant risks such as extreme variation in blood glucoses and/or comorbidities that would make participation in the study unsafe), failure to obtain informed consent from the participant, current participation in another clinical trial, and (9) subjects who are not available by telephone during the hours of 8am to 6pm.

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