Nurse-led Case Management for Diabetes and Cardiovascular Disease Patients With Depression

This study will evaluate the effectiveness of a nurse-led case management intervention in improving disease control and depression symptoms in adults with diabetes and/or heart disease who are also depressed.

Depression is a serious medical illness that has been associated with increased risk for heart disease and diabetes. Depression may negatively impact aspects of self-care that are required to effectively manage such long-term diseases. In depressed people who have heart disease and/or diabetes, treatment for depression appears to result in only limited improvements in depression symptoms and no improvements in heart disease and diabetes symptoms. An integrated treatment approach may be more effective in improving all three conditions. This study will evaluate the effectiveness of a nurse-led case management intervention in improving disease control and depression symptoms in adults with diabetes and/or heart disease who are also depressed. Participants in this single-blind study will be randomly assigned to take part in the case management intervention or receive usual care. All participants will attend 5 in-person study evaluation visits and receive 4 follow-up phone calls over 24 months. At each of the study visits, measurements of height, weight, waist size, and blood pressure will be taken. At study evaluations, blood and urine samples will also be taken. Participants will be asked not to eat for 8 hours before providing blood samples at 3 of the visits. During follow-up phone calls participants will answer various questions. The case management intervention will entail approximately 10 visits with a trained nurse at the clinic or by telephone. Participants in this group will receive educational materials about how to manage diabetes and/or heart disease and stress or depression. Nurses will also provide guidance and support in managing medications, phone calls to check participants' progress, and assistance in setting personal goals and in managing physical health problems and symptoms of depression or stress. Outcomes will be measured at Months 6, 12, 18, and 24 months.

The case management intervention will entail approximately 10 visits with a trained nurse at the clinic or by telephone. Participants in this group will receive educational materials about how to manage diabetes and/or heart disease and stress or depression. Nurses will also provide guidance and support in managing medications, phone calls to check participants' progress, and assistance in setting personal goals and in managing physical health problems and symptoms of depression or stress.

Participants will attend 10 study visits and receive 4 follow-up phone calls over 24 months. During this time, participants will receive usual care.

A scaled marginal model approach was used to jointly describe the four 12 month outcomes (SCL-20, HbA1c, systolic BP, LDL: all data submitted as Outcome Measures #2-5 below) and allowed use to test for a primary effect of the intervention among outcomes, scaling each outcome by its standard error, so the intervention effects could be interpreted as effect sizes.The model was estimated by iterating between estimation of the covariance associated with the outcomes and generalized-estimating equation estimation of scaled outcomes. Effect size is estimated as Cohen d effect size that was use for the depression outcome is the difference in change from baseline to 12 months in the intervention and usual care groups divided by the pooled base line standard deviation. Thus, a d of 0.25 indicates that one-quarter of a standard deviation separates the two means. Cohen has suggested that an effect size of 0.20 would be considered small, 0.50 medium and 0.80 large.

SCL-20 is a 20 question checklist in which items are averaged to yield a potential score of 0 to 4 with higher scores indicating more severe depression symptoms. For the Primary Outcome (Outcome Measure #1 above), a scaled marginal model approach was used to jointly describe the four 12 month outcomes (SCL-20, HbA1c, systolic BP, LDL) and allowed use to test for a primary effect of the intervention among outcomes, scaling each outcome by its standard error, so the intervention effects could be interpreted as effect sizes.

Systolic Blood Pressure was measured at Baseline, 6 months and 12 months For the Primary Outcome (Outcome Measure #1 above), a scaled marginal model approach was used to jointly describe the four 12 month outcomes (SCL-20, HbA1c, systolic BP, LDL) and allowed use to test for a primary effect of the intervention among outcomes, scaling each outcome by its standard error, so the intervention effects could be interpreted as effect sizes.

LDL Cholesterol was measured at Baseline and 12 months For the Primary Outcome (Outcome Measure #1 above), a scaled marginal model approach was used to jointly describe the four 12 month outcomes (SCL-20, HbA1c, systolic BP, LDL) and allowed use to test for a primary effect of the intervention among outcomes, scaling each outcome by its standard error, so the intervention effects could be interpreted as effect sizes.

Glycated hemoglobin (HbA1c) was measured at Baseline, 6 months and 12 months For the Primary Outcome (Outcome Measure #1 above), a scaled marginal model approach was used to jointly describe the four 12 month outcomes (SCL-20, HbA1c, systolic BP, LDL) and allowed use to test for a primary effect of the intervention among outcomes, scaling each outcome by its standard error, so the intervention effects could be interpreted as effect sizes.

Disability was measured by the Sheehan Disability scale which measures the extent to which health interferes with social, vocational and familial functioning each on a 0 to 10 Likert scale where 0 is "not at all" and 10 is "extremely". This scale consists of 3 items which are averaged together to create the average disability score, which ranges from 0 to 10.

Mean total outpatient costs for 2 years post baseline adjusted for age, gender and previous 12 months of outpatient costs

Inclusion Criteria: Diagnosis of diabetes and/or heart disease Poor disease control (defined as an HbA1c level of at least 8.5%, blood pressure greater than 140/90 mm Hg, LDL cholesterol greater than 130 mg/dL) Diagnosis of major depressive disorder Exclusion Criteria: History of psychosis At high risk for suicide Cognitive impairment Current alcohol or substance abuse disorder Does not own a telephone Currently seeking psychiatric care Pregnant or breastfeeding Currently enrolled in a Group Health Cooperative disease management program Terminal illness Plans to leave Group Health Cooperative in less than a year Does not speak English

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