Longitudinal differences in glycemic control by race/ethnicity among veterans with type 2 diabetes.

OBJECTIVE: To examine longitudinal differences in glycemic control between non-Hispanic white and non-Hispanic black veterans with type 2 diabetes. DESIGN: Retrospective cohort study. SETTING: VA facility in the Southeastern United States. PARTICIPANTS: A 3-month person-period dataset was created for 8813 veterans with type 2 diabetes between June 1997 and May 2006. MAIN OUTCOME MEASURES: Primary outcome was mean change in hemoglobin A1c (HbA1c) over time. Secondary outcome was the odds of poor glycemic control over time (HbA1c >8%). For the primary outcome, a linear mixed model (LMM) approach was used to model the relationship of HbA1c levels and race/ethnicity over time. For the secondary outcome, generalized LMMs were used to assess whether glycemic control changed over time and whether change in glycemic control varied by racial/ethnic group. RESULTS: Mean age was 66.3 years, 36% were non-Hispanic black (NHB), 98% were male, 65% were married, and 50% were unemployed. Mean follow-up time was 4.4 years. Least square mean HbA1c levels from LMM adjusted for time and relevant confounders showed that NHBs had higher HbA1c values over time (mean difference of 0.54% [P < 0.001]). The final model with poor versus good glycemic control as the dependent variable, race/ethnicity as primary independent variable adjusted for time, and relevant confounders showed that NHBs were likely to have poor control compared with NHWs (OR: 1.8, 95% CI, 1.7; 2.0, P < 0.0001). CONCLUSIONS: NHB veterans were more likely to have higher mean HbA1c values and less likely to have good glycemic control over time compared with NHW veterans.

Longitudinal effects of depression on glycemic control in veterans with Type 2 diabetes.

OBJECTIVES: To examine the longitudinal effects of depression on glycemic control in veterans with Type 2 diabetes. METHODS: Data on 11,525 veterans with Type 2 diabetes were analyzed. A person-period dataset for each subject to cover 3-month intervals (36 time intervals) from April 1997 to March 2006 was created. Subjects were classified as depressed based on ICD-9 codes for depression. General linear mixed model regression was used to examine changes over time in HbA(1c) levels and whether the changes from baseline were different in depressed and nondepressed diabetic veterans, sequentially adjusting for baseline age, demographic variables and comorbidities (coronary heart disease, stroke and hypertension). Pooled t-tests were used to compare unadjusted mean HbA(1c) at each time point across the depressed and nondepressed groups. SAS was used for statistical analysis. RESULTS: Ninety-seven percent were men, 48% were white, 27% were blacks and 25% were other. Mean age was 66 years and mean follow-up period was 4.1 years. Six percent (696/11,525) of the sample had diagnosed depression. Unadjusted mean HbA(1c) values were significantly higher in depressed vs. nondepressed subjects at all time points. The adjusted mean HbA(1c) values over time in the final mixed model were significantly higher in depressed vs. nondepressed subjects (mean difference of 0.13; 95% CI [0.03; 0.22]; P=.008). In all adjusted models, differences in mean HbA(1c) values were significantly higher in depressed vs. nondepressed subjects with Type 2 diabetes. CONCLUSION: This study of veterans with Type 2 diabetes demonstrates that there is a significant longitudinal relationship between depression and glycemic control as measured by HbA(1c) and that depression is associated with persistently higher HbA(1c) levels over time.