Data on the effect of trajectories in long-term glycemia and all-cause mortality are lacking. The authors studied the effect of trajectories in long-term glycemic control on all-cause mortality in patients with type 2 diabetes. A cohort of 8,812 veterans with type 2 diabetes was assembled retrospectively using Veterans Affairs registry data. For each veteran in the cohort, a 3-month person-period data set was created from April 1997 to May 2006. The average duration of follow-up was 4.5 years. The overall mortality rate was 15.3%. Using a novel approach for joint modeling of time to death and longitudinal measurements of hemoglobin A1c (HbA1c) level, after adjustment for all significant baseline covariates, baseline HbA1c was found to be significantly associated with mortality (hazard ratio = 2.1, 95% confidence interval: 1.3, 3.6) (i.e., a 1% increase in baseline HbA1c level was associated with an average 2-fold increase in mortality risk). Similarly, the slope of the HbA1c trajectory was marginally significantly associated with mortality (hazard ratio = 7.3, 95% confidence interval: 0.9, 57.1) after adjustment for baseline covariates (i.e., a 1% increase in HbA1c level over 3 months was associated with a 22% increase in mortality risk). The authors conclude that a positive trajectory of long-term hyperglycemia is associated with increased mortality.
4 Figures and Tables
Table 1. Characteristics of Veterans With Type 2 Diabetes (n ¼ 8,812) by Vital Status as of May 31, 2006, Charleston, South Carolina, April 1997–May 2006
Figure 1. Kaplan-Meier survival curves for veterans with type 2 diabetes (n ¼ 8,812) by baseline hemoglobin A1c (HbA1c) concentration, Charleston, South Carolina, April 1997–May 2006.
Table 2. Hazard Ratios From 3 Different Cox Models for the Association Between Mortality and Mean, Baseline, and Last Observed Hemoglobin A1c Value Among Veterans With Type 2 Diabetes (n ¼ 8,812), Charleston, South Carolina, April 1997–May 2006
Table 3. Hazard Ratios From a Fully Adjusted Cox Model for Mortality Among Veterans With Type 2 Diabetes (n ¼ 8,812), Charleston, South Carolina, April 1997–May 2006
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