Egede LE (Charleston VA TREP), Mauldin PD
(Charleston VA TREP), Mueller M
(Charleston VA TREP), Chen GJ
(Charleston VA TREP), Durkalski VL
(Charleston VA TREP), Moran PW
(Charleston VA TREP)
To assess the effect of medication non-adherence on survival of veterans with type 2 diabetes.
In this retrospective study, fiscal year 2004 data were analyzed on 4,695 veterans from the Ralph H. Johnson VA Medical Center in Charleston SC with type 2 diabetes. Veterans were identified through administrative data using established algorithms. Medication non-adherence was calculated as the summation (in days) of excessive refill gaps (15 days or more) over multiple intervals within the year. The sample was limited to only non-Hispanic (NH) Whites and NH Blacks. A Cox proportional-hazards model was used to examine the effect of medication non-adherence on survival controlling for age, gender, and race. SAS was used for statistical analysis.
Out of the 4,695 type 2 diabetic veterans in our sample, 2,812 (60%) were considered non-adherent. Mean age was 60.7 years for non-adherent veterans, compared to 59.8 years for adherent veterans (p=0.011). 97% were men in both groups, and approximately 63% overall were NH Whites. There was no significant difference in race between the two groups. 67.6% of the adherent veterans were married and 25.5% separated or divorced, compared to 65.0% of non-adherent veterans being married, and 29.0% separated or divorced (p=0.023). Roughly 22% of the veterans in each group were active duty or employed. The unadjusted Cox proportional-hazards model revealed that non-adherent type 2 diabetic veterans were 7.94 (95% CI: 3.4, 18.2) times more likely to die within the year than adherent veterans. When adjusting for baseline age, gender and race, the model revealed that non-adherent type 2 diabetic veterans were 7.46 (95% CI: 3.3, 17.2) times more likely to die than adherent veterans.
Type 2 diabetic veterans who are non-adherent with their medications are nearly 8 times more likely to die within the year than those veterans who are adherent with their medications.
Multilevel interventions to enhance medication adherence in veterans with type 2 diabetes are urgently needed. Interventions that address patient, provider, and systems level barriers to optimal medication adherence are likely to be most effective.