Background
Medication non-adherence is a known risk factor for adverse outcomes in the general population. However, little is known about the association of pre-dialysis medication adherence among patients with advanced chronic kidney disease with mortality following their transition to dialysis.
Study Design
Observational study.
Setting & Participants
32,348 US veterans who transitioned to dialysis during 2007–2011.
Predictors
Adherence to treatment with cardiovascular drugs, ascertained from pharmacy database records using proportion of days covered (PDC) and persistence during the pre-dialysis year.
Outcomes
Post-dialysis initiation all-cause and cardiovascular mortality, using Cox models with adjustment for confounders.
Results
The mean age of the cohort was 72±11 (SD) years, among whom 96% were male, 74% were white, 23% were African American, and 69% were diabetic. During median follow-up of 23 (IQR, 9–36) months, 18,608 patients died. Among patients with PDC >80%, there were 14,006 deaths (mortality rate, 283 [95% CI, 278–288]/1000 patient-years [PY]); among patients with PDC >60%–80%, there were 3,882 deaths (mortality rate, 294 [95% CI, 285–304]/1000 PY); among patients with PDC ≤60%, there were 720 deaths (mortality rate, 291 [95% CI, 271–313]/1000 PY). Compared to patients with PDC >80%, adjusted HR for post-dialysis initiation all-cause mortality for patients with PDC >60%–80% was 1.12 (95% CI, 1.08–1.16) and for patients with PDC ≤60% was 1.21 (95% CI, 1.11–1.30). In addition, compared to patients showing medication persistence, adjusted HR risk for post-dialysis initiation all-cause mortality for patients with non-persistence was 1.11 (95% CI, 1.05–1.16). A similar trend was detected for cardiovascular mortality and in subgroup analyses.
Limitations
Large number of missing values; the results may not be generalizable to women or the general US population.
Conclusions
Pre-dialysis cardiovascular medication non-adherence is an independent risk factor for post-dialysis mortality among advanced chronic kidney disease patients transitioning to dialysis. Further studies are needed to assess whether interventions targeting adherence improve survival after dialysis initiation.