Medication Exposure and Health Outcomes in Older Patients with End-Stage Kidney Disease: A Prospective Study Undertaken in New Zealand.

BACKGROUND

The impact of multiple medication exposure on health outcomes among older patients with end-stage kidney disease (ESKD) is unknown.

OBJECTIVE

The objective of this study was to identify the impact of medicine exposure on hospitalisation rates and mortality in a prospective longitudinal observational study of older dialysis patients.

METHODS

Patient demographics, medication use, hospitalisation, mortality and co-morbidity data were collected through the prospective longitudinal cohort study DOS65 + (Dialysis Outcomes in those aged ≥ 65 years Study) (n = 225). Medication exposure was measured by the total number of individual medications and the number of predetermined 'medication groups'. Associations between medications prescribed at recruitment and health outcomes as measured by hospitalisation and mortality were assessed by univariate and multivariable regression analyses.

RESULTS

Older ESKD patients were exposed to a median of ten (0-20) medications and eight (0-15) medication groups. Multivariate analyses estimate each additional medication increased mortality risk by 8% (relative risk [RR] = 1.08; 95% confidence interval [CI] 1.07-1.09); each medication group increased mortality risk by 11% (RR = 1.11; 95% CI 1.09-1.12). Similar trends were observed for hospitalisation. Certain medication groups were associated with reduced hospitalisation rates, namely angiotensin converting enzyme (ACE) inhibitors/angiotensin receptor blockers (RR = 0.62; 95% CI 0.53-0.72) and dihydropyridines (RR = 0.64; 95% CI 0.54-0.76). Warfarin, gastric acid suppressants, diuretics and β-blockers were associated with increased hospitalisation rates. Warfarin was associated with an increased mortality rate (RR = 1.40; 95% CI 1.19-1.65).

CONCLUSIONS

Multiple medication exposure was prevalent in this older ESKD population, and was associated with an increased risk of mortality and hospitalisation. While this study is not able to determine the cause of these relationships, review of medication use is warranted in this population.

TRIAL REGISTRATION: ACTRN12611000024943.