Reduced kidney function associated with higher mortality
Chronic kidney disease (CKD) is highly prevalent among older post-myocardial infarction (MI) patients, but it was not yet known whether CKD is an independent risk factor for mortality in older post-MI patients with optimal cardiovascular drug-treatment.
Therefore, we studied the relationship between kidney function and all-cause and specific mortality in the Alpha Omega Cohort, by estimating Glomerular Filtration Rate (eGFR) with cystatin C (cysC) and creatinine (cr) using the CKD-EPI equations. We further analysed the relation with any and major causes of death using Cox models and restricted cubic splines.
Participants were part of the Alpha Omega Cohort (read more about that here). Median follow-up was 6.4 years. During follow-up, 873 (19%) patients died: 370 (42%) from cardiovascular causes, 309 (35%) from cancer, and 194 (22%) from other causes.
Outcome measures: Kidney function as measured with Glomerular Filtration Rate (eGFR) with cystatin C (cysC) and creatinine (cr)
Patients were divided into four categories of baseline eGFRcysC: ≥90 (33%; reference), 60–89 (47%), 30–59 (18%), and <30 (2%) ml/min/1.73m.
After adjustment for age, sex and classic cardiovascular risk factor, hazard ratios (95%-confidence intervals) for any death according to the four eGFRcysC categories were: 1 (reference), 1.4 (1.1–1.7), 2.9 (2.3–3.6) and 4.4 (3.0–6.4). The hazard ratios of all-cause and cause-specific mortality increased linearly below kidney functions of 80 ml/min/1.73 m. Weaker results were obtained for eGFRcr.