Cause of Death in Patients with Reduced Kidney Function

Information on common causes of death in people with CKD is limited. We hypothesized that, as eGFR declines, cardiovascular mortality and mortality from infection account for increasing proportions of deaths. We calculated eGFR using the CKD Epidemiology Collaboration equation for residents of Alberta, Canada who died between 2002 and 2009. We used multinomial logistic regression to estimate unadjusted and age- and sex-adjusted differences in the proportions of deaths from each cause according to the severity of CKD. Cause of death was classified as cardiovascular, infection, cancer, other, or not reported using International Classification of Diseases codes. Among 81,064 deaths, the most common cause was cancer (31.9%) followed by cardiovascular disease (30.2%). The most common cause of death for those with eGFR≥60 ml/min per 1.73 m(2) and no proteinuria was cancer (38.1%); the most common cause of death for those with eGFR<60 ml/min per 1.73 m(2) was cardiovascular disease. The unadjusted proportion of patients who died from cardiovascular disease increased as eGFR decreased (20.7%, 36.8%, 41.2%, and 43.7% of patients with eGFR≥60 [with proteinuria], 45-59.9, 30-44.9, and 15-29.9 ml/min per 1.73 m(2), respectively). The proportions of deaths from heart failure and valvular disease specifically increased with declining eGFR along with the proportions of deaths from infectious and other causes, whereas the proportion of deaths from cancer decreased. In conclusion, we found an inverse association between eGFR and specific causes of death, including specific types of cardiovascular disease, infection, and other causes, in this cohort.