A population-based assessment of the familial component of chronic kidney disease mortality.

While the familial nature of chronic kidney disease (CKD) has been recognized, it has primarily been defined from studies of first-degree relatives of selected sets of cases. The goal of this study is an evaluation of the familial clustering of end-stage renal disease (ESRD) and CKD mortality using a population-based genealogy of Utah. This is the first population-based analysis of the familial component of ESRD and non-ESRD CKD. We have defined two distinct patient groups for this analysis, using individuals with death certificates in the Utah Population Database indicating ESRD (n = 192) and non-ESRD CKD (n = 335) as the cause of death. Two measures of familiality were used: (1) relative risk (RR) of CKD or ESRD death in relatives of cases and (2) an average relatedness statistic, i.e., the Genealogical Index of Familiality. The RR for dying with ESRD among the first-degree relatives of individuals dying with ESRD is estimated to be 10.1 (p = 0.0007, 95% confidence interval CI 2.76-25.95), but is not significantly elevated among second-degree relatives. The RR for dying with non-ESRD CKD among first- and second-degree relatives of individuals dying with non-ESRD CKD was 3.89 (p = 0.0051, 95% CI 1.43-8.46) and 3.11 (p = 0.04, 95% CI 0.85-7.95), respectively. The Genealogical Index of Familiality statistic demonstrated that the individuals dying with ESRD are significantly more related than expected in this population (p = 0.013); significant excess relatedness was also observed for individuals dying with non-ESRD CKD (p = 0.006), suggesting a familial component for both, with evidence for common environmental and genetic effects. The results of this analysis of individuals dying with ESRD and non-ESRD CKD supports a significant and independent familial component to both conditions, suggesting a heritable factor playing a role. Copyright 2006 S. Karger AG, Basel