Familial risks of kidney failure in Sweden: a nationwide family study.

Background: The value of family history as a risk factor for kidney failure has not been determined in a nationwide setting.
Aim: This nationwide family study aimed to determine familial risks for kidney failure in Sweden.
Methods: The Swedish multi-generation register on 0-78-year-old subjects were linked to the Swedish patient register and the Cause of death register for 1987-2010. Individuals diagnosed with acute kidney failure (n = 10063), chronic kidney failure (n = 18668), or unspecified kidney failure (n = 3731) were included. Kidney failure patients with cystic kidney disease, congenital kidney and urinary tract malformations, urolithiasis, and rare inherited kidney syndromes, and hyperoxaluria were excluded. Standardized incidence ratios (SIRs) were calculated for individuals whose parents/siblings were diagnosed with kidney failure compared to those whose parents or siblings were not.
Results: The concordant (same disease) familial risks (sibling/parent history) were increased for chronic kidney failure SIR = 2.02 (95% confidence interval, CI 1.90-2.14) but not for acute kidney failure SIR = 1.08 (95% CI 0.94-1.22) and for unspecified kidney failure SIR = 1.25 (95% CI 0.94-1.63). However, the discordant (different disease) familial risk for acute kidney failure SIR = 1.19 (95% CI 1.06-1.32) and unspecified kidney failure SIR = 1.63 (95% CI 1.40-1.90) was significantly increased in individuals with a family history of chronic kidney failure. The familial risk for chronic kidney failure was similar for males SIR = 2.04 (95% CI 1.90-2.20) and females SIR = 1.97 (95% CI 1.78-2.17). Familial risks for chronic kidney failure were highest at age of 10-19 years SIR = 6.33 (95% CI 4.16-9.22).
Conclusions: The present study shows that family history is an important risk factor for chronic kidney failure but to a lower degree for acute kidney failure and unspecified kidney failure.