Association between higher variability in kidney function and long-term mortality

Aim We evaluated whether estimated glomerular filtration rate variability in the general population could be associated with all-cause mortality. Methods Health examination data from 7842 individuals aged >20 years who visited for health check-ups at least thrice at >= 6-month intervals between May 1, 1995 and November 30, 2010 were collected. Estimated glomerular filtration rate variability was defined as the coefficient of variation of the estimated glomerular filtration rate, that is, standard deviation/mean value multiplied by 100. The study population was divided into three groups based on the coefficient of variation tertiles, and the mortality risks were compared across groups. Results The mean duration from the final visit to the outcome was 10.3 +/- 2.9 years. The mean coefficient of variations of estimated glomerular filtration rate variability from the lowest to the highest variability group were 5.1 +/- 1.8%, 9.0 +/- 1.0%, and 14.4 +/- 3.9%, respectively. There was a 1.3 times higher risk of mortality in the group with the highest variability (hazard ratio: 1.300, 95% confidence interval: 1.013-1.669) after adjustment. The findings were similar in patients with diabetes and those >60 years old (hazard ratio: 1.635, 95% confidence interval: 1.076-2.483; hazard ratio: 1.585, 95% confidence interval: 1.107-2.269). Conclusion Higher estimated glomerular filtration rate variability was associated with increased 10-year mortality in the general population. This variability was very small, but considering the patients' long-term prognoses, it was significant.