Koopman, Jacob J. E.; Kramer, Anneke; van Heemst, Diana; Asberg, Anders; Beuscart, Jean-Baptiste; Buturovic-Ponikvar, Jadranka; Collart, Frederic; Couchoud, Cecile G.; Finne, Patrik; Heaf, James G.; Massy, Ziad A.; De Meester, Johan M. J.; Palsson, Runolfur; Steenkamp, Retha; Traynor, Jamie P.; Jager, Kitty J.; Putter, Hein
(2016)
Purpose: Although a population's senescence rate is classically measured as the increase in mortality rate with age on a logarithmic scale, it may be more accurately measured as the increase on a linear scale. Patients on dialysis, who suffer from accelerated senescence, exhibit a smaller increase in their mortality rate on a logarithmic scale, but a larger increase on a linear scale than patients with a functioning kidney transplant. However, this comparison may be biased by population heterogeneity. Methods: Follow-up data on 323,308 patients on dialysis and 91,679 patients with a functioning kidney transplant were derived from the ERA-EDTA Registry. We measured the increases in their mortality rates using Gompertz frailty models that allow individual variation in this increase. Results: According to these models, the senescence rate measured as the increase in mortality rate on a logarithmic scale was smaller in patients on dialysis, while the senescence rate measured as the increase on a linear scale was larger in patients on dialysis than patients with a functioning kidney transplant. Conclusions: Also when accounting for population heterogeneity, a population's senescence rate is more accurately measured as the increase in mortality rate on a linear scale than a logarithmic scale. (C) 2016 Elsevier Inc. All rights reserved.