Low serum creatinine levels are associated with an increased death risk among patients on peritoneal dialysis (PD), a study found.
In addition, a decline in serum creatinine level within the first three months of study entry was associated with increased death risk independent of baseline serum creatinine level.
The findings validate the prognostic value of serum creatinine level as a surrogate of muscle mass, concluded a research team led by Kamyar Kalantar-Zadeh, MD, PhD, of the University of California Irvine School of Medicine in Orange, Calif.
Dr. Kalantar-Zadeh and his colleagues studied a cohort of 10,896 PD patients. Compared with patients whose baseline serum creatinine level was 8.0-9.0 mg/dL (reference), those with baseline levels below 4.0 and 4.0-5.9 had a 36% and 19% increased risk of all-cause mortality, respectively, in a fully adjusted model, according to findings published online ahead of print in Nephrology Dialysis Transplantation. In contrast, patients with baseline serum creatinine levels of 14.0 or higher, 12.0-13.9, and 10.0-11.9 had a 36%, 29%, and 12% decreased risk of all-cause mortality, respectively.
The study revealed no association between baseline serum creatinine level and mortality in patients with a PD duration less than three months. Among patients who had been on PD for at least three months but less than 12 months, baseline serum creatinine levels of 12.0-13.9 and 14.0 or higher were associated with 40% and 46% decreased risk of all-cause mortality, respectively, compared with patients with baseline serum creatinine levels of 8.0-9.9. Among patients on PD for 12 months or more, patients with baseline serum creatinine levels of 4.0-5.9 had a 29% increased risk of all-cause mortality and those with levels of 14.0 or higher, 12.0-13.9, and 10.0-11.9, had a 40%, 29%, and 17% decreased risk, respectively.
During the first three months after study entry, serum creatinine levels were stable (the change was -1.0 to 1.0) in 5,835 patients (65%), increased by more than 1.0 in 2,138 patients (24%), and decreased by more than 1.0 in 1,008 patients (11%). Compared with patients who had stable levels, patients who levels fell by more than 1.0 had a 16% increased risk of all-cause mortality. An increase in serum creatinine level of more than 1.0 was not associated with a survival benefit.
Dr. Kalantar-Zadeh’s team noted that residual glomerular filtration rate typically declines with increasing dialysis duration, so reductions in serum creatinine level “more likely reflects loss of muscle mass or poor protein intake, which are consequently associated with increased mortality.”