Researchers create metric to predict mortality in patients on dialysis
Click Here to Manage Email Alerts
Researchers created a new metric among patients on dialysis according to the ratio between phosphorous and normalized protein catabolic rate that correlates with their survival.
Further, investigators noted that the metric enables improved phosphorus monitoring.
“Lowering serum phosphorus in people on hemodialysis may improve their survival. However, prior studies have shown that restricting dietary protein intake, a major source of phosphorus, is associated with higher mortality,” Dana Bielopolski, MD, PhD, from the Harold Simmons Center for Kidney Disease Research and Epidemiology in the division of nephrology and hypertension at the University of California, and colleagues wrote. They added, “Our objective was to combine the two, protein consumption and phosphorous levels, in one novel parsimonious metric and assess the relative contribution of each to mortality in people on maintenance hemodialysis (MHD).”
From a total of 1,737 facilities operated by a large dialysis organization in the U.S. between Jan. 1, 2007, and Dec. 31, 2011, researchers evaluated 63,016 patients on hemodialysis a year after initiation. All patients had reported data of phosphorous and normalized protein catabolic rate (nPCR) in the first 90 days of treatment. Follow-ups occurred in three 91-day intervals.
Researchers divided nPCR by nP to create the new variable R, which was designed to evaluate mortality among patients on dialysis.
Researchers used the Kaplan-Meier method and the log-rank test to measure the cumulative incidence of all-cause death as per the R groups. Using Cox proportional hazards models, researchers identified the relationship between R values and all-cause mortality. All survival models were adjusted for case-mix, malnutrition-inflammation cachexia syndrome and residual kidney function.
Based on R-values, researchers categorized patients into five groups in which group 1 consisted of sick patients with high phosphorus and low nPCR, and group 5 consisted of patients with low phosphorous and high nPCR.
Patients in group 1 were young, more likely to be women and initiated dialysis therapy with a catheter. They also had the highest prevalence of Black patients compared with the other groups. Those in group 5 were older, more likely to be white, used a permanent access and were less likely to be hypertensive.
A 1-year follow-up revealed an increase in R correlated with improved survival. Researchers observed the correlation of R with mortality was strengthened by adjustment in demographic variables and attenuated after adjustment to malnutrition-inflammation cachexia syndrome. Additionally, residual kidney function did not impact mortality associations in accordance with R.
“The relationship of nutritional status and mortality in people on MHD is multifaceted and involves multiple influencing factors. Scaling people on MHD according to R value might provide the clinician insight into nutritional status that will mandate intervention and direct the intensity,” Bielopolski and colleagues wrote. “People scoring low on the R value are being persistently attacked by two competing threats to their survival — they have low nutritional status as indicated by nPCR and a high phosphorous level. This combination is the result of not only low compliance to medical therapy and dietary counseling but also of a high inflammatory state.”
Collapse
Read more about
Click Here to Manage Email Alerts