PTH may predict early mortality in incident patients on hemodialysis: results from a large cohort.

Abstract

Parathyroid hormone (PTH) is merit as a risk factor for mortality in patients with chronic kidney disease in prevalent hemodialysis patients in a U shape. Most studies, however, do not focus on incident patients and those who died within the first 90days of therapy. We evaluated PTH as a risk factor for mortality in a large cohort population in Brazil. This is an observational cohort study that included 4317 adult patients who initiated hemodialysis between July 1st, 2012 and June 30, 2017. The main outcome was all-cause mortality. Fine-gray sub-distribution hazard models were used to evaluate survival in the presence of a competing event (kidney transplant). Median PTH levels of 252 (118, 479) pg/mL. There were 331 deaths during the first 90days of therapy (6.7%), 430 in a 1-year follow-up (10.7%) and 1282 (32%) during the 5-year study period. Deaths according to PTH < 150, 150-600 and > 600pg/mL corresponded to 38.1%, 33.0% and 28.5%, respectively (p < 0.001). In an adjusted model, patients who started dialysis with PTH < 150pg/mL had a higher mortality risk within the first 90days, but not in 1year and 5years after starting dialysis. Analyses in a subset of patients with a repeated PTH in 1year (N = 1954) showed that although persistent PTH low levels (< 150pg/mL) at 1year were significantly associated with all-cause mortality, this result was not sustained after multiple adjustments. PTH < 150pg/mL confers a high mortality risk in the first 90days of dialysis. If this result reflects poor nutritional conditions, it deserves further investigations.