The association of parathyroid hormone with ESRD and pre-ESRD mortality in the kidney early evaluation program

Context: Studies have suggested that PTH may influence mortality and progression of chronic kidney disease. However, the development of either event may influence the development of the other as a competing risk. Objective: The objective of the study was to examine the association of PTH with end-stage renal disease (ESRD) and pre-ESRD death using a competing risk survival model. Design, Setting, and Patients:Atotal of 10,823 participants in the Kidney Early Evaluation Program with chronic kidney disease (estimated glomerular filtration rate < 60 ml/min per 1.73m²) were examined from 2005 to 2010. Main Outcome Measures: The association of PTH levels with ESRD and pre-ESRD mortality was ascertained by linking Kidney Early Evaluation Program data to the Social Security Administration Death Master File and the U.S. Renal Data System.Results: Among the cohort, the incidence of ESRD and pre-ESRD mortality was 6.4 and 20.1 events per 1000 person-years. Higher PTH levels were associated with increasing age, black race, lack of a high school education, cardiovascular disease, hypertension,andlower glomerular filtration rate. The incidence of ESRD and pre-ESRD mortality was lowest among participants in the second PTH quintile. After multivariate adjustment, as compared with the second quintile, the risk of pre-ESRD mortality was higher in the third [subhazard ratio (SHR) 1.52 (95% confidence interval 1.04-2.22)], fourth [SHR 1.73 (95% confidence interval 1.19-2.52)], and fifth [SHR 1.86 (1.28 -2.52)] quintiles, respectively. Conversely, PTH was not associated with ESRD after multivariate adjustment. The association was not modified by diabetic status, gender, race, or glomerular filtration rate status. Conclusions: Elevated PTH levels are associated with increased pre-ESRD mortality but not with ESRD.