Parathyroidectomy rates among United States dialysis patients: 1990-1999

Background. Medical therapy for secondary hyperparathyroidism (SHPTH) has evolved considerably during the past decade. It is not known how changes in medical therapy might impact the parathyroidectomy (PTX) rate among dialysis patients. Relatively low parathyroid hormone (PTH) levels have been found among elderly dialysis patients and those with diabetes. Clinical factors associated with differing PTX rates among United States dialysis patients have not been reported. We report PTX rates in the United States from 1990 to 1999 among persons with end- stage renal disease, accounting for changes in patient characteristics. Methods. Data from the United States Renal Database were utilized. Patients insured by Medicare or Medicaid and receiving renal replacement therapy between January 1, 1990, and December 31, 1999 were considered for analysis. PTX was determined by ICD- 9 procedure codes. Multivariate Poisson models were used to estimate adjusted PTX rates. Results. The overall observed PTX rate in the study sample was 7.16 per 1000 person- years at risk. After a slight rise during the early 1990s, adjusted PTX rates declined by approximately 30% between 1995 and 1999. Adjusted PTX rates were higher among patients who were younger, female, nondiabetic, receiving peritoneal dialysis, and those with a longer cumulative duration of dialysis. Conclusion. PTX rates have recently decreased in the United States, independent of changes in patient characteristics. The effectiveness of medical therapy in targeting secondary hyperparathyroidism may be improving. Younger, nondiabetic patients with a longer cumulative dialysis burden are at particularly high risk for PTX.