The fall and rise of parathyroidectomy in U.S. hemodialysis patients, 1992 to 2002

Abstract

Although the therapeutic approach to managing hyperparathyroidism has changed dramatically, it is unknown whether parathyroidectomy rates continue to decline in the United States. Parathyroidectomy rates were studied in successive annual national cohorts, prevalent on hemodialysis on January 1 of 1992 to 2002, with Medicare as primary payer. Parathyroidectomy was defined as International Classification of Diseases, Ninth Revision, Clinical Modification code 068. The annual incidence of parathyroidectomy was 11.6 per 1000 patient-years in 1992. The incidence declined progressively after 1994, reaching a low of 6.8 per 1000 patient-years in 1998. Rates increased progressively after 1998, reaching 11.8 per 1000 patient-years in 2002. Using proportional hazards modeling, with adjustment for comorbidity and 1992 as the reference group, the lowest adjusted hazards ratio, 0.32 (P < 0.0001), was seen in 1998, followed by hazards ratios of 0.39 (P < 0.0001) in 1999, 0.41 (P < 0.0001) in 2000, 0.52 (P < 0.0001) in 2001, and 0.53 (P < 0.0001) in 2002. Other antecedents of parathyroidectomy in multivariate models included ESRD network, younger age, female gender, white race, absence of diabetes, longer duration of previous hemodialysis, use of intravenous vitamin D, previous renal transplantation, several comorbid conditions, and parathyroid hormone measurement in the preceding year. With a case-control method, parathyroidectomy was associated with higher mortality rates immediately after surgery, followed, subsequently, by lower long-term rates. Parathyroidectomy rates in U.S. hemodialysis patients increased between 1998 and 2002, a period in which the therapeutic armamentarium for preventing severe hyperparathyroidism expanded considerably.