Clinical outcomes after parathyroidectomy in a nationwide cohort of patients on hemodialysis

Abstract

Background and objectives: Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis.

Design, setting, participants, & measurements: Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods.

Results: Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1).

Conclusions: Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.

Keywords: hemodialysis; hyperparathyroidism; mortality.

Figure 1.

Patient flow chart.

Figure 2.

Event rates in the 1 year before and 1 year after parathyroidectomy. (A) Total hospitalizations. (B) Total hospitalizations with hypocalcemia. (C) Total emergency department or observation visits. (D) Total emergency department or observation visits with hypocalcemia. RR and 95% CI values are based on the ratio of postparathyroidectomy to prior parathyroidectomy. 95% CI, 95% confidence interval; ED, emergency department; PTx, parathyroidectomy; RR, rate ratio.

Figure 3.

Outcomes by select patient characteristics. Data points in gray represent subgroups in which a significant interaction (P<0.05) exists between the subgroup and parathyroidectomy. Data points in black have a nonsignificant P for interaction (P>0.05). ASHD, atherosclerotic heart disease; BMI, body mass index; CHF, congestive heart failure; CVA/TIA, cerebrovascular accident/transient ischemic attack; ICU, intensive care unit; PVD, peripheral vascular disease.