Survival in primary hyperparathyroidism over five decades (1965-2010) a population-based retrospective study

Context: Survival in patients with primary hyperparathyroidism (PHPT) remains uncertain. Objective: To update survival in patients with PHPT in a United States community population. Design: Retrospective cohort study. Setting: Community population in Rochester, Minnesota. Participants: Residents who met criteria for PHPT from 1965 to 2010. I Interventions: Survival was estimated using the Kaplan Meier product-limit method. The Cox proportional hazards model was used to determine associations, as relative hazards (RR) with 95% confidence intervals (CI), of various risk factors with time to death. Main outcome measure: The overall age and gender-adjusted survival compared to white Minnesota residents. Results: We identified 1139 PHPT individuals, 76% female, with a median age of 58 years. Most were observed without parathyroidectomy (69%). The relative risk of death among the entire cohort was 0.996 (95% CI: 0.91-1.09, P = 0.935) which was not different compared to Minnesota residents. Those with maximum serum calcium level > 10.8 mg/dL (0.7 mg/dL above the reference range) had an increase in mortality (RR 1.32, 95% CI: 1.10-1.58, P = 0.002). Survival among all PHPT individuals after parathyroidectomy was no different from expected (RR = 1.06, 95% CI 0.89-1.28; P = 0.508). Mortality was significantly decreased after parathyroidectomy in those with serum calcium levels >10.8 mg/dL (HR 0.47, 95% CI: 0.36-0.61, P < 0.001). Conclusions: Mortality in the entire cohort was not different from expected. PHPT patients with a maximum serum calcium level > 10.8 mg/dL had increased mortality. Survival was improved after parathyroidectomy in those with this degree of hypercalcemia.