ABSTRACT
BACKGROUND: A majority of patients with end-stage renal disease suffer from secondary hyperparathyroidism, which is associated with osteoporosis and cardiovascular disease. Parathyroidectomy (PTX) is often necessary despite medical treatment. However, the effect of PTX on cardio- and cerebrovascular events (CVE) remains unclear. Data on the effect of PTX from population-based studies are scarce. Some studies have shown decreased incidence of CVE after PTX. The aim of this study was to evaluate the effect of PTX on risk of CVE in patients on renal replacement therapy. METHODS: We performed a nested case-control study within the Swedish Renal Registry (SRR) by matching PTX patients on dialysis or with functioning renal allograft with up to five non-PTX controls for age, sex and underlying renal disease. To calculate time to CVE, i.e., myocardial infarct, stroke and transient ischemic attack, control patients were assigned the calendar date (d) of the PTX of the case patient. Crude and adjusted proportional hazards regressions with random effect (frailty) were used to calculate hazard ratios for CVE. RESULTS: The study cohort included 20,056 patients in the SRR between 1991 and 2009. Among these, 579 patients had undergone PTX, 423 during dialysis and 156 during time with functioning renal allograft. These patients were matched with 1234 dialysis and 736 transplanted non-PTX patients. The adjusted hazard ratio (HR) with 95% confidence interval (CI) of CVE after PTX was 1.24 (1.03-1.49) for dialysis patients compared with non-PTX patients. Corresponding results for patients with renal allograft at d were HR (95% CI) 0.53 (0.34-0.84). CONCLUSIONS: PTX patients on dialysis at d had a higher risk of CVE than patients without PTX. Patients with renal allograft at d on the other had a lower risk after PTX than patients without PTX.
Subject(s)
Hyperparathyroidism, Secondary/surgery , Ischemic Attack, Transient/epidemiology , Kidney Failure, Chronic/therapy , Myocardial Infarction/epidemiology , Parathyroidectomy , Stroke/epidemiology , Aged , Aged, 80 and over , Case-Control Studies , Cohort Studies , Female , Humans , Hyperparathyroidism, Secondary/etiology , Incidence , Kidney Failure, Chronic/complications , Kidney Transplantation , Male , Middle Aged , Proportional Hazards Models , Registries , Renal Dialysis , Risk Factors , Sweden/epidemiologyABSTRACT
BACKGROUND: Secondary hyperparathyroidism is a common condition in patients with end-stage renal disease and is associated with osteoporosis and cardiovascular disease. Despite improved medical treatment, parathyroidectomy (PTX) is still necessary for many patients on renal replacement therapy. The aim of this study was to evaluate the effect of PTX on patient survival. METHODS: A nested index-referent study was performed within the Swedish Renal Registry (SRR). Patients on maintenance dialysis and transplantation at the time of PTX were analysed separately. The PTX patients in each of these strata were matched for age, sex and underlying renal diseases with up to five referent patients who had not undergone PTX. To calculate survival time and hazard ratios, indexes and referents were assigned the calendar date (d) of the PTX of the index patient. The risk of death after PTX was calculated using crude and adjusted Cox proportional hazards regressions. RESULTS: There were 20 056 patients in the SRR between 1991 and 2009. Of these, 579 (423 on dialysis and 156 with a renal transplant at d) incident patients with PTX were matched with 1234/892 non-PTX patients. The adjusted relative risk of death was a hazard ratio (HR) of 0.80 [95% confidence interval (CI) 0.65-0.99] for dialysis patients at d who had undergone PTX compared with matched patients who had not. Corresponding results for the patients with a renal allograft at d were an HR of 1.10 (95% CI 0.71-1.70). CONCLUSIONS: PTX was associated with improved survival in patients on maintenance dialysis but not in patients with renal allograft.
