Baseline renal dysfunction determines mortality following parathyroidectomy in primary hyperparathyroidism: analysis of Indian PHPT registry

Introduction: Primary hyperparathyroidism (PHPT) in India is mostly symptomatic with renal and skeletal complications. Evidence on mortality outcomes following parathyroidectomy from India, where the disease is predominantly symptomatic is limited.

Material and methods: This was a prospective study to evaluate mortality outcomes in the Indian PHPT registry over the past 25 years (n = 464). Pre- and postoperative parameters and mortality data were obtained from medical records and/or by verbal autopsy, a method validated by WHO for data collection in settings where several deaths are noninstitutional. Patients were divided into survivor (SG) and nonsurvivor groups (NSG) to ascertain differences in presentation and the effect of parathyroidectomy.

Results: The overall mortality was 8.8% at a median follow-up of 8 years (IQR 1-13) after parathyroidectomy. Chronic kidney disease was the most common background cause of death (43.5%), followed by pancreatitis (28.2%). NSG had significantly more frequent renal dysfunction (91.9% vs 73.9%), anaemia (50 vs 16.6%) and pancreatitis (24.3 vs 6.4%). PTH (61.9 vs 38.3 pmol/l) and baseline creatinine (97.2 vs 70.7 µmol/l) were significantly higher and eGFR lower (66.7 vs 90.7 ml/min/1.73m²) in the NSG than SG. By Cox proportional modelling, renal dysfunction [HR 2.88 (1.42-5.84)], anaemia [HR 2.45 (1.11-5.42)] and pancreatitis [HR 2.65 (1.24-5.66)] on univariate and renal dysfunction [HR 3.33 (1.13-9.77)] on multivariate analysis were significant for mortality. Survival curves demonstrated a significantly higher mortality with lower eGFR values.

Conclusions: Nonsurvivors in PHPT had greater prevalence and more severe baseline renal dysfunction than survivors. Survival after parathyroidectomy was significantly associated with estimated glomerular filtration rate at baseline.