Normohormonal primary hyperparathyroidism: A systematic review and meta-analysis.

Objective: We aim to evaluate the body of evidence reporting on normohormonal primary hyperparathyroidism (NHpHPT) patients to help guide their diagnosis, characterization and treatment.

Background: Normohormonal primary hyperparathyroidism is a term used to describe patients with a normal PTH and elevated calcium levels. There is limited understanding regarding the presentation and appropriate management of these patients.

Methods: A systematic review was conducted: abstract and full-text screening were independently conducted by 2 investigators. Odds ratios (OR), standard mean differences (SMD) and 95% confidence intervals were calculated.

Results: Twenty-two studies were identified. Patients with NHpHPT were more likely to present with lower PTH (p < 0.00001) and calcium (p < 0.00001) levels. Intraoperatively, the NHpHPT group was 1.8 times more likely to undergo bilateral neck exploration (BNE) and harbor multigland disease. The rates of surgical cure were 93% in the NHpHPT and 96% in the pHPT groups (p = 0.0003).

Conclusion: Symptomatic patients with NHpHPT benefit from parathyroidectomy with prolonged intraoperative PTH monitoring, and a low threshold for conversion to BNE.