The Impact of Late Secondary Hyperparathyroidism on Mortality in COVID-19 Patients: A Longitudinal Study

Adverse effects of high parathormone hormone (PTH) in critical illness have been described in some studies. 

The relationship between high PTH levels with mortality in hospitalized patients with COVID-19 was evaluated in the present study.

A total of 123 patients were included in the study. The patients were evaluated in phase 1 (on admission) and phase 2 (days 4-6 of hospitalization). The patients were categorized into four groups based on the PTH status in both phases: normal PTH1/normal PTH2 (group 1), high PTH1/normal PTH2 (group 2), high PTH1/high PTH2 (group 3), and normal PTH1/high PTH2 (group 4). The multiple logistic regression analysis was performed to examine the independent association of late hyperparathyroidism with mortality. After excluding ineligible participants, 115 patients in phase 1 and 96 patients in phase 2 (days 4-6 of hospitalization) were evaluated.

The level of phase 2 PTH in non-survivors was significantly higher than in survivors (57.5±40.9 pg/mL vs. 27.6±16.2 pg/mL, P=0.001). The mortality rate was significantly higher in high-PTH groups in phase 2 compared to normal-PTH groups in this phase (50% and 42.9% in groups 3 and 4 vs. 6.6% and 18.2% in PTH groups 1 and 2, respectively, P=0.007). Late hyperparathyroidism was associated with 11.4 times higher mortality risk (95% CI: 2.3-56.1, P=0.003).

Late hyperparathyroidism remained a significant predictor of mortality after adjusting for the main PTH secretion modulators and disease severity. Late hyperparathyroidism is an independent and strong risk factor for mortality in COVID-19. Further studies are necessary to clarify the mechanisms involved.