In the hemodialysis population, patients with low parathyroid hormone levels (PTH) have comparable survival to those with high PTH, a new study finds.
In a retrospective study, all-cause mortality over 72 months occurred in 429 of 1166 patients (36.8%) with low PTH and 284 of 1116 patients (25.5%) with high PTH. The investigators defined low PTH as intact PTH less than 100 pg/mL and high PTH as intact PTH of 600 pg/mL or more (secondary hyperparathyroidism).
To reduce confounding, investigators propensity-score matched 619 patients with low PTH and 619 patients with high PTH by age, sex, diabetes status, and dialysis vintage. After matching, all-cause mortality did not differ significantly between the low and high PTH groups (31.5% vs 31.2%), Wenhu Liu, MD, and colleagues from Beijing Friendship Hospital, Capital Medical University in Beijing, China, reported in Frontiers in Endocrinology. Rates of cardio-cerebrovascular death (ie, cardiac arrest or death from heart failure, ischemic heart disease, or cerebrovascular disease) also did not differ significantly between groups. The investigators obtained similar survival results when low PTH was defined at cutoff points of less than 30, 30-60, and 60-100 pg/mL.
Among the study’s limitations, some relevant risk factors were not matched between groups, such as dry weight and blood pressure. The investigators also lacked data on patient use of parathyroidectomy and other treatments, including phosphate binders, active vitamin D or its analogs, and calcimimetics.
According to Dr Liu’s team, reported rates of low and high PTH are 40% and 10%, respectively. Patients with low PTH are likely to have low-turnover bone disease. If low and high PTH have similar survival rates, the possibility of total parathyroidectomy causing low PTH concentrations may not be acceptable.
Guo W, Zhang H, Zhang Y, Huang H, Liu W, Diao Z. Low parathyroid hormone versus secondary hyperparathyroidism and survival in patients undergoing hemodialysis: A propensity-matched analysis. Front Endocrinol. Published online May 13, 2022. doi:10.3389/fendo.2022.869330