Parathyroidectomy Study in Norway

Parathyroidectomy in middle-aged and older patients with mild asymptomatic primary hyperparathyroidism (PHPT) does not appear to reduce morbidity or mortality, according to results from a 10-Year Prospective Randomized Controlled Trial of Parathyroidectomy Versus Observation. Further, no evidence of adverse effects of observation was seen for at least a decade.

In simpler words, mild primary hyperparathyroidism (PHPT) patients do well with observation alone. When patients opt for surgery, they should be referred to surgeons who are experienced in modern, minimally invasive techniques. The study was published in the journal Annals of Internal Medicine on 19 April 2022.

Background

Primary hyperparathyroidism is a common endocrine disorder tied to an increased risk of cardiovascular disease, fractures, kidney disease, mortality, and cancer. In mild PHPT with modest hypercalcemia and without known morbidities, parathyroidectomy (PTX) is debated as no long-term randomized trials have been performed.

To fill this knowledge gap, Mikkel Pretorius, University of Oslo, Oslo, Norway, and colleagues aimed to examine the effect of PTX on mild PHPT with regard to mortality (primary endpoint) and key morbidities (secondary endpoint) in a prospective randomized controlled trial.

Study Design

The trial was set across eight Scandinavian referral centers. It included 191 patients with mild PHPT from 1998 to 2005. Ninety-five patients were randomly assigned to PTX, and 96 were assigned to observation without intervention (OBS).

The researchers obtained data and causes of death from the Swedish and Norwegian Cause of Death Registries 10 years after randomization and after an extended observation period lasting until 2018. Morbidity events were prospectively registered annually.

Findings

• After 10 years, 15 patients had died (8 in the PTX group and 7 in the OBS group).
• Within the extended observation period, 44 deaths occurred, which were evenly distributed between groups (24 in the PTX group and 20 in the OBS group).
• A total of 101 morbidity events (cardiovascular events, cerebrovascular events, cancer, peripheral fractures, and renal stones) were also similarly distributed between groups (52 in the PTX group and 49 in the OBS group).
• During the study, a total of 16 vertebral fractures occurred in 14 patients (7 in each group).

Limitations

The limitation of the study was that during the study period, 23 patients in the PTX group and 27 in the OBS group withdrew.

Conclusion

"PHPT does not appear to reduce morbidity or mortality in mild PHPT," wrote the authors. "Thus, no evidence of adverse effects of observation was seen for at least a decade with respect to fractures, mortality, cancer, cardiovascular and cerebrovascular events, or renal morbidities."

Reference

Pretorius M, Lundstam K, Heck A, Fagerland MW, Godang K, Mollerup C, Fougner SL, Pernow Y, Aas T, Hessman O, Rosén T, Nordenström J, Jansson S, Hellström M, Bollerslev J. Mortality and Morbidity in Mild Primary Hyperparathyroidism: Results From a 10-Year Prospective Randomized Controlled Trial of Parathyroidectomy Versus Observation. Ann Intern Med. 2022 Apr 19. doi: 10.7326/M21-4416. Epub ahead of print. PMID: 35436153.