Cinacalcet: A Viable Therapeutic Option for Primary Hyperparathyroidism in the Elderly

Parathyroidectomy is usually curative in primary hyperparathyroidism (PHPT), but its utility would be limited if patients are elderly who may either refuse surgery or may have advanced frailty and multimorbidity. We evaluated the effectiveness of cinacalcet, an allosteric modulator of calcium-sensing receptor in PHPT in an elderly cohort of patients.

A prospective analysis of 29 patients who had PHPT and despite fulfilling criteria for surgery were unable to undergo parathyroidectomy either due to self-refusal (n = 12) or due to advanced multimorbidity (n = 17). All patients completed treatment with cinacalcet for at least for 6 months. Analysis were performed as per age (<75 and ≥75 years) and Charlson comorbidity index (CCI) score (≤5 and >5).

Our patients were the elderly (77 ± 12.7 years). In the whole group, complete normocalcemia was observed in 72.4% of patients (mean reduction: -0.55 mmol/l [confidence interval (CI) 0.4--0.7; P < 0.0001]) and parathormone (PTH) normalized (≤6.9 pmol/l) in 33.4% of patients [mean reduction: -5.5 pmol/l (CI -11.6-0.6; P = 0.0015)]. In subgroup analysis, the severity of hypercalcemia was found to be higher patients with age <75 years and also in patients with CCI score >5. Cinacalcet lowered adjusted calcium in both age groups (P < 0.0001) with a greater reduction (20.5% vs. 16.2%; P < 0.0001 for both) in patients with CCI score >5. PTH fell in both age groups but significantly (-6.7 pmol/l [CI -14.9-1.5]; P = 0.008) in ≥ 75 years category and likewise, the drop was greater in patients with higher CCI scores (-7.1 pmol/l [CI -15.8-1.6); P = 0.009] vs. [-4.5 pmol/l [CI -3.9--5.10]; P = 0.001). Patients with age <75 years and with CCI score ≤5 needed higher doses of cinacalcet to achieve biochemical targets.

Cinacalcet is a viable and valuable treatment strategy for elderly patients with multiple comorbidities who suffer from PHPT but either cannot or refuse to undergo parathyroidectomy.