Prolia (Denosumab) Cognitive Function Impact: What the Evidence Actually Shows

Does denosumab affect cognitive function?

The Prolia label's warnings cover hypocalcemia, serious infections, osteonecrosis of the jaw, atypical femoral fractures, multiple vertebral fractures after stopping, dermatologic reactions, severe bone, joint or muscle pain, bone turnover suppression and hypersensitivity. Cognitive impairment is not among them [1].

Severe hypocalcemia is a known risk of Prolia and can cause confusion [2]. The FDA lists confusion alongside seizures, irregular heart rhythm, fainting, facial twitching, muscle spasms, and weakness, tingling or numbness as ways severe hypocalcemia can present [2].

What the large trials measured

FREEDOM randomly assigned postmenopausal women with osteoporosis to denosumab 60 mg or placebo every 6 months for three years. The Prolia label describes 7,808 women aged 60 to 91 (3,886 on denosumab vs 3,876 on placebo), all instructed to take at least 1,000 mg calcium and 400 IU vitamin D daily [1]. The primary endpoint was new vertebral fracture [3]. New vertebral fracture occurred in 2.3% vs 7.2%, hip fracture in 0.7% vs 1.2%, and nonvertebral fracture in 6.5% vs 8.0% [3].

Safety was reported as overall event counts: all-cause mortality 1.8% vs 2.3%, nonfatal serious adverse events 25.0% vs 24.2%, and withdrawal because of adverse events 2.4% vs 2.1% [1]. The most frequent reactions were back pain (34.7% vs 34.6%) and pain in extremity (11.7% vs 11.1%) [1].

The open-label extension enrolled 4,550 women; those who continued denosumab had up to 10 years of exposure, and those who switched from placebo had up to seven years [4].

Hypocalcemia and confusion

In FREEDOM, serum calcium below 8.5 mg/dL at any visit occurred in 1.7% of denosumab-treated women vs 0.4% of those on placebo, with the lowest level about day 10 after dosing [1]. Prolia carries a boxed warning for severe hypocalcemia in advanced chronic kidney disease (eGFR below 30 mL/min/1.73 m2), including dialysis patients [1]. In female dialysis-dependent Medicare patients the 12-week incidence of severe hypocalcemia was 41.1% with denosumab (n=1,523) vs 2.0% with oral bisphosphonates (n=1,281), and most cases begin 2 to 10 weeks after an injection [2].

The label calls for weekly calcium monitoring for the first month, then monthly, in advanced kidney disease. For patients without advanced kidney disease who are predisposed to hypocalcemia, it calls for calcium, phosphorus and magnesium checks 10 to 14 days after an injection [1]. It also states that pre-existing hypocalcemia must be corrected before the first dose and that all patients should take calcium 1,000 mg and at least 400 IU vitamin D daily [1].