R JALLEH1, G BASU1, S JESUDASON1
1Central and Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, South Australia
Aim: To review cases of hypocalcaemia attributed to denosumab in patients with CKD and raise awareness amongst medical practitioners of this significant risk.
Background: Hypocalcaemia is increasingly recognized as a complication of denosumab in CKD patients. Despite Therapeutic Goods Administration (TGA) notifications in 2013 of this adverse effect, we found that denosumab was still being prescribed by primary care providers raising concern that there is a lack of awareness of this risk.
Methods: From December 2013 to February 2017, a retrospective case series of 8 patients with clinically significant hypocalcaemia was collated. Results are displayed as a mean ± standard deviation.
Results: 8 patients with age 52-85 years developed clinically significant hypocalcaemia. All patients had stage 4-5 CKD with a mean creatinine of 375±171µmol/L and estimated glomerular filtration rate 13±6ml/min/1.73m2. All patients were on denosumab therapy for osteoporosis. The onset of hypocalcaemia was highly variable ranging from 15 days after the first dose of denosumab to 14 months after first initiating denosumab, having had 3 doses. 3 patients required intravenous calcium replacement with cardiac monitoring in a high dependency unit setting, 4 were managed as inpatients and 1 was managed as an outpatient. All required regular outpatient monitoring of calcium levels on discharge. The degree of hypocalcaemia ranged from a corrected calcium level of 0.88-1.80mmol/L (mean 1.36±0.31). Mean parathyroid hormone level was 55.1±24.2pmol/L, mean phosphate level was 1.70±0.71mmol/L and mean vitamin D level was 59.5±28.3nmol/L.
Conclusion: Despite TGA warnings, we have observed multiple cases of severe hypocalcaemia associated with considerable morbidity in CKD patients. We advocate greater awareness amongst the medical fraternity to prevent further future occurrence.