High Prevalence Of Vitamin D Deficiency And Secondary Hyperparathyroidism In Irish Patients With Acute Hip Fracture

Background Vitamin D deficiency can cause secondary hyperparathyroidism (SHPT) which results in bone loss, particularly at cortical sites such as neck of femur, distal radius and humerus. Hip fracture patients have a higher prevalence of frailty and are at greater risk for vitamin D deficiency (25(OH)D< 30 nmol/l) or insufficiency (25(OH)D 30-49.9 nmol/l). Vitamin D replete status is also important in preventing hypocalcaemia in patients receiving zoledronate. We aimed to determine the prevalence of low vitamin D status and SHPT in acute hip fractures patients at our hospital. Methods Data on demographics, vitamin D status and PTH levels were recorded on acute hip fracture patients (aged >65 years) over a 12 month period from April 2023. A serum PTH level above 65 pg/ml in the presence of normal or low serum calcium was considered to represent SHPT. We explored for prevalence of vitamin D deficiency/insufficiency and predictors of SHPT in regression analysis. Results 149 patients were reviewed, mean age 82.5 years, 76.2% female. 22.8 % were vitamin D deficient and 16.1% had vitamin D insufficiency. Overall, 38.9% had serum 25(OH)D below 50 nmol/l. SHPT occurred in 22.9% and was predicted by low vitamin D status (<50 nmol/l, P=0.011) but not by age or gender. Conclusion Roughly 25% with hip fractures had vitamin D deficiency and about 40% suboptimal levels. Importantly, one in four also had SHPT. Vitamin D levels should be >50 nmol/l prior to zoledronic acid therapy. However, vitamin D results during the acute admission are often not available. In such cases, a consensus opinion has suggested 100,000 – 250,000 IU over 1-7 days. We suggest that if PTH results (that are more readily available) confirm SHPT, then large loading doses of vitamin D before zoledronic acid is advisable.