Re-evaluating Vitamin D testing prior to Zoledronic Acid Administration in Fragility Fracture Cohorts
Abstract
Introduction:
Vitamin D levels are routinely tested prior to Zoledronic Acid (ZA) administration in patients <80 years old(YO). Testing remains expensive compared to Vitamin D loading regimens with minimal risk of adverse effects. We performed a quality improvement project reducing the age of Vitamin D Testing (VDT) prior to ZA in a fragility fracture cohort, aiming to reduce cost and time to ZA administration.
Methodology:
205 Hip fragility-fracture patients undergoing fixation were retrospectively identified within the Royal Victoria Hospital, Belfast between 01/06/25-31/08/25. Patients <80YO underwent VDT, with pre-ZA Vitamin D levels and post-ZA bone profiles documented. VDT age was reduced to <70YO with 2 further audit cycles performed between 25/11/25-25/12/25 and 25/03/26-25/04/26. Timeframe post-op to zoledronic acid receival was documented in all cycles.
Results:
Of 205 patients identified in our initial cycle, 70 underwent VDT aged <80 with deficiency demonstrated in 44(63%). 146 patients received ZA, at an average time of 5.8 days post-op. 101 patients received bone profiles following ZA, with hypophosphataemia noted in 24(23.7%) and hypocalcaemia in 6(5.9%). The second cycle identified 61 patients who received ZA post-op, however VDT protocol was incorrectly followed. 26 patients were tested, however only 13 were <70YO with a further 13 >70YO. Subsequently, a 3rd cycle demonstrated 70 patients who received ZA, with VDT in 25 patients <70YO as per the novel protocol. 17(68%) of these patients were Vitamin D deficient and required loading. 2 patients >70years old were incorrectly checked. Average time to ZA administration decreased to 5.6 days, with 24.2% of patients hypophosphataemic post-ZA and no patients hypocalcaemic.
Conclusion:
Age reduction for VDT demonstrated an improved time to ZA administration, reduced overall expense and no significant impact on post-ZA bone profiles. This age could be further reduced in future studies as the majority of tested patients remained Vitamin D deficient.