Guideline-recommended calcium and vitamin D supplementation during androgen deprivation therapy for prostate cancer: Documentation patterns and bone outcomes in a real-world cohort.

Abstract

614 Background: Men initiating androgen deprivation therapy (ADT) for prostate cancer face accelerated bone loss, and guidelines recommend calcium and vitamin D supplementation as baseline bone-protective care. Real-world documentation of this care, and its relationship to bone outcomes, is poorly characterized. Methods: In the TriNetX Research network (~149 million patients; 112 health care organizations), we identified men with confirmed prostate cancer (ICD-10 C61) initiating ADT (leuprolide, goserelin, triptorelin, degarelix, histrelin, or relugolix) from 2005-2024 with no calcium or vitamin D documented before ADT. Patients were classified by whether calcium or vitamin D was subsequently documented in the electronic health record (EHR). Cohorts were 1:1 propensity score-matched on age, race, comorbidities (including diabetes, smoking, obesity, and chronic kidney disease), bone-active drugs (bisphosphonates, denosumab, glucocorticoids), baseline bone disease, bone metastases, and calcium/vitamin D testing. Incident bone outcomes and all-cause mortality were assessed over 3 years from first ADT (Kaplan-Meier, Cox). Results: Of 82,526 men, only 27,778 (33.7%) had documented calcium/vitamin D supplementation; 54,748 (66.3%) had none. After matching (24,953/arm; all standardized mean differences <0.1), incident bone-complication rates were higher in the documented supplementation arm across all outcomes (Table); all-cause mortality was similar (14.2% vs 13.3%). These findings likely reflect residual confounding by indication and differential surveillance, as supplementation is more commonly documented in patients perceived to be at higher risk for skeletal complications and receiving closer bone-health monitoring. Conclusions: Two-thirds of men initiating ADT (66%) had no documented calcium/vitamin D supplementation in the EHR despite guideline recommendations, exposing a substantial gap in the documentation of baseline bone-protective care for a high-fracture-risk population. The observed association between documented supplementation and higher rates of bone complications underscores the limitations of using observational EHR data to evaluate the effectiveness of incompletely captured supportive care interventions and emphasizes the need for improved documentation and proactive bone-health management in men receiving ADT. Incident bone outcomes by supplementation documentation status, matched cohorts (n=24,953/arm), 3-year follow-up. Outcome Documented supplementation Not documented HR (95% CI) Major osteoporotic fracture 4.9% 1.7% 2.53 (2.26-2.82) Osteoporosis 7.1% 3.2% 2.01 (1.84-2.18) Osteopenia 5.3% 2.6% 1.78 (1.62-1.96) Hip fracture 1.5% 0.3% 4.07 (3.19-5.20) All p<0.0001.