Background/Purpose: In 2010, the Canadian Osteoporosis guidelines recommended that patients with osteoporosis be supplemented with vitamin D and to achieve serum levels ≥75nmol/L. Past studies, most of which were completed before these guidelines could be implemented, showed that there is a large proportion of patients whose levels are below this target. For this reason, we aimed to assess the current uptake of these guidelines in osteoporosis patients by: 1) Determining the current prevalence of patients who are vitamin D-sufficient (≥75nmol/L); 2) Assessing factors associated with vitamin D insufficiency; and 3) Identifying groups of patients who are not on vitamin D supplementation.

Methods: We retrospectively reviewed charts of patients referred to a single osteoporosis clinic in Hamilton, Canada, seen between April and October 2017. Inclusion criteria were a lumbar spine or femoral neck T-score ≤-2.5 or a major fragility fracture, and age above 18 years. Data from the initial consultation appointment was extracted. We also collected absolute vitamin D levels and determined vitamin D insufficiency (<75nmol/L) as well as its prevalence. Further, we determined the effects of age, sex, vitamin D intake, BMI, eGFR, fracture history, and PPI use on vitamin D sufficiency and supplementation rates and investigated their role on PTH, calcium levels, fracture prevalence, and BMD. Where appropriate, we completed a Pearson’s chi-squared analysis or a Pearson correlation analysis.

Results: Charts were reviewed from 180 patients, mean age 65.8 years (SD 11.9) 78.3% (141/180) female, 82.2% (148/180) reported taking vitamin D supplements. The average vitamin D level was 93.7nmol/L (SD 34.1) and 75% (135/180) were vitamin D-sufficient. We found that patients with vitamin D insufficiency were significantly older (69.2 vs 64.6 years, r=0.169, p=0.023) with no effect on other bone parameters. We also found that vitamin D-insufficient patients had a significantly lower eGFR (69.6 vs 78.3mmol/L, r=0.210, P=0.005), which was inversely correlated with PTH level (r=-0.229, p=0.002). Lastly, we found a difference in sex and vitamin D supplementation rates, as males were less likely to be on vitamin D supplementation (57.9% vs. 91.3%, X²=24.86, p<0.001). Other bone parameters were not significantly affected.

Conclusion: In our retrospective analysis, we found that currently, there is strong adherence to the Canadian guidelines for vitamin D status in patients with osteoporosis in Hamilton, Ontario. However, we identified that there continues be a care gap for patients who are older, male, or have a lower eGFR with regards to their vitamin D status, which are factors that we recommend for practitioners to follow more closely.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/current-factors-associated-with-insufficient-vitamin-d-status-in-patients-with-osteoporosis/