Vitamin D Deficiency in patient with cystic fibrosis: are we adhering to monitoring recommendations

Objectives: To describe the prevalence of vitamin D deficiency and evaluate risk factors for low vitamin D in a cohort of pediatric and adult CF patients. To assess adherence to U.S. CF Foundation guidelines for monitoring vitamin D levels annually and 3 months after a vitamin D dose adjustment in this cohort. Methods: 3-center retrospective, observational study using electronic health records during the 2 year period January, 2014 to December, 2015. Descriptive statistics were used to assess vitamin D monitoring and prescription patterns. Logistic regression was used to assess risk factors for vitamin D deficiency (\u3c 30 ng/mL). Results: 578 patients were included in the cohort (Arkansas: 129, Rochester: 183, Seattle: 266). Median age at enrollment was 16.9 years (IQR = 16.9), with 58% pediatric patients. 134 (23%) patients had no vitamin D levels recorded during the study period; 154 (27%) had 1 level and 290 (50%) had 2 or more levels. Of the patients with \u3e18 months follow-up (n = 270), 146 (54%) had 2 annual levels. Among patients with vitamin D levels recorded during follow up (N = 444), 355 (80%) had at least one low value, of whom 284 (80%) received at least 1 prescription for Vitamin D. Patients with low vitamin D were more likely to be male (OR = 1.9, 95% CI = 1.2, 3.0) and of a race/ethnicity other than non-Hispanic white (OR = 4.4, 95% CI = 1.3, 15.1), after controlling for FEV1, age and insurance status. There were 202 patients with an initial low serum vitamin D who had a follow-up level during the study period; however, only 40 patients (20%) had the follow-up level obtained within 4 months. Conclusion: The study identified a high prevalence of vitamin D deficiency in this CF cohort. Gender and race may be associated with deficiency. Importantly, this study found that adherence to the US CF Foundation guidelines was moderate. Improved adherence to these guidelines could decrease the prevalence and severity of bone disease in our CF patients