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Vitamin D Deficiency Treatment Patterns in Academic Urban Medical Center | Page 2

Published Online: February 19, 2014
Paulette D. Chandler, MD, MPH; Edward L. Giovannucci, MD, ScD; Michelle A. Williams, ScD; Meryl S. LeBoff, MD; David W. Bates, MD, MSc; and LeRoi S. Hicks, MD, MPH
We evaluated how frequently different types of vitamin D supplements were prescribed within 30 days for patients with a laboratory diagnosis of serum 25OHD deficiency. We then developed a series of logistic regression models to examine the association of patients’ socioeconomic characteristics and comorbidities with the outcome of prescribing high-dose vitamin D or other forms of vitamin D within 30 days of a laboratory diagnosis of serum 25OHD deficiency. Insurance status was dichotomized as Medicare, Medicaid, and self-pay versus private insurance. Age was dichotomized as less than 65 years and 65 years or older. Comorbidity score was dichotomized as 0 and greater than 0 based on the median Elixhauser comorbidity score of 0 for the study population. We then conducted multivariable logistic regression modeling to examine the independent association of patients’ race/ethnicity with differences in prescribing of high-dose vitamin D or other forms of vitamin D, adjusting for patient age, sex, insurance status, and Elixhauser comorbidity score. For each patient’s characteristics, we report adjusted odds ratios (ORs) and 95% confidence intervals (CIs) representing the odds of being prescribed high-dose vitamin D or some other form of vitamin D. We used SAS version 9.2 (SAS Institute, Inc, Cary, North Carolina) for the analysis.

RESULTS

Baseline Patient Characteristics

Among the 2140 patients evaluated for vitamin D deficiency, non-Hispanic white patients were significantly older, more likely to be privately insured, and had more comorbid diseases (Table 1). Among blacks, whites, and Hispanics, more women than men had vitamin D deficiency (women: 83.7%, 70.1%, and 80.8%, respectively; men: 16.3%, 29.9%, and 19.2%, respectively; Table 1). Most patients were aged less than 65 years (blacks 76.8%, whites 67.9%, Hispanics 79.3%; Table 1).

Comorbidities

Of patients with identified comorbidities and vitamin D deficiency (n = 1396), hypertension was the most common comorbidity, present in 51.7% of blacks; 37.2% of whites, and 48% of Hispanics (Table 2). (Note: comorbidities were not available for all patients.)

Frequency and Likelihood of Vitamin D Therapy

Among the 11,454 patients tested for vitamin D status, 2140 (18.7%) were 25OHD deficient (Figure). From this group, we identified 723 non-Hispanic black, Hispanic, or non-Hispanic white patients prescribed some type of vitamin D within 30 days, 561 of whom received at least 1 prescription dose of 50,000 IU of ergocalciferol (Figure). High-dose ergocalciferol represented 77.6% of vitamin D medications prescribed during the 30-day period. Overall, only 33.8% of vitamin D–deficient patients received a vitamin D prescription within 30 days of diagnosis of vitamin D deficiency. Blacks and Hispanics received vitamin D prescriptions more often than whites: 37.8%, 38.4%, and 30.9%, respectively (P = .003; Table 3). The vitamin D prescription rate for women versus men was 26.3% and 7.5%, respectively (P = .003; Table 3). In unadjusted analyses, 25OHD-deficient women had 25% higher odds of getting a vitamin D prescription compared with men (P = .03; Table 4).

We assessed whether race/ethnicity, age, sex, Elixhauser comorbidity score, or insurance status modified the likelihood of receiving a vitamin D prescription. In a fully adjusted model, we found no difference in prescription likelihood for blacks and whites (OR = 1.18, 95% CI, 0.88-1.58; P = .29) or Hispanics and whites (OR = 1.01, 95% CI, 0.70-1.45; P = .73). Similarly, the fully adjusted model showed no difference in prescription likelihood for females and males (OR = 1.23, 95% CI, 0.93-1.63; P = .12) (Table 4). Comorbidities did not influence likelihood of receiving a vitamin D prescription (Table 4).

DISCUSSION

Many studies have documented disparities in vitamin D deficiency prevalence.31-39 Correction of vitamin D deficiency in ambulatory care, an important strategy to reduce vitamin D deficiency disparities, is less well studied. In this large, racially and ethnically diverse cohort of primary care patients with 25OHD deficiency, 66.2% of patients did not receive a vitamin D prescription for vitamin D deficiency. Furthermore, in terms of prescriptions given, male patients received fewer prescriptions. Lastly, the rate of vitamin D prescriptions for blacks and Hispanics was significantly higher than that for whites,and white women received fewer prescriptions than black and Hispanic women. To our knowledge, this is the first examination of vitamin D prescribing for 25OHD deficiency among patients in a primary care clinic in the United States.

Given the recent IOM report, we chose the threshold of 20 ng/mL to determine appropriateness of therapy in order to be consistent with the most conservative guidelines. 27 The IOM recommends that children and adults (1-70 years) need 600 IU/day of vitamin D, whereas adults 71 years and older need 800 IU of vitamin D. In contrast to the IOM, the Endocrine Society Task Force recommends screening for vitamin D deficiency with serum 25OHD in individuals at risk for deficiency and treatment with supplements when vitamin D deficiency is identified. 29 The Task Force suggests using either vitamin D2 or vitamin D3 for the treatment of vitamin D deficiency. The Task Force guidelines state that all vitamin D-deficient adults should be treated with 50,000 IU of vitamin D2 or D3 once a week for 8 weeks or its equivalent of 6000 IU of vitamin D2 or D3 daily to achieve a 25OHD blood level above 30 ng/mL.29

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Issue: January/February 2014
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