Pattern of vitamin D in patients with chronic obstructive pulmonary diseases and in patients with bronchial asthma

ObjectiveTo determine the prevalence of vitamin D deficiency in patients with COPD and bronchial asthma, and the relation of vitamin D serum levels to pulmonary spirometric measures as well as other important clinical parameters that could affect quality of life in these patients.Subjects and methodsThe study included 80 subjects: 30 patients with COPD and 30 patients with bronchial asthma and 20 healthy volunteers. Patients and control groups were subjected to vitamin D assay by ELISA as well as spirometric assessment. Assessment of patients with COPD was done according to GOLD guidelines 2013: using (mMRCs), CAT score, spirometric assessment of FEV1, and exacerbation assessment. They were also subjected to Combined COPD assessment and BODE index calculation. For all patients with bronchial asthma, GINA classification 2014 of bronchial asthma severity and asthma control assessment were done.ResultsStatistically significant lower values of vitamin D were found in patients with COPD (11.94 ± 7.66 ng/ml) compared to patients with bronchial asthma (22.03 ± 8.19 ng/ml) with p < 0.001, while mean ± SD values of 25-hydroxy vitamin D of both groups of patients (COPD and bronchial asthma) were statistically significant lower than control group (35.21 ± 6.04 ng/ml) with (p2, p3 < 0.001) respectively. Seventeen patients that is to say (56.7%) of patients with COPD and 11 patients that is to say (36.7%) patients with bronchial asthma demonstrated a mild to moderate degree of vitamin D deficiency, whereas 13 that is to say (43.3%) patients of COPD and 4 that is to say (13.3%) patients with bronchial asthma showed severe deficiency and all control subjects (n = 20) had a normal concentration of 25-hydroxy vitamin D. Statistically significant positive correlation was found between serum level of 25-hydroxy vitamin D and FEV1% of predicted in patients with COPD with (p = 0.002), whereas no statistically significant correlation was found between serum level of 25-hydroxy vitamin D and FEV1% of predicted in patients with bronchial asthma with (p = 0.120). Statistically significant negative correlations existed between serum level of 25-hydroxy vitamin D and exacerbation risk of patients with COPD and bronchial asthma with (rs = −0.481 and p = 0.007), and (rs = −0.496 and p = 0.005), respectively. Statistically significant negative correlations were found between serum level of 25-hydroxy vitamin D and exacerbation risk of patients with COPD and bronchial asthma with (rs = −0.481 and p = 0.007), and (rs = −0.496 and p = 0.005), respectively. Regarding relation between vitamin D level and grading severity of COPD, we found a significant correlation between serum 25-hydroxy vitamin D level and severity of COPD as assessed by GOLD spirometric classification, with decreased serum level of vitamin D as gold severity increased (19.12 ± 4.37, 9.97 ± 7.64, 8.21 ± 5.72 ng/ml) in gold I, II, III respectively with p = 0.012. Also it was found that CAT score increased and got worse as serum level of vitamin D decreased (16.65 ± 6.98, 8.68 ± 2.27, 9.01 ± 5.67 ng/ml) in categories II, III, IV respectively with rs = −0.468 and p = 0.034, and according to Combined COPD assessment, vitamin D levels were (19.78 ± 4.66, 17.38 ± 4.59, 6.75 ± 4.77, 7.56 ± 5.83 ng/ml) in groups A, B, C and D respectively with rs = −0.448 and p = 0.001. A statistically significant negative correlation was found between serum 25-hydroxy vitamin D level and BODE index score of COPD assessment with rs = −0.421, p = 0.020. According to the correlation of bronchial asthma severity and control to serum level of 25-hydroxy vitamin D, we found a statistically significant negative correlation between mean ± SD of serum level of 25-hydroxy vitamin D and different levels of asthma control with (rs = −0.636, p < 0.001) as well as a statistically significant negative correlation between quantification of 25-hydroxy vitamin D and levels of asthma severity with (rs = −0.875, p < 0.001).ConclusionVitamin D deficiency was highly prevalent in COPD and bronchial asthma (100% and 50%) respectively. Low levels of vitamin D were associated with low FEV1%, frequent exacerbations in patients with COPD and bronchial asthma, and increased COPD severity as assessed by GOLD guidelines. Important statistically significant negative associations between vitamin D level and both asthma control and asthma severity according to GINA classification were also found. Thus it is advised to include vitamin D levels in the routine assessment of patients with bronchial asthma and COPD, as well as studying the importance and clinical impact of oral supplementation of vitamin D in patients with COPD and bronchial asthma should be an important goal of future research.