Vitamin D status and the response of anti- IL 5 drugs in severe asthma.

<bold>Background:</bold> Vitamin D acts as an immunomodulator affecting both innate and adaptive immune systems. A low vitamin D state has been associated with severe asthma and treatment with oral corticosteroids increases the risk of vitamin D deficiency. It remains unknown whether a low vitamin D state affects the response to anti-IL5 drugs. <bold>Objective:</bold> The aim of the study was to assess vitamin D state on the clinical response at baseline and at third dose of anti-IL5 drugs. <bold>Methods:</bold> Data collected from January to August 2023 including demographics, baseline and at third dose of anti-IL5 drugs vitamin D level, Asthma ACQ 5, HADS anxiety and depression scores. T- test paired samples statistics was used for analysis. <bold>Results:</bold> A total of 24 patients were included. Mean age was 57 (SD±15). Mean BMI was 33 (SD± 9). 71 % (n=17) were female. 50% (n=12) were ex-smokers and 46% (n=11) were non-smokers. 50% (n=12) on current oral steroids, 29 % (n=7) had prior ICU admissions and 63 % (n=15) on vitamin D supplements. None of the patients have CKD. Mean vitamin D level at baseline was 49 (SD± 24) and 54 (SD±1 17) at third dose with significance of 0.234. Mean asthma ACQ 5 at baseline was 3.58 (SD± 3) and at third dose was 1.7(SD±2) with significance of 0.00. Mean anxiety HADS score at baseline was 8 (SD± 5) and 6 (SD± 4) at third dose with significance of 0.016. Mean depression HADS score at baseline was 8 (SD± 4) and 5 (SD± 3) at third dose with significance of 0.09. <bold>Conclusion:</bold> Anti-IL5 treatment works as an adjunct to standard of care in severe eosinophilic asthma and vitamin D enhances the response to corticosteroids. Further studies are needed to assess the low vitamin D on the clinical response to such treatment.