Low Vitamin D Levels in Rheumatoid Arthritis Patient is Associated with Poor Disability Index and Increased Patient Global Disease Assessment Score.

Background: Rheumatoid arthritis (RA) is a chronic inflammatory connective tissue disorder with wide spectrum of presentation from polyarthritis to multisystem involvement. Apart from bones, muscles and other soft tissues, Vitamin D receptors have been found on many immune cells and tissues. The most vital function of Vitamin D is calcium and phosphorus absorption but it can also act as an immune-modulator hormone, which can affects both innate and adaptive immune responses leading to autoimmune diseases.

Objectives: To study the relationship of vitamin D insufficiency with disease activity and functional disability in patients of Rheumatoid Arthritis.

Material And Methods: The present study was an observational, cross sectional study done in a tertiary care hospital in New Delhi, India. The inclusion criteria comprised of patients attending the inpatient (IPD) and outpatient department (OPD), age above 18 years and fulfilling 1987 American college of Rheumatology (ACR) criteria for RA. The exclusion criteria was patients suffering from any other connective tissue disorder (CTD) and patients who were taking vitamin D supplements for past 6 months. Thirty patients were enrolled in the study after satisfying inclusion and exclusion criteria and appropriate clinical data and blood sample were collected after informed consent. Joint examination were performed and swollen joint count (SJC), tender joint count (TJC), patient global assessment (PGA) and evaluator global assessment (EGA) scores were recorded. Disease activity using DAS28ESR, DAS28CRP and CDAI were calculated and disability index was assessed using Short Fries Health Assessment Questionnaire.

Results: In our study mean vitamin D level was 18.93 ng/ml (S.D. 6.64 ng/ml). Mean DAS28 ESR was 4.57±1.48. Mean Disability Index was 0.52±0.89. All the study population had low Vitamin D level (100%), while 50% patients had vitamin D level in deficiency range (<20ng/ml). On analysis by student t-test, statistically higher PGA (p value 0.024) and Disability Index (p value < 0.001) in vitamin D deficient patients, compared to vitamin D insufficient patient group was observed, however there was no significant difference in disease activity between the groups.

Conclusion: Low Vitamin D levels are common in Indian rheumatoid arthritis patients. Mean PGA significantly increased, and disability index significantly increased in Vitamin D deficient group compared to insufficient group suggesting vitamin D deficient patients poor wellbeing and more disability.