AB0409 An observational study of vitamin d in systemic lupus erythematosus patients: associations among vitamin d status, fatigue, quality of life and disease activity
Authors: L. C. Breslin, E. Ball, D. Armstrong, A. Bell, P. Magee, E. Laird, J. Wallace, E. McSorley
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease in which fatigue and impaired quality of life (QoL) commonly manifest. Fatigue has been associated with increased disease activity in SLE<sup>1-3</sup> and both fatigue and disease activity are considered predictors of impaired QoL<sup>2-4</sup>, although some studies have not reported any association between disease activity and QoL<sup>5-6</sup>. <h3>Objectives</h3> The aim of this study was twofold, firstly to determine whether vitamin D is associated with fatigue and QoL in SLE patients during the winter when status would be expected to be lowest and again during summer when vitamin D levels are thought to be highest and secondly to examine for any relationship between fatigue, QoL and disease activity. <h3>Methods</h3> SLE patients were recruited from November to March (winter) (n=52) and followed up during June and July (summer) (n=50). Serum 25-hydroxyvitamin D (25(OH)D) was measured by liquid chromatography mass spectrometry. Fatigue was assessed using the fatigue severity score (FSS) and QoL was examined using the 36-item short form questionnaire (SF-36). Disease activity and damage were scored using versions of Systemic Lupus Activity Measure, Systemic Lupus Erythematosus Disease Activity Index, British Isles Lupus Assessment Group and Systemic Lupus International Collaborative Clinics/American College of Rheumatology. Primary statistical analysis included Spearman's rho correlation and two tailed paired <i>t</i>-test. Multivariate and logistic regression analysis was employed to investigate potential predictors of fatigue and QoL. To investigate whether vitamin D was associated with fatigue and QoL, data from the serial winter and summer measurements were combined to give a larger sample (n=102) with greater power and regression analysis was reapplied. <h3>Results</h3> During the winter and summer months respectively 47 (96%) and 49 (98%) SLE patients reported fatigue (FSS ≥ 3) and 98% of the cohort presented with vitamin D inadequacy (25(OH)D &lt; 75 nmol/L) throughout the year. The mental component score (MCS) (95% CI 0.02, 5.42, <i>P</i>=0.049) and social functioning (SF) (95% CI 1.01, 13.27 <i>P</i>=0.023) subscales of the SF-36 were reduced during the summer. Analysis from the serial winter and summer data, reported vitamin D status to be reduced in those with fatigue (n=96) (95% CI -39.46, -2.03, <i>P</i>=0.030) and FSS and SF-36 significantly correlated with all disease activity measures. <h3>Conclusions</h3> Vitamin D inadequacy, fatigue and poor QoL were prevalent in this cohort of Northern Irish SLE patients. Given the observation of reduced vitamin D in those with fatigue and the association between vitamin D and disease activity, it is plausible that improvements in fatigue mediated via increasing 25(OH)D may indirectly improve disease activity and possibly enhance QoL. Further research such as placebo controlled vitamin D intervention trials are warranted to investigate this hypothesis before any firm conclusions can be made. <h3>References</h3> Zonana-Nacach <i>et al</i>. Lupus 2000; 9(2):101-9. Kozora E <i>et al</i>. Arthritis Rheum 2006; 55(4):628-35. Mattsson <i>et al.</i> Scand J Rheumatol 2008; 37(4):269-77. Jolly &amp; Utset. Lupus 2004; 13(12):924-6. Moldovan <i>et al</i>. Lupus 2011; 20(12):1285-92. Leong <i>et al</i>. Lupus 2010; 19(1):100-6. <h3>Disclosure of Interest</h3> None Declared