Prevalence and factors associated with fatigue in female patients with systemic lupus erythematosus

To determine the prevalence of fatigue in our cohort as well as the factors to which it is associated, its relationship with demographic variables, vitamin D levels, treatment, systemic lupus erythematosus (SLE) symptoms and disease activity.

A cross-sectional study was carried out including 102 consecutive female patients with SLE (American College of Rheumatology 1997 criteria) who attended the Parc de Salut Mar between January 2012 and May 2014. Variables collected were: sociodemographic data, vitamin D supplementation, fatigue VAS, pharmacological treatment, main serological markers of SLE, and plasma levels of 25(OH)-vitD. The association between fatigue and the different variables was evaluated by the Spearman's Rho correlation coefficient for the continuous variables, the Mann-Whitney U test for the categorical and the Kruskal-Wallis test for the seasons of the year.

The fatigue variable was evaluated through a fatigue VAS with a mean score of 52.84 (range 0-100), a median of 59 and a standard deviation of 29.86. A statistically significant relationship was found between fatigue and age, MHAQ, SLICC, summer and photosensitivity. As for the relationship between fatigue and vitamin D insufficiency (defined as 25-(OH)-vitD≤30 levels), the sample was divided into patients receiving vitamin D supplements (n=60) and patients without supplements (n=40), finding a significant relationship in that last group.

A statistically significant association was found between the presence of fatigue and age, MHAQ, SLICC, photosensitivity, fibromyalgia and summer, and with vitamin D insufficiency in the group of patients without supplements (n=40).