Association of sunlight exposure and photoprotection measures with clinical outcome in Systemic Lupus Erythematosus

ABSTRACT

This study was designed to explore the relationship of sunlight exposure and ultraviolet (UV) light protection measures with clinical outcome in systemic lupus erythematosus (SLE). A structured questionnaire was administered to sixty Puerto Rican SLE patients, to assess their attitudes and behavior regarding sunlight exposure and photoprotection measures. Medical records were reviewed to evaluate the clinical outcome measures that included: clinical manifestations, number of SLE-related hospitalizations, number of exacerbations and pharmacologic treatment. Almost all (98.3 percent) patients were well acquainted of sunlight effects on disease activity. Two thirds were exposed to direct sunlight for an average of less than one hour per day and 33.3 percent for one hour or more. Thirty patients (50 percent) reported use of sunscreen, with sun protective factor of 15 or greater, when exposed to sunlight. Less than 40 percent of patients regularly wore hat or long-sleeves clothes to protect from sunlight. Although there were some clinical differences between the groups with different sunlight exposure times, none reached statistical significance. Also, no significant differences were found between the groups in regards to sunlight protective clothes. However, patients that regularly used sunscreen had significantly lower renal involvement (13.3 vs 43.3 percent), thrombocytopenia (13.3 vs 40 percent), hospitalizations (26.7 vs. 76.7 percent), and requirement of cyclophosphamide treatment (6.7 vs. 30 percent) than patients that did not used it (P < 0.05). We conclude that use of sunscreen photoprotection was associated with a better clinical outcome in our SLE patients. These findings further support the importance and benefits of photoprotective measures in patients with SLE