The impact of obesity and age at diagnosis on the chronic quality of life and long-term outcomes of psoriasis patients

Abstract

Background: Psoriasis is a chronic inflammatory skin disorder that detracts from quality of life, including elements of physical, psychological, and social functioning. Objective: The purpose of this study was to (1) investigate whether retrospective questions about chronic quality of life (CQoL) were better predictors of poor socioeconomic and medical outcomes than the current Dermatology Life Quality Index (DLQI) and (2) to evaluate the relative impact of body mass index (BMI) and (3) age at diagnosis on the long-term outcomes and CQoL of psoriasis patients. Methods: 114 subjects were examined and asked to complete a self-administered questionnaire regarding disabilities, relationships, education, as well as medical and economic outcomes. Participants also answered the ten questions used in the Dermatology Life Quality Index (DLQI) modified to ask “over the last week,” “over the last year,” and “over your lifetime with psoriasis.” Survey responses were compared amongst BMI groups (normal, overweight, obese) and age-at-diagnosis quartiles. Results: Greater lifetime DLQI (LT DLQI) correlated with lower satisfaction with treatment (P=0.007), greater concern that psoriasis will worsen (P=0.012), worse perceived general health (P=0.003), younger age at which weight became problematic (P=0.002), greater likelihood of believing psoriasis had caused weight gain (P<0.001), shorter retention of current job (P=0.001), more experiences of discrimination at work (P=0.002) and in social settings (P<0.001) over one’s lifetime, and more severe discrimination in social settings over one’s lifetime (P=0.002). Greater LT DLQI predicted more packs smoked per day (P=0.005), greater likelihood of believing psoriasis caused smoking (P=0.012), greater likelihood of recreational drug use (P=0.004), greater likelihood of a depression diagnosis (P<0.001), greater likelihood of having felt depressed (P=0.011), and greater likelihood of believing psoriasis caused depression (P<0.001). Patients with elevated BMI were more likely to rate their general health lower (P<0.001), believe that psoriasis caused their weight gain (P=0.014), experience sleep problems over their lifetime (P=0.016), hide their psoriasis over their lifetime (P=0.010), have their self-confidence affected by their psoriasis over their lifetime (P=0.011), and avoid common activities over their lifetime (P=0.012). Those diagnosed at a younger age were more likely to have a greater LT DLQI (P<0.001), have felt depressed (P=0.003), believe that their psoriasis had caused their depression (P<0.001), experience sleep problems over their lifetime (P=0.004), use recreational drugs (P<0.001), hide their psoriasis over their lifetime (P<0.001), and experience more severe discrimination in social settings over their lifetime (P=0.002). Conclusion: Compared to the standard LW DLQI, LT DLQI was a better predictor of patient outcomes related to weight, discrimination, and depression. While obesity is linked to impaired self-confidence, early-onset psoriasis is associated with depression, social discrimination, and greater LT DLQI. Both BMI and age at diagnosis independently cause a negative effect on sleep quality and recreational drug use.