Use of the SF-12 questionnaire to assess physical and mental health status in patients with psoriasis

Health-related quality of life (HRQoL) in psoriasis patients is generally measured using disease- or dermatology-specific questionnaires. Our objective was to use the generic 12-item Short Form Health Survey (SF-12) instrument to measure the physical and mental impact of psoriasis and to compare scores with those already published for different diseases. An observational study was conducted among mild-to-severe psoriasis outpatients. Health status was assessed by the SF-12, which includes a physical (PCS) and a mental (MCS) scale. The 12-item General Health Questionnaire (GHQ-12) was used to assess the possible presence of depression or anxiety, and the Skindex-17 to measure dermatology-specific HRQoL. Statistical analyses were performed to estimate the association between physical and mental health status and demographic and clinical characteristics. The study population included 1592 patients. Psoriasis PCS scores were similar to the general population and to non-severe diseases such as allergies, dermatitis, or back pain, while MCS mean scores were very similar to that of depression, and lower than those of all the other chronic conditions. Poor physical health was associated with female sex, older age, lower educational level, joint involvement, ≥2 comorbidities, moderate to very severe clinical status, GHQ-12 score ≥4, and moderate to severe Skindex-17 psychosocial scores. Poor mental health was associated with younger age (<30 years), GHQ ≥ 4, and severe Skindex-17 psychosocial scores. In conclusion, a general health measure, such as the SF-12, appears to be able to capture, in psoriasis patients, the burden of the disease both from a physical and a mental point of view.