Co‐morbidities in psoriasis: a hospital‐based case‐control study

Background Recent researches show that psoriasis is frequently associated with systemic co‐morbidities. Objectives This study aimed to identify possible associated co‐morbidities in psoriatic patients stratified by age and sex. Methods In this retrospective hospital‐based case‐control study, patients diagnosed as psoriasis at the Kaohsiung Veterans General Hospital in Taiwan between January 2008 and December 2009 were enrolled as cases and classified into severe and mild based on their use of systemic therapy. The controls were the patients without psoriasis matched the cases in 1 : 1 ratio with same birth year, sex and calendar date. Odds ratios (ORs) and 95% confidence intervals (CIs) from the conditional logistic regression method were used to assess the risk of co‐morbidities between psoriatic and non‐psoriatic patients. Results A total of 447 cases and 447 matched controls, with mean age of 51.3 ± 18.3 years and male‐to‐female ratio of 2.17 : 1 were enrolled. The ratio of mild‐to‐severe was 3.5 : 1. Compared with non‐psoriatic patients, psoriatic patients had significantly higher OR of hypertension (1.85), diabetes mellitus (2.88) and obesity (1.66). Among those aged ≥51 years old, there was significant risk in male psoriatic patients with ischaemic and hypertensive heart disease (IHHD) (OR = 2.167) after eliminating female IHHD psoriatic patients (OR = 0.125). Psoriasis was significantly negatively associated with cancers (OR = 0.267). Psoriasis patients often had the usual drinking habit (OR = 2.23) and seldom had an occasional drinking habit (OR = 0.25). Conclusions Psoriasis is strongly associated with hypertension, diabetes mellitus and obesity. The association between psoriasis and IHHD, stroke, cancers, smoking and alcohol habits warrant more investigation.