Psoriasis severity and the prevalence of major medical comorbidity: a population-based study.

IMPORTANCE: Despite the growing literature on comorbidity risks in psoriasis, there remains a critical knowledge gap on the degree to which objectively measured psoriasis severity may affect the prevalence of major medical comorbidity.

OBJECTIVE: To examine the prevalence of major medical comorbidity in patients with mild, moderate, or severe psoriasis, classified objectively based on body surface area involvement, compared with that in patients without psoriasis.

DESIGN, SETTING, AND PARTICIPANTS: Population-based cross-sectional study of patient data from United Kingdom-based electronic medical records; analysis included 9035 patients aged 25 to 64 years with psoriasis and 90,350 age- and practice-matched patients without psoriasis.

MAIN OUTCOMES AND MEASURES: Prevalence of major medical comorbidity included in the Charlson comorbidity index.

RESULTS: Among patients with psoriasis, 51.8%, 35.8%, and 12.4%, respectively, had mild, moderate, or severe disease based on body surface area criteria. The mean Charlson comorbidity index was increasingly higher in patients with mild (0.375 vs 0.347), moderate (0.398 vs 0.342), or severe psoriasis (0.450 vs 0.348) (each P < .05). Psoriasis overall was associated with higher prevalence of chronic pulmonary disease (adjusted odds ratio, 1.08; 95% CI, 1.02-1.15), diabetes mellitus (1.22; 1.11-1.35), diabetes with systemic complications (1.34; 1.11-1.62), mild liver disease (1.41; 1.12-1.76), myocardial infarction (1.34; 1.07-1.69), peptic ulcer disease (1.27; 1.03-1.58), peripheral vascular disease (1.38; 1.07-1.77), renal disease (1.28; 1.11-1.48), and rheumatologic disease (2.04; 1.71-2.42). Trend analysis revealed significant associations between psoriasis severity and each of the above comorbid diseases (each P < .05).

CONCLUSIONS AND RELEVANCE: The burdens of overall medical comorbidity and of specific comorbid diseases increase with increasing disease severity among patients with psoriasis. Physicians should be aware of these associations in providing comprehensive care to patients with psoriasis, especially those presenting with more severe disease.