Severe, But Not Mild, Psoriasis May Increase Mortality by 50%

Laurie Barclay
December 20, 2007 — Patients with severe psoriasis had a 50% increased risk for mortality, but those with mild psoriasis had no overall increase in risk, according to the results of a population-based cohort study reported in the December issue of the Archives of Dermatology.
"Few studies have assessed the risk of mortality in patients with psoriasis, and most have focused on patients hospitalized for treatment," write Joel M. Gelfand, MD, MSCE, from the University of Pennsylvania School of Medicine in Philadelphia, and colleagues. "Presently, there are mixed data regarding the risk of mortality among patients with severe psoriasis, and the available data suggest a hypothesis that the risk of mortality may be related to disease severity. To further investigate the relationship of psoriasis and mortality, we performed a population-based cohort study in the United Kingdom to determine the risk of mortality in patients with psoriasis."
In this cohort study, patients and control subjects were identified from the practices of general practitioners participating in the General Practice Research Database in the United Kingdom from 1987 to 2002. Mild psoriasis was defined as a diagnostic code of psoriasis but no history of systemic therapy, whereas severe psoriasis was defined as a diagnostic code of psoriasis and a history of systemic therapy consistent with severe psoriasis. Control patients, with no history of a psoriasis diagnostic code, were selected in a 5:1 ratio from the same practice and date as the patients with psoriasis. The primary endpoint was hazard ratio (HR) of time to death with use of Cox proportional hazards models, after adjustment for age and sex.
Mild psoriasis had no overall effect on mortality (HR, 1.0; 95% confidence interval [CI], 0.97 - 1.02). In contrast, overall mortality risk was increased in patients with severe psoriasis (HR, 1.5; 95% CI, 1.3 - 1.7). Adjustment for other risk factors for mortality did not significantly affect the association of severe psoriasis with mortality (HR, 1.4; 95% CI, 1.3 - 1.6), nor did exclusion of patients with inflammatory arthropathy (HR, 1.5; 95% CI, 1.3 - 1.8).
Compared with control patients, male and female patients with severe psoriasis died 3.5 years younger (95% CI, 1.2 - 5.8) and 4.4 years younger (95% CI, 2.2 - 6.6), respectively (P < .001).
"Patients with severe psoriasis have a 50% increased risk of mortality, whereas patients with milder psoriasis have no overall increased risk," the study authors write.
Limitations of the study include possible misclassification of death from coding errors, failure to examine patients with exclusively incident (new-onset) psoriasis, possible misclassification of mild and severe psoriasis based on therapy, and inability to determine why patients with severe psoriasis died at higher rates than patients without psoriasis.
"Patients treated for severe psoriasis have an increased risk of death and die at a younger age than patients without psoriasis," the study authors conclude. "Further studies are necessary to determine the cause of excess mortality in patients with severe psoriasis, how the extent of skin disease affects mortality risk, and whether the risk of mortality in patients with severe psoriasis is altered by various systemic therapies. Patients with severe psoriasis should receive comprehensive health assessments to enhance preventive health practices, improve overall health, and decrease the risk of mortality."
The Trustees of the University of Pennsylvania and the National Institute of Arthritis and Musculoskeletal and Skin Diseases supported this study. Some of the study authors have disclosed various financial relationships with Amgen Inc, Astellas Pharma Inc, Biogen Idec, Centocor, Genentech Inc, Novartis, Warner Chilcott, Wyeth, Johnson & Johnson, Abbott Laboratories, Bristol-Myers Squibb, and the US Food and Drug Administration.
Arch Dermatol. 2007;143:1493-1499.