8/8/13
by Charles Bankhead
Staff Writer, MedPage Today
Patients with psoriasis had an increased risk of multiple comorbid conditions affecting most major organ systems, including the lungs, liver, kidneys, and cardiovascular system, a large cross-sectional study showed.
The magnitude of comorbidity ranged from about a 10% increase in the odds of chronic pulmonary disease to a doubling of the odds of rheumatologic diseases, reported Joel M. Gelfand, MD, of the University of Pennsylvania in Philadelphia, and colleagues.
The comorbidity burden increased significantly with the severity of psoriasis, they wrote online in JAMA Dermatology.
“The burdens of overall medical comorbidity and of specific comorbid diseases increase with increasing disease severity among patients with psoriasis,” the authors concluded. “Physicians should be aware of these associations in providing comprehensive care to patients with psoriasis, especially those presenting with more severe disease.”
Gelfand and co-authors acknowledged a large and growing volume of literature showing a high comorbidity burden among psoriasis patients, particularly patients treated with systemic agents or phototherapy. However, few studies have examined the relationship between psoriasis severity and comorbidities. The few studies that have examined severity have relied on indirect and imprecise measures of comorbidity, the authors noted.
To assess comorbidity prevalence by psoriasis severity, investigators relied on a general practice database encompassing 7.5 million patients and 415 practices throughout England. They searched the data for adults, ages 25 to 64, whose medical records showed at least one psoriasis-related diagnosis in the previous 2 years.
An age-representative sample of patients who met the initial criteria were evaluated further by questionnaires sent to their general practitioners, who confirmed the psoriasis diagnoses and reported the severity of the disease, as determined by affected body surface area (BSA):
- Mild: ≤2% BSA
- Moderate: scattered disease with 3% to 10% BSA involvement
- Severe: Extensive disease with >10% BSA affected
Comorbid disease burden was determined by the Charlson comorbidity index, which measures 17 major systemic comorbid diseases.
Patients whose questionnaires were returned and who had complete medical records were included in the analysis. Each patient was matched with 10 similar patients with no history of psoriasis. The resulting population comprised 9,035 patients with psoriasis and a control group of 90,350 patients matched by age and practice.
On the basis of BSA criteria, 51.8% of patients with psoriasis had mild disease, 35.8% had moderately severe disease, and 12.4% had severe disease. The mean Charlson score increased with psoriasis severity and was significantly higher (P<0.05) for all severity levels compared with the patients without psoriasis: 0.375 versus 0.347 for mild, 0.398 versus 0.342 for moderate, and 0.450 versus 0.348 for severe.
The analysis showed that psoriasis patients had significantly increased odds for:
- Chronic pulmonary disease: odds ratio 1.08 (95% CI 1.02-1.15)
- Diabetes: OR 1.22 (95% CI 1.11-1.35)
- Diabetes with systemic complications: OR 1.34 (95% CI 1.11-1.62)
- Mild liver disease: OR 1.41 (95% CI 1.12-1.76)
- Myocardial infarction: OR 1.34 (95% CI 1.07-1.69)
- Peptic ulcer disease: OR 1.27 (95% CI 1.03-1.58)
- Peripheral vascular disease: OR 1.38 (95% CI 1.07-1.77)
- Renal disease: OR 1.28 (95% CI 1.11-1.48)
- Rheumatologic disease: OR 2.04 (95% CI 1.71-2.42)
Trend analysis revealed significant associations (P<0.05) between psoriasis severity and each of the comorbidities. Prevalence odds ratios for comorbid conditions showed that a patient’s odds of having at least one comorbid condition increased with psoriasis severity as compared with the nonpsoriasis control group: OR 1.11 for mild (95% CI 1.03-1.19), OR 1.15 for moderate (95% CI 1.05-1.25), and OR 1.35 for severe (95% CI 1.16-1.56).
The authors cautioned that they did not evaluated the “degree to which these associations are due primarily to psoriasis or to confounding factors, such as smoking, obesity, or treatment. Therefore, our results should be considered hypothesis generating and require confirmation in prospective studies.”
Nonetheless, the results add weight to the argument that patients with psoriasis require comprehensive care, said another dermatology researcher who has reported findings similar to those of Gelfand and colleagues.
“Psoriasis patients often have multiple comorbidities that need to be treated,” said Wayne Gulliver, MD, of Memorial University of Newfoundland in St. John’s, told MedPage Today. “In the past, dermatologists did not recognize this association, but it has now become a major topic. In a sense, it has brought dermatology back into medicine. We’re now looking at our patients as having more than just a skin disease; they have a systemic inflammatory disorder.”
Recent studies have produced “good evidence” that effective treatment of psoriasis can reduce the comorbidity burden to some extent, particularly joint symptoms and damage related to arthritis, he added. Data also have begun to emerge to suggest that effective treatment might reduce the risk of myocardial infarction in patients with psoriasis.
The study was supported by the NIH, the National Psoriasis Foundation, and the American College of Rheumatology.
Gelfand disclosed relationships with Abbott, Amgen, Celgene, Centocor, Merck, Novartis, Pfizer, and Genentech. One or more co-authors disclosed relationships with Centocor, Merck, Novartis, and Pfizer.
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