Psoriasis is a poorly understood skin disorder and auto-immune disease characterized by rapidly dividing skin cells that reach the surface of the skin, eventually leading to red plaques and scales. In the United States, 2% of the population is thought to be affected with psoriasis. Although very little is known about the causes of the disorder, previous work has shown an association between psoriasis and hepatitis B and C. Hepatitis C is caused by the hepatitis C virus (HCV) and chronically affects 71 million people worldwide. Hepatitis B, on the other hand, is caused by the hepatitis B virus (HBV) and it is estimated that 257 million people have HBV.
There have been contradictory reports about the relationship between psoriasis and hepatitis, leading researchers at the Department of Dermatology at the Northwestern University Feinberg School of Medicine in Chicago, Illinois to assess the prevalence of psoriasis in patients infected with HCV or HBV. The cross-sectional, single-center study, led by principal investigator Beatrice Nardone, MD, PhD, was recently published in the Journal of the American Academy of Dermatology.
The authors utilized the Northwestern Medicine Enterprise Data Warehouse (NMEDW), a large electronic medical database with information on more than 4 million patients. They searched the database for patients between the ages of 18 and 89 who were screened for either HBV or HCV between September 2010 and September 2016. This group was then divided into those diagnosed with psoriasis and those unaffected with the disease.
The study consisted of 114,855 patients that were screened utilizing a serology-based test for HBV or HCV. The majority of patients were from the Chicago metropolitan area, with a small group of patients originating from rural areas. Out of the total 114,855 included in the study, 2,590 patients were diagnosed with psoriasis.
After utilizing logistic regression analysis, the authors found that there was no significant difference between patient groups that were diagnosed with psoriasis and those that were not in terms of HCV or HBV prevalence.
Of note is the fact that the authors did not account for the presence of additional risk factors for HCV and HBV, which is a major limitation of this work. Additional limitations of the study are the limited demographic utilized, with the majority of patients coming from an urban, midwestern United States population which is not indicative or representative of the general US population. In addition, the authors had no way to assess patients that were diagnosed with psoriasis but were not screened for HBV or HCV. On the other hand, strengths of this study include its large sample size, good gender representation, as well as serology-based screening and diagnosis for chronic HCV and HBV.
Overall, the authors concluded that there is no statistically significant correlation between being infected with chronic HBV or HCV and having psoriasis. This work is significant as it shed light on a previously reported correlation that had been poorly explored in the literature. Larger, multicenter studies using a larger demographic are needed to truly determine any correlation.
By Samar Mahmoud