When results were adjusted with Cox regression analyses, the psoriasis group had a significantly increased risk compared with the RA group with regard to mild liver disease (hazard ratio, 2.22; 95% CI, 1.81-2.72), moderate to-severe liver disease (HR, 1.56; 95% CI, 1.05-2.31), cirrhosis (HR, 3.38; 95% CI, 2.44-4.68), and cirrhosis-related hospitalization (HR, 2.25; 95% CI, 1.37-3.69). Compared with patients with RA, patients with PsA had a significantly increased risk of mild liver disease (HR, 1.27; 95% CI, 1.01-1.60) and cirrhosis (HR, 1.63; 95% CI, 1.10-2.42), but not moderate to severe liver disease or hospitalizations related to cirrhosis.
The researchers noted it is unclear why there was a difference in risk between the three groups of patients.
“While such differences in hepatotoxicity risk were previously attributed to differences in rates of alcoholism, obesity, diabetes, and other comorbidities between the disease populations, our study finds that the underlying disease influences liver disease risk independent of age, sex, smoking, alcohol use, diabetes, hyperlipidemia, overall comorbidity, and weekly methotrexate dose,” wrote Dr. Gelfand and colleagues.
As far as they know, their study “ is one of the first and largest population-based studies to directly compare” liver disease in these three groups of patients on methotrexate, they wrote, noting that earlier studies were smaller and frequently used indirect hepatic injury measures.
Limitations of the study included the inability to account for disease severity as well as the potential for disease misclassification, surveillance bias, and confounding by unmeasured variables such as body mass index. Further, the results do not show whether “liver disease is attributed to methotrexate use, the underlying disease, or a combination of both,” the researchers noted.
Four authors report relationships in the form of consultancies, continuing medical information payments, deputy editor positions, fellowship support, individual or spousal honoraria, patents, research grants, and/or speaker positions with various pharmaceutical companies, medical journals, societies, and other organizations; two authors had no disclosures. There was no funding source.