Liver steatosis in patients with rheumatoid arthritis treated with methotrexate is associated with body mass index

BACKGROUND Methotrexate(MTX) is the usual first-line treatment for rheumatoid arthritis(RA). Long-term use of MTX has been associated with liver steatosis(LS) and liver fibrosis(LF).AIM To determine if LS in patients treated with MTX for RA is associated with MTX cumulative dose(MTX-CD), metabolic syndrome(Mt S), body mass index(BMI), the male sex, or LF.METHODS A single-center, prospective study of patients receiving MTX for RA was performed from February 2019 to February 2020. The inclusion criteria were patients aged 18 years or older diagnosed with RA by a rheumatologist and being treated with MTX(without limitation on the duration of treatment). The exclusion criteria were previous diagnosis of liver disease(hepatitis B or C virus infection, known nonalcoholic fatty liver disease), alcohol consumption greater than 60 g/d in males or 40 g/d in females, human immunodeficiency virus infection on antiretroviral therapy, diabetes mellitus, chronic renal failure, congestive heart failure, or BMI greater than 30 kg/m2. Patients receiving leflunomide in the 3 years prior to the study were also excluded. Transient elastography(Fibro Scan, Echosens?, Paris, France) was used for fibrosis determination(LF > 7 Kp A) and computer attenuation parameter(CAP) for LS(CAP > 248 d B/m). Demographic variables, laboratory data, MTX-CD(> 4000 mg), Mt S criteria, BMI(> 25), transient elastography, and CAP scores were collected from all patients.RESULTS Fifty-nine patients were included. Forty-three were female(72.88%), and the mean age was 61.52 years(standard deviation: 11.73). When we compared MTX-CD ≤ 4000 mg(26 patients; 14 with LS and 12 without) with > 4000 mg(33 patients; 12 with LS and 21 without), no statistical differences were found(P = 0.179). We compared CAP scores stratified by Mt S, BMI, sex, and LF. There were no significant differences in CAP scores based on the presence of Mt S [CAP/Mt S: 50 no Mt S(84.75%); 9 Mt S(15.25%); P = 0.138], the male sex(CAP/sex: 8 male/18 female LS; 8 male/25 female no LS; P = 0.576), or LF [CAP/fibrosis: 53 no LF(89.83%); 6 LF(10.17%); P = 0.239]. LS determined by CAP was significantly associated with BMI > 25(CAP/BMI: 22 BMI ≤ 25(37.29%); 37 BMI > 25(62.71%); P = 0.002].CONCLUSION LS in patients with RA treated with MTX was not associated with MTX-CD, LF, the male sex, or Mt S. However, BMI was significantly related to LS in these patients.