Rheumatoid Arthritis (RA) patients taking Methotrexate (MTX) are often advised to decrease their alcohol intake due to the increased risk of hepatotoxicity. However, there is lack of data showing the interaction of alcohol with MTX.

Therefore, a study was conducted to assess the risk of developing abnormal liver blood tests at different alcohol consumption levels. Routinely collected data from primary care was used for assessment. The RA patients in the Clinical Practice Research Datalink, who start taking MTX between 1987 and 2016 were included. Hepatotoxicity was described as transaminitis: the level of alanine transaminase or aspartate aminotransferase higher than three times the upper limit of normal. Crude rates of transaminitis were measured per 1000 person-years, classified by weekly consumption of alcohol in units. Cox proportional hazard models examined the relationship between alcohol consumption and transaminitis.

A total of 11839 patients were included in the study, with 530 transaminitis episodes, occurring among 47090 person-years follow-up. Weekly consumption of alcohol between 15 and 21 units was associated with a reasonable increased risk of hepatotoxicity while consuming >21 units per week considerably increased rates of transaminitis.

It can be presumed from the findings of the study that weekly alcohol consumption of fewer than 14 units per week does not seem to be linked with an increased risk of transaminitis.