Background Methotrexate (MTX) is the most commonly prescribed disease modifying anti-rheumatic drug in the treatment of rheumatoid arthritis (RA). Patients taking MTX are advised to restrict their alcohol consumption because of a theoretical hepatotoxic interaction between alcohol and MTX. However data are limited to support this advice.
Objectives To quantify the association between alcohol consumption and abnormal serum liver function tests (LFTs) in patients with RA taking MTX, using routinely collected clinical data.
Methods Patients with RA in the Clinical Practice Research Database (CPRD) starting MTX between 1987 and 2011 were studied. Patients were included if they had alcohol consumption details recorded in CPRD and ≥6 LFTs per year, indicating adequate monitoring. Patients were grouped by reported weekly alcohol consumption. Crude rates of abnormal LFTs (defined as alanine transaminase or aspartate aminotransferase level ≥3 times the upper limit of normal) per 1000 person-years follow up were calculated. Cox proportional hazards models described the association between alcohol consumed and development of abnormal LFTs whilst taking MTX univariately, then adjusting for age and gender. Patients were censored at time of first abnormal LFT, death or the end of follow up (31/12/2011).
Results 8801 patients were included in the study, 6285 (71%) female, mean age (SD) was 58 (14) years. There were 241 abnormal LFTs in 38000 person-years follow up. There was no difference in rates of abnormal LFTs between drinkers and non-drinkers, adjusted hazard ratio (HR) (95% confidence interval (CI)) 1.12 (0.82–1.51). Crude rates of abnormal LFTs appeared to increase with increasing levels alcohol consumption (table 1); similarly when treated as a continuous variable, each increased unit of alcohol consumed was associated with a higher risk of abnormal LFTs, adjusted HR (95%CI) 1.01 (1.00–1.02). In the adjusted Cox model, moderate alcohol consumption (≤14 units per week) was not associated with a statistically significant risk of developing abnormal LFTs (table 1). There was a non-significant trend to higher HR with higher levels of alcohol consumption, however power was limited in the patients consuming >14 units per week.
Conclusions In patients with RA taking MTX, increasing alcohol consumption is associated with an increased risk of developing abnormal LFTs. The clinical importance of this increased risk may be small when drinking ≤14 units per week.
Disclosure of Interest None declared