Continuous MTX use lowers risk of CV events in patients with rheumatoid arthritis
Recent continuous use of methotrexate (MTX) is associated with a 20-percent decrease in cardiovascular events (CVE) in patients with early-onset rheumatoid arthritis (RA), a recent study has shown. In addition, greater MTX use in the first year of cohort entry appears to lower the risk of CVE.
CVE occurred in 3,294 (13.7 percent) patients (28.5 events per 1,000 patient-years; 95 percent CI, 27.6–29.5) over 115,453 patient-years. Multivariate analyses revealed that the model assessing time-varying continuous use in the most recent year produced the best fit.
There was an association between increasing recent MTX and lower CVE risks (hazard ratio [HR] for continuous use vs no use in past 12 months, 0.79; 95 percent CI, 0.70–0.88; p<0.0001). Greater MTX use in the first year after cohort entry also conferred protection against CVE (HR, 0.84; 0.72–0.96; p=0.0048), but this effect decreased with increasing follow-up.
On the other hand, there was no clear association between longer MTX use during the entire follow-up and CVE risk (HR, 0.98; 0.95–1.01; p=0.1441).
This study analysed an inception cohort of 23,994 patients with RA diagnosed after their 65th birthday. Multivariable Cox regression models were fit to examine the associations between time-varying MTX use and time to CVE, controlling for other risk factors.
The investigators used alternative models to assess the cumulative duration of MTX use over the first year, previous year (recent use) and entire duration of follow-up. They also determined whether the strength of the association varied over time.