Methotrexate therapy associates with reduced prevalence of the metabolic syndrome in rheumatoid arthritis patients over the age of 60- more than just an anti-inflammatory effect? A cross sectional study

Abstract

Introduction: The metabolic syndrome (MetS) may contribute to the excess cardiovascular burden observed in rheumatoid arthritis (RA). The prevalence and associations of the MetS in RA remain uncertain: systemic inflammation and anti-rheumatic therapy may contribute. Methotrexate (MTX) use has recently been linked to a reduced presence of MetS, via an assumed generic anti-inflammatory mechanism. We aimed to: assess the prevalence of the MetS in RA; identify factors that associate with its presence; and assess their interaction with the potential influence of MTX.

Methods: MetS prevalence was assessed cross-sectionally in 400 RA patients, using five MetS definitions (National Cholesterol Education Programme 2004 and 2001, International Diabetes Federation, World Health Organisation and European Group for Study of Insulin Resistance). Logistic regression was used to identify independent predictors of the MetS. Further analysis established the nature of the association between MTX and the MetS.

Results: MetS prevalence rates varied from 12.1% to 45.3% in RA according to the definition used. Older age and higher HAQ scores associated with the presence of the MetS. MTX use, but not other disease modifying anti-rheumatic drugs (DMARDs) or glucocorticoids, associated with significantly reduced chance of having the MetS in RA (OR = 0.517, CI 0.33-0.81, P = 0.004).

Conclusions: The prevalence of the MetS in RA varies according to the definition used. MTX therapy, unlike other DMARDs or glucocorticoids, independently associates with a reduced propensity to MetS, suggesting a drug-specific mechanism, and makes MTX a good first-line DMARD in RA patients at high risk of developing the MetS, particularly those aged over 60 years.

Figure 1

The relationship between methotrexate use and the presence of the metabolic syndrome according to the definition used. * P < 0.05. EGIR = European Group Against Insulin Resistance; IDF = International Diabetes federation; NCEP = National Cholesterol Education Programme; WHO = World Health Organisation.

Figure 2

Frequency of individual components of the metabolic syndrome (NCEP 2004) among patients taking methotrexate and not taking methotrexate. * P < 0.05. BP = blood pressure; FPGM = fasting plasma glucose > 5.6 mmol/L; HDL = high density lipoproteins; NCEP = National Cholesterol Education programme; TG = triglycerides.