Table 2

Incidence rates and adjusted incidence rate ratios (IRRs) of myocardial infarction from Poisson regression analysis (overall estimates)

General populationRADMRA + DMTest for difference RA versus DM*
Myocardial infarction (n)75 8702653,94821
Time at risk (1000 person-years)37 139464891.6
Mean follow-up time (years (SD))4.6 (2.8)3.9 (2.8)3.0 (2.3)
Crude incidence (n/1000 person-years (CI))2.0 (2.0 to 2.1)5.7 (5.1 to 6.5)8.1 (7.8 to 8.3)13.0 (8.3 to 20.0)
Risk of myocardial infarction (IRR (CI))
Overall risk, gender-adjusted and age-adjustedReference1.7 (1.5 to 1.9)p<0.0011.9 (1.8 to 2.0)p<0.0012.9 (1.9 to 4.4)p<0.001p=0.06
Overall risk, fully adjustedReference1.7 (1.5 to 1.9)p<0.0011.7 (1.6 to 1.8)p<0.0012.6 (1.7 to 3.9)p<0.001p=0.64
  • * Wald χ2 test for difference of RA and DM IRR estimates.

  • After entry into disease-specific group.

  • Adjusted for gender, age, calendar year, cardioprotective medication, comorbidity and socioeconomic status.

    DM, diabetes mellitus; RA, rheumatoid arthritis.