Table 2

HRs for the risk of RA

ModelHR (95% CI)P values
Unadjusted model
 Depression1.31 (1.25 to 1.36)<0.0001
Multivariable adjusted model*
 Depression1.38 (1.31 to 1.46)<0.0001
 Age (per 1 year)1.03 (1.03 to 1.03)<0.0001
 Male sex 0.48 (0.46 to 0.49)<0.0001
 Charlson comorbidity index1.41 (1.39 to 1.43)<0.0001
 BMI1.02 (1.02 to 1.03)<0.0001
 Smoking
  Current1.74 (1.69 to 1.80)<0.0001
  Ex-smoker1.40 (1.34 to 1.46)<0.0001
 Antidepressant use0.74 (0.71 to 0.76)<0.0001
  • Cox proportional hazards models were used to estimate the HRs of developing RA based on whether patients had depression or not (ie, depression vs general population). Depression significantly increases the risk of developing RA when using unadjusted models as well as models accounting for numerous covariates. Values show the number (per cent) of patients with a given characteristic.

  • * Observations with missing data were omitted from the models, except BMI which was handled using multiple imputation.

  • BMI, body mass index; RA, rheumatoid arthritis.