Model | HR (95% CI) | P values |
Unadjusted model | ||
Depression | 1.31 (1.25 to 1.36) | <0.0001 |
Multivariable adjusted model* | ||
Depression | 1.38 (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 index | 1.41 (1.39 to 1.43) | <0.0001 |
BMI | 1.02 (1.02 to 1.03) | <0.0001 |
Smoking | ||
Current | 1.74 (1.69 to 1.80) | <0.0001 |
Ex-smoker | 1.40 (1.34 to 1.46) | <0.0001 |
Antidepressant use | 0.74 (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.