Risk of out-of-hospital cardiac arrest in patients with rheumatoid arthritis: a nationwide study.

AIM

Inflammatory cytokines in patients with rheumatoid arthritis (RA) directly affect cardiac electrophysiology by inhibiting cardiac potassium currents, leading to delay of cardiac repolarisation and QT-prolongation. This may result in lethal arrhythmias. We studied whether RA increases the rate of out-of-hospital cardiac arrest (OHCA) in the general population.

METHODS

We conducted a nested case-control in a cohort of individuals between 1 June 2001 and 31 December 2015. Cases were OHCA patients from presumed cardiac causes, and were matched with non-OHCA-controls based on age, sex and OHCA date. Cox-regression with time-dependent covariates was conducted to assess the association between RA and OHCA by calculating the HR and 95% CI. Stratified analyses were performed according to sex and presence of cardiovascular diseases. Also, the association between OHCA and use of non-steroidal anti-inflammatory drugs (NSAIDs) in patients with RA was studied.

RESULTS

We included 35 195 OHCA cases of whom 512 (1.45%) had RA, and 351 950 non-OHCA controls of whom 3867 (1.10%) had RA. We found that RA was associated with increased rate of OHCA after adjustment for cardiovascular comorbidities and use of QT-prolonging drugs (HR: 1.22, 95% CI: 1.11 to 1.34). Stratification by sex revealed that increased OHCA rate occurred in women (HR: 1.32, 95% CI: 1.16 to 1.50) but not in men (HR: 1.12, 95% CI: 0.97 to 1.28; P value interaction=0.046). OHCA rate of RA was not further increased in patients with cardiovascular disease. Finally, in patients with RA, use of NSAIDs was not associated with OHCA.

CONCLUSION

In the general population, RA is associated with increased rate of OHCA in women but not in men.