Dear Editor

Lindhardsen and colleagues have recently reported a study which found increased risks of stroke and atrial fibrillation were associated with rheumatoid arthritis in the Danish population[1]. The incidence rate ratio of stroke for people with rheumatoid arthritis was 1.33 (1.22 to 1.46) for women and 1.34 (1.19 to 1.51) for men. The findings are very similar to the increased risk of cardiovascular disease in patients with rheumatoid arthritis reported in the QRISK2[2] study where the adjusted hazard ratio for women was 1.50 (1.39 to 1.61) with 1.38 (1.25 to 1.52) for men. The QRisk2 algorithms also include terms for atrial fibrillation which had overall adjusted hazard ratios of 3.06 (2.39 to 3.93) in women and 2.40 (2.07 to 2.79) in men in the QRisk2 study. These results support the inclusion of atrial fibrillation and rheumatoid arthritis in the calculation of cardiovascular risk.

References

1. Lindhardsen J, Ahlehoff O, Gislason GH, Madsen OR, Olesen JB, Svendsen JH, et al. Risk of atrial fibrillation and stroke in rheumatoid arthritis: Danish nationwide cohort study. BMJ 2012;344.
2. Hippisley-Cox J, Coupland C, Vinogradova Y, Robson J, Minhas R, Sheikh A, et al. Predicting cardiovascular risk in England and Wales: prospective derivation and validation of QRISK2. BMJ 2008:bmj.39609.449676.25.

Competing interests: JHC is professor of clinical epidemiology at the University of Nottingham and co-director of QResearch® – a not-for-profit organisation which is a joint partnership between the University of Nottingham and EMIS (leading commercial supplier of IT for 60% of general practices in the UK). JHC is also director of ClinRisk Ltd which produces open and closed source software to ensure the reliable and updatable implementation of clinical risk algorithms within clinical computer systems to help improve patient care. CC is associate professor of Medical Statistics at the University of Nottingham and a consultant statistician for ClinRisk Ltd. JR and PB have received no financial support for undertaking this work. JR and PB were previously members of the NICE Guideline Development Group for Lipid Modification of which JR was chair. This work and any views expressed within it are solely those of the co-authors and not of any affiliated bodies or organisations. There are no other relationships or activities that could appear to have influenced the submitted work.