LAUSR

Background There is no data specific to the addition of renal dysfunction and age 50–64 years as risk parameters to the CHA 2 DS 2 -VA score, which is known as the R 2 CHA 2 DS 2 -VA score, among NVAF patients. Accordingly, the aim of this study was to validate the R 2 CHA 2 DS 2 -VA score for predicting thromboembolism in Thai NVAF patients. Methods Thai NVAF patients were prospectively enrolled in a nationwide multicenter registry from 27 hospitals during 2014–2020. Each component of the CHA 2 DS 2 -VA and R 2 CHA 2 DS 2 -VA scores was scored and recorded. The main outcomes were thromboembolism, including ischemic stroke, transient ischemic attack (TIA), and/or systemic embolism. The annual incidence rate of thromboembolism among patients in each R 2 CHA 2 DS 2 -VA and CHA 2 DS 2 -VA risk score category is shown as hazard ratio (HR) and 95% confidence interval (95% CI). The performance of the R 2 CHA 2 DS 2 -VA and CHA 2 DS 2 -VA scores was demonstrated using c-statistics. Net reclassification index was calculated. Calibration plat was used to assess agreement between observed probabilities and predicted probabilities of both scoring system. Results A total of 3402 patients were enrolled during 2014–2020. The average age of patients was 67.38 ± 11.27 years. Of those, 46.9% had renal disease, 30.7% had a history of heart failure, and 17.1% had previous stroke or TIA. The average R 2 CHA 2 DS 2 -VA and CHA 2 DS 2 -VA scores were 3.92 ± 1.92 and 2.98 ± 1.43, respectively. Annual thromboembolic risk increased with incremental increase in R 2 CHA 2 DS 2 -VA and CHA 2 DS 2 -VA scores. Oral anticoagulants had benefit in stroke prevention in NVAF patients with an R 2 CHA 2 DS 2 -VA score of 2 or more (adjusted HR: 0.630, 95% CI 0.413–0.962, p  = 0.032). The c-statistics were 0.630 (95% CI 0.61–0.65) and 0.627 (95% CI 0.61–0.64), for R 2 CHA 2 DS 2 -VA and CHA2DS2-VA scores respectively. NRI was 2.2%. The slope and R2 of the calibration plot were 0.73 and 0.905 for R 2 CHA 2 DS 2 -VA and 0.70 and 0.846 for CHA 2 DS 2 -VA score respectively. Conclusions R 2 CHA 2 DS 2 -VA score was found to be at least as good as CHA 2 DS 2 -VA score for predicting thromboembolism in Thai patients with NVAF. Similar to CHA 2 DS 2 -VA score, thromboembolism increased with incremental increase in R 2 CHA 2 DS 2 -VA score.