Development and validation of a bleeding risk prediction score for patients with mitral valve stenosis and atrial fibrillation or mechanical heart valves receiving long‐term warfarin therapy

AIMS: This study aimed to develop and validate a new bleeding risk score to predict warfarin-associated major bleeding for patients with mitral valve stenosis with atrial fibrillation (MSAF) or mechanical heart valves (MHV). METHODS: A multicentre, retrospective cohort study was conducted at 3 hospitals in Thailand. Adult patients with MSAF or MHV receiving warfarin for ≥3 months during 2011-2015 were identified. Data collection and case validation were performed electronically and manually. Potential variables were screened using the least absolute shrinkage and selection operator. Multivariate logistic regression analysis using stepwise backward selection was used to construct a risk score. Predictive discrimination of the score was evaluated using the C-statistic. Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit test. RESULTS: There were 1287 patients (3903.41 patient-year of follow-up), with 192 experiencing bleeding (4.92 event/100 patient-year) in the derivation cohort. A new bleeding risk score termed, the HEARTS-60 + 3 score (hypertension/history of bleeding; external factors, e.g., alcohol/drugs aspirin or nonsteroidal anti-inflammatory drugs; anaemia/hypoalbuminaemia; renal/hepatic insufficiency; time in therapeutic range of <60%; stroke; age ≥60 y; target international normalized ratio of 3.0 2.5-3.5), was developed and showed good predictive performance (C-statistic 95% confidence interval of 0.88 0.85-0.91). In the external validation cohort of 832 patients (2018.45 patient-year with a bleeding rate of 4.31 event/100 patient-year), the HEARTS-60 + 3 score showed a good predictive performance with a C-statistic (95% confidence interval) of 0.84 (0.81-0.89). CONCLUSION: The HEARTS-60 + 3 score shows a potential as a bleeding risk prediction score in MSAF or MHV patients.