SAMe-TT 2 R 2 Score to Predict Time in Therapeutic Range of Vitamin K Antagonists in Asian and Non-Asian patients: A Systematic Review and Meta-analysis

Background Sex, age, medical history, treatment, tobacco use, and race (SAMe-TT 2 R 2 ) score helps detect patients at risk of suboptimal anticoagulation control. A score above two suggests poor control; however, non-Caucasian status being assigned two points might hinder the recognition of poor control in patients of other races. Objective To evaluate the SAMe-TT 2 R 2 score’s ability to predict poor anticoagulation control [defined as time in therapeutic range (TTR) < 60–70%] in Asian and non-Asian populations on vitamin K antagonists (VKAs). Methods We searched PubMed, Cochrane Library, Scopus, SpringerLink, and Web of Science using the keyword “SAMe-TT 2 R 2 .” Articles published before April 2022 were screened. We gathered mean TTR and diagnostic accuracy data for different SAMe-TT 2 R 2 thresholds and conducted meta-analyses using random-effects models. Results A total of 30 studies were included ( N = 36,690). The overall mean TTR differences were − 4.88 and − 6.41 for the cutoffs of ≥ 3 and ≥ 4, respectively. For non-Asian patients, the mean TTR differences were − 3.86, − 5.12, and − 8.09 for the cutoffs ≥ 2, ≥ 3, and ≥ 4, respectively. For Asian patients, the mean TTR differences were − 3.99 and − 4.07 for the cut-offs ≥ 3 and ≥ 4, respectively. The highest positive likelihood ratio (LR+) for the Asian subgroup was 1.17 [95% confidence interval (CI): 1.06–1.28; I 2 = 0%, p heterogeneity = 0.500] at cutoff ≥ 4 and for the non-Asian subgroup, at cut-off ≥ 3, the LR+ was 1.24 (95% CI 1.14–1.34; I 2 = 0% p heterogeneity = 0.455). The lowest LR− was found at a lower cutoff for both races (at cutoff ≥ 3 and ≥ 2 for Asian and non-Asian subgroups, respectively). The pooled results of other accuracy parameters were modest at all cutoffs, except for the sensitivity at cutoff ≥ 3 in the Asian subgroup (83.05%). Conclusion Our study results suggest that a higher SAMe-TT 2 R 2 score resulted in a greater reduction of TTR among Asian and all races. The accuracy parameters showed the highest sensitivity for poor TTR at the SAMe-TT 2 R 2 cutoff of ≥ 3 for Asian patients. However, the ability to identify patients likely to have poor TTR was limited. Further research is needed to enhance the risk assessment for poor anticoagulation control with VKAs. Registration The protocol of this systematic review was registered in the International Prospective Register of Scientific Reviews: PROSPERO, registration number CRD42021291865. Graphical Abstract