The SAMe-TT2R2 score as an indicator of warfarin control for patients with deep vein thrombosis in Queensland, Australia

SAMe-TT2R2 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-TT2R2) 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-TT2R2 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-TT2R2." Articles published before April 2022 were screened. We gathered mean TTR and diagnostic accuracy data for different SAMe-TT2R2 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; I2 = 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; I2 = 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-TT2R2 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-TT2R2 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.

Evaluation of the SAMe-TT2R2 score to predict the quality of anticoagulation control in patients with venous thromboembolism treated with vitamin K antagonists: Findings from the RIETE registry

BACKGROUND

The time in therapeutic range (TTR) of patients with venous thromboembolism (VTE) treated with vitamin K antagonists (VKA) is usually below recommended, leading to higher frequency of vascular events, bleeding and mortality. The SAMe-TT2R2 prediction score discriminates those patients with high or low probability of obtaining poor INR control and its use is recommended in patients with atrial fibrillation. Its usefulness has been evaluated in patients with VTE, with conflicting results.

METHOD

We included consecutive patients enrolled in Registro Informatizado Enfermedad TromboEmbolica (RIETE), a prospective multicenter VTE registry, treated with VKA for >90 days and a minimum of 3 INR determinations. We analyzed the relationship between the SAMe-TT₂R₂ score and TTR, determined by the Rosendaal method and by the percentage of INR determinations (after excluding the first month). A ROC curve was calculated considering a cut-off point of TTR ≥65% for good anticoagulation control.

RESULTS

3893 patients were included and classified in high (1411 patients) or low (2482 patients) probability of obtaining poor INR control according to the total score obtained (0-1 points versus 2 points, respectively). TTR, calculated by direct method and Rosendaal method, was 51.2 (±23.4) and 55.4 (±25.9) in the high probability group; and 54.4 (±23.0) and 58.2 (±25.6) in the low probability group, respectively (p < 0.001 for both comparisons). The outcomes were similar between groups. The predictive capacity of the SAMe-TT2R2 score showed an area under the ROC curve of 0.54 (CI 95% 0.52-0.56) and 0.53 (CI 95% 0.51-0.55).

CONCLUSIONS

In patients with VTE treated with VKA, the SAMe-TT2R2 score discriminated those patients with high probability of obtaining poor INR control, but with a low predictive capacity. Further studies are required to assess the usefulness of the score in clinical decision-making.