Clinical usefulness of the SAMe-TT2R2 score: A systematic review and simulation meta-analysis

Abstract

BackgroundVitamin K antagonist (VKA) therapy is safer and more effective when patients have a high time within the therapeutic range and low international normalised ratio variability. The SAMe-TT2R2 score aims to identify those at risk for poor VKA control.ObjectivesTo evaluate the predictive value and clinical usefulness of the SAMe-TT2R2 score to identify those at risk for poor VKA control.MethodsWe performed a systematic review in MEDLINE and Embase for original research papers assessing the SAMe-TT2R2’s relation to poor TTR. We performed a meta-analysis where scores ≥ 2 and ≥ 3 predicting TTR < 70%. When studies evaluated other cutoffs for TTR or SAMe-TT2R2, they were harmonised by multiple simulations with patient characteristics from the individual studies, if the data were available.Results16 studies were identified and used in the meta-analysis: 4 and 2 times directly, 8 and 8 times harmonised for scores ≥ 2 and ≥ 3, respectively (not all studies provided information about both cutoffs). The sensitivities and specificities were too heterogeneous to pool. The positive likelihood ratios were 1.25 (1.14-1.38) for a score ≥ 2, and 1.24 (1.09-1.40) for a score ≥ 3; the negative ones were 0.87 (0.82-0.93) and 0.96 (0.91-1.02), respectively. This shows that the post-test probabilities hardly differ from the prior probability (prevalence).ConclusionThe SAMe-TT2R2 score does predict low TTR, but the effect is small. Its effect on individual patients is too limited to be clinically useful.

A nurse‐led atrial fibrillation clinic: Impact on anticoagulation therapy and clinical outcomes

“…Regarding the SAMe‐TT 2 R 2 score, in this study, we found that higher scores were related to switching, consistent with its original objective that was to predict which patients do well with VKAs, and several studies have demonstrated that it was able to predict poor INR (ie poor TTR), thus, aiding decision‐making 22,24‐26 . However, the predictive ability of the SAMe‐TT 2 R 2 score for switching in the present study was limited, which has also been observed in the past 22,27 . Nevertheless, we found higher switching to DOACs in the nurse‐led clinic.…”

“…22,[24][25][26] However, the TA B L E 1 Baseline characteristics predictive ability of the SAMe-TT 2 R 2 score for switching in the present study was limited, which has also been observed in the past. 22,27 Nevertheless, we found higher switching to DOACs in the nurse-led clinic. This is of importance since DOACs have shown a clear benefit over warfarin in terms of safety and efficacy.…”

SAMe-TT2R2 score for prediction of suboptimal time in therapeutic range in a Thai population with atrial fibrillation

“…(25) A recent systematic review on 16 studies summarised that although the SAMe-TT2R2 score can predict low TTR, the effect is too small to be clinically useful. (26) In our study, 67.4% of the patients had TTR < 65%, which is considered suboptimal. Even at a SAMe-TT2R2 score of 2, 64.1% of the patients had a TTR of < 65%, indicating that the discriminative power of the score is limited; this correlated with the low C-statistic.…”

Is the time in therapeutic range on coumarins predicted by previous time in therapeutic range?

“…This can be problematic because even significant differences between groups allow for considerable overlap (eg, in our data set, analysis of variance for TTR by strata resulted in a P value <.01 for all time points in Figure 2). Furthermore, these tools do not provide a probability for a certain TTR, making them less clinically useful 19 …”