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Meta-Analysis
. 2018 Mar 13;13(3):e0194208.
doi: 10.1371/journal.pone.0194208. eCollection 2018.

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

Jasper H A van Miert  1 , Sarah Bos  2 , Nic J G M Veeger  3 , Karina Meijer  1
Affiliations
Meta-Analysis

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

Jasper H A van Miert et al. PLoS One. .

Abstract

Background: Vitamin 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.

Objectives: To evaluate the predictive value and clinical usefulness of the SAMe-TT2R2 score to identify those at risk for poor VKA control.

Methods: We 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.

Results: 16 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).

Conclusion: The SAMe-TT2R2 score does predict low TTR, but the effect is small. Its effect on individual patients is too limited to be clinically useful.

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Conflict of interest statement

Competing Interests: Mr. van Miert reports speaker fees from Federatie Nederlandse Trombosediensten, outside the submitted work. Ms. Bos reports that she is currently working from an unrestricted research grant. This grant was requested to be used on an investigator initiated research and it was acknowledged by Daiichi Sankyo. This grant is used outside the scope of the submitted work. Dr. Veeger has nothing to disclose. Dr. Meijer reports other from Baxter, grants and other from Bayer, grants and other from Sanquin, grants and other from Pfizer, other from Boehringer Ingelheim, other from BMS, other from Aspen, other from Uniqure, outside the submitted work. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1
Fig 1. PRISMA flowchart [14] detailing the search strategy used.
Fig 2
Fig 2. Calibration plot comparing simulated values with the corresponding values from the original studies.
Fig 3
Fig 3. Forest plots showing positive and negative likelihood ratios (LR+, LR-) of the SAMe-TT2R2 score, using cutoffs of ≥2 and ≥3 to predict a TTR <70%.
Fig 4
Fig 4. Pre-test and post-test probabilities plot for the possible SAMe-TT2R2 scores.
Results from individual studies are indicated by dots, with the horizontal and vertical lines representing the 95% confidence interval.
See this image and copyright information in PMC

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