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Multicenter Study
. 2015 Dec 4;10(12):e0144314.
doi: 10.1371/journal.pone.0144314. eCollection 2015.

Center-Related Determinants of VKA Anticoagulation Quality: A Prospective, Multicenter Evaluation

Alberto Tosetto  1 , Cesare Manotti  2 , Francesco Marongiu  3 ; Italian Federation of Anticoagulation Clinics (FCSA) clinical quality study group
Collaborators, Affiliations
Multicenter Study

Center-Related Determinants of VKA Anticoagulation Quality: A Prospective, Multicenter Evaluation

Alberto Tosetto et al. PLoS One. .

Abstract

Background: Center-specific TTR (c-TTR) is a measure reporting the mean patient TTR within an anticoagulation clinic describing the quality of anticoagulant monitoring offered by that clinic. c-TTR has a considerable between-center variation, but its determinants are poorly understood.

Objectives: We aimed at evaluating which clinical, procedural or laboratory factors could be associated with c-TTR variability in a multicenter, observational cross-sectional study over a five-year period.

Patients/methods: Data from 832,204 individual patients followed for VKA therapy in 292 Centers affiliated with the Italian Federation of Anticoagulation Clinics (FCSA) were analyzed. c-TTR was computed based on the TTR of patients followed at each Center, and a mixed linear regression model was used for a predefined set of explanatory variables.

Results: The Center next-visit interval ratio (the mean number of days after a visit with an INR outside the therapeutic range, divided by the days after a visit with an INR within the therapeutic range), the Center mean patient INR and the Center laboratory performance at EQA proficiency testing were the only variables that were independently associated with c-TTR (β-coefficients -17.32, 9.67, and -0.11, respectively; r2 = 0.635).

Conclusions: These findings suggest that c-TTR associates with proactive strategies aimed at keeping patients very close to their target INR with a prompt re-evaluation of those patients with under- or over-therapeutic INR.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Boxplot of Center TTR by study year, showing the overall increase of anticoagulation quality over the years.
Fig 2
Fig 2. Boxplot of Center TTR by quintiles of Center mean patient INR, showing an inverse U-shaped relationship between mean patient INR and TTR.
Fig 3
Fig 3. Relationship between Center TTR and Center Next Visit Interval (NVI) ratio, which is defined as the ratio of days between visits when the INR was below or above range divided by days between visits when the INR was in the therapeutic range.
Fig 4
Fig 4. Boxplot of Center Next Visit Interval (NVI) ratio by number of physicians attending the Anticoagulation Clinic, showing an inverse relationship (p<0.0001 for trend).
See this image and copyright information in PMC

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