A before and after study of warfarin monitoring in a single region as part of the Scottish patient safety programme in primary care

Abstract

Introduction

Warfarin is an effective drug for patients at risk of thromboembolic events, but sub-optimal pharmacological management may cause significant harm. As part of the Scottish patient safety programme in primary care, one health board region aimed to determine if the international normalised ratio control for patients taking warfarin in general practice improved over the first 12 months of participation.

Methods

A before and after study of a multi-intervention improvement strategy was employed that combined financial incentivisation, a regional learning collaborative, clinical care bundle implementation, audit and feedback and clinical ‘safety champions’. The main patient outcome measures were: mean time in therapeutic range; proportion with good control (time in therapeutic range >60%) and excellent control (time in therapeutic range > 75%); and the proportion of very abnormal results (international normalised ratio < 1.5 or >5). Chi-square tests were used to determine statistical differences.

Results

In total, 49 of 55 general practices participated (89%) with 33/55 providing usable data (60%) on 1480 patients (before) and 1946 patients (after), respectively. Improvements were observed in mean time in therapeutic range (P < 0.05) as well as in the proportion of patients with good control (time in therapeutic range > 60%, P < 0.01) and excellent control (time in therapeutic range > 75%, P = 0.06). A reduction in the proportion of very abnormal results (international normalised ratio < 1.5 or >5) was also observed (P < 0.01), while the mean number of patient attendances reduced (P < 0.05).

Conclusions

The introduction of a complex safety improvement intervention via a national patient safety programme has resulted in modest improvements in the control of warfarin monitoring in a single region. These improvements may potentially reduce the incidence of serious adverse events. The study method, interventions and findings should be of interest to primary care settings with similar warfarin management arrangements internationally.