INTRODUCTION: Oral anticoagulation treatment (OACT)with warfarin is common in general practice. Increasingly,international normalised ratio (INR) point of care testing(POCT) is being used to manage patients. The aim of thisstudy was to describe and analyse the quality of OACT withwarfarin in general practice in the Capital Region of Denmarkusing INR POCT.
METHODS: A total of 20 general practices, ten singlehandedand ten group practices using INR POCT, were randomlyselected to participate in the study. Practice organisationand patient characteristics were recorded. INRmeasurements were collected retrospectively for a periodof six months. For each patient, time in therapeutic range(TTR) was calculated and correlated with practice and patientcharacteristics using multilevel linear regressionmodels.
RESULTS: We identified 447 patients in warfarin treatmentin the 20 practices using POCT (median: 19 patients; range:6-55). The mean TTR for all patients was 69.3% (standarddeviation (SD) = 24%), and for all practices the mean TTRwas 67.3% (SD = 6.7%). The TTR in single-handed practiceswas lower than in group practices, 64.6% (SD = 8.0%) and70.0% (SD = 3.6%), respectively; but the difference was notsignificant (4.2 percentage points (pp); 95% confidenceinterval (CI): –0.8-9.2). Short sampling intervals, e.g. 10-20days (–11 pp, 95% CI: –16-–6)) and lack of diagnostic coding(–11.8 pp; 95% CI: –19.9-–3.7) were correlated with a lowTTR.
CONCLUSION: In our study most of the general practices usingINR POCT in the management of patients in warfarintreatment provided good quality of care. Sampling intervaland diagnostic coding were significantly correlated withtreatment quality.
FUNDING: The study received financial support from theSarah Krabbe Foundation, the General Practitioners’ Educationand Development Foundation, and Quality in PrimaryCare (KAP-H) – the Capital Region of Denmark.
TRIAL REGISTRATION: not relevant.