Abstract
BackgroundNearly 20% of patients > 85 are treated with vitamin K antagonist (VKA) in France. VKAs have a narrow therapeutic margin and are responsible for the majority of iatrogenic accidents. They require close biological monitoring of the International Normalized Ratio (INR) by venipuncture. Average time in therapeutic range (TTR) in nursing homes is only 57.9%. Coagulometers allow measurement of INR by capillary puncture with an immediate result.AimsThe main objective of the study was to evaluate the concordance on the therapeutic adaptation of a weekly capillary INR surveillance strategy compared to venous INR monitoring in elderly patients in a nursing home, treated by VKA.MethodsThis is a prospective interventional study of a strategy of monitoring INR by weekly capillary sampling in all patients residing in a nursing home treated with VKA for six months. Venous INR was performed when capillary INR was out of normal range, and every month systematically. Decisional concordance was analysed by the weighted kappa coefficient.ResultsA total of 31 patients were included, and 392 concomitant specimens were analysed.The decisional concordance was good (κw = 0.76, 95% CI: [0.72; 0.81]). The mean TTR was 78% during the study versus 65% during the six months prior to the study.ConclusionMonitoring by capillary INR in elderly patients is reliable and can be used alone. This technique will improve the TTR and decrease iatrogenicity associated with VKAs. It avoids the fragile venous access of these frail elderly patients and improves the care organisation.