V. Rollason, I. Welle, J. Iavindrasana, R. Meyer, P. Chopard, J. A. Desmeules; Geneva University Hospitals, Geneva 14, Switzerland

BACKGROUND: Studies focusing on oral anticoagulation control while the patient is hospitalized are lacking. Oral vitamin-K antagonist (VKA) anticoagulants have a narrow therapeutic index and bleeding as a frequent and serious adverse drug reaction (ADR). The Internationalized Normalized Ratio (INR) is one of the only valid and accepted measures for evaluation of the “therapeutic range” (INR=2-3). The aim of our study was to identify parameters that could lead to a better surveillance of these patients through our electronic medical records system (EMRS).
METHODS: Data from all patients hospitalized in our university hospital in 2012 were retrieved from our EMRS. The population was separated into patients with or without VKA. Outcome measures suggesting a possible complication related to anticoagulation included death and transfer to intensive care unit (ICU). Proportion of INRs in range was defined as the number of “in range” INRs for one patient over the total number of the patient’s INR results during VKA treatment.
RESULTS: Among the 37,572 patients, 3,555 (9.5%) had taken a VKA. VKA patients were older (74.5 vs. 63.3 yrs), stayed longer (25 vs. 12 days) and were transferred to ICU twice as often (19.0% vs. 9.4%). Surprisingly, death was identical between both groups (3.74% vs. 3.81%). Among the VKA patients that died, 59% experienced an INR > 4.5 compared to 25% for survivors. Indicators of an ADR in the acenocoumarol population showed that 25.9% experienced an INR > 4.5. The proportion of in range INRs was of 25%.
CONCLUSION: VKA patients differed significantly from the rest of our hospitalized population and are at higher risk of prolonged hospitalization or transfer to ICU. Oral anticoagulation quality control could be improved by a more accurate tracking of selected ADR indicators in our EMRS.