Qualitative study of patient experiences of responsibility in warfarin therapy

PURPOSE Results of a study to characterize the experiences of warfarin-treated patients, including their experiences in taking medication, communicating with clinical pharmacists, and International Normalized Ratio (INR) monitoring, are reported. METHODS A qualitative analysis of data obtained during interviews with 40 patients at a Veterans Affairs medical center warfarin clinic was conducted. In semistructured interviews, the patients were asked to describe the process whereby their INR values were monitored by pharmacists and their understanding of self-management responsibilities, including medication adherence and implementation of lifestyle modifications that might influence the effectiveness of anticoagulation therapy. RESULTS Analysis of interview results indicated that patients' experience in the event of variation in INR levels is characterized by misperceptions of the instructions regarding appropriate dietary and lifestyle behaviors, misattribution of responsibility for abnormal readings, and provider uncertainty in ascertaining causation for out-of-range INR values. Patients frequently reported that they interpret pharmacist questions to imply that they are responsible for variable INR values. This perception may indirectly lead to adverse consequences such as withholding of information from anticoagulation care providers and skipping clinic appointments, which could in turn result in suboptimal clinical outcomes. CONCLUSION Analysis of results of qualitative interviews of patients receiving warfarin indicated that patients may interpret routine questioning about INR variation as implying that they are to blame for poor anticoagulation control.