Time in Therapeutic Range for Dialysis Patients on Warfarin: Determination and the Effect of Dietary Intervention

This study aimed to identify the time in therapeutic range (TTR) for dialysis patients on warfarin, and improve TTR with dietary review and intervention of interacting foods. We identified 151 patients undergoing hemodialysis in two units who were being treated with warfarin from January 1, 2010, through February 1, 2018, who were included in the overall TTR study. Of these, 15 patients were available to undergo the dietary intervention. International normalized ratio values were collected retrospectively for all eligible hemodialysis patients, and TTR was calculated for each period in which the patient was on hemodialysis. Patients who were available and agreed to the intervention underwent targeted dietician review of interacting foods, and their TTR post-treatment was calculated. The median (interquartile range [IQR]) TTR was 44 (IQR, 29 to 53) % among the 151 patients. Among the 15 patients who underwent the intervention, median (IQR) TTR was 52 (IQR, 32 to 56) pre-intervention and 51 (IQR, 38 to 69) post-intervention (P=0.53). TTR for dialysis patients is low in this overall cohort despite patients being seen at an integrated health care system. Focused improvement projects such as dietary review of interacting foods may help increase a patient's TTR.