Impact of Personal Handy-phone System (PHS) Reminder System on Practitioner Performance and Patient Outcomes in Warfarin Users

Warfarin is a common oral anticoagulant that prescribed for the management of thromboembolic disorders. It has narrow therapeutic range, and its therapeutic effect was varied due to multiple factors such as a patient’s physical condition, diet habits, and concurrently used medicines etc. Higher dosage of warfarin may increase the risk of bleeding, but lower dosage may lead to thromboembolism. Therefore, clinicians monitored warfarin effect with prothrombin time (PT) tests and standardized international normalized ratio (INR) to ensure patients’ safety and effectiveness. In general, a recommendation of a therapeutic INR value of 2 to 3 was made for most indications for Caucasians, but a lower dosage of warfarin treatment might be appropriate for Asians. e included relevant records of outpatients receiving warfarin at National Taiwan University Hospital (NTUH) from January1st, 2006 to December 31st, 2008. In this study, a total of 4794 outpatients were included, and the mean INR values of them were 2.00 ± 1.20. The incidence rate of adverse drug events was 6.1% per patient-year. PHS alert system for high PT/INR threshold values (PT > 50 seconds) has been established since May 17th, 2007 in NTUH. We defined January 1st, 2006 to May 16th, 2007 as the manual reminders period, and starting from September 1st, 2007 to December 31st, 2008 as the PHS alert system period. We assessed the impact of the new PHS alert system by comparing practitioner performance and patient outcomes between manual reminders and PHS periods. Adverse drug events in one calendar year were also analyzed between 2 groups considering seasonal effect. Physician specialty and seniority were took into account when practitioner performance was evaluated.ower dosage of warfarin treatment might be considered as appropriate for patients in Taiwan. A switch to PHS alert system from manual reminders did not compromise patient outcomes and clinician performance, and indeed improved quality of care in senior physicians. PHS alert system was promising as a reminder of laboratory alert values to clinicians.