Objective: This study was to determine the effect of patient booklet and the dosage adjustment protocol on oral anticoagulant therapy monitoring. The outcome measures were (1) number of International Normalized Ratio (INR) results/number of clinic visits (2) number of INR within therapeutic range (TR)/number of INR results (3) number of dosage adjustments following the protocol/number of INR outside TR (4) number of clinic visits/number of appointments (5) number of emergency room (ER) visits and/or hospital admissions associated with warfarin therapy.
Materials and Methods: The study was divided into 3 phases. Phase 1 was a 10-month control phase (January – October 1997). During phase 1, patients received only anticoagulants as issued in the prescriptions without INR monitoring by pharmacists. Phase 2 was a 12-month counseling phase (November 1997 - October 1998) during which patients were interviewed and counseled by a pharmacist. Along with counseling, the pharmacist provided a warfarin leaflet to patients. Pharmacist counseling continued for every warfarinised patients in the heart clinic. Nurses in the heart clinic transferred OPD cards to the pharmacists by asking patients to carry the card with their prescriptions. Phase 3 was an 8-month study phase (November 1998 - June 1999). During the phase 3, patients received drug counseling similar to phase 2 but instead of a warfarin leaflet, patient booklets on warfarin with an INR record table were given. Twelve patients were interviewed for satisfaction with the booklet. Eleven of them (91.7%) were satisfied with the booklet, the other one had his own booklet from another hospital. In this phase, the investigator also provided the dosage adjustment protocol to every physician in the heart clinic. The investigator described the details of dosage adjustment protocol individually. The patients attending the heart clinic were divided into 2 groups. Group 1 was patients visi-ting the heart clinic before and during phase 1. Group 2 was those entering the heart clinic during phase 2.
Results: The study showed that, in group 1 patients (n = 38), the number of INR results in phase 3 was increased as compared to phase 1 and phase 2 (p < 0.001 and < 0.025, respectively). In group 2 patients (n = 24), the number of INR results in phase 3 was increased as compared to that of phase 2 (p < 0.001). The number of INR within therapeutic range (TR) in group 1 patients was significantly increased in phase 3 as compared to those of phase 1 and phase 2 (p = 0.001 and 0.005, respectively). The corresponding figures in group 2 patients were not different between phase 3 and phase 2 (p > 0.05). The number of dosage adjustments following the protocol when INR was outside the TR was not different between each phase in either group of patients. Except for group 1 patients, the number of dosage adjustments was increased in phase 3 as compared to that of phase 2 (p < 0.05). The number of clinic visits following appointments was not different between each phase in either group of patients. For group 1 patients, the number of hospital admissions and ER visits associated with warfarin therapy were 10, 2 and 4 in phases 1, 2 and 3, respectively. The corresponding figures in group 2 patients were 2 in both phases 2 and 3.
Conclusion: The results showed that the patient booklet increased patient compliance to clinic visit, according to the physician's appointment, to have INR tested. The dosage adjustment protocol could contribute to INR being in the TR in group 1 patients, but it had no effect in group 2 patients. The explanation may be that some of the group 1 patients had received dosage adjustments from specialty hospitals and had been recommended to keep the target INR similar to the dosage adjustment protocol in this study. But group 2 patients had received warfarin in Maharaj Nakhon Sri Thammarat Hospital, where physicians had different dosage adjustment protocols. The dosage adjustment protocol was not followed except for group 1 patients. This might be due to the variation in warfarin adjustment of individual physicians. Further study should focus on the consensus guideline agreement between physicians and pharmacists. Patients attending the clinic should be monitored more frequently and regularly.