Anticoagulation control and cost of monitoring of older patients on chronic warfarin therapy in three settings in North East England.

BACKGROUND

novel oral anticoagulants may be particularly cost-effective when INR control (TTR) with warfarin is poor or monitoring difficult.

SETTING

the Newcastle upon Tyne monitoring service, set in hospital or general practice and a domiciliary-based service for housebound patients.

OBJECTIVES

to examine anticoagulation stability and costs of monitoring.

SUBJECTS

three hundred and twenty-six atrial fibrillation patients, 75 years and over, with target INR of two to three, accessing hospital (n = 100), general practice (n = 122) and domiciliary (n = 104) service.

METHODS

age, co-morbidities, length of warfarin treatment, medications, INR values and dose changes from January to December 2011 were recorded, and costs analysed.

RESULTS

home-monitored patients had taken warfarin for longer, mean 5.2 years, than hospital (3.7) or general practice (3.1) patients. Age and total number of drugs prescribed chronically were negatively related to TTR. INR measurements and dose changes were negatively associated with the duration of treatment, positively correlated with co-morbidities. The mean TTR was 78% in hospital, 71% in general practice and 68% in domiciliary monitored patients. INR was monitored more often in hospital and domiciliary groups than in general practice and more dose changes occurred in the domiciliary group than in others. Costs of warfarin and monitoring were £128 per patient per year for hospital, £126 for general practice and £222 for domiciliary patients.

CONCLUSIONS

further exploration of the clinical effectiveness of novel anticoagulants in dependent patients is warranted to determine to what extent trial outcomes so far achieved in a fitter elderly population are influenced by the chronic co-morbidities of old age.