Original Research Article
Joseph R Smith and Manraj Barh
This retrospective multi-centred cohort study assessed non-vitamin K oral anticoagulation (NOAC) prescribing in 4 separate general practices in the UK. Using NICE clinical knowledge skills (NICE-CKS) guidelines we assessed the accuracy and validity of NOAC prescribing. We identified 337 patients on NOACs. The most commonly prescribed NOAC was Apixaban (65.3%), followed by Rivaroxaban (20.5%), Dabigatran (10.4%) and Edoxaban (3.8%). Prescribing was predominantly carried out in secondary care (wards 51.9%, clinics 19.3%) with 28.8% of prescribing in general practice. The most common indication requiring anticoagulation was arrhythmias (80.1%), followed by venous thrombus embolus (VTE) (18.1%). The remaining indications were for unlicensed use (1.8%) including left ventricular thrombus, portal vein thrombus, and cardiac transplant. Furthermore, of the patients on a NOAC for an arrhythmia, 2.1% and 0.6% were for atrial tachycardia and recurrent sinus ventricular tachycardia respectively, also unlicensed indications. We found 80 patients (23.7%) on the incorrect NOAC dose with 62% under anti-coagulated 38% over anti-coagulated. Of the patients under anti-coagulated, one had subsequently had a stroke and one a transient ischaemic attack. Of the patients over anti-coagulated, one patient had a significant upper gastrointestinal bleed. The reasons for incorrect prescribing included worsening renal function (64%), deteriorating weight (24%), and increasing age (12%). We found only 30% of patients were followed up adequately at three and twelve months post NOAC prescribing. We found patients that had direct contraindications to NOACs. These contraindications included two patients with an abdominal aortic aneurism, two patients with active cancer and one with a recent haemorrhage. We also found five patients with provoked VTEs still on a NOAC beyond 6 months treatment. Furthermore, in those patients with unprovoked VTEs requiring lifelong prophylaxis-treatment, we found three patients still on the higher treatment-dose NOAC.