Resource Utilization and Outcomes in Patients with Atrial Fibrillation

Article excerpt

Key points for decision makers

* Estimates of resource utilization based on 'real world' clinical practice are required to evaluate the cost effectiveness of novel treatments for atrial fibrillation (AF)

* Resource utilization of GPs, hospitalizations and prescribing is significantly increased in AF patients compared with controls

* Increases in resource utilization were present across stroke risk categories and current (or past) use of warfarin or aspirin

* The mortality rate amongst patients with AF was 3-fold higher than controls, and the increase in risk was not restricted to cardiovascular deaths alone

Introduction

Atrial fibrillation (AF) is the most common sustained disorder of cardiac rhythm. The condition is associated with an increased mortality and morbidity from stroke, thromboembolism and heart failure.[1] The approach to management of AF emphasizes thromboprophylaxis, then consideration of rate or rhythm control, although this is largely symptom directed.[2]

Various new anticoagulation and antiarrythmic treatments are being investigated for the treatment of AF. Before novel treatments can be used widely in actual clinical practice, the cost effectiveness of such novel treatments may need to be determined. In England and Wales, formal cost-effectiveness analyses are now required and several years ago the National Institute for Health and Clinical Excellence (NICE) was established to balance the financial costs and clinical benefits of health technologies and evaluate their cost effectiveness.[3,4] Cost effectiveness is typically evaluated in models that vary treatment in a given scenario of drug effects, incidence rates of outcomes and costs. Randomized clinical trials (RCTs) are typically used not only for the estimate of drug effect but also for the absolute incidence rates.[5,6] Indeed, several cost-effectiveness analyses of treatments in AF used RCT data for incidence rates in the modelling.[7-12] Nonetheless, recent research has found that cost-effectiveness analyses based on RCTs may lack external validity, unless they reflect the experience of patients in actual 'real world' clinical practice.[13] One of the reasons for this is that patients in actual clinical practice may be different from those enrolled into RCTs and that incidence rates of outcomes may vary.

The objectives of this study were to describe the resource utilization (primary and secondary care) in AF and control patients in 'real world' clinical practice, and to describe the incidence rates of clinical outcomes and mortality and primary causes of death.

Patients and Methods

Data for this study were obtained from the General Practice Research Database (GPRD, April 2009 version, covering approximately 6% of the UK population). GPRD collates the computerized medical records of general practitioners (GPs). GPs play a key role in the UK healthcare system, as they are responsible for primary healthcare and specialist referrals. Patients are registered with one general practice that centralizes the medical information from the GPs, specialist referrals and hospitalizations. The data recorded in the GPRD include demographic information, prescription details, clinical events, preventive care provided, specialist referrals, hospital admissions and major outcomes. GPRD currently includes data on over 10 million patients and has been shown to be representative of the UK population.[14] GPRD patients in over 210 English practices are now linked individually and anonymously to the national registry of hospital admission (Hospital Episode Statistics [HES]) and to the death certificates (as collected by the Office of National Statistics [ONS]). For each hospitalized patient, the hospital charts are reviewed, dates of admission and discharge and main diagnoses are extracted, coded by coding staff and collated nationally. The death certificates list the date and causes of death. HES data were available from April 1997 and death certificate data from January 2001 for about 40% of GPRD practices and only those practices that had HES and ONS data available were included in this study. …