Quality of life as an endpoint for atrial fibrillation research: pitfalls and practice

There have been few health-related quality-of-life (HR-QOL) studies of atrial fibrillation in nontreated cohorts, even though it often is used as an endpoint in clinical trials. Nonintervention data now available are selected for those in whom novel therapies are most often offered. These data suggest that atrial fibrillation confers an HR-QOL impact commensurate with postangioplasty and significant coronary disease groups. The correlation of HR-QOL measures and formal measures of atrial fibrillation "burden" (frequency or duration) is either poor or unknown (in the case of permanent atrial fibrillation). HR-QOL tools, although relevant, may not be as precise as traditional outcome measures. As a result, a 0.5 standard deviation unit of change in scale is needed to be considered moderate. There is a need to use validated instruments that are hypothesized to be sensitive to any intervention under study. The most studied area in atrial fibrillation has been that of ablation and pacing as rate control strategy. Depending on selection bias, SF-36 full standard deviation unit changes have been observed. Less controlled studies have documented significant benefit to left atrial ablative strategies. Device- and drug-based strategies in atrial fibrillation management have not demonstrated significant HR-QOL benefits, other than one controlled evaluation of an atrial defibrillator. Further study is needed both to refine instrument precision and to translate HR-QOL data into the denominator of cost-efficacy evaluations.