Health-related quality of life: a primer for gastroenterologists.

The evolution of health care has required physicians to evaluate more critically the impact of interventions on their patients' well-being. Prior clinical interventions focused primarily on biochemical and histological endpoints. These outcomes frequently were tenuously linked to patient benefit. Recently there has been a movement toward patient-oriented outcomes, including health-related quality of life (HRQL). The medical literature now frequently describes the effects of therapies on HRQL. Gastroenterologists need to understand the concepts behind HRQL and the use and utility of the various instruments employed to measure this outcome. The purpose of this article is: 1) to define the concept of health-related quality of life (HRQL); 2) to assess when measurement of HRQL can guide clinical decision-making; 3) to describe the desired properties of an HRQL instrument; and 4) to distinguish types of HRQL instruments. We discuss the varied definitions of HRQL and the clinical scenarios in which they are important. The psychometric properties of HRQL instruments, including validity, reliability, responsiveness, sensitivity, and coverage are defined and discussed. The types of instruments such as health profile, time trade-off, and standard gamble are contrasted. Finally, we compare generic and disease-specific instruments regarding their uses, strengths, and weaknesses. HRQL reflects patients' perceptions of disease and its impact on health status. It is becoming an increasingly important endpoint in therapeutic trials. By understanding its components and how it can meaningfully be measured, gastroenterologists may be better able to optimize the benefit patients receive from their medical interventions.