QUALITY-OF-LIFE - RATIONALE AND METHODS FOR DEVELOPING A DISEASE-SPECIFIC INSTRUMENT FOR INFLAMMATORY BOWEL-DISEASE

Quality of Life (QOL) is a composite descriptor applied to an unlimite d spectrum of tangible and intangible parameters of life satisfaction and capacity. Because of the breadth of determinants of QOL, most rese archers prefer to focus on a specific segment of it, such as health-re lated quality of life (HRQOL). Generally, HRQOL indices incorporate ph ysical, emotional and social aspects of both health perception and fun ction. Most instruments are also subjective and quantitative. As in cl inical trials, several elements are critical to the development of a H RQOL measure. Most importantly, the putative application of the instru ment should be determined beforehand. The clinical setting and disease -specific population of interest must be identified. The questionnaire must be as simple as possible and easy to administer. The final instr ument must be shown to be a valid measure of HRQOL, which is reproduci ble, with limited variability and observer bias on repeated administra tions, when no clinical change has occurred. If applicable, the instru ment should demonstrate responsiveness to important changes in clinica l status. Finally, the value of the instrument in relevant clinical st udies should be demonstrated. The critical phases of development of th e McMaster IBDQ are outlined. The IBDQ is a quantitative index of HRQO L intended as a measure of therapeutic outcome for clinical trials in patients with inflammatory bowel disease.