Evolution of the measurement of quality of life in migraine.

Although headache is among the most common pain complaints seen by physicians, the measurement of health-related quality of life (HRQoL) in headache patients is in its earliest stages. Two types of questionnaire have been used to measure HRQoL in headache sufferers: general and disease-specific instruments. General quality-of-life (QoL) instruments use scales to assess QoL with respect to a number of activities within physical, social, psychological, and behavioral life domains. Disease-specific instruments reflect particular limitations or restrictions associated with specific disease states. These instruments are designed to be most sensitive in determining the effects of treatment or the longitudinal course of disease. Data from the Medical Outcomes Study Short Form (SF)-20 and SF-36 generic QoL instruments demonstrated that chronic headache disorders were associated with significant limitations in all eight health domains of patient wellbeing and functioning. The SF-20 outcomes profiles for each of the common benign headache disorders (migraine, tension-type headache, mixed headache, and cluster headache) appear to be unique for the specific headache diagnosis. The SF-20 and SF-36 were also used to compare headache disorders with other chronic illnesses. Chronic headache disorders, including migraine, were found to cause significantly more impairment of function than diabetes, hypertension, osteoarthritis, and low back pain. Preliminary studies of QoL during pharmacologic therapy have suggested that disease specific instruments may be more sensitive than generic instruments for evaluating the longitudinal impact of treatment. Generic QoL instruments, such as the SF-20 or SF-36, may be more useful to define populations being studied than to measure changes in the population over time. The publication of headache-specific QoL instruments, which have been widely used in clinical trials and have been validated, is awaited. Until such time, the SF-36 will remain the standard measure of QoL in headache.