Assessing the quality of health-related quality of life measures

In the current issue of Cephalalgia, Manhalter and colleagues present their validation of a new headachespecific health-related quality of life (HRQoL) instrument, the Comprehensive Headache-related Quality of life Questionnaire (CHQQ) (1). Primary headache disorders can have a significant impact on all aspects of life, including daily functioning, productivity and HRQoL (2,3). There are a range of commonly used and psychometrically valid instruments developed to measure HRQoL in headache clinical care and research (4). Each of these instruments has strengths and limitations (4). Manhalter et al. reviewed existing generic and migraine-specific HRQoL instruments and concluded that there was the need for an instrument validated for both migraine and tension-type headache that better captured the reported experience of patients. As comparative effectiveness research increases in importance, patient-reported outcomes, including measures of HRQoL, will play an expanding role in assessing the burden of illness and measuring the benefits of treatment (5,6). This is particularly true for conditions that influence quality of life more than quantity of life (i.e. mortality), including the primary headache disorders. Cost effectiveness metrics often place HRQoL measures in the denominator and cost in the numerator to compute the cost per unit improvement in health outcomes. These economic indices will increasingly inform policy decisions regarding regulatory approval and reimbursement for therapeutics (7). Manhalter et al. point out that there are two broad categories of HRQoL measures: generic and disease specific. Generic measures are designed to assess the impact of a wide range of medical conditions while disease-specific measures capture the burdens of particular conditions. Generic measures facilitate the comparisons across disease categories by providing a common yardstick. They can be used to contrast the burden of a variety of disorders and to determine which treatments, across therapeutic areas, deliver the most HRQoL bang for the buck. Using these measures may help stakeholders, including healthcare professionals (HCPs), third-party payers, and funders of research to assess the relative benefits of investing in migraine care as opposed to other chronic illnesses (e.g. asthma or multiple sclerosis). Disease-specific instruments more accurately reflect the burden of specific conditions. They can be used to compare the benefits of different treatments for a condition but not to compare migraine with other disorders. In the present report, Manhalter et al. engaged in an orderly process of instrument development to create a novel headache-specific HRQoL instrument. Below, we review commonly employed procedures for developing HRQoL measures, highlighting the work done by Manhalter and colleagues in the development of the CHQQ.