International Psychogeriatric Association consensus statement on defining and measuring treatment benefits in dementia.

Current symptomatic treatments for dementia have only modest efficacy. Assessing meaningful benefits in this variably progressive syndrome is complex and difficult. This consensus statement was generated by an international group representing caregivers, organizations and professionals with expertise in dementia. We recommend the statement of clear, pre-defined diagnostic and severity criteria and outcome measures, which include functional and executive capacity, in treatment trials. Outcomes can include effects on people with dementia (PWD) with regard to cognition, behavioral and psychological symptoms, quality of life, global assessments, and activities of daily living, and must be tailored to the education and culture of the participants. Outcomes can also appropriately encompass effects on caregivers. New instruments may be needed, as validation of many existing measures has been in relatively homogenous populations. Treatment goals can be to prevent dementia emerging, or in those with established dementia to slow deterioration, and to postpone, stabilize or improve symptoms. Comparisons between treatment groups should be on the basis of clinically relevant measures with both risk and benefit reported for all participants regardless of whether or not they continue to receive treatment throughout the trial. Characterization of any groups that respond well to treatment has been unsuccessful to date, but may be facilitated in the future by measurement of putative biomarkers. Despite considerable recent progress and several 'candidate' biomarkers, none is yet satisfactory for determining diagnosis, severity, progression or prediction of response. To provide meaningful data, economic analyses should use up-to-date, country-specific data. Health economic measures should be incorporated as secondary outcomes in all Phase 3 trials since health systems are concerned with cost-effectiveness as well as clinical outcome. Health utility measures are not, however, validated satisfactorily in dementia, thus calling into question previous health economic analyses. While current drugs appear to reduce the amount of family caregiver time required by PWD, these costs fall in the main on older individuals who often exert little political leverage, rather than on society at large. Traditionally, elderly people have been marginalized in the political process. The growth in the older population across the world, and their potential for increasing political empowerment may lead to a radical re-evaluation of the economics of treatment in dementia.