Commentary on “Health economics and the value of therapy in Alzheimer's disease.” Quality of life in dementia: Development and use of a disease‐specific measure of health‐related quality of life in dementia

1. Has our intervention helped? Generally when we intervene in a particular situation, we want to know whether the intervention has been of use overall as well as whether specific aims have been achieved. Therefore, if one were to invade a country to depose a despotic leader and one was successful in doing so, then by using a discrete, specific outcome measure (the deposition of the despot), one might assess the intervention as a success. However, if a broad view of the costs of the intervention were undertaken and that showed undesirably high casualties for combatants and the general population and widespread impairment in living conditions for those freed from the despot, one might question the value of the intervention at a global level. In evaluating interventions in dementia there are two possible scenarios that follow from the above considerations. First, we might imagine a spouse caregiver reporting that her husband has repetitive questioning and some agitation in moderate Alzheimer’s disease (AD); a physician consulted might prescribe antipsychotic medication. This might result in sedation, with the individual sitting in the corner doing nothing with markedly decreased social communication of all kinds, not just the questioning. If measured with a specific measure of agitation or behavioral disturbance, then the treatment might be deemed to be a success, even though the lives of the person with dementia and their family caregiver might be far less rewarding. A global measure of overall impact would be expected to pick up this negative impact. Second, it might be possible for an antidementia medication to have only an equivocal effect on cognition or activity limitation in an individual with mild dementia and so to be believed to be not worth persevering with. However, if this medication also, for example, improved communication, social behavior, and the initiation of conversation and purposeful activity, then it might overall be having a useful positive effect. This might well not be picked up by prespecified discrete measures, but again one would expect a measure of overall impact to identify this beneficial impact. Thus, a lack of broad outcome measurement in intervention in dementia and a reliance on measures of discrete functions such as cognition or activity limitation could lead to the positive effects of treatments being overlooked or to potential negative effects of intervention being missed.