Assessment of quality of life as outcome in dementia and MCI intervention trials : A systematic review

We conducted a systematic review of the use of quality of life (QoL) measures as outcome in pharmacological and nonpharmacologic intervention trials in patients with Mild Cognitive Impairment or dementia, and their proxies. Randomized controlled trials (RCTs) were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group in April 2006. We also checked references and systematic reviews. Primary and secondary end points were screened for QoL-scales, and it was registered whether information on responsiveness was provided. We found 117 pharmacologic and 108 nonpharmacologic RCTs. One of the pharmacologic and 4 of the nonpharmacologic studies used QoL as primary outcome, and 2 and 3, respectively, as secondary end point. Altogether QoL was assessed in only 10 (4.4%) of these RCTs, of which 2 reported on responsiveness of QoL. This review provides evidence that QoL-instruments are seldom used as outcome measures in RCTs in dementia and Mild Cognitive Impairment, and that information on responsiveness is scarce. QoL-measures should be applied more often in clinical trials, as currently no disease modifying drugs are available, although there are valid and reliable QoL-measures for dementia that reflect the aims of palliative care and provide transparent information about patient's and caregiver's treatment benefits. We recommend further research efforts aimed at the determination of the minimal important difference in QoL-scales and the responsiveness of QoL-scales. Subsequently, QoL should be measured as relevant end point, both in patients and their proxies, in all clinical trials in dementia.