Recommendations on screening for cognitive impairment in older adults

Cognitive impairment occurs in a continuum, starting with aging-related cognitive decline, transitioning to mild cognitive impairment and ending with dementia. Mild cognitive impairment is noticeable but does not substantially affect daily function, whereas dementia involves cognitive changes that are severe enough to affect daily function.2,3 Although some people with mild cognitive impairment may be at higher risk of dementia than others with the diagnosis, over time some will remain stable and a few will show improvements in their cognitive abilities.1 The incidence of dementia among Canadian adults aged 65-79 years is 43 per 1000 population and rises with age (to 212 per 1000 among those aged 85 or older).4 The reported prevalence of mild cognitive impairment varies because of several factors, such as the diagnostic test score (i.e., cut-off) used to define mild cognitive impairment, age at the initial assessment and length of follow-up.5 Published Canadian cohort prevalence rates for mild cognitive impairment are not available. Studies from the United States have reported prevalence ranging from 9.9% to 35.2% among adults aged 70 or older.6-8 The US Preventive Services Task Force recently published a systematic review on screening and treatment for cognitive impairment.11 Initially, the Canadian task force updated the US task force review, assessing the effects of screening for cognitive impairment on health outcomes.9 The Evidence Review and Synthesis Centre at McMaster University independently conducted the systematic review evaluating the effectiveness of screening for cognitive impairment (Appendix 1, available at www.cmaj.ca/lookup/suppl/doi:10.1503/ cmaj.141165/-/DC1). The systematic review included the following patient-important outcomes from the US task force review: safety, healthrelated quality of life (HRQoL), cognitive function or decline, unanticipated health care utilization, independent living, medication adherence or errors, and other symptoms (e.g., insomnia, depression or agitation). Caregiver outcomes included HRQoL and caregiver burden. The study selection included randomized controlled trials (RCTs) published from Dec. 8, 2012, to Nov. 7, 2014, in the databases MEDLINE, PsychINFO and the Cochrane Central Register of Controlled Trials. No trials were identified that investigated the benefits of screening for cognitive impairment. The results are shown in Appendix 1. Given that the Evidence Review and Synthesis Centre found no evid