Editorials: Controversies in Family Medicine
Should Family Physicians Routinely Screen Patients for Cognitive Impairment? No: Screening Has Been Inappropriately Urged Despite Absence of Evidence
Am Fam Physician. 2014 Jun 1;89(11):864-865.
Related editorial: Should Family Physicians Routinely Screen Patients for Cognitive Impairment? Yes: Screening Is the First Step Toward Improving Care
This is one in a series of pro/con editorials discussing controversial issues in family medicine.
The evidence base and principles that underpin the introduction of population screening for any condition are accepted internationally.1,2 Dementia screening should not be exempt from the requirement that it first be shown to improve outcomes before being implemented in practice, despite growing pressure to do so in the United States and the United Kingdom. In the United Kingdom, this is partly driven by an expressed need to increase the proportion of persons diagnosed with dementia to come closer to the government's geographic estimates.3 Yet, the evidence base for rolling out screening campaigns is not yet available, and accordingly, screening is not supported by expert groups in the United States4 or the United Kingdom.5,6
Several questions should be asked before instituting a broad screening campaign. First, are the tests precise and validated? No. Screening tests for dementia include a range of brief cognitive tests, such as the Abbreviated Mental Test, Mini-Mental State Examination, General Practitioner Assessment of Cognition, and Cambridge Neuropsychological Test Automated Battery.7 These tests may be useful as part of the evaluation of a patient with cognitive problems, provided there is additional evidence of functional decline and other features of dementia; however, such tests are influenced by many factors apart from dementia, including education, ethnicity, sensory impairment, mood, and comorbidities.8 When performed in community populations with low prevalence, they can have false-positive rates as high as 23%.9 Screening methods based on detection of “preclinical” neuropsychological profiles and Alzheimer disease neuropathology (e.g., amyloid scans, cerebral spinal fluid protein measurements) have not yet been validated in relevant population studies for diagnostic or prognostic value.10,11 Moreover, in older persons in whom the incidence of dementia is greatest, many persons who will never develop dementia have Alzheimer disease pathology.12
Next, are there any interventions with demonstrable value in reducing mortality and morbidity for those persons identified by screening as having dementia at an earlier stage than usual clinical presentation? No. Rigorous trial evidence of benefit does not yet exist. Advice regarding exercise, nutrition, smoking, avoiding medications that impair cognition, and making advance care directives is useful for all older persons, not just those with screening tests positive for cognitive impairment.
No pharmacologic therapies delay progression of dementia. Cholinesterase inhibitors and memantine (Namenda) have only modest symptomatic effectiveness,13,14 and there is no current evidence that patients with cognitive impairment detected by screening will benefit in a meaningful way. Studies that suggest dementia-specific counseling and advice following early diagnosis might decrease institutionalization are inconclusive.15
Finally, are there potential harms of dementia screening and subsequent interventions? Yes. The U.S. Preventive Services Task Force (USPSTF) indicates that harms can be associated with any type of screening, including psychological harms from labeling, and direct harms associated with diagnostic tests, early treatments, and overtreatment.1 There are reports of stress, stigmatization, suicidality, and loss of autonomy following evaluation for and diagnosis of early dementia,3,16 and there are clear adverse effects from dementia medications.13 Screening campaigns also may divert societal attention and resources from those patients with established dementia whose care needs are greatest. A survey in the United Kingdom reported that one in five physicians had received complaints from patients who were unhappy about dementia screening, whereas two-thirds had noted increased waiting times for memory clinics.17
Both the USPSTF4 and the U.K. National Screening Committee5 have found insufficient evidence to recommend dementia screening. This emphasizes the need for ongoing research into all elements of dementia screening, from tests to robust prognosis and effective interventions. Physicians also need to ensure that resources are not diverted and patients are not alienated by the premature implementation of a screening program that is not yet supported by an appropriate evidence base, including randomized clinical trials.
REFERENCESshow all references
1. U.S. Preventive Services Task Force. Procedure manual. July 2008. AHRQ Publication No. 08-05118-EF. http://www.uspreventiveservicestaskforce.org/uspstf08/methods/procmanual.pdf. Accessed March 6, 2014....
2. UK National Screening Committee. Programme appraisal criteria. http://www.screening.nhs.uk/criteria. Accessed March 6, 2014.
3. Le Couteur DG, Doust J, Creasey H, Brayne C. Political drive to screen for pre-dementia: not evidence based and ignores the harms of diagnosis. BMJ. 2013;347:f5125.
4. Screening for cognitive impairment in older adults: U.S. Preventive Services Task Force recommendation statement [published online ahead of print March 25, 2014]. Ann Intern Med. http://annals.org/article.aspx?articleid=1850963. Accessed March 26, 2014.
5. UK National Screening Committee. The UK NSC policy on Alzheimer's disease screening in adults. June 2010. http://www.screening.nhs.uk/alzheimers. Accessed March 6, 2014.
6. Burns A, Buckman L. Timely diagnosis of dementia: integrating perspectives, achieving consensus. July 2013. British Medical Association and NHS England. http://www.dementiaaction.org.uk/assets/0000/3808/NHS_England_BMA_Diagnosis_Consensus.pdf. Accessed March 6, 2014.
7. Lin JS, O'Connor E, Rossom RC, et al. Screening for cognitive impairment in older adults: an evidence update for the U.S. Preventive Services Task Force. Rockville, Md.: Agency for Healthcare Research and Quality; 2013. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0063382/. Accessed March 20, 2014.
8. Fox C, Lafortune L, Boustani M, Dening T, Rait G, Brayne C. Screening for dementia—is it a no brainer? Int J Clin Pract. 2013;67(11):1076–1080.
9. Mitchell AJ, Meader N, Pentzek M. Clinical recognition of dementia and cognitive impairment in primary care: a meta-analysis of physician accuracy. Acta Psychiatr Scand. 2011;124(3):165–183.
10. Stephan BC, Kurth T, Matthews FE, Brayne C, Dufouil C. Dementia risk prediction in the population: are screening models accurate? Nat Rev Neurol. 2010;6(6):318–326.
11. Pearson SD, Ollendorf DA, Colby JA. Amyloid-ß positron emission tomography in the diagnostic evaluation of alzheimer disease: summary of primary findings and conclusions. JAMA Intern Med. 2014;174(1):133–134.
12. Wharton SB, Brayne C, Savva GM, et al.; Medical Research Council Cognitive Function and Aging Study. Epidemiological neuropathology: the MRC Cognitive Function and Aging Study experience. J Alzheimers Dis. 2011;25(2):359–372.
13. O'Brien JT, Burns A; BAP Dementia Consensus Group. Clinical practice with anti-dementia drugs: a revised (second) consensus statement from the British Association for Psychopharmacology. J Psychopharmacol. 2011;25(8):997–1019.
14. Masoodi N. ACP Journal Club. Review: cholinesterase inhibitors do not reduce progression to dementia from mild cognitive impairment. Ann Intern Med. 2013;158(4):JC3.
15. Waldorff FB, Buss DV, Eckermann A, et al. Efficacy of psychosocial intervention in patients with mild Alzheimer's disease: the multicentre, rater blinded, randomised Danish Alzheimer Intervention Study (DAISY). BMJ. 2012;345:e4693.
16. Haw C, Harwood D, Hawton K. Dementia and suicidal behavior: a review of the literature. Int Psychogeriatr. 2009;21(3):440–453.
17. Stirling A. GPs hit by widespread complaints from patients ‘unhappy’ over dementia screening. Pulse. November 2013. http://www.pulsetoday.co.uk/clinical/therapy-areas/elderly-care/gps-hit-by-widespread-complaints-from-patients-unhappy-over-dementia-screening/20005138.article#.U1aChMdOhZY. Accessed March 6, 2014.
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