title: Drug and Exercise Treatment of Alzheimer Disease and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis of Effects on Cognition in Randomized Controlled Trials.
abstract: OBJECTIVE
  Demographic changes are increasing the pressure to improve therapeutic strategies against cognitive decline in Alzheimer disease (AD) and mild cognitive impairment (MCI). Besides drug treatment, physical activity seems to be a promising intervention target as epidemiological and clinical studies suggest beneficial effects of exercise training on cognition. Using comparable inclusion and exclusion criteria, we analyzed the efficacy of drug therapy (cholinesterase inhibitors, memantine, and Ginkgo biloba) and exercise interventions for improving cognition in AD and MCI populations.
  
  
  METHODS
  We searched The Cochrane Library, EBSCO, OVID, Web of Science, and U.S Food and Drug Administration data from inception through October 30, 2013. Randomized controlled trials in which at least one treatment arm consisted of an exercise or a pharmacological intervention for AD or MCI patients, and which had either a non-exposed control condition or a control condition that received another intervention. Treatment discontinuation rates and Standardized Mean Change score using Raw score standardization (SMCR) of cognitive performance were calculated.
  
  
  RESULTS
  Discontinuation rates varied substantially and ranged between 0% and 49% with a median of 18%. Significantly increased discontinuation rates were found for galantamine and rivastigmine as compared to placebo in AD studies. Drug treatments resulted in a small pooled effect on cognition (SMCR: 0.23, 95% CI: 0.20 to 0.25) in AD studies (N = 45, 18,434 patients) and no effect in any of the MCI studies (N = 5, 3,693 patients; SMCR: 0.03, 95% CI: 0.00 to 0.005). Exercise interventions had a moderate to strong pooled effect size (SMCR: 0.83, 95% CI: 0.59 to 1.07) in AD studies (N = 4, 119 patients), and a small effect size (SMCR: 0.20, 95% CI: 0.11 to 0.28) in MCI (N = 6, 443 patients).
  
  
  CONCLUSIONS
  Drug treatments have a small but significant impact on cognitive functioning in AD and exercise has the potential to improve cognition in AD and MCI. Head-to-head trials with sufficient statistical power are necessary to directly compare efficacy, safety, and acceptability. Combining these two approaches might further increase the efficacy of each individual intervention.
  PROSPERO (2013:CRD42013003910).
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany. Electronic address: andreas.stroehle@charite.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ströhle
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Dietlinde K
authors.initials: DK
authors.lastname: Schmidt
authors.affiliation: Psychologische Hochschule Berlin, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Schultz
authors.affiliation: Psychologische Hochschule Berlin, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Fricke
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Theresa
authors.initials: T
authors.lastname: Staden
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hellweg
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Germany; Department of Neuropsychiatry, Charité - Universitätsmedizin Berlin, Germany; Cluster of Excellence, NeuroCure, German Center for Neurodegenerative Diseases and BIH, Berlin, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Priller
authors.affiliation: Social and Preventive Medicine, University of Potsdam, Potsdam, Germany.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rapp
authors.affiliation: Berlin School of Public Health, Charité - Universitätsmedizin Berlin, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Rieckmann
mesh_terms: D000544:Alzheimer Disease / Q000503:physiopathology / Q000628:therapy*; D003071:Cognition / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology / Q000628:therapy*; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
keywords: Alzheimer dementia; drug; exercise; mild cognitive impairment