title: Clinical observational research on Alzheimer's disease: what clinical trial registries can tell.
abstract: This study describes the main characteristics of ongoing observational studies on Alzheimer's disease (AD) to help identify any important research gaps. A search through the WHO International Clinical Trials Registry Platform and on the Primary Registries was conducted on 9 June 2012. The descriptors 'recruiting' or 'open' were used to describe a study's recruitment status. 62 studies are being conducted in 18 countries (Australia, Far-East, Middle-East, North America, and Western Europe). The US and France are involved in 55% of these studies. The studies aimed to recruit 20 to 10,000 participants, lasting 8 months to 24 years; 46% are case-control, whereas 44% are cohort studies; 60% and 34% are longitudinal and cross-sectional, respectively. The majority are sponsored by hospitals, universities, medical centers, or public health systems (63%), and are conducted in single centers (55%). 37 use imaging (MRI, PET, SPECT), 18 conduct lumbar puncture, 21 collect DNA and/or RNA, and 15 collect ApoE genotyping. 17 studies are medium-term prospective disease progression studies, the majority to assess mild cognitive impairment (MCI) or/and AD progression; only 3 are on cognitively normal older people at risk (2 studies, n = 180) or not (1 study, n < 200) of developing MCI. Observational studies are being conducted in few countries, with very few in low and middle-income countries where the majority of AD patients live. There is a remarkable interest in disease progression studies; however, longitudinal, long-term studies, on cognitively normal middle-age individuals, of key importance to try to fully understand the preclinical phase of AD, are lacking.
authors.affiliation: Clinical Research Program, Pasqual Maragall Foundation, Barcelona, Spain. rdal-re@fpmaragall.org
authors.forename: Rafael
authors.initials: R
authors.lastname: Dal-Ré
authors.forename: Karine
authors.initials: K
authors.lastname: Fauria
authors.forename: Nina
authors.initials: N
authors.lastname: Gramunt
authors.forename: José Luis
authors.initials: JL
authors.lastname: Molinuevo
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000628:therapy*; D001057:Apolipoproteins E; D002986:Clinical Trials as Topic; D060825:Cognitive Dysfunction / Q000209:etiology / Q000628:therapy; D003430:Cross-Sectional Studies; D016208:Databases, Factual / Q000706:statistics & numerical data; D003952:Diagnostic Imaging; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D019370:Observation; D012042:Registries
chemical_list: D001057:Apolipoproteins E