Schneider L S, Olin J T, Lyness S A, Chui H C
Department of Psychiatry, Los Angeles 90033, USA.
J Am Geriatr Soc. 1997 Aug;45(8):923-8. doi: 10.1111/j.1532-5415.1997.tb02960.x.
To identify the percentage of patients with Alzheimer's disease (AD) in a general clinic population who would be provisionally eligible for randomized clinical trials and the extent to which these patients represent the overall clinic-based population.
Many randomized clinical trials have restricted enrollment criteria that may limit generalizability, i.e., AD patients who fulfill selection criteria for phase III clinical trials may not be representative of other AD patients in clinical settings.
Patients diagnosed as probable or possible AD from the nine clinical sites of the State of California's Alzheimer's Disease Diagnostic and Treatment Centers (ADDTC) were selected on the basis of their provisionally fulfilling the inclusion and exclusion criteria of two typical AD clinical trials at the time of their first visit (ECG and brain imaging criteria were not available).
From a sample of 3470 subjects with possible or probable AD, overall, only 4.4% or 7.9% would have been provisionally eligible for each of two trials. Patients provisionally eligible were younger, relatively underrepresented by women, better educated, wealthier, and more likely to be white than ineligible patients. The major independent demographic predictors for eligibility were (1) income greater than $15,000 per year, (2) male gender, and (3) college education. More than 60% of probable AD patients were excluded because of significant behavioral problems; approximately one-quarter each were excluded because of significant medical or neurological problems. Allowing patients with probable or possible AD to enroll would have resulted in 10.6% being eligible.
Selection criteria for AD clinical trials result in a demographically and clinically constrained subgroup that is not representative of the overall clinic population.
确定普通门诊人群中可能符合随机临床试验条件的阿尔茨海默病（AD）患者的比例，以及这些患者在整个门诊人群中的代表性程度。
许多随机临床试验都有严格的纳入标准，这可能会限制研究结果的普遍性，即符合III期临床试验入选标准的AD患者可能无法代表临床环境中的其他AD患者。
从加利福尼亚州阿尔茨海默病诊断与治疗中心（ADDTC）的九个临床站点中，选取首次就诊时初步符合两项典型AD临床试验纳入和排除标准的患者（当时无法获取心电图和脑成像标准）。
在3470例可能患有或确诊为AD的受试者样本中，总体而言，两项试验中分别只有4.4%或7.9%的患者可能初步符合条件。与不符合条件的患者相比，初步符合条件的患者更年轻，女性比例相对较低，受教育程度更高，更富有，且更可能是白人。符合条件的主要独立人口统计学预测因素为：（1）年收入超过15,000美元；（2）男性；（3）大学学历。超过60%的确诊AD患者因严重行为问题被排除；约四分之一的患者因严重医疗或神经问题被排除。允许可能患有或确诊为AD的患者入组将使10.6%的患者符合条件。
AD临床试验的入选标准导致了一个在人口统计学和临床特征上受限的亚组，该亚组不能代表整个门诊人群。
