Department of Public Health and Primary Care, Institute of Public Health, Cambridge, UK.
Am J Geriatr Psychiatry. 2010 Aug;18(8):662-73. doi: 10.1097/jgp.0b013e3181e0450d.
Criteria for mild cognitive impairment (MCI) predict dementia risk in the clinic. Dementia risk in the population is different and whether there is an optimal MCI-derived threshold for discriminating at-risk from not-at-risk cases in the general older population is not known.
Data were from the Medical Research Council Cognitive Function and Ageing Study. Two risk thresholds were derived from each of seven different concepts of MCI including: Mayo Clinic-defined amnestic, nonamnestic, multiple, and revised MCI, MCI based on Mini-Mental State Examination derived categories, and the definitions of Cognitive Impairment No Dementia and Age-Related Cognitive Decline (ARCD). Receiver operating characteristic analysis was used to compare the predictive validity of 2-year incident dementia for each risk threshold across the different MCI definitions.
MCI-derived risk thresholds varied in their ability to predict dementia. MCI thresholds were accurate in identifying individuals not at-risk of dementia progression (false-negative range: 0%–3.4%). No MCI-derived threshold accurately identified an at-risk group with a 2-year progression rate greater than 20%. Criteria for ARCD defined the threshold with the highest sensitivity and specificity for dementia conversion.
MCI-derived thresholds do not reliably identify individuals at-risk of incident dementia at 2 years when applied in the general population. A large subpopulation of individuals not at-risk was more reliably identified. What is considered a sufficient level of accuracy for identification of individuals at increased risk of dementia depends on the motivation for screening and on the safety and efficacy of available interventions.
轻度认知障碍（MCI）的标准可预测临床中的痴呆风险。人群中的痴呆风险不同，对于一般老年人，是否存在一个最佳的 MCI 衍生阈值来区分有风险和无风险的病例尚不清楚。
数据来自医学研究委员会认知功能和衰老研究。从包括以下七种不同概念的 MCI 中，为每个风险阈值确定了两个风险阈值：梅奥诊所定义的遗忘型、非遗忘型、多种和修订型 MCI、基于 Mini-Mental State Examination 衍生类别的 MCI，以及认知障碍无痴呆和年龄相关认知减退（ARCD）的定义。使用受试者工作特征分析比较不同 MCI 定义的每个风险阈值对 2 年新发痴呆的预测效力。
MCI 衍生的风险阈值在预测痴呆方面的能力各不相同。MCI 阈值可以准确识别没有痴呆进展风险的个体（假阴性范围：0%–3.4%）。没有任何 MCI 衍生的阈值可以准确识别出具有 2 年进展率大于 20%的风险组。ARCD 标准定义了用于痴呆转换的具有最高敏感性和特异性的阈值。
当应用于一般人群时，MCI 衍生的阈值不能可靠地识别出 2 年内发生痴呆的个体。更多的个体被更可靠地识别为无风险。确定具有增加痴呆风险的个体的准确性水平取决于筛查的动机以及现有干预措施的安全性和有效性。
