Chan Calvin Ch, Fage Bruce A, Burton Jennifer K, Smailagic Nadja, Gill Sudeep S, Herrmann Nathan, Nikolaou Vasilis, Quinn Terry J, Noel-Storr Anna H, Seitz Dallas P
School of Medicine, Queen's University, 49 King Street East, Kingston, ON, Canada, K7L 2Z5.
Cochrane Database Syst Rev. 2019 Sep 14;9(9):CD011414. doi: 10.1002/14651858.CD011414.pub2.
The diagnosis of Alzheimer's disease dementia and other dementias relies on clinical assessment. There is a high prevalence of cognitive disorders, including undiagnosed dementia in secondary care settings. Short cognitive tests can be helpful in identifying those who require further specialist diagnostic assessment; however, there is a lack of consensus around the optimal tools to use in clinical practice. The Mini-Cog is a short cognitive test comprising three-item recall and a clock-drawing test that is used in secondary care settings.
The primary objective was to determine the diagnostic accuracy of the Mini-Cog for detecting Alzheimer's disease dementia and other dementias in a secondary care setting. The secondary objectives were to investigate the heterogeneity of test accuracy in the included studies and potential sources of heterogeneity. These potential sources of heterogeneity will include the baseline prevalence of dementia in study samples, thresholds used to determine positive test results, the type of dementia (Alzheimer's disease dementia or all causes of dementia), and aspects of study design related to study quality.
We searched the following sources in September 2012, with an update to 12 March 2019: Cochrane Dementia Group Register of Diagnostic Test Accuracy Studies, MEDLINE (OvidSP), Embase (OvidSP), BIOSIS Previews (Web of Knowledge), Science Citation Index (ISI Web of Knowledge), PsycINFO (OvidSP), and LILACS (BIREME). We made no exclusions with regard to language of Mini-Cog administration or language of publication, using translation services where necessary.
We included cross-sectional studies and excluded case-control designs, due to the risk of bias. We selected those studies that included the Mini-Cog as an index test to diagnose dementia where dementia diagnosis was confirmed with reference standard clinical assessment using standardised dementia diagnostic criteria. We only included studies in secondary care settings (including inpatient and outpatient hospital participants).
We screened all titles and abstracts generated by the electronic database searches. Two review authors independently checked full papers for eligibility and extracted data. We determined quality assessment (risk of bias and applicability) using the QUADAS-2 tool. We extracted data into two-by-two tables to allow calculation of accuracy metrics for individual studies, reporting the sensitivity, specificity, and 95% confidence intervals of these measures, summarising them graphically using forest plots.
Three studies with a total of 2560 participants fulfilled the inclusion criteria, set in neuropsychology outpatient referrals, outpatients attending a general medicine clinic, and referrals to a memory clinic. Only n = 1415 (55.3%) of participants were included in the analysis to inform evaluation of Mini-Cog test accuracy, due to the selective use of available data by study authors. There were concerns related to high risk of bias with respect to patient selection, and unclear risk of bias and high concerns related to index test conduct and applicability. In all studies, the Mini-Cog was retrospectively derived from historic data sets. No studies included acute general hospital inpatients. The prevalence of dementia ranged from 32.2% to 87.3%. The sensitivities of the Mini-Cog in the individual studies were reported as 0.67 (95% confidence interval (CI) 0.63 to 0.71), 0.60 (95% CI 0.48 to 0.72), and 0.87 (95% CI 0.83 to 0.90). The specificity of the Mini-Cog for each individual study was 0.87 (95% CI 0.81 to 0.92), 0.65 (95% CI 0.57 to 0.73), and 1.00 (95% CI 0.94 to 1.00). We did not perform meta-analysis due to concerns related to risk of bias and heterogeneity.
AUTHORS' CONCLUSIONS: This review identified only a limited number of diagnostic test accuracy studies using Mini-Cog in secondary care settings. Those identified were at high risk of bias related to patient selection and high concerns related to index test conduct and applicability. The evidence was indirect, as all studies evaluated Mini-Cog differently from the review question, where it was anticipated that studies would conduct Mini-Cog and independently but contemporaneously perform a reference standard assessment to diagnose dementia. The pattern of test accuracy varied across the three studies. Future research should evaluate Mini-Cog as a test in itself, rather than derived from other neuropsychological assessments. There is also a need for evaluation of the feasibility of the Mini-Cog for the diagnosis of dementia to help adequately determine its role in the clinical pathway.
阿尔茨海默病性痴呆及其他痴呆的诊断依赖于临床评估。在二级医疗环境中，认知障碍的患病率很高，包括未被诊断出的痴呆。简短的认知测试有助于识别那些需要进一步进行专科诊断评估的人；然而，对于临床实践中使用的最佳工具，目前尚未达成共识。简易认知测试（Mini-Cog）是一种简短的认知测试，包括三项回忆测试和一项画钟测试，用于二级医疗环境。
主要目的是确定在二级医疗环境中，简易认知测试检测阿尔茨海默病性痴呆及其他痴呆的诊断准确性。次要目的是调查纳入研究中测试准确性的异质性以及异质性的潜在来源。这些潜在的异质性来源将包括研究样本中痴呆的基线患病率、用于确定测试阳性结果的阈值、痴呆的类型（阿尔茨海默病性痴呆或所有痴呆病因）以及与研究质量相关的研究设计方面。
我们于2012年9月检索了以下来源，并更新至2019年3月12日：Cochrane痴呆诊断测试准确性研究组登记册、MEDLINE（OvidSP）、Embase（OvidSP）、BIOSIS Previews（Web of Knowledge）、科学引文索引（ISI Web of Knowledge）、PsycINFO（OvidSP）和LILACS（BIREME）。我们对简易认知测试的实施语言或出版物语言不设排除标准，必要时使用翻译服务。
我们纳入了横断面研究，排除了病例对照设计，因为存在偏倚风险。我们选择那些将简易认知测试作为诊断痴呆的索引测试的研究，其中痴呆诊断通过使用标准化痴呆诊断标准的参考标准临床评估得以确认。我们仅纳入二级医疗环境中的研究（包括住院和门诊医院参与者）。
我们筛选了电子数据库检索生成的所有标题和摘要。两位综述作者独立检查全文的 eligibility 并提取数据。我们使用QUADAS-2工具确定质量评估（偏倚风险和适用性）。我们将数据提取到二乘二表格中，以便计算各个研究的准确性指标，报告这些指标的敏感性、特异性和95%置信区间，并使用森林图以图形方式进行汇总。
三项研究共2560名参与者符合纳入标准，这些研究分别来自神经心理学门诊转诊患者、综合内科门诊患者以及记忆门诊转诊患者。由于研究作者选择性地使用可用数据，只有n = 1415（55.3%）的参与者被纳入分析以评估简易认知测试的准确性。在患者选择方面存在与高偏倚风险相关的问题，在索引测试实施和适用性方面存在偏倚风险不明确且关注度高的问题。在所有研究中，简易认知测试均是从历史数据集中回顾性得出的。没有研究纳入急性综合医院的住院患者。痴呆的患病率在32.2%至87.3%之间。各个研究中简易认知测试的敏感性分别报告为0.67（95%置信区间（CI）0.63至0.71）、0.60（95% CI 0.48至0.72）和0.87（95% CI 0.83至0.90）。简易认知测试在每个单独研究中的特异性分别为0.87（95% CI 0.81至0.92）、0.65（95% CI 0.57至0.73）和1.00（95% CI 0.94至1.00）。由于担心偏倚风险和异质性，我们未进行荟萃分析。
本综述仅发现了少数在二级医疗环境中使用简易认知测试的诊断测试准确性研究。所发现的研究在患者选择方面存在高偏倚风险，在索引测试实施和适用性方面存在高关注度问题。证据是间接的，因为所有研究对简易认知测试的评估与综述问题不同，预计研究应独立且同时进行简易认知测试并执行参考标准评估以诊断痴呆。三项研究的测试准确性模式各不相同。未来的研究应将简易认知测试本身作为一种测试进行评估，而不是从其他神经心理学评估中得出。还需要评估简易认知测试用于痴呆诊断的可行性，以帮助充分确定其在临床路径中的作用。
