Discriminative performance of the clock drawing test for screening cognitive function in hypertensive patients aged ≥ 50 years: a cross-sectional study
摘要
Hypertension is associated with an increased risk of cognitive impairment, yet brief and practical screening tools suitable for routine clinical settings remain needed. This study evaluated diagnostic accuracy of the Clock Drawing Test (CDT) for identifying screen-positive cognitive impairment in hypertensive adults aged ≥ 50 years.
MethodsWe conducted a cross-sectional study among 365 patients with essential hypertension attending neurology and family medicine outpatient clinics of a secondary-care hospital in Turkey. CDT was administered by two trained family physicians using a standardized instruction and scored using two methods: CDT-1 (0–4 points) and CDT-2 (dichotomous normal/abnormal; scored as 1/0). The Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) were administered by a gerontologist blinded to CDT results; CDT, MoCA, and MMSE were scored independently by neurologists blinded to each other’s scores and to other cognitive test results. Screen-positive cognitive impairment was operationally defined as MoCA ≤ 21 (primary reference) and low global cognitive performance as MMSE < 24 (secondary reference). Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) analyses, including the area under the ROC curve (AUC), sensitivity, and specificity at clinically feasible CDT cut-offs.
ResultsThe mean age was 63.7 ± 7.9 years; 53.5% were male. The prevalence of screen-positive cognitive impairment was 49.9% by MoCA ≤ 21 (182/365) and 33.2% by MMSE < 24 (121/365). CDT-1 demonstrated good discrimination against MoCA ≤ 21 (AUC 0.830; 95% confidence interval [CI] 0.787–0.873) and MMSE < 24 (AUC 0.834; 95% CI 0.787–0.881). For MoCA ≤ 21, sensitivity/specificity were 62.1%/91.3% at CDT-1 ≤ 2 and 83.0%/65.6% at CDT-1 ≤ 3. For MMSE < 24, sensitivity/specificity were 74.4%/84.0% at CDT-1 ≤ 2 and 88.4%/56.1% at CDT-1 ≤ 3.
ConclusionsIn hypertensive adults aged ≥ 50 years, CDT-1 showed good overall discrimination and a clear sensitivity–specificity trade-off depending on the cut-off, supporting its use as a rapid pre-screening/triage tool to identify individuals who may warrant more comprehensive cognitive assessment.