Objectives: We aimed to determine an optimal cut-off score for the Clock Drawing Test (CDT), scored by the scale of Freund, for efficient screening for cognitive impairment in elderly (cancer) patients within a Comprehensive Geriatric Assessment (CGA) and to compare the Freund CDT to the Mini-Cog.
Materials and methods: Data of 221 elderly (≥70years) patients, comprising of an OncoGeriatric (OG) and General Geriatric (GG) group, were retrospectively reviewed. All patients were evaluated with both the CDT and Mini Mental State Examination (MMSE) as the gold standard. Receiver Operating Characteristics (ROC) analysis was used to determine diagnostic performance. A pre-established algorithm was applied to retrieve Mini-Cog results through a combination of the CDT and the 3-Word Delayed Recall (3-WDR) test (included within MMSE).
Results: Data of 105 OG and 116 GG patients were evaluated. Potential cognitive impairment (MMSE≤23) was detected in 29.5% and 65.8% of patients, respectively. The CDT showed good diagnostic accuracy in the OG (0.88±0.03) and GG (0.85±0.03) group, based on the area under the ROC curve (AUC±SE). CDT (cut-off≤4) provided good sensitivity (80.7%) and specificity (81.1%) in the OG group and excellent sensitivity (89.6%) and moderate specificity (51.3%) in the GG group. Addition of the 3-WDR test, to form the Mini-Cog, resulted in similar positive and negative predictive values for the OG group and higher negative predictive value for the GG group.
Conclusion: These data suggest that the Freund CDT, at the cut-off score of ≤4, is promising for use within a CGA. The Mini-Cog might be preferable in the GG population.
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