The Cognitive Abilities Screening Instrument – Short (CASI-S) is a brief cognitive screening test. However, there is limited information regarding its applicability in primary care.

To ascertain whether the CASI-S differentiates between dementia patients and normal controls in primary care; to examine its correlation with other cognitive instruments, to analyze its internal consistency, test-retest stability, and diagnostic accuracy.

In a case-control study, carried out at two Primary Care Units (PCUs) in the eastern region of the city of São Paulo, 47 older adults were diagnosed with dementia according to DSM-IV criteria (mean age = 76.81 ± 7.03 years), and 55 were classified as normal controls (mean age = 72.78 ± 7.37 years), by a multidisciplinary panel which had access to results from a comprehensive cognitive battery and the patients’ health data. The present analyses included results from the Mini-Mental State Examination (MMSE). The CASI-S was not used to determine diagnostic status.

The CASI-S was easily applied in the primary care setting. There was a significant performance difference (p < 0.001) between dementia patients (15.57 ± 7.40) and normal controls (26.67 ± 3.52) on the CASI-S. CASI-S scores correlated with age (ρ = −0.410, p < 0.001), educational level (ρ = 0.373, p < 0.001), and MMSE score (ρ = 0.793, p < 0.001). The internal consistency of the CASI-S was high (α = 0.848) and the correlation between test and retest was 0.688, suggesting adequate temporal stability. In the ROC curve analyses, scores of 22/23 generated an area under the curve of 0.907, with sensitivity of 93% and specificity of 81%.

The CASI-S can be useful for dementia screening in primary care in Brazil.