Clinical parameters predicted the progression to dementia in oldest old patients with mild cognitive impairment (MCI)

This study intends to assess to what extent instruments commonly used in clinical practice, as well as plasma p-tau-181, can predict the progression from MCI to dementia. The usefulness of a disease progression model (DPM) is also explored.

A longitudinal, prospective nested case-control study was conducted with patients from the Geriatrics outpatient clinics who met the MCI International Working Group criteria. The patients had a first clinical interview and two follow-ups after 12 and 24 months. Validated Spanish instruments were used for assessment, including the Mini-Mental State Examination (MMSE), the clock test, verbal fluency, the EURO-D depression scale, Barthel's Index, and Lawton's Index. P-tau-181 analysis was performed with SIMOA (Single MOlecule Array). A robust parametric disease progression model (RPDPM) was developed.

Fifty-nine patients fulfilled the inclusion criteria. The median age was 82.7 + /-8.7 years, 93 % had amnestic MCI and 45.8 % progressed to dementia (ICD-11 criteria) in two years. P-tau-181 was not prognostic. An RPDPM with the MMSE, clock test, and Lawton's Index could predict progression to dementia with an AUC of 0.945.

A combination of the MMSE, clock test, and Lawton's Index in a DPM model predicted progression from MCI to dementia best. P-tau and other blood biomarkers did not predict progression. Our results highlight the strength of clinical variables to predict the progression of MCI.