RESUMO
INTRODUCTION: Rapid cognitive decline (RCD) occurs in dementia due to Alzheimer's disease (AD). METHODS: Literature review, consensus meetings, and a retrospective chart review of patients with probable AD were conducted. RESULTS: Literature review showed that RCD definitions varied. Mini-Mental State Examination scores <20 at treatment onset, vascular risk factors, age <70 years at symptom onset, higher education levels, and early appearance of hallucinations, psychosis, or extrapyramidal symptoms are recognized RCD risk factors. Chart review showed that RCD (Mini-Mental State Examination score decline ≥3 points/year) is more common in moderate (43.2%) than in mild patients (20.1%; P < .001). Rapid and slow decliners had similar age, gender, and education levels at baseline. DISCUSSION: RCD is sufficiently common to interfere with randomized clinical trials. We propose a 6-month prerandomization determination of the decline rate or use of an RCD risk score to ensure balanced allocation among treatment groups.