Dementia affects millions globally, with a subset of cases potentially reversible. This study evaluates the incidence, clinical markers and treatment outcomes of reversible dementias (ReDem).

This retrospective study included 370 ReDem cases from 1810 dementia patients. The ReDem cohort was split into potentially reversible dementias (PRD) and dual etiology (DE) groups. PRD encompassed secondary, potentially treatable dementia conditions, while DE included primary degenerative dementia (DD) with ≥1 uncontrolled comorbidity or new disease that worsened symptoms.

ReDem cases comprised 20.4% (n = 370 out of 1810) of dementia patients, with ReDem patients being younger (mean 56.2 vs. 61.9 years, p < 0.001) and exhibiting shorter illness durations than DD patients (p < 0.001). Key red flags, including young age (<45 years) at onset (DD = 8.6% vs. ReDem = 18.1%), fluctuation in symptoms (DD = 3.4% vs. ReDem = 11.6%), rapid cognitive decline (DD = 6.9% vs. ReDem = 18.4), high-risk exposures (DD = 0.1% vs. ReDem = 0.8%), high-risk behavior (DD = 0.1% vs. ReDem = 2.4%) and incongruent neuropsychological findings(DD = 1.0% vs. 12.7%), were significantly more frequent in ReDem cases (p < 0.05). Odds increased with each red flag present (≥1: OR = 5.94; ≥2: OR = 20.69; ≥3: OR = 25.14, p < 0.05). Reversible etiologies included immune (20.0%), neuroinfectious (6.6%), psychiatric (7.6%), nutritional/metabolic (10.5%), neurosurgical (14.6%) and other causes (12.2%). Of the 41% (152/370) followed, 19 expired, 63.9% (85/133) reported subjective improvement, and 31.6% (42/133) showed clinical dementia rating improvement.

This large-scale study underscores the importance of comprehensive diagnostic evaluations for ReDem. Identifying and treating reversible conditions and comorbidities in DD can improve patient outcomes, emphasizing the need for thorough evaluations in memory clinics and targeted interventions in dementia care.