Every row of the evidence table

The review's own summary points two ways: CSF biomarker tests were mostly cost-effective against cognitive assessment or imaging, while blood biomarker tests showed mixed results; every included study was model-based.

The findings point two ways: the p-tau217/Aβ42 ratio tracked AD-related factors (MCI, AD dementia, future progression, age, APOE ε4) more closely than either marker alone and had few intermediate results, but it was also related to kidney function, diabetes and hearing loss, and medical morbidities were most frequent among intermediate classifications.

Direction is for the test's accuracy against the reference standard; an accuracy result, not a health outcome. Performance varied widely across tests, from 49.3% to 91.4% pooled sensitivity and 61.5% to 96.7% pooled specificity at a single cut-point, with most studies at high risk of bias.

The results point different ways: diagnostic confidence rose 1.43 points, but diagnosis changed in only 17.2% and management in 27.7%, below the 30% threshold the investigators set as clinically significant; a non-elevated result reduced amyloid PET use, and patients with elevated results had higher anxiety at 2-3 months.

The findings point different ways: lower eGFR raised every blood biomarker except Aβ42/40 (a test-interpretation caveat), yet impaired kidney function did not itself raise dementia risk (HR 0.93), while the association between high NfL and dementia was about twice as strong in people with impaired kidneys.

The two measures behaved differently: baseline plasma p-tau217 predicted later cognitive decline about as well as entorhinal tau PET (ρ -0.47 vs -0.55), but over time p-tau217 rose then decelerated and tracked concurrent cognitive change only weakly (ρ -0.24) or not at all in the PET substudy, whereas regional tau PET change correlated strongly with concurrent decline.

The three markers pointed different ways: plasma p-tau217 distinguished amyloid/tau stages, GFAP tracked amyloid-driven tau progression, and NfL was only weakly linked to Alzheimer pathology and, in the authors' words, inadequate as a neuronal injury biomarker for AD.

The result points two ways: p-tau181 gave the best AUC for separating AD from controls, frontotemporal dementia and amyloid-negative Lewy body dementia, but that discrimination could not be reproduced when pre-defined cut-offs were applied, so cohort-specific cut-offs were needed.

Direction is for the test's accuracy against the reference standard; an accuracy result, not a health outcome. Results ranged from 55% to 100% sensitivity and 60% to 100% specificity across four laboratories using different protocols, with only fair agreement between them (kappa 0.246).

Peer support reduced distress to behavioural symptoms and increased social support and quality of life immediately after the intervention, but had no effect on depression/anxiety, loneliness, burden or competence, and no outcome was sustained at follow-up.

The two comparisons point different ways: overall utilization and payments were similar between amyloid-positive (A4) and amyloid-negative (LEARN) participants, but among A4 participants claims indicators of progression carried 45-103% higher payments.

The review splits by drug class: at $100,000 per QALY every study found memantine cost-effective and more than half found the cholinesterase inhibitors so, whereas aducanumab, lecanemab and donanemab were not cost-effective in any study. A value result, not a clinical harm.

Direction is for value for money: APPLE-Tree had a 96% probability of being cost-effective per cognition point at a £30 000 threshold but only 12% on QALYs, which were slightly lower in the intervention arm. Post hoc subgroups suggested better value in non-White and socioeconomically disadvantaged participants.

The two perspectives disagree: the digitally supported care management system dominated usual care for the public payer (lower costs, marginally more QALYs, 72-79% probability of cost-effectiveness) but cost €331,000 per QALY from a societal perspective (33-35% probability).

MCI was diagnosed sooner (HR 1.21) but dementia diagnosis barely moved (HR 1.04, 95% CI 1.02-1.06). The outcome is detection, not health.

Admission showed no evidence of an effect on 30-day mortality or subsequent inpatient days, but raised 30-day health care spending by $2547. An instrumental-variable estimate for marginal admissions.

Advance care planning strongly increased DNR documentation (OR 14.12) but did not change whether residents died in the nursing home (OR 1.62, 95% CI 0.72-3.66). Evidence on other end-of-life outcomes was limited and inconsistent, and no study came from a non-Western setting.