Summary of findings 2. Antiplatelet therapy compared to placebo for prevention of cognitive decline and dementia in people with cerebral small vessel disease and no dementia.

Antiplatelet therapy compared to placebo in antiplatelet naive populations for prevention of cognitive decline and dementia in people with cerebral small vessel disease and no dementia
Patient or population: people with cerebral small vessel disease and no dementia not on antiplatelet therapy Setting: outpatient services Intervention: antiplatelet therapy Comparison: placebo
Outcomes	Impact	№ of participants (studies)	Certainty of the evidence (GRADE)
Change in cognitive function from baseline assessed with: NPB,  MMSE	1 trial reported no difference between treatment groups.	50 (1 RCT)	⊕⊝⊝⊝ Very lowa,b,c
Incident dementia	No studies reported this outcome	—	—
Major bleeding (intracranial and extracranial)	No studies reported this outcome	—	—
Functional ability	1 trial reported no difference in activities of daily living between treatment groups.	50 (1 RCT)	⊕⊝⊝⊝ Very lowa,b,c
Stroke or transient ischaemic attack	1 trial reported no difference between treatment groups.	50 (1 RCT)	⊕⊝⊝⊝ Very lowa,b,c
Any adverse events (excluding major bleeding)	1 trial reported no difference between treatment groups.	50 (1 RCT)	⊕⊝⊝⊝ Very lowa,b,c
Withdrawal from study medication	1 trial reported slightly more dropout in the intervention group (33.3%) than in the placebo group (19.2%)	50 (1 RCT)	⊕⊝⊝⊝ Very lowa,b,c
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). MMSE: Mini‐Mental State Examination; NPB: Neuropsychological test Battery; RCT: randomised controlled trial.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

^aDowngraded one level as there was no (clear) statement whether participants with dementia were actively excluded.
^bDowngraded one level due to serious risk of bias in included studies.
^cDowngraded one level due to imprecision.