Table 3.
Certainty assessment | No. of patients | Effect of aspirin vs control | Confidence in efficacy statement | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
No. of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | Aspirin | No aspirin | Relative (95% CI) | Absolute (95% CI) | Efficacy statement | |
MMSE decline (follow up: mean 24 months) | ||||||||||||
1 | Randomised trials | Seriousa | Not serious | Seriousb | Seriousc | Inconsistency with below | 83 | 86 | - | MD 0.2 pts. less decline (2.4 more to 2.6 less) | Aspirin has no significant effect on MMSE decline |
⨁◯◯◯ Very low |
4.8 pt. decline | 5.0 pt. decline | |||||||||||
Rapid MMSE decline (follow-up: mean 24 months; assessed with above median decline of 2 pts. in first year and 4 pts. in 2 years) | ||||||||||||
1 | Observational studies | Seriousd | Not serious | Seriouse | Not serious | Strong association; inconsistency with above | 73 | 87 | OR 0.34 (0.11 to 0.88) | 262 fewer rapid decliners per 1000 (from 31 fewer to 458 fewer) | Aspirin protects against rapid MMSE decline |
⨁◯◯◯ Very low |
Adjusted model | Adjusted model |
CI, confidence interval; MD, mean difference; OR, odds ratio
aCochrane risk of bias tool highlighted risk from deviation from intended treatment (includes lack of blinding) and missingness
bIncludes only those with Alzheimer’s disease and without high vascular risk
cAlthough this measure of difference does not have pre-specified line of clinical effect, the authors considered that > 2.5-pt. difference on MMSE was significant, and therefore, this was imprecise
dNewcastle-Ottawa assessment scale highlighted concern re-ascertainment of exposure, no detail on those followed up vs. not followed up and no mention of assessor blinding
eIncludes only those with Alzheimer’s disease who were followed up