Interaction between aspirin and ACE Inhibitors: resolving discrepancies using a meta-analysis.

Area of Science:

• Cardiology
• Pharmacology
• Biostatistics

Background:

• Conflicting study results exist on the interaction between ACE inhibitors and aspirin in coronary artery disease (CAD) patients.
• Sub-optimal methodologies have contributed to discrepancies in understanding this drug interaction.
• Exploring this interaction is crucial for optimizing patient outcomes in CAD management.

Purpose of the Study:

• To systematically review and meta-analyze studies on mortality in patients treated with ACE inhibitors and aspirin.
• To accurately quantify the interaction effect between ACE inhibitors and aspirin using the synergy index (S).
• To resolve discrepancies in previous findings and compare results with conventional interaction assessment methods.

Main Methods:

• Systematic review and meta-analysis of eight studies meeting inclusion criteria.
• Calculation of the synergy index (S) and 95% confidence interval (CI) to quantify drug interaction.
• Comparison of S statistic results with the 'product term' method in logistic regression.

Main Results:

• The pooled synergy index (S) indicated a slight but precise antagonism between ACE inhibitors and aspirin (S = 0.91; 95% CI 0.80 to 1.03).
• The conventional 'product term' method yielded non-significant results (p = 0.15), suggesting no interaction.
• This highlights the inadequacy of the 'product term' method for assessing drug interactions in this context.

Conclusions:

• A slight antagonistic interaction exists between ACE inhibitors and aspirin.
• Inadequate assessment of interaction was the cause of previous conflicting results.
• Future trials like WATCH may provide further insights, though SOLVD and HOPE data were insufficient for this analysis.