E.g. #1 The primary outcome of DAPA-HF (McMurray JJV et al.), a trial comparing dapagliflozin vs. placebo in patients with heart failure with reduced ejection fraction (HFrEF), was a composite of:

• Hospitalization for heart failure (HF) resulting in intravenous therapy
• Urgent HF visit resulting in intravenous therapy
• Death from cardiovascular (CV) causes

These are all outcomes of significant importance to patients. 

E.g. #2 The primary outcome of CONDOR (Chan FKL et al.), a trial comparing celecoxib vs NSAID+PPI, was a composite of:

• Gastrointestinal (GI) bleed
• GI obstruction
• GI perforation
• Clinically significant anemia (decrease in hemoglobin  ≥ 20 g/L or decrease in hematocrit ≥10%)

The latter of which was notably less important than the other components.

E.g. #1 HRs in DAPA-HF (McMurray JJV et al.) for dapagliflozin vs. placebo:

• Composite HR = 0.74 (95% CI 0.65-0.85)
• Hospitalization or urgent visit for heart failure HR = 0.70 (95% CI 0.59-0.83)
• Cardiovascular death HR = 0.82 (95% CI 0.69-0.98)

Since all the CIs overlap and are sufficiently narrow, there can be greater confidence that the composite outcome is not misleading.

E.g. #2 Relative risk reductions (RRRs) in CONDOR (Chan FKL et al.) for celecoxib vs NSAID+PPI:

• Composite RRR = 75%
• GI bleed RRR = 0%
• Clinically significant anemia RRR = 80% 

Since there is a very large difference in the point estimates, it is better to consider the individual endpoints rather than the composite endpoint.