Meta-analysis of noninferiority and equivalence trials: ignoring trial design leads to differing and possibly misleading conclusions

OBJECTIVE

The objective of the study is to examine the analytic approach of meta-analyses that include noninferiority or equivalence (NI/EQ) trials.

STUDY DESIGN AND SETTING

We used Scopus to identify meta-analyses including NI/EQ trials. We extracted data from the meta-analyses and their included randomized clinical trials (RCTs). We used the RCT's NI/EQ margins to reinterpret the results of the meta-analyses, assessed for risk of biases unique to NI/EQ trials, and evaluated the consistency of the meta-analysis interpretation when using NI/EQ margins.

RESULTS

We identified 38 unique meta-analyses including 515 RCTs, of which 125 (24.3%) were NI/EQ trials. Fourteen meta-analyses (36.8%) reported the study design of their included trials, but only one (2.6%) interpreted their pooled estimates using NI/EQ margins and none assessed for risks of bias unique to NI/EQ trials. Nearly all NI/EQ trials (n = 116, 92.8%) included in the meta-analyses reported NI/EQ margins. The meta-analyses of 30 outcomes were reinterpreted using the NI/EQ margins; reinterpretations conflicted with the conclusion of the meta-analyses in most cases (n = 20, 66.7%).

CONCLUSION

Most meta-analyses including NI/EQ trials ignore trial design and do not assess risks of bias unique to NI/EQ studies. Meta-analyses addressing questions previously explored as NI/EQ should conduct an NI/EQ meta-analysis or use clear language when performing standard (i.e., superiority) meta-analyses.

Antiplatelet Management for Coronary Heart Disease: Advances and Challenges

Coronary heart disease (CHD) remains the leading cause of death in the USA. CHD accounts for 48 % of all cardiovascular mortality or approximately one of every seven deaths. Disruption of atherosclerotic plaques--usually by rupture or erosion--and superimposed thrombosis can result in acute coronary syndromes and sudden cardiac death. Silent plaque disruption may also occur and result in coronary plaque progression and ultimately the symptomatic manifestations of stable CHD. Antiplatelet agents remain the cornerstone therapy for acute thrombotic coronary syndromes and are essential for thromboprophylaxis against these events in patients with stable CHD. Antiplatelet drugs are also important adjunct therapies during percutaneous coronary intervention (PCI) as they mitigate equipment-associated thrombotic complications that are partially induced by iatrogenic plaque rupture by interventionalists during balloon angioplasty in the cardiac catheterization laboratory. Since the introduction of clopidogrel, there has been considerable development in this field with at least three novel P2Y12 antagonists approved by the Food and Drug Administration (FDA) over the past decade. Rapidly accumulating evidence is helping to guide the optimal duration of treatment with dual antiplatelet therapy after stenting, especially with the newer drug-eluting stents. More data are also emerging on the hazards and long-term safety of these agents. It is therefore prudent for clinicians to remain current on treatment options and recent advances in this area. We herein review current and emerging antiplatelet therapies and summarize their characteristics and indications of use as well as challenges and areas of ongoing research.