Reporting and interpretation of subgroup analyses in heart failure randomized controlled trials

Area of Science:

• Cardiology
• Clinical Trials
• Biostatistics

Background:

• Subgroup analyses in randomized controlled trials (RCTs) are common but their reporting and credibility can be variable.
• Heart failure (HF) is a significant cardiovascular condition where subgroup findings could influence treatment decisions.

Purpose of the Study:

• To assess the reporting quality of subgroup analyses in HF RCTs.
• To evaluate the strength and credibility of subgroup effect claims in HF research.

Main Methods:

• Systematic review of primary HF RCTs published in high-impact journals (2008-2017).
• Analysis of reporting frequency, strength of claims (strong, likely, suggestive), and credibility using a 10-point criteria.
• Multivariable regression to identify factors influencing subgroup analysis reporting.

Main Results:

• 107 of 261 (41%) HF RCTs reported subgroup analyses; 25 (23%) claimed subgroup effects for the primary outcome.
• Only 6 RCTs made strong claims, with many lacking interaction testing or adequate power.
• Credibility criteria were poorly met, even for strong subgroup claims; funding source did not impact reporting frequency.

Conclusions:

• Subgroup analyses in HF RCTs frequently lack sufficient credibility and methodological rigor.
• Recommendations include pre-specification, adequate power, interaction testing, and independent replication before clinical application.
• Improved standards are needed for reporting subgroup findings to ensure reliable clinical decision-making.