Cardiovascular and Renal Outcomes Trials-Is There a Difference?

Area of Science:

• Nephrology
• Cardiology
• Clinical Trials

Background:

• Outcomes trials in dialysis patients often lack statistically significant benefits compared to cardiovascular trials in the general population.
• The reasons for this discrepancy are not well understood, and methodological factors are being investigated.

Purpose of the Study:

• To investigate whether methodological differences explain the lower frequency of statistically significant results in cardiovascular outcomes trials for patients receiving dialysis compared to the general population.

Main Methods:

• A systematic MEDLINE search identified 115 randomized trials with mortality endpoints for common cardiovascular drugs in the general population.
• Nine mortality endpoint trials in patients receiving dialysis were also reviewed.
• Trial characteristics, including sample size and statistical significance, were compared between the two groups.

Main Results:

• Cardiovascular trials in the general population enrolled an average of 4,910 participants, with 59% showing statistically significant results.
• Trials in dialysis patients enrolled an average of 1,500 participants, with only 22% showing statistically significant results.
• The average hazard ratio was similar (0.77) in both groups, and reported limitations were comparable, except for sample size.

Conclusions:

• No significant methodological differences, apart from sample size, were found to explain the lower success rate of trials in dialysis patients.
• A key factor appears to be the limited number of trials conducted for each drug in dialysis cohorts, reducing the probability of achieving statistical significance.