Smyth and colleagues performed this meta-analysis to determine if participants in large, multicenter dialysis randomized clinical trials (RCTs) were similar to the general population undergoing dialysis in terms of age, comorbidities, and mortality rate. A total of 189 trials, including 80 104 participants, were identified after searching 3 major databases across a 10-year period. Results demonstrated that trial participants were significantly younger, more likely to be male, and less likely to have diabetes or diabetic nephropathy than patients in the US national registry. Moreover, the mortality rate of dialysis-dependent patients recruited to large, multicenter RCTs was substantially lower than that of registry patients, both overall and when only studies recruiting participants from the United States were considered. Ross and Covinsky provide the Editor’s Note.