Dialysis patients in the real world differ from those in clinical trials in several key respects and have worse survival, according to results from 2 new studies published in JAMA Internal Medicine.

“This finding has implications for the generalization of trial results to the broader patient population and for future trial design,” Brendan Smyth, MBBS, of The George Institute for Global Health and University of New South Wales in Australia, and colleagues wrote.

According to their meta-analysis of 189 randomized controlled trials (RCT) involving 80,104 patients, RCT participants were significantly more likely to be younger (mean age 58.9 years) and male (58.8%). More had coronary artery disease (26.7% vs 17.7%) and fewer had diabetes (40.4% vs 44.2%), diabetic nephropathy (27.4% vs 44.2%), and heart failure (19.9% vs 29.8%). Most importantly, the mortality rate in trials was less than half that of the US Renal Data System (USRDS) population: 8.9 vs 18.6 per 100 patient-years.

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In the other study, investigators found that real-world dialysis patients often have unrealistic or uncertain expectations of their survival. In that study, Ann M. O’Hare, MD, of VA Puget Sound Health Care System in Seattle, and colleagues asked 996 dialysis patients (mean age 62.7; 44% female) how long people of their same age and health usually live. One third said more than 10 years, 15.1% said 5 to 10 years, and 11.2% said fewer than 5 years; another 40.6% were unsure. In contrast, an analysis of 185,427 hemodialysis patients from USRDS showed that 60.3% died within 5 years, 19.0% died within 5 to 10 years, and just 20.7% lived more than 10 years. Those with the optimistic expectation of living more than 10 years vs less than 5 years had significant 40%, 60%, and 90% decreased odds of having a surrogate decision maker, treatment preferences, and comfort vs life extension as a top goal, respectively, in adjusted analyses. They also had significant 5- and 2-fold greater odds of wanting cardiopulmonary resuscitation and mechanical ventilation, respectively.

“These findings highlight the need for a deeper understanding of what drives the prognostic expectations of patients undergoing dialysis and call for efforts to raise prognostic awareness and manage prognostic uncertainty among members of this population,” Dr O’Hare’s team concluded.

They also observed: “Uncertain and overly optimistic prognostic expectations may limit the benefit of advance care planning and contribute to high-intensity end-of-life care in patients undergoing dialysis.”

In an accompanying editorial, Joseph S. Ross, MD, MHS, of Yale University, and Ken Covinsky, MD, of the University of California, San Francisco, advocated for more inclusive trials: “Randomized clinical trials should include older patients and those with serious comorbid illness if we want evidence that can be used to inform decision making for all our patients.”

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Smyth B, Haber A, Trongtrakul K, et al. Representativeness of randomized clinical trial cohorts in end-stage kidney disease: A meta-analysis. (Published online July 8, 2019.) JAMA Intern Med. doi:10.1001/jamainternmed.2019.1501

O’Hare AM, Kurella Tamura M, Lavallee DC, et al. Assessment of self-reported prognostic expectations of people undergoing dialysis United States Renal Data System Study of Treatment Preferences (USTATE). (Published online July 8, 2019). JAMA Intern Med. doi:10.1001/jamainternmed.2019.2879

Ross JS, Covinsky K. Clinical trial evidence for the real world. (Published online July 8, 2019). JAMA Intern Med. doi:10.1001/jamainternmed.2019.1500