Abstract
BackgroundThe hemodialysis setting is suitable for trials that use cluster randomization, where intact groups of individuals are randomized. However, cluster randomized trials (CRTs) are complicated in their design, analysis, and reporting and can pose ethical challenges. We reviewed CRTs in the hemodialysis setting with respect to reporting of key methodological and ethical issues.MethodsWe conducted a systematic review of CRTs in the hemodialysis setting, published in English, between 2000 and 2019, and indexed in MEDLINE or Embase. Two reviewers extracted data, and study results were summarized using descriptive statistics.ResultsWe identified 26 completed CRTs and five study protocols of CRTs. These studies randomized hemodialysis centers (n = 17, 55%), hemodialysis shifts (n = 12, 39%), healthcare providers (n = 1, 3%), and nephrology units (n = 1, 3%). Trials included a median of 28 clusters with a median cluster size of 20 patients. Justification for using a clustered design was provided by 15 trials (48%). Methods that accounted for clustering were used during sample size calculation in 14 (45%), during analyses in 22 (71%), and during both sample size calculation and analyses in 13 trials (42%). Among all CRTs, 26 (84%) reported receiving research ethics committee approval; patient consent was reported in 22 trials: 10 (32%) reported the method of consent for trial participation and 12 (39%) reported no details about how consent was obtained or its purpose. Four trials (13%) reported receiving waivers of consent, and the remaining 5 (16%) provided no or unclear information about the consent process.ConclusionThere is an opportunity to improve the conduct and reporting of essential methodological and ethical issues in future CRTs in hemodialysis.Review RegistrationWe conducted this systematic review using a pre-specified protocol that was not registered.
Highlights
Patients on hemodialysis are often excluded from clinical trials, and many trials in the hemodialysis setting suffer from poor recruitment, inadequate sample sizes, and poor adherence to allocated treatment and treatment contamination [1–5]
The cluster randomized trials (CRTs) is an attractive design in the hemodialysis setting, where interventions are often delivered at the center-level and where staff follow the same protocol for patients under their care
Reporting of research ethics review We found that 26 trials (84%) reported research ethics committee approval, one (3%) reported that the study was exempt from review, and four (13%) did not report whether the study was reviewed by a research ethics committee (Table 5)
Summary
Patients on hemodialysis are often excluded from clinical trials, and many trials in the hemodialysis setting suffer from poor recruitment, inadequate sample sizes, and poor adherence to allocated treatment and treatment contamination [1–5]. Cluster randomized trials (CRTs) randomize intact groups of individuals (rather than independent individuals) to different arms. This design can offer a logistically convenient method to produce highquality evidence, can be effective in avoiding treatment contamination, and may be better received by participants and healthcare staff when delivered to a group of individuals rather than select patients. Failing to account for clustering in the sample size calculation implies that the study may not have adequate power to detect meaningful differences between the groups, while failing to account for clustering in the analysis implies that standard errors of treatment effects will be under-estimated, increasing the risk of spurious statistical significance [6–9]. We reviewed CRTs in the hemodialysis setting with respect to reporting of key methodological and ethical issues
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