From challenge to innovation: a narrative review on innovation in nephrology and hemodialysis randomized trials.

Randomized controlled trials (RCTs) are the cornerstone of evidence-based medicine, yet their distribution across clinical disciplines is far from uniform. Nephrology and kidney failure are a striking example of fields where the number, quality, and applicability of trials remain suboptimal, despite the high disease burden and cost of care. The dearth of high-quality trials persists due to numerous systemic and practical barriers, including the unwillingness of patients and clinicians to participate, ethical constraints, logistical complexity, and financial limitations. These barriers are compounded by the typical exclusion of vulnerable populations (frail individuals) from trials, thereby limiting generalizability. In this narrative review, we examine why RCTs remain scarce in these specific fields and propose innovative methodological solutions to address this persistent gap. We discuss target trial emulation using real-world data as a powerful approach to approximate RCT-level causal inference, with particular reference to trials in hemodialysis. We further explore the emerging field of digital twins, ie AI-powered, data-driven simulations of individual patients, and their use in conducting fully virtual randomized trials. Through these examples, we outline a potential path towards a more inclusive, efficient, and timely evidence-generation framework for disciplines historically underserved by traditional trial infrastructure.