The right methodology for long-term vascular access research: Three burning questions.

Over the last 20 years, there has been a great proliferation of studies of different aspects of the long-term vascular access field. Despite the availability of such studies, methodological pitfalls surrounding long-term vascular access research are rarely mentioned. Methodological issues inherent to retrospective analyses make them very poor tools for providing generalizable results, as they often become estimates of local experiences rather than reflections of up-to-date practices. Second, despite being an often-ignored element when designing studies on catheter-related complications, a proper follow-up time definition and its length are crucial to limiting the impact of attrition bias on research results. Finally, meta-analyses constitute a powerful tool in modern evidence-based era, but several pitfalls can affect overall results. When designing a systematic review and meta-analytic process, study selection should always reflect the relevance of clinical questions and the capability to contextualize results in the modern and evidence-based vascular access era.