Monitoring of inflammation in patients on dialysis: forewarned is forearmed

Current evidence about the effects of inflammation on the outcomes of patients with advanced chronic kidney disease (CKD) generally originates from single measurements of inflammatory biomarkers. Patients with CKD, however, are exposed to persistent low-grade inflammation and levels of serum inflammatory markers are subjected to a substantial variability over time, being influenced by multiple processes, such as transient infections, comorbidities, and the intermittent stimulus of dialysis. Understanding and evaluating inflammation in the context of its time-dependent oscillations in renal disease fluctuation is, therefore, important. Nevertheless, the relationship between longitudinal inflammatory variation and risk prediction has so far been addressed in only a few studies, not all of which have been sufficiently powered. Consequently, uncertainty exists about how to interpret the findings of these studies in the clinical setting. The purpose of this Review is to explore the reasons and implications of variability in levels of inflammatory biomarkers in patients with uremia, specifically focusing on C-reactive protein (CRP) measurements. We also discuss the value of repeated versus single measurements of inflammation in the clinical setting and provide solutions to reduce both sample size and intraindividual variability in hypothetical, randomized controlled trials aimed at reducing CRP levels in patients undergoing hemodialysis.