NIHR Open Res. 2026 Aug 4;6:27. doi: 10.3310/nihropenres.14213.2. eCollection 2026.
ABSTRACT
BACKGROUND: The mortality rate of kidney dialysis patients remains high, predominantly due to cardiovascular disease. The clearance of uraemic solutes with standard high-flux haemodialysis (HD) is mainly mediated by diffusion. More recently, haemodiafiltration (HDF), which adds convection, thus increasing the spectrum of cleared uraemic toxins, has been introduced into clinical practice. Recent reports have suggested that HDF treatment improves patient outcomes. However, it is unclear as to the amount of HDF treatment required or why HDF should improve patient outcomes.The UK High-Volume Haemodiafiltration vs. High-Flux Haemodialysis Registry Trial (H4RT) study compared a composite of non-cancer mortality or hospital admission with a cardiovascular event or infection over 3 years. However, this study was not designed to investigate why HDF may have improved patient outcomes; therefore, the STITCHED study (Study To Investigate The Change in Hypotensive Episodes during Dialysis) was designed to be nested within the larger H4RT study.
OBJECTIVE: The STITCHED study was designed to investigate the potential mechanisms underlying the improved survival reported with HDF.
DESIGN AND METHODS: The STITCHED study was designed to investigate changes in intra- and inter-dialytic blood pressure; differences in the clearance of uraemic toxins, temperature, sodium, and calcium balance between HDF and HD treatments; and the effects on the heart and brain by measuring differences in arterial stiffness, cardiac dimensions, and cognitive function.
SETTING AND PARTICIPANTS: Nine acute hospital trusts across England were contacted and involved in the STITCHED study. However, after delays due to covid-19 only the Royal Free Hospital in London recruited participants.
RESULTS: After disruptions due to the covid-19 pandemic the study was stopped before any results were obtained.
CONCLUSION: The STITCHED study was halted before any relevant information was obtained, and as such was unable to answer the question of why one mode of dialysis should improve patient survival.
PMID:42732118 | PMC:PMC13563014 | DOI:10.3310/nihropenres.14213.2