Dialysis timing may be deferred toward very late initiation: An observational study

Update of dialysis initiation timing in end stage kidney disease patients: is it a resolved question? A systematic literature review

BACKGROUND

The exact optimal timing of dialysis for ESKD patients remains unknown. This study systematically reviewed the available evidence with regard to the optimal initiation of maintenance dialysis in ESKD patients.

METHODS

An electronic search was performed in Embase, PubMed and the Cochrane Library in order to find studies investigating associations between variables reference to "start of dialysis" and outcomes. Quality assessment and bias assessment were performed by the Newcastle-Ottawa scale and the ROBINSI tool. Due to the heterogeneity of studies, a meta-analysis could not be performed.

RESULTS

Thirteen studies were included; four studies included only haemodialysis patients, three peritoneal dialysis, six both; study outcomes included mortality, cardiovascular events, technique failure, quality of life and others. Nine studies mainly focused on the optimal GFR of maintenance dialysis initiation; five studies showed none association between GFR and mortality or other adverse outcomes, two studies showed dialysis initiation at higher GFR levels were with poor prognosis, and 2 studies showed higher GFR levels with better prognosis. Three studies paid attention to comprehensive assessment of uremic signs and/or symptoms for optimal dialysis initiation; uremic burden based on 7 uremic indicators (hemoglobin, serum albumin, blood urea nitrogen, serum creatinine, potassium, phosphorus, and bicarbonate) were not associated with mortality; another equation (combination of sex, age, serum creatinine, blood urea nitrogen, serum albumin, haemoglobin, serum phosphorus, diabetes mellitus, and heart failure) based on fuzzy mathematics to assess the timing of haemodialysis initiation was accuracy to prognose 3-year survival; the third study found that volume overload or hypertension was associated with the highest risk for subsequent mortality. Two studies compared urgent or optimal start in dialysis, a study reported increased survival in optimal start patients, another reported no differences between Urgent-Start-PD and Early-Start-PD regarding 6-month outcomes.

LIMITATIONS

Heterogeneity among the studies was quite high, with differences in sample size, variable and group characteristics; no RCT studies were included, which weakened the strength of evidences.

CONCLUSIONS

The criteria for dialysis initiation were varied. Most studies proved that GFR at dialysis initiation was not associated with mortality, timing of dialysis initiation should not be based on GFR, assessments of volume load and patient's tolerance to volume overload are prospective approaches.

The ratio and difference of urine protein-to-creatinine ratio and albumin-to-creatinine ratio facilitate risk prediction of all-cause mortality

The role of the difference and ratio of albuminuria (urine albumin-to-creatinine ratio, uACR) and proteinuria (urine protein-to-creatinine ratio, uPCR) has not been systematically evaluated with all-cause mortality. We retrospectively analyzed 2904 patients with concurrently measured uACR and uPCR from the same urine specimen in a tertiary hospital in Taiwan. The urinary albumin-to-protein ratio (uAPR) was derived by dividing uACR by uPCR, whereas urinary non-albumin protein (uNAP) was calculated by subtracting uACR from uPCR. Conventional severity categories of uACR and uPCR were also used to establish a concordance matrix and develop a corresponding risk matrix. The median age at enrollment was 58.6 years (interquartile range 45.4-70.8). During the 12,391 person-years of follow-up, 657 deaths occurred. For each doubling increase in uPCR, uACR, and uNAP, the adjusted hazard ratios (aHRs) of all-cause mortality were 1.29 (95% confidence interval [CI] 1.24-1.35), 1.12 (1.09-1.16), and 1.41 (1.34-1.49), respectively. For each 10% increase in uAPR, it was 1.02 (95% CI 0.98-1.06). The linear dose-response association with all-cause mortality was only observed with uPCR and uNAP. The 3 × 3 risk matrices revealed that patients with severe proteinuria and normal albuminuria had the highest risk of all-cause mortality (aHR 5.25, 95% CI 1.88, 14.63). uNAP significantly improved the discriminative performance compared to that of uPCR (c statistics: 0.834 vs. 0.828, p-value = 0.032). Our study findings advocate for simultaneous measurements of uPCR and uACR in daily practice to derive uAPR and uNAP, which can provide a better mortality prognostic assessment.