Hemodialysis Adequacy: A Review

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Adequacy of hemodialysis in acute kidney injury: Real-time monitoring of dialysate ultraviolet absorbance vs. blood-based Kt/Vurea

BACKGROUND

Current guidelines recommend monitoring the adequacy of hemodialysis (HD) treatments in patients with acute kidney injury (AKI). Blood-based methods for calculating urea such as reduction ratio (URR) and single-pool Kt/Vurea (spKt/Vurea) require pre- and post-HD blood urea nitrogen (BUN) measurements. This study aims to compare real-time monitoring of urea clearance using dialysate ultraviolet absorbance (UV) with laboratory-measured spKt/Vurea.

METHODS

We conducted a single-center, retrospective study among hospitalized patients with AKI, who required intermittent hemodialysis (IHD). Those patients whose dialysis dose was simultaneously monitored by spKt/Vurea and UV-absorbance (UV-spKt/Vurea) were included in the study. The statistical correlation between both methods was assessed by means of the Pearson moment product correlation, Mann-Whitney U-test and Bland-Altman analysis of agreement.

RESULTS

Thirty patients with AKI were evaluated. There was no statistical difference between the mean spKt/Vurea calculated by traditional methods and the mean UV-spKt/Vurea. (1.37 ± 0.37 vs. 1.28 ± 0.36, P = 0.12, CI: 95%). A Pearson moment correlation analysis revealed a close agreement between both methods (r = 0.79, P < 0.001). Furthermore, Bland-Altman analysis showed that >95% of the data points were confined within the upper and lower levels of agreement.

CONCLUSION

In this pilot study of patients with AKI, UV-spKt/Vurea correlated with standard blood-based spKt/Vurea and may be a useful tool to monitor dialysis adequacy. Larger studies evaluating multiple UV and blood-based measurements per patient and a more diverse AKI population are needed to confirm this initial observation.

Being on hemodialysis during the COVID-19 outbreak: A mixed-methods' study exploring the impacts on dialysis adequacy, analytical data, and patients' experiences

For individuals with end-stage renal disease (ESRD), the novel coronavirus can present several additional challenges in disease self-management. This study aimed to explore the impacts of the COVID-19 pandemic in non-COVID-19 patients with ESRD undergoing in-center hemodialysis (HD). A mixed-methods study was conducted with a purposive sample recruited from one dialysis unit in Portugal. Quantitative data were collected retrospectively from patients' medical records from February 2020 (T1-before the outbreak) and from April 2020 (T2-during lockdown). Semi-structured interviews were conducted with 20 patients (66.9 ± 11.9 years old) undergoing HD for an average of 46.1 months (±39.5) in April 2020. Overall results suggested that dialysis adequacy and serum albumin levels decreased significantly at T2, while phosphorus levels increased. The findings from thematic analysis suggested several psychosocial negative impacts and impacts on disease and treatment-related health behaviors (eg, difficulties managing dietary restrictions during the lockdown and diminished physical activity), which can partially explain these quantitative results. However, some patients were also able to find positive impacts in this experience and problem-focused and emotional strategies were identified to cope with the demands of COVID-19. Several recommendations have been made to mitigate patients' emotional, relational, and educational unmet needs during the current pandemic and in the event of new outbreaks.