A recent Nephrology digest,
as sent to subscribers

Study Type: Narrative review / educational Core Curriculum article (not original research).

Key Question: How should hematuria be evaluated and managed, distinguishing glomerular from nonglomerular causes and identifying patients at risk of urologic malignancy?

Key Findings:

• Dipstick-positive hematuria should be confirmed by urine microscopy; the AUA defines significant microscopic hematuria as ≥3 RBC/HPF.
• Updated AUA guidance advocates risk stratification for malignancy to tailor investigation, aiming to detect urologic cancers while reducing unnecessary procedures, cost, and patient harm.
• Scenario-based recommendations are given for malignancy, kidney stones, and glomerular disease. The abstract provides no quantitative data.

Clinical Relevance: Useful teaching resource for nephrology trainees and referral-pathway discussions, but it follows US (AUA) thresholds and guidance, so UK clinicians should interpret it alongside NICE, BAUS, and local haematuria pathways, which differ in definitions and referral criteria.

Limitations: As a narrative review based on US guidelines, it offers no systematic evidence appraisal and may not map directly onto UK practice.

Study Type: Observational cohort analysis of the CONVINCE RCT population (multicentre).

Key Question: Does a brief patient-reported physical function measure predict mortality as well as a performance-based test in people on dialysis?

Key Findings:

• Among 1,360 patients (mean age 62.4; 19.6% died over median 30 months), adjusted HRs per 1-point higher PF score were 0.96 (95% CI 0.95–0.98) for PROMIS-PF4a, 0.95 (0.94–0.97) for the Physical Performance Test, and 0.96 (0.94–0.97) for the composite.
• Discrimination was modest and near-identical across measures (adjusted C-index ≈ 0.71).
• Severe impairment (T-score <30) was associated with substantially higher mortality across all measures.

Clinical Relevance: A four-item questionnaire could provide routine, low-burden prognostic assessment of physical function in UK haemodialysis units without the staff time and space needed for performance testing.

Limitations: Trial participants (haemodialysis/HDF, selected for CONVINCE eligibility) limit generalisability, and only baseline PF was assessed with one PRO and one PerfO tool.

Study Type: Observational cohort study (phenome-wide association study with post-hoc CAC analyses) within the CRIC cohort.

Key Question: Is carbamylated albumin (C-Alb), a urea-driven protein modification, associated with clinical phenotypes in CKD, particularly coronary artery calcification (CAC)?

Key Findings:

• Of 212 phenotypes tested in 3,111 participants, 47 associated significantly with C-Alb after multiple-testing correction; BUN and coronary calcification measures showed the strongest associations.
• Among 1,046 participants with CAC data (CAC present in 65%), each SD increase in log C-Alb associated with 41% greater CAC severity; prevalence was highest in the top C-Alb quartile.
• Longitudinally, C-Alb associated with progressive CAC (≥50 units/year) after adjustment for traditional risk factors; 55/269 developed incident CAC (incident-CAC effect estimates not reported in the abstract).

Clinical Relevance: Carbamylation may offer a mechanistic link between uraemia and vascular calcification, but C-Alb is a research biomarker with no current role in UK CKD practice.

Limitations: Observational design with residual confounding and limited power for incident CAC; correlation with BUN and eGFR makes independence from urea exposure difficult to establish.

Study Type: New-user active-comparator cohort study (US claims data; Medicare and MarketScan), using propensity-score matching and a tree-based scan statistic for hypothesis-free safety signal detection.

Key Question: Does SGLT2 inhibitor initiation in people with T2D and CKD stage 3-4 carry unrecognised adverse events compared with GLP-1RA initiation?

Key Findings:

• 22,328 matched pairs (Medicare, mean age 74) and 8,918 matched pairs (MarketScan, mean age 65) were analysed.
• In both cohorts, outpatient coding showed a signal for genital infections in men and women (p < 0.001), an established SGLT2 inhibitor effect.
• No signals emerged from inpatient or ED diagnosis codes, and no novel adverse events were identified.

Clinical Relevance: Provides reassurance, in a population underrepresented in trials, that SGLT2 inhibitor use in CKD stage 3-4 raises no unexpected safety concerns beyond genital infection, supporting continued prescribing in line with UK guidance.

Limitations: Claims-based ICD-10 outcome coding with residual confounding, misclassification and limited power, and results are expressed as signals only, with no effect sizes reported in the abstract.

Study Type: Nationwide retrospective observational cohort study (Korean NHIS data, 9,134 kidney transplant recipients; median follow-up 6 years)

Key Question: Is living alone associated with worse mental health, neurodegenerative, cardiovascular, and graft outcomes in kidney transplant recipients?

Key Findings:

• Single-person households (10.0% of cohort) had higher risk of composite mental health disorders (aHR 1.28, 95% CI 1.02–1.60), driven mainly by depression (aHR 1.42, 1.04–1.94), and of dementia (aHR 1.68, 1.05–2.70).
• Higher risk of cardiovascular disease (aHR 1.40, 1.00–1.96), particularly MI (aHR 1.80, 1.16–2.80), and Parkinson disease (aHR 4.40, 1.48–13.09, with a wide CI).
• All-cause mortality and allograft failure did not differ between groups. Those living alone were far more likely to be in the lowest income quintile (52.1% vs 18.8%).

Clinical Relevance: Supports routine psychosocial and social-isolation screening in UK transplant follow-up, alongside cardiovascular risk review, though generalisability from Korea to NHS populations is uncertain.

Limitations: Retrospective design with possible residual confounding, notably socioeconomic status, and an imprecise definition of single-person household, limiting causal inference.

Study Type: Randomised controlled trial (single-country, n=36, 4-week intervention)

Key Question: Does a normoproteic (0.8 g/kg/day) diet with 70% plant-derived protein, compared with 50%, alter uremic toxins and gut microbiota in patients with advanced CKD?

Key Findings:

• Serum TMAO fell significantly with the 70% plant-protein diet (between-group difference −4.6 μg/mL, 95% CI −7.2 to −2.0; FDR-adjusted P=0.003); indoxyl sulfate and p-cresyl sulfate did not differ significantly.
• Venous bicarbonate, serum calcium and acetate increased, PTH fell, and gut microbiota shifted towards SCFA-producing genera.
• Serum potassium did not differ between groups (patients on RAS inhibitors, K⁺ <5.5 mEq/L at baseline); adherence was good (94%).

Clinical Relevance: Supports plant-dominant diets as a feasible option in advanced CKD without apparent hyperkalaemia risk in selected patients, relevant to UK dietetic and conservative-care practice.

Limitations: Small sample, 4-week duration and a selected Japanese cohort with pre-prepared meals limit generalisability, and effects on hard clinical outcomes remain unknown.

Study Type: Expert workshop report (National Kidney Foundation Scientific Workshop); not original research and no new data.

Key Question: Can a hierarchical composite endpoint (HCE) improve the efficiency of RCTs of CKD progression compared with conventional time-to-event kidney composite endpoints?

Key Findings:

• The proposed kidney HCE ranks outcomes in order of clinical importance: all-cause mortality, kidney failure (with or without kidney replacement therapy initiation), time to sustained GFR decline, then GFR slope.
• Participants judged it a promising candidate for establishing efficacy in settings where large trials with kidney composite endpoints are currently needed.
• It may suit populations at risk of progression but unlikely to accrue enough events for a traditional time-to-event analysis. No single endpoint was considered universally applicable.

Clinical Relevance: HCEs could shape the design of future CKD trials, including those that UK centres may join, and may widen the range of therapies that can be tested efficiently in slowly progressive disease.

Limitations: This is consensus opinion without empirical validation; key methodological issues, notably how best to compare individual GFR slopes, remain unresolved.

Study Type: Perspective/commentary (no original data)

Key Question: What role should nephrologists play within the newly defined cardio-kidney-metabolic (CKM) syndrome framework?

Key Findings:

• No empirical findings; this is an expert opinion piece.
• The authors argue nephrology should broaden its focus beyond organ failure (dialysis, transplantation) to include prevention, early diagnosis and slowing CKD progression.
• They propose nephrologists contribute diagnostic precision for CKD and kidney outcomes, question the linearity of the CKM model given CKD/CVD complexity, and call for revised training and care models, with greater involvement in test interpretation, pharmacology, research and holistic CVD risk management.

Clinical Relevance: Relevant to UK nephrology workforce, training curricula and service planning, particularly as CKD, cardiovascular and diabetes/obesity pathways increasingly overlap and require clearer specialty boundaries and shared care models.

Limitations: *Not applicable (perspective article); however, recommendations are not evidence-based and no specific implementation strategies are described in the abstract.*