Reliability of urinalysis for identification of proteinuria is reduced in the presence of other abnormalities including high specific gravity and hematuria

Proteinuria Assessment and Therapeutic Implementation in Chronic Kidney Disease Patients-A Clinical Audit on KDIGO ("Kidney Disease: Improving Global Outcomes") Guidelines

Background/Objectives: Chronic kidney disease (CKD) is a major health problem with a rising prevalence due to comorbidities like diabetes and hypertension. The aim of this research was to audit the assessment and therapeutic management of proteinuria in CKD patients at the Cantonal Hospital Baselland (KSBL) in Switzerland and determine associations between patient comorbidities, rehospitalisation, death, and the quality of therapeutic management. Methods: We analysed data from 427 adults with CKD (eGFR < 45 mL/min/1.73 m2) hospitalised on the internal medicine ward in 2022. Results: The mean age was 85 years (range: 79-89), 45.9% were female, and the median eGFR was 32.8 mL/min/1.73 m2 (range: 25-40). Proteinuria assessment was performed in 120 (28.1%) patients (the ProtU group), and a corresponding treatment was prescribed in 59%. The ProtU group had a higher quota of patients with diabetes (44.1% vs. 33%, p = 0.048) and obesity (21.2% vs. 12.5%, p = 0.039) when compared to the group without proteinuria assessment (the Ustix group). Twelve-month survival was not significantly different between the groups (HR: 0.75; 95% CI: 0.488-1.154; p-value = 0.191). However, survival was significantly better in patients who received an antiproteinuric treatment compared to those who did not (HR: 0.30; 95% CI: 0.121-0.0761; p = 0.011). Conclusions: Improvements need to be made in managing CKD at the KSBL in accordance with the guidelines.

Trace proteinuria detected via dipstick test is associated with kidney function decline and new-onset overt proteinuria: the Japan Specific Health Checkups (J-SHC) Study

BACKGROUND

Microalbuminuria is associated with mortality, cardiovascular disease, and end-stage kidney disease. The association between trace proteinuria (detected via dipstick test) and kidney outcomes is unclear.

METHODS

This nationwide longitudinal study used data from the Japan Specific Health Checkups Study conducted during 2008-2014. The frequency of trace proteinuria (detected via dipstick test) during first two visits was used as an exposure variable (TrUP 0/2, no trace proteinuria; TrUP 1/2, detected once; TrUP 2/2, detected twice), and kidney outcomes were evaluated. The association between the frequency of trace proteinuria and incidence of 1.5-fold increase in serum creatinine levels and overt proteinuria was analyzed using Cox regression analysis. Trajectories of estimated glomerular filtration rate (eGFR) were compared using a mixed-effect model.

RESULTS

Among 306,317 participants, 3188 and 17,461 developed a 1.5-fold increase in serum creatinine levels and new-onset overt proteinuria, respectively, during the median follow-up period of 36.2 months. The adjusted hazard ratio (HR) and 95% confidence interval (CI) for 1.5-fold increase in serum creatinine level in the TrUP 1/2 and TrUP 2/2 groups, compared to TrUP 0/2 group, were 1.23 (1.07-1.42) and 1.39 (1.01-1.92), respectively, and the adjusted HR (95% CI) for overt proteinuria were 2.94 (2.83-3.06) and 5.14 (4.80-5.51), respectively. The eGFR decline rates in the TrUP 1/2 and TrUP 2/2 groups were higher than that in the TrUP 0/2 group (p for interaction < 0.001).

CONCLUSIONS

Trace proteinuria (detected via dipstick test) was associated with subsequent kidney function decline and overt proteinuria in the general population.

Utilisation and clinical outcomes of kidney transplants from deceased donors with albuminuria in the UK: a national cohort study

BACKGROUND

Urinalysis is a standard component of potential deceased kidney donor assessment in the UK. The value of albuminuria as a biomarker for organ quality is uncertain. We examined the relationship between deceased donor albuminuria and kidney utilisation, survival, and function.

METHODS

We performed a national cohort study on adult deceased donors and kidney transplant recipients between 2016 and 2020, using data from the UK Transplant Registry. We examined the influence of donor albuminuria, defined as ≥ 2 + on dipstick testing, on kidney utilisation, early graft function, graft failure, and estimated glomerular filtration rate (eGFR).

RESULTS

Eighteen % (1681/9309) of consented donors had albuminuria. After adjustment for confounders, kidneys from donors with albuminuria were less likely to be accepted for transplantation (74% vs 82%; OR 0.70, 95% CI 0.61 to 0.81). Of 9834 kidney transplants included in our study, 1550 (16%) came from donors with albuminuria. After a median follow-up of 2 years, 8% (118/1550) and 9% (706/8284) of transplants from donors with and without albuminuria failed, respectively. There was no association between donor albuminuria and graft failure (HR 0.91, 95% CI 0.74 to 1.11). There was also no association with delayed graft function, patient survival, or eGFR at 1 or 3 years.

CONCLUSIONS

Our study suggests reluctance in the UK to utilise kidneys from deceased donors with dipstick albuminuria but no evidence of an association with graft survival or function. This may represent a potential to expand organ utilisation without negatively impacting transplant outcomes.

Enhanced prediction of renal function decline by replacing waist circumference with "A Body Shape Index (ABSI)" in diagnosing metabolic syndrome: a retrospective cohort study in Japan

Background

Abdominal obesity as a risk factor for diagnosing metabolic syndrome (MetS) is conventionally evaluated using waist circumference (WC), although WC does not necessarily reflect visceral adiposity.

Objective

To examine whether replacing WC with “A Body Shape Index (ABSI)”, an abdominal obesity index calculated by dividing WC by an allometric regression of weight and height, in MetS diagnosis is useful for predicting renal function decline.

Subjects/Methods

In total, 5438 Japanese urban residents (median age 48 years) who participated in a public health screening program for 4 consecutive years were enrolled. Systemic arterial stiffness was assessed by cardio-ankle vascular index (CAVI). The predictability of the new-onset renal function decline (eGFR < 60 mL/min/1.73 m²) by replacing high WC with high ABSI (ABSI ≥ 0.080) was examined using three sets of MetS diagnostic criteria: Japanese, IDF and NCEP-ATPIII.

Results

In Japanese and NCEP-ATPIII criteria, MetS diagnosed using ABSI (ABSI-MetS) was associated with significantly higher age-adjusted CAVI compared to non-MetS, whereas MetS diagnosed using WC (WC-MetS) showed no association. Kaplan–Meier analysis of the rate of new-onset renal function decline over 4 years (total 8.7%) showed remarkable higher rate in subjects with ABSI-MetS than in those without (log-rank test p < 0.001), but almost no difference between subjects with and without WC-MetS (p = 0.014–0.617). In gender-specific Cox-proportional hazards analyses including age, proteinuria, and treatments of metabolic disorders as confounders, ABSI-MetS (Japanese criteria for both sexes, IDF criteria for men) contributed independently to the new-onset renal function decline. Of these, the contribution of IDF ABSI-MetS disappeared after adjustment by high CAVI in the subsequent analysis.

Conclusion

In this study, replacing WC with ABSI in MetS diagnostic criteria more efficiently predicted subjects at risk of renal function decline and arterial stiffening.

Proteinuria in hospitalised internal medicine adult patients

RATIONALE

Dipstick proteinuria may be a sign of a renal disorder, false-positive or associated with acute disease, and consequently, transient in hospitalised patients.

OBJECTIVE

To assess (a) the prevalence of proteinuria in hospitalised patients; (b) its association with estimated glomerular filtration rate (eGFR), findings known to cause false-positive test results and indicators of acute disease and (c) the need for follow-up after discharge.

SETTING AND PARTICIPANTS

All patients who had a dipstick urinalysis on admission to medical wards of a 400-bed regional hospital in 2018-2019.

OUTCOME VARIABLE

Proteinuria.

INDEPENDENT VARIABLES

(a) Other findings on dipstick urinalysis; (b) patients' age, gender, presence of urinary catheter and eGFR and (c) white blood cell count (WBC) and fever.

RESULTS

Of 22 329 patients, 6609 (29.6%) had urinalysis. Of those, 2973 patients (45.0%) had proteinuria of ≥+1 (≥0.30 g/L). The variables independently associated with proteinuria were other dipstick findings known to cause false-positive test results, elevated WBC, fever on presentation, presence of a urethral catheter and a low eGFR. eGFR alone was a poor predictor of proteinuria (c-stat 0.62); however, addition of the remaining independent variables to the model significantly improved its predictive ability (c-stat 0.80).

CONCLUSIONS

Dipstick proteinuria is common in hospitalised patients. Although weakly associated with eGFR, proteinuria is mainly associated with confounding factors that may result in false-positive test results. The need for follow-up of proteinuria after discharge has questionable clinical utility and its high frequency would entail a considerable cost.