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Chronic kidney disease (CKD) is a progressive condition that affects more than 10% of the world's population. Monitoring urine albumin-to-creatinine ratio (uACR) has become the gold standard for nephropathy diagnosis and control. The objective of the present study was to develop a simple, accurate, sensitive, and rapid point-of-care test (PoCT) device, MyACR, for uACR measurement, intended for use in community healthcare to screen for the risk and monitor the progress of CKD. Albumin and creatinine concentrations in urine samples were determined using spectrophotometric dye (tetrabromophenol blue)-binding and colorimetric Jaffe assay, respectively. Urine samples were diluted with distilled water (1:80) and mixed separately with albumin and creatinine reaction mixture. The creatinine reaction was incubated at room temperature (25 °C) for 30 min before analysis. Optical density (OD) was measured at the wavelengths of 625 nm (albumin) and 515 nm (creatinine). All calibration curves (0–60 mg/L and 0–2 mg/dL for albumin and creatinine) yielded linear relationships with correlation coefficients (R2) of >0.997. Good accuracy (% deviation of mean value (DMV) ≤ 5.42%) and precision (% coefficients of variation (CV) ≤ 12.69%) were observed from both the intra- and inter-day assays for the determination of albumin and creatinine using MyACR. The limit of quantification (LOQ) of albumin and creatinine in urine samples determined using MyACR and a laboratory spectrophotometer were 5 mg/L and 0.25 mg/dL, respectively, using 37.5 μL urine spiked samples (n = 5). The device was well-applied with clinical samples from 20 CKD patients. The median (range) of %DMV of the central (hospital) laboratory method (immune-based assay) was 3.48 (−17.05 to 21.64)%, with a high correlation coefficient (R2 > 0.98). In conclusion, MyACR showed satisfactory test performance in terms of accuracy, reproducibility, and sensitivity. Cost-effectiveness and improvement in clinical decision making need to be proven in future multisite community and home studies. [ABSTRACT FROM AUTHOR]

Background: Idiopathic membranous nephropathy (IMN) is a leading cause of end-stage renal disease (ESRD). The purpose of this study was to evaluate whether urinary albumin-to-creatinine ratio (UACR) diurnal variation rate calculated by spot urinary protein test predicts 1-year nephrotic outcomes as a biomarker of proteinuria severity in patients with IMN. Methods: Patients' baseline demographics, blood and urinary biomarkers, and clinical and pathological characteristics were collected retrospectively. Urine samples were collected at 7:00 (before breakfast) and 19:00 (after dinner) to calculate the UACR diurnal variation rate. A prediction model for no remission (NR) was developed statistically based on differences between prognosis groups. Receiver operating characteristic curve (ROC) analysis was performed to evaluate prediction abilities and determine optimal cut-off points of the model and UACR diurnal variation rate alone. Results: The formula for calculating the probability of NR was exp(L)/(1 + exp(L)), where the linear predictor L = – 22.038 + 0.134 × Age (years) + 0.457 × 24-h urinary protein + 0.511 × blood urea nitrogen (BUN) + 0.014 × serum uric acid (SUA) + 2.411 if glomerular sclerosis + 0.816 × fasting blood glucose (FBG)-0.039 × UACR diurnal variation rate (%). Optimal cut-off points for NR prediction by the final model and UACR diurnal variation rate alone were 0.331 and 58.5%, respectively. Sensitivity and specificity were 0.889 and 0.859 for the final model, and 0.926 and 0.676 for UACR diurnal variation rate alone. Conclusion: UACR diurnal variation using spot urinary protein is a simpler way to predict nephrotic outcomes and is a highly sensitive screening tool for identifying patients who should undergo further comprehensive risk assessment. [ABSTRACT FROM AUTHOR]

Introduction: The aim of the study was to investigate associations between diabetic retinopathy (DR) and chronic kidney disease (CKD) in patients with type 2 diabetes (TD2). Methods: The participants of the cross-sectional, community-based Tongren Health Care Study underwent a detailed medical and ophthalmological examination. We defined TD2 by a fasting plasma glucose concentration of ≥7.0 mmol/L or a medical history. CKD was classified as either reduced estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 mm2 or presence of albuminuria. DR was assessed using color fundus photographs. Results: Out of 62,217 participants of the Tongren Health Care Study, 5,103 (8.2%) patients had TD2. The prevalence of DR was 12.8% (95% CI, 11.8%, 13.7%), CKD was 13.3% (95% CI, 12.4%, 14.3%), and the subtypes of CKD including reduced eGFR and albuminuria was 4.6% (95% CI, 4.2%, 5.1%) and 10.1% (95% CI, 9.3%, 10.9%), respectively. DR was detectable in 21.0% of the patients with CKD, while CKD was present in 20.9% of the DR patients. Higher DR prevalence was associated with higher prevalence of albuminuria and reduced eGFR (both p < 0.05). Factors independently associated with the presence of CKD instead of DR were older age (p < 0.001, OR = 1.05), a higher body mass index (p < 0.001, OR = 1.14), a higher serum concentration of triglycerides (p < 0.001, OR = 1.26), and a lower blood glucose (p < 0.001, OR = 0.93). Having hypertension was additionally associated with the presence of reduced eGFR as compared with DR (p = 0.005, OR = 4.47). Conclusions: TD2 patients of older age and with higher body mass index, hypertension, and dyslipidemia had a higher probability of being affected by CKD rather than DR, while those with a higher blood glucose level were more prone to DR than CKD. [ABSTRACT FROM AUTHOR]

To evaluate the potential diagnostic value of the albumin-to-creatinine ratio (ACR) in screening for early kidney injury in a physically examined population from Southeast China.Methods: A total of 13,250 candidates were selected. Urinary ACR values < 30, 30– 300, and > 300 mg/g were utilized as positive cut-off points to denote normal proteinuria, microalbuminuria, and macroalbuminuria, respectively.Results: Age, systolic blood pressure, diastolic blood pressure, body mass index, waistline, fasting blood glucose, glycated hemoglobin, triglycerides, and high-density lipoprotein cholesterol were significantly different among the three groups. eGFR was negatively correlated with the levels of sCr, BUN, and UA in the microalbuminuria and macroalbuminuria groups. Furthermore, there was a significant difference in CKD stage between the normal and abnormal urine ACR groups. Meanwhile, for the 20– 40 years patients, the eGFR, sCr and BUN showed no significant difference between microalbuminuria group compared with the normal proteinuria group; in contrast, for the 41– 60 years and > 61 years patients, eGFR, sCr, BUN and UA were all markedly increase in microalbuminuria and macroalbuminuria group in comparison with the normal proteinuria group. Finally, for the 41– 60 males, only eGFR significantly decreased in microalbuminuria group compared with the normal proteinuria group, while for the 41– 60 females, only UA showed no significant difference between microalbuminuria group and normal proteinuria group. On the other hand, for the > 61 males, eGFR, sCr and BUN all significantly changed between microalbuminuria group and normal proteinuria group, while for the > 61 females, eGFR, sCr and BUN all showed no significant difference between microalbuminuria group and normal proteinuria group, as well as microalbuminuria group and macroalbuminuria group.Conclusion: We proposed using the urinary ACR for the screening of physically examined patients, especially among the elderly males. This approach would assist in the early diagnosis and treatment of renal damage. [ABSTRACT FROM AUTHOR]

Background: The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known. Methods: The present observational study analyzed data on children with CAKUT (stage 2–4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated. Results: In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/−, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3–4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data. Conclusion: AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information [ABSTRACT FROM AUTHOR]

Background: Most studies of chronic kidney disease (CKD) in Sub-Saharan Africa (SSA) have been conducted in urban settings. They relied on GFR estimated from serum creatinine alone and on the inexpensive, convenient urinary dipstick to assess proteinuria. The dipstick for proteinuria has not been directly compared with the gold standard albumin-to-creatinine ratio (ACR) in a large-sized study in SSA. We hereby assessed the influence of rural versus urban location on the level, interpretation, and diagnostic performance of proteinuria dipstick versus ACR.Methods: In a cross-sectional population-based study of CKD in both urban (n = 587) and rural (n = 730) settings in South-Kivu, Democratic Republic of Congo (DRC), we assessed the prevalence, performance (sensitivity, specificity, positive predictive value and negative predictive value) and determinants of a positive dipstick proteinuria as compared with albuminuria (ACR). Albuminuria was subdivided into: A1 (< 30 mg/g creatinine), A2 (30 to 299 mg/g creatinine) and A3 (≥ 300 mg/g creatinine).Results: The overall prevalence of positive dipstick proteinuria (≥ 1+) was 9.6 % (95 % CI, 7.9-11.3) and was higher in rural than in urban residents (13.1 % vs. 4.8 %, p < 0.001), whereas the prevalence of albuminuria (A2 or A3) was similar in both sites (6 % rural vs. 7.6 % urban, p = 0.31). In both sites, dipstick proteinuria ≥ 1 + had a poor sensitivity (< 50 %) and positive predictive value (< 11 %) for the detection of A2 or A3. The negative predictive value was 95 %. Diabetes [aOR 6.12 (1.52-24.53)] was a significant predictor of A3 whereas alkaline [aOR 7.45 (3.28-16.93)] and diluted urine [aOR 2.19 (1.35-3.57)] were the main predictors of positive dipstick proteinuria.Conclusions: ACR and dipstick proteinuria have similar positivity rates in the urban site whereas, in the rural site, dipstick was 2-fold more often positive than ACR. The poor sensitivity and positive predictive value of the dipstick as compared with ACR makes it unattractive as a screening tool in community studies of CKD in SSA. [ABSTRACT FROM AUTHOR]

To understand the relationship between nativity and measures of kidney function including estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR). Seven waves of data from the National Health and Nutrition Examination Survey (2001–2014) was analyzed. General linear regression methods were used to assess the relationship between eGFR, ACR and nativity (foreign-born vs. US-born). Models were adjusted for length of time in the US, demographic variables, comorbidities, lifestyle factors, and access to healthcare. There were 27,111 individuals representing 217,842,257 US adults included in the study. Approximately 26.1% were immigrants, with 40.4% of immigrants having resided < 15 years in the US. Among immigrants with < 15 years of residence, 51% were Hispanic, and 54.4% had high school or below education. After controlling for demographics and length of time in the US, immigrants were 26% more likely to have an ACR ≥ 30 mg/g (OR 1.26, 95% CI: 1.08–1.47); however, after controlling for demographics, length of time, comorbidities, and lifestyle factors the results were no longer significant. Immigrants were significantly less likely to have an eGFR < 60 (OR 0.42, 95% CI 0.36–0.50), which remained after adjustment (OR 0.75, 95% CI 0.61–0.93). Immigrants had significantly lower odds of having an eGFR < 60 compared to US-born adults. Additionally, immigrants with ≥ 15 years in the US had mean eGFR values that were less than immigrants < 15 years in the US, indicating that there is some decrease in kidney function as the length of US residence increases. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the prevalence of chronic kidney disease (CKD) in individuals with arterial hypertension (AH) and/or diabetes mellitus (DM) accompanied by Primary Health Care (PHC) in Brazil. The estimated glomerular filtration rate (eGFR) based on creatinine, and urinary albumin-to-creatinine ratio (ACR) were measured in 841 subjects with AH and/or DM, followed by PHC in the city of Viçosa. The CKD was diagnosed according to KDIGO criteria. Sociodemographic, clinical, and anthropometric factors related to the prevalence of CKD were investigated through multiple logistic regression. The prevalence of hidden CKD was 15.4%. Of these, 7.5% were identified by albuminuria (ACR ≥30 mg/g) with slightly decreased eGFR. Age, baseline disease, waist circumference (WC), and systolic blood pressure remained associated with CKD after multivariate analysis. The two major risk factors for hidden CKD were the presence of AH in association with DM and an increase in age. Hidden CKD was more common within people with AH and DM, and with high WC, glycosylated hemoglobin, and serum phosphorus as well as male gender and decreased serum albumin. This knowledge of risk associations can help avoid progression to CKD. [ABSTRACT FROM AUTHOR]

Background Gait disturbance is proposed as a mechanism for higher risk of fall in kidney disease patients. We investigated the association of kidney function with gait pattern in the general population and tested whether the association between impaired kidney function and fall is more pronounced in subjects with lower gait function. Methods We included 1430 participants (mean age: 60 years) from the Rotterdam Study. Kidney function was assessed using estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR). We assessed global gait, gait velocity and seven independent gait domains: Rhythm, Phases, Variability, Pace, Tandem, Turning and Base of Support. Regression models adjusted for cardiometabolic and neurological factors were used. We evaluated whether participants with impaired kidney function and impaired gait fell more in the previous year. Results The study population had a median (interquartile range) ACR of 3.6 (2.5–6.2) mg/g and mean ± SD eGFR of 87.6 ± 15 mL/min/1.73 m2. Higher ACR and lower eGFR were associated with lower global gait score [per doubling of ACR: −0.10, 95% confidence interval (CI): −0.14 to −0.06, and per SD eGFR:−0.09, 95% CI: −0.14 to −0.03] and slower gait speed (ACR: −1.44 cm/s, CI: −2.12 to −0.76; eGFR: −1.55 cm/s, CI: −2.43 to −0.67). Worse kidney function was associated with lower scores in Variability domain. The association between impaired kidney function and history of fall was present only in participants with lower gait scores [odds ratio (95% CI): ACR: 1.34 (1.09–1.65); eGFR: 1.58 (1.07–2.33)]. Conclusions We observed a graded association between lower kidney function and impaired gait suggesting that individuals with decreased kidney function, even at an early stage, need to be evaluated for gait abnormalities and might benefit from fall prevention programmes. [ABSTRACT FROM AUTHOR]

Background: High-normal albuminuria is an important risk factor for incident chronic kidney disease in diabetic populations, in contrast to an uncertain association in nondiabetic populations. This study aimed to reveal the relationship between high-normal albuminuria and incident chronic kidney disease in a Japanese nondiabetic population.Methods: A 10-year follow-up retrospective cohort study was performed involving 1378 Japanese men (mean age 44 ± 5.3 years) without chronic kidney disease and diabetes mellitus. Chronic kidney disease was diagnosed as either estimated glomerular filtration rate < 60 mL/min/1.73 m2 or a urine albumin-to-creatinine ratio ≥ 30 mg/g.Results: At baseline, age, estimated glomerular filtration rate, and the presence of hematuria, hypertension, and dyslipidemia were independently associated with the albumin-to-creatinine ratio. Among the 1378 participants, 185 (13.4%) fulfilled diagnostic criteria for chronic kidney disease over the 10-year follow-up period. Median annual estimated glomerular filtration rate decline showed a deterioration with increasing quartiles of baseline albumin-to-creatinine ratio (P = 0.004). Participants who had a baseline albumin-to-creatinine ratio in the highest quartile (5.9-28.9 mg/g) were more likely to develop micro- or macroalbuminuria (odds ratio: 16.23, 95% confidence interval 6.56-54.03), chronic kidney disease (odds ratio: 2.48, 95% confidence interval 1.64-3.82), and hypertension (odds ratio 2.06, 95% confidence interval 1.30-3.31), but not diabetes mellitus compared with those who had an albumin-to-creatinine ratio in the lowest quartile (1.3-3.6 mg/g) after adjustment for potential confounders.Conclusions: High-normal albuminuria was associated with incident chronic kidney disease in this Japanese nondiabetic male population. [ABSTRACT FROM AUTHOR]

Background: Proteinuria is well recognised as a marker of chronic kidney disease (CKD), as a risk factor for progression of CKD among those with known CKD, and as a risk factor for cardiovascular events and death among both the general and CKD populations. Which measure of proteinuria is most predictive of renal events remains uncertain.Methods: We conducted a prospective study with 144 proteinuric CKD and kidney transplant recipients attending an outpatient clinic of a tertiary care hospital in Australia. We concurrently collected morning spot urine protein-to-creatinine ratio (UPCR), albumin-to-creatinine ratio (UACR) and 24-h urinary protein excretion (24-UPE) from each participant at baseline. The primary outcome was a composite of death, ESKD or > 30% decline in eGFR over 5-years. Secondary outcomes were each component of the composite outcome. For each proteinuria measure, we performed a Cox Proportional Hazards model and calculated the Harrell's C-statistic and Akaike's Information Criterion (AIC).Results: After a mean follow-up of 5 years (range 4.4-6), 85 (59%) patients met the primary composite outcome including 23 deaths (16%). The multivariable analysis showed strong evidence of an association between each log-transformed proteinuria measurement and the primary composite outcome. [Log-UPCR 1.31 (95% CI 1.18-1.63), log-UACR 1.27 (1.11-1.45) and log-24-UPE 1.43 (1.20-1.71)]. The C-Statistic were similar for all three measures of proteinuria [UPCR: 0.74 (95% CI: 0.69-0.80), UACR: 0.75 (0.69-0.81), 24-UPE: 0.75 (0.69-0.81)] as were the models' AIC (671, 668 and 665 respectively). For secondary outcomes, no proteinuria measure was significantly associated with death alone ([log-UPCR = 1.18 (0.96-1.84), log-UACR = 1.19 (1.00-1.55), log-24-UPE = 1.19 (0.83-1.71)], whilst UACR and 24-UPE demonstrated marginally better association with ESKD and > 30% decline in eGFR respectively. [For ESKD, adj log-UACR HR = 1.33 (1.07-1.66). For > 30% decline in eGFR, log-24-UPE adj HR = 1.54 (1.13-2.09)].Conclusion: In patients with stable, non-nephrotic CKD, all three measures of proteinuria were similarly predictive of hard clinical endpoints, defined as a composite of death, ESKD and > 30% decline in eGFR. However, which measure best predicted the outcomes individually is less certain. [ABSTRACT FROM AUTHOR]