Spot urinary microalbumin concentration, metabolic syndrome and type 2 diabetes: Tehran lipid and glucose study.

AIM: This study aimed to determine the association of urinary microalbumin concentrations with type 2 diabetes mellitus (T2DM), metabolic syndrome (MetS), and its phenotypes. The optimum cut-off values of urinary microalbumin and microalbumin-to-creatinine ratio (MCR) for predicting the chance of having T2DM and MetS were also defined. METHODS: Adult men and women (n = 1192) participated in the sixth phase (2014-2017) of the Tehran Lipid and Glucose Study (TLGS), with completed data, were included in the analyses. Odds ratios (ORs) (and 95% confidence intervals (CIs)) of T2DM, MetS, and its components across tertile categories of urinary microalbumin concentrations were estimated using multivariable logistic regressions. The optimal cut-off points of urinary microalbumin and MCR were determined using the receiver operator characteristic (ROC) curve analysis. RESULTS: Participants' mean (±SD) age was 44.9 (±14.0) years, and 44.6% of the participants were men. The prevalence of microalbuminuria was 14.4%. Chance of having T2DM was significantly higher in the highest tertile of urinary microalbumin concentration (OR = 2.29, 95% CI = 1.43-3.67) and MCR (OR = 1.82, 95% CI = 1.15-2.89). Subjects with the highest urinary microalbumin concentration were more likely to have MetS (OR = 1.66, 95% CI = 1.17-2.35), hypertension (OR = 1.63, 95% CI = 1.16-2.30) and hyperglycemia (OR = 1.78, 95% CI = 1.24-2.56). No significant association was observed between urinary microalbumin concentrations and other components of MetS. The optimal cut-off points of urinary microalbumin for predicting the chance of having T2DM and MetS were 14.0 and 13.6 mg/L, respectively. CONCLUSIONS: Elevated spot urinary microalbumin, below the values defined as microalbuminuria, was associated with the chance of having T2DM and MetS.

Evaluation of iodine nutritional status during pregnancy by estimated 24-h urinary iodine excretion: population variation range and individual accuracy.

OBJECTIVE: To explore the accuracy of estimated 24-h urinary iodine excretion (24-h UIEest) in assessing iodine nutritional status. DESIGN: Fasting venous blood, 24-h and spot urine samples were collected during the day. The urinary iodine concentration (UIC) and urinary creatinine concentration (UCrC) were measured, and the urinary iodine-to-creatinine ratio (UI/Cr), 24-h UIEest, and 24-h urinary iodine excretion (24-h UIE) were calculated. At the population level, correlation and consistency between UIC, UI/Cr, 24-h UIEest and 24-h UIE were assessed using correlation analysis and Bland-Altman plots. At the individual level, receiver operating characteristic (ROC) curves were used to analyse the accuracy of the above indicators for evaluating insufficient and excessive iodine intake. The reference interval of 24-h UIEest was established based on percentile values. SETTING: Indicator can accurately evaluate individual iodine nutrition during pregnancy remains controversial. PARTICIPANTS: Pregnant women (n 788). RESULTS: Using 24-h UIE as standard, the correlation coefficients of 24-h UIEest from different periods of the day ranged from 0·409 to 0·531, and the relative average differences ranged from 4·4 % to 10·9 %. For diagnosis of insufficient iodine intake, the area under the ROC curve of 24-h UIEest was 0·754, sensitivity and specificity were 79·6 % and 65·4 %, respectively. For diagnosis of excessive iodine intake, the area of 24-h UIEest was 0·771, sensitivity and specificity were 66·7 % and 82·0 %, respectively. The reference interval of 24-h UIEest was 58·43-597·65 µg. CONCLUSIONS: Twenty-four-hour UIEest can better indicate iodine nutritional status at a relatively large sample size in a given population of pregnant women. It can be used for early screening at the individual level to obtain more lead time for pregnant women.

Invited Commentary: Theoretical Considerations and Real-World Challenges for Research on Proxy Exposures and Ovarian Reserve.

In this issue of the Journal, Upson et al. (Am J Epidemiol. 2021;190(1):116-124) assess urinary cadmium level as a potential environmental influence on ovarian reserve, as measured using serum follicle-stimulating hormone, in data from 1,681 US women (1988-1994). They compare 3 methods for modeling urinary proxy exposures-standardization, covariate adjustment, and covariate-adjusted standardization. Observing positive associations with all 3 approaches but higher-magnitude estimates using covariate adjustment as compared with standardization and covariate-adjusted standardization-proposed to be the result of collider-stratification bias-the authors conclude that cadmium may affect ovarian aging, and they recommend careful consideration of modeling approach. Comparisons of methodology in practice using real data are not straightforward, and additional complication arises from using a proxy outcome-serum follicle-stimulating hormone level to represent diminished ovarian reserve. In this commentary, I describe the theoretical basis for approaches for modeling urinary proxy exposures; consider potential explanations for why the approaches may yield different results in practice and describe why measurement error may play a larger role than collider-stratification bias; discuss challenges related to studies of ovarian reserve; and emphasize the importance of addressing both theoretical concerns and real-world challenges in methodological research and epidemiologic studies of ovarian reserve.

Estimation of glomerular filtration rate from skeletal muscle mass. A new equation independent from age, weight, gender, and ethnicity.

BACKGROUND AND AIMS: The most used indicator for the renal function is the glomerular filtration rate (GFR). Current used predictive GFR equations were calibrated on patients with chronic kidney disease. Thus, they are not very precise in healthy individuals. The estimation of skeletal muscle mass (SMM) allows the prediction of the daily urinary creatinine excretion (24hUCrE). This study proposes an equation for the estimation of GFR based on SMM (eGFRMuscle) and serum creatinine (SCr). METHODS AND RESULTS: Four hundred sixty-six free-living men underwent a bioelectrical impedance analysis for the evaluation of SMM (kg), a blood withdrawal for the measurement of SCr (mg/dL), and a 24-h urinary collection for the assessment of 24hUCrE (g/24 h). The linear regression analysis between SMM and 24hUCrE and the measurement of SCr allowed developing a predictive equation of eGFRMuscle. The equation predicting eGFRMuscle (ml/min/1.73 m2) was SMM (kg) × 3.06/SCr (mg/dL). eGFRMuscle was statistically different from eGFR predicted by Cockroft-Gault, MDRD Study, and CKD-EPI equations (p = 0.017, p < 0.001, and p < 0.001, respectively). Pairwise comparison of standard error of the area under the ROC curve (AUC) of eGFRMuscle with all the other AUCs of ROC curves highlighted significant differences. CONCLUSIONS: The equation presented in this study results in age, weight, gender, and ethnicity independent because it arises directly from SMM estimation. Therefore, the proposed equation could allow evaluating the GFR also in healthy people with low, average, or high weight, and in older people, regardless of GFR and SCr levels.

Dilute-and-Shoot HPLC-UV Method for Determination of Urinary Creatinine as a Normalization Tool in Mycotoxin Biomonitoring in Pigs.

A simple, rapid, and accurate HPLC-UV method was developed for the determination of creatinine in pig urine. Usually, it is determined in urine in biomonitoring of xenobiotics to correct for variations in dilutions of urine samples. The colorimetric method (based on Jaffe reaction), which was mainly used for this purpose in mycotoxin biomonitoring, is not a reliable approach for pig urine. Therefore, a novel and accurate HPLC method for creatinine determination was developed. The sample preparation was based on the dilute and shoot approach. An HPLC separation was performed with a porous graphitic carbon column with an aqueous mobile phase to achieve satisfactory retention time for creatinine. The method has been successfully validated, applied for the determination of creatinine in pig urine, and compared with other methods commonly used for that purpose-a colorimetric method based on Jaffe reaction and commercial ELISA test. The developed HPLC method shows the highest precision and accuracy for pig urine samples. Finally, the method was applied as a normalization tool in LC-MS/MS mycotoxin biomarkers analysis. The standardization to a constant creatinine level (0.5 mg/mL) enables similar matrix effects for eleven mycotoxin biomarkers for pig urine samples with different creatinine levels.

Validation of daily urinary creatinine excretion measurement by muscle-creatinine equivalence.

BACKGROUND: Twenty-four-hour urinary creatinine excretion (24hUCrE) is strongly correlated with skeletal muscle mass (SMM). This study suggests how to exploit the power of the SMM-24hUCrE correlation to assess the accuracy of 24hUCrE measurement. METHODS: Four hundred and sixty-six men, a subgroup of participants in the 2002-2004 follow-up examination of the Olivetti Heart Study, performed a 24-h urine collection to measure 24hUCrE and underwent bioelectrical impedance analysis to evaluate SMM. Linear regression analysis between 24hUCrE and SMM was used to calculate the muscle-creatinine equivalence and to develop an equation to predict the 24hUCrE depending on SMM. The accuracy of the 24hUCrE measurement was assessed using the change in the SMM-24hUCrE correlation coefficient upon variation in the percentage deviation (%D) between the measured and predicted 24hUCrE. RESULTS: The calculated muscle-creatinine equivalence was 1 g of 24hUCrE = 22.73 kg of SMM. The %Ds and the corresponding SMM-24hUCrE correlation coefficients were as follows: %D = 3.0, r = .997; %D = 4.7, r = .989; %D = 8.1, r = .963; %D = 10.5, r = .940; %D = 12.6, r = .909; %D = 18.9, r = .825; %D = 25.8, r = .707; %D = 33.5, r = .595; %D = 41.4, r = .453. CONCLUSION: The increase in %D corresponds to a reduced correlation between muscle mass and creatinine excretion, which indicated a poor performance in the measurement of the 24hUCrE. For studies on single individuals, where small variations in 24hUCrE could be significant, a %D up to 12.6% is suggested; on the other hand, a wider %D interval could be acceptable for population studies.

[Assessment of iodine nutritional status for pregnant women using adjusted urine creatinine from spot and 24-hour urine].

OBJECTIVE: To establish a reliable method of iodine nutritional assessment for pregnant women using the adjusted urinary creatinine of spot urine and 24-hour urine samples. METHODS: The spot urine in the morning at 8 00-11:30 and the following 24-hour urine samples of pregnant women were collected in Peking Union Medical College Hospital during March to October in 2016. The urinary iodine and urinary creatinine concentrations were determined. The estimated 24-hour urinary iodine excretion( 24-h UIE) was calculated using the urinary iodine/urinary creatinine( UIC/Cr) ratio of spot urine, and 24-hour urinary creatinine excretion( 24-h UCr E). RESULTS: There was a significant difference in the UIC, UIC/Cr ratio between spot urine and 24-h urine( P <0. 05). The UIC, UIC/Cr ratio of spot urine, and the estimated 24-h UIE all were significantly correlated with the real 24-h UIE( P < 0. 01), especially the estimated 24-h UIE were taking up 70%-80% for the real 24-h UIE in the period of gestation. CONCLUSION: The UIC, UIC/Cr, and the estimated 24-h UIE cannot directly replace the relevant values derived of the 24-hour urine samples. But the estimated 24-h UIE can reflect the iodine nutritional status of pregnant women in recent days, and the method could be a reliable reference for the iodine nutritional assessment of the pregnant women in practice.

Estimation of Urinary Creatinine Excretion and Prediction of Renal Function in Morbidly Obese Patients: New Tools from Body Composition Analysis.

BACKGROUND/AIMS: In obese subjects the accuracy of prediction of renal function is quite low. The aim of this study was to obtain a more accurate estimate of urinary creatinine excretion (UCr), creatinine clearance (CCr), and GFR from body cell mass (BCM). METHODS: Seventy-three adult morbidly obese patients (BMI 35.2-64.5 kg/m2) were examined. BCM was calculated from body impedance analysis. CCr was measured (mCCr) and was predicted from BCM and antropometric data (MR-BCMCCr), with Cockcroft and Gault (C&GCCr) and Salazar and Corcoran (S&CCCr) formulas. GFR was predicted from BCM (BCM GFR) and with MDRD and CKD-EPI formulas. RESULTS: Multiple regression (MR) indicated a strict linear correlation between UCr, BCM and anthropometric data. UCr predicted from MR equation (MR-BCMUCr) was very similar to measured UCr. MR-BCMCCr (168±46 mL/min) and mCCr (167±51 mL/min) were also similar, while significant differences were found between mCCr, C&GCCr and S&CCCr. The correlation and the agreement between MR-BCMCCr and mCCr were closer and prediction error was lower than the other formulas. BCM GFR (125±32 mL/min) had close correlations and agreements with MDRD GFR and CKD EPI formulas. CONCLUSIONS: In morbidly obese patients the measurement of BCM meliorates the prediction of UCr and CCr, and allows the prediction of GFR.

24-Hour Urine Samples Are More Reproducible Than Spot Urine Samples for Evaluation of Iodine Status in School-Age Children.

BACKGROUND: Variation in different urinary measurements for evaluation of iodine status is of concern to clinicians and researchers. OBJECTIVE: This study evaluated variations between urine iodine concentration (UIC), spot and 24-h urine sample creatinine concentrations, and 24-h urine iodine excretion (24-h UIE) in repeated samples from school-age children. METHODS: Urine samples (24 h and morning spot) were collected on 2 occasions from 981 children in Ningjin and Lingxian counties, China. Samples from Ningjin were collected in October and November 2013, and samples from Lingxian were collected in April and May 2014. Morning spot urine iodine concentration (MUIC), morning spot urine creatinine, 24-h UIC, and 24-h urine creatinine were measured in all samples. The 24-h UIE was calculated by multiplying the 24-h UIC by the 24-h urine volume. RESULTS: In Ningjin County, the 24-h UIC and 24-h UIE did not differ between repeated collections [192 and 172 µg/L, respectively, for 24-h UIC (P = 0.08); 123 and 120 µg/L, respectively, for 24-h UIE (P = 0.56)], whereas the MUIC was lower in November 2013 than in October 2013 (170 and 190 µg/L, respectively; P = 0.034). In Lingxian County, no significant differences were observed in 24-h UIC between the repeated collections (230 and 218 µg/L, respectively; P = 0.79), whereas the 24-h UIE and MUIC were higher in the samples collected in May 2014 than in April 2014 [161 and 155 µg/L, respectively, for 24-h UIE (P = 0.002); 244 and 203 µg/L, respectively, for MUIC (P < 0.001)]. When data from both counties were combined, no difference was observed between repeated 24-h UIC (214 compared with 196 µg/L; P = 0.17) and 24-h UIE (143 compared with 143 µg/d; P = 0.06), but MUICs were lower in the first collection than in the second collection (199 and 207 µg/L, respectively; P = 0.002). The κ values were >0.4 for 24-h UIC and mean UIE, whereas relatively low κ values were observed for MUIC and mean UIE. CONCLUSION: The 24-h UIC was more accurate and reproducible than the MUIC in evaluating iodine status in a large-scale population study of school-age children.

Estimation of the 24-h urinary protein excretion based on the estimated urinary creatinine output.

BACKGROUND: The urinary protein/creatinine ratio [Up/Ucr (g/gCr)] has been used in the clinical management of patients with chronic kidney disease (CKD). However, a discrepancy is often noted between the Up/Ucr and 24-h urinary protein excretion [24hUp (g/day)] in patients with extremes of muscle mass. We examined devised a method for precise estimation of the 24-h urinary protein excretion (E-24hUp) based on estimation of 24-h urinary creatinine output (E-24hCr). METHODS: Three parameters, spot Up/Ucr, 24hUP and E-24hUp (=Up/Ucr × E-24hCr), were determined in 116 adult patients with CKD. The correlations among the groups were analyzed. RESULTS: There was a significant correlation between the Up/Ucr and 24hUp (p < 0.001). We divided the patients into three groups according to the 24hUp; the low urinary protein group (<1.0 g/day), the intermediate urinary protein group (1.0-3.5 g/day), and the high urinary protein group (>3.5 g/day). There was a significant correlation between the Up/Ucr and 24hUp in the low (p = 0.04) and high urinary protein (p = 0.01) groups, whereas the correlation coefficient was lower in the intermediate urinary protein (p = 0.07) group. Thus, we found a significant correlation between 24hUp and E-24hUp in the study population overall (p < 0.001), in the low (p = 0.01), in the intermediate (p < 0.001), and in the high urinary protein group (p < 0.001). CONCLUSION: We conclude that a poor correlation exists between the Up/Ucr and 24hUp in patients with intermediate urinary protein excretion levels. The recommended parameter for monitoring proteinuria in such patients may be the E-24hUp, which is calculated using the E-24hCr.

Urinary creatinine excretion, measured glomerular filtration rate and CKD outcomes.

BACKGROUND: Muscle wasting predicts mortality in patients with end-stage renal disease (ESRD), but its role in the progression of chronic kidney disease (CKD) is uncertain. We studied CKD outcomes associated with low muscle mass, assessed by urinary creatinine excretion (UCr). METHODS: The NephroTest cohort included 1429 patients with CKD stages 1-4 and both measured glomerular filtration rate (mGFR) (by (51)Cr-EDTA) and estimated glomerular filtration rate (eGFR) (by CKD-Epidemiology Collaboration equation). We used cause-specific Cox models to estimate hazard ratios (HRs) for the competing risks of ESRD and death associated with gender-specific UCr quartiles. RESULTS: UCr was 13.6 ± 3.2 mmol/24 h (0.17 ± 0.05 mmol/kg/24 h) in men and 9.2 ± 2.1 (0.14 ± 0.05) in women. It was positively associated with mGFR, but not with eGFR. Over a median follow-up of 3.6 (2.1-5.8) years, 229 patients developed ESRD and 113 patients died before ESRD. Compared with patients in the highest UCr quartile, those in the lowest quartile had a higher crude HR (95% confidence interval) for pre-ESRD death: 4.3 (2.4-7.7), which was weakened, but remained statistically significant, independent of demographics, mGFR and several other factors: 2.1 (1.04-4.3). Their crude ESRD risk was not higher: HR: 0.95 (0.65-1.4), and even tended to be lower after adjusting for mGFR and log-proteinuria: HR: 0.70 (0.45-1.1). Adjustment for eGFR instead of mGFR reversed this relationship: HR: 1.7 (1.1-2.7). CONCLUSIONS: In early stage CKD, low UCr is associated with higher risk for mortality, but not for ESRD. Using creatinine-based equation to adjust for GFR may bias the relationship of UCr with ESRD risk.

Association of arsenic with kidney function in adolescents and young adults: Results from the National Health and Nutrition Examination Survey 2009-2012.

BACKGROUND: Long-term exposure to arsenic is a major public health concern. Emerging evidence suggests adverse health effects even at low levels of exposure. This study examined the association of arsenic exposure with estimated glomerular filtration rate (eGFR) and compared methods of adjustment for urinary dilution in a representative sample of U.S. adolescents and young adults. METHODS: We performed a cross-sectional study of 1253 participants ages 12-30 years in the 2009-2012 National Health and Nutrition Examination Survey (NHANES) with available urinary arsenic and eGFR measures. Multivariable linear regression was used to model the association of urinary total arsenic and dimethylarsinate (DMA) with eGFR. RESULTS: The median urinary total arsenic and DMA concentrations were 6.3 µg/L (IQR 3.3-12.7 µg/L) and 3.3 µg/L (IQR 1.7-5.7 µg/L), respectively. Median eGFR was 109 mL/min/1.73 m(2). Adjusting arsenic for urine concentration with urinary creatinine, eGFR was 4.0 mL/min/1.73 m(2) higher (95% confidence interval [CI] 1.0-7.1 mL/min/1.73 m(2)) and 4.3mL/min/1.73 m(2) higher (95% CI 0.5-8.0 mL/min/1.73 m(2)) per log-unit increase in total arsenic and DMA, respectively. When using urine osmolality to adjust for urine concentration, a log-unit increase in total arsenic and DMA was associated with a 0.4 mL/min/1.73 m(2) (95% CI -1.8 to 1.1 mL/min/1.73 m(2)) and 0.01 (95% CI -1.9 to 1.9 mL/min/1.73 m(2)) lower eGFR, respectively. CONCLUSIONS: Discordant associations were observed between arsenic and eGFR levels depending on whether urinary creatinine or osmolality was used to adjust for urine concentration. Further study should be dedicated to validating the best approach to account for urinary dilution in research in toxicants, and this may have implications for all studies which examine urinary biomarkers.

Weaning from Kidney Replacement Therapy in the Critically Ill Patient with Acute Kidney Injury.

Around 10% of critically ill patients suffer acute kidney injury (AKI) requiring kidney replacement therapy (KRT), with a mortality rate approaching 50%. Although most survivors achieve sufficient renal recovery to be weaned from KRT, there are no recognized guidelines on the optimal period for weaning from KRT. A systematic review was conducted using a peer-reviewed strategy, combining themes of KRT (intermittent hemodialysis, CKRT: continuous veno-venous hemo/dialysis/filtration/diafiltration, sustained low-efficiency dialysis/filtration), factors predictive of successful weaning (defined as a prolonged period without new KRT) and patient outcomes. Our research resulted in studies, all observational, describing clinical and biological parameters predictive of successful weaning from KRT. Urine output prior to KRT cessation is the most studied variable and the most widely used in practice. Other predictive factors, such as urinary urea and creatinine and new urinary and serum renal biomarkers, including cystatin C and neutrophil gelatinase-associated lipocalin (NGAL), were also analyzed in the light of recent studies. This review presents the rationale for early weaning from KRT, the parameters that can guide it, and its practical modalities. Once the patient's clinical condition has stabilized and volume status optimized, a diuresis greater than 500 mL/day should prompt the intensivist to consider weaning. Urinary parameters could be useful in predicting weaning success but have yet to be validated.

Association between Urinary Creatinine Excretion and Hypothyroidism in Patients with Chronic Kidney Disease.

While hypothyroidism increases serum creatinine (Cr) levels, it is uncertain whether the elevation is mediated via a decline in the glomerular filtration rate (GFR) or the reflection of enhanced Cr production from the muscles or both. In the present study, we explored an association between urinary Cr excretion rate (CER) and hypothyroidism. A total of 553 patients with chronic kidney disease were enrolled in a cross-sectional study. Multiple linear regression analysis was performed to explore the association between hypothyroidism and urinary CER. The mean urinary CER was 1.01 ± 0.38 g/day and 121 patients (22%) had hypothyroidism. The multiple linear regression analysis revealed explanatory variables with urinary CER, including age, sex, body mass index, 24 h Cr clearance (24hrCcr), and albumin while hypothyroidism was not considered an independent explanatory variable. In addition, scatter plot analysis with regression fit line representing the association between estimated GFR calculated using s-Cr (eGFRcre) and 24hrCcr revealed that eGFRcre and 24hrCcr had strong correlations with each other in hypothyroid patients as well as euthyroid patients. Collectively, hypothyroidism was not considered an independent explanatory variable for urinary CER in the present study and eGFRcre is a useful marker to evaluate kidney function regardless of the presence of hypothyroidism.

Onset timing and duration of augmented renal clearance in a mixed intensive care unit.

BACKGROUND: Augmented renal clearance (ARC) is associated with lower blood plasma concentrations of renally excreted drugs; however, its time course is unknown. The current study aimed to determine the onset timing/duration of ARC, its risk factors, and its association with clinical outcomes by continuous monitoring of urinary creatinine clearance (CrCl) in critically ill patients. METHODS: Data were retrospectively obtained from the medical records of 2592 critically ill patients admitted to the intensive care unit (ICU) from January 2019 to June 2022 at a tertiary emergency hospital. Among these, patients with continuously measured urinary CrCl were selected and observed over time. We evaluated the onset timing and duration of ARC by plotting Kaplan-Meier curves. Furthermore, by multivariate analyses, factors associated with the onset and persistence of ARC were analyzed, and the association between the ARC time course and clinical outcomes was evaluated. RESULTS: The prevalence of ARC was 33.4% (245/734). ARC onset was within 3 days of admission in approximately half of the cases, and within 1 week in most of the other cases. In contrast, the persistence duration of ARC varied widely (median, 5 days), and lasted for more than a month in some cases. Multivariate analysis identified younger age, male sex, lower serum creatinine at admission, admission with central nervous system disease, no medical history, use of mechanically assisted ventilation, and vasopressor use as onset factors for ARC. Furthermore, factors associated with ARC persistence such as younger age and higher urinary CrCl on ARC day 1 were detected. The onset of ARC was significantly associated with reduced mortality, but persistent of ARC was significantly associated with fewer ICU-free days. CONCLUSIONS: Despite the early onset of ARC, its duration varied widely and ARC persisted longer in younger patients with higher urinary CrCl. Since the duration of ARC was associated with fewer ICU-free days, it may be necessary to consider a long-term increased-dose regimen of renally excreted drugs beginning early in patients who are predicted to have a persistent ARC.

Correlation between glycated hemoglobin A1c, urinary microalbumin, urinary creatinine, ß2 microglobulin, retinol binding protein and diabetic retinopathy.

BACKGROUND: Retinopathy is the most common microvascular disease of type 2 diabetes, and seriously threatens the life, health and quality of life of patients. It is worth noting that the development of diabetic retinopathy (DR) can be hidden, with few symptoms. Therefore, the preliminary screening of diabetic patients should identify DR as soon as possible, delay disease progression, and play a vital role in its diagnosis and treatment. AIM: To investigate the correlation between glycated hemoglobin A1c (HbA1c), urinary microalbumin (U-mALB), urinary creatinine (U-CR), mALB/U-CR ratio, ß2 microglobulin (ß2MG), retinol binding protein (RBP) and DR. METHODS: A total of 180 patients with type 2 diabetes mellitus attending the Second People's Hospital of Hefei from January 2022 to August 2022 were retrospectively enrolled by ophthalmologists. Based on whether they had combined retinopathy and its degree, 68 patients with diabetes mellitus without retinopathy (NDR) were assigned to the NDR group, 54 patients with non-proliferative DR (NPDR) to the NPDR group, and 58 patients with proliferative DR to the PDR group. General data, and HbA1c, mALB, ß2MG, RBP, mALB/U-CR and U-CR results were collected from the patients and compared among the groups. Pearson's correlation method was used to analyze the correlation between HbA1c, mALB, ß2MG, RBP, mALB/U-CR and U-CR indices, and multiple linear regression was applied to identify the risk factors for DR. Receiver operator characteristic (ROC) curves were also drawn. RESULTS: The differences in age, gender, systolic and diastolic blood pressure between the groups were not statistically significantly (P > 0.05), but the difference in disease duration was statistically significant (P < 0.05). The differences in fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, and triglyceride between the groups were not statistically significant (P > 0.05). HbA1c in the PDR group was higher than that in the NPDR and NDR groups (P < 0.05). The levels of mALB, ß2MG, RBP, mALB/U-CR and U-CR in the PDR group were higher than those in the NPDR and NDR groups (P < 0.05). Multiple linear regression analysis showed that disease duration, HbA1c, mALB, ß2MG, RBP, mALB/U-CR and U-CR were risk factors for the development of DR. The ROC curve showed that the area under the curve (AUC) for the combination of indices (HbA1c + mALB + mALB/U-CR + U-CR + ß2MG + RBP) was 0.958, with a sensitivity of 94.83% and specificity of 96.72%, which was higher than the AUC for single index prediction (P < 0.05). CONCLUSION: HbA1c, mALB, mALB/U-CR, U-CR, ß2MG and RBP can reflect the development of DR and are risk factors affecting PDR, and the combination of these six indices has predictive value for PDR.

Rapid Electrochemical Flow Analysis of Urinary Creatinine on Paper: Unleashing the Potential of Two-Electrode Detection.

The development of low-cost, disposable electrochemical sensors is an essential step in moving traditionally inaccessible quantitative diagnostic assays toward the point of need. However, a major remaining limitation of current technologies is the reliance on standardized reference electrode materials. Integrating these reference electrodes considerably restricts the choice of the electrode substrate and drastically increases the fabrication costs. Herein, we demonstrate that adoption of two-electrode detection systems can circumvent these limitations and allow for the development of low-cost, paper-based devices. We showcase the power of this approach by developing a continuous flow assay for urinary creatinine enabled by an embedded graphenic two-electrode detector. The detection system not only simplifies sensor fabrication and readout hardware but also provides a robust sensing performance with high detection efficiencies. In addition to enabling high-throughput analysis of clinical urine samples, our two-electrode sensors provide unprecedented insights into the fundamental mechanism of the ferricyanide-mediated creatinine reaction. Finally, we developed a simplified circuitry to drive the detector. This forms the basis of a smart reader that guides the user through the measurement process. This study showcases the potential of affordable capillary-driven cartridges for clinical analysis within primary care settings.

Effect of antiresorptive therapy on urinary hydroxyproline in postmenopausal osteoporosis.

Osteoporosis becomes a serious health threat for older postmenopausal women by predisposing them to an increased risk of fracture. Osteoporosis and associated fractures are an important cause of morbidity and mortality. Special attention is being paid to early detection, management, and treatment of postmenopausal osteoporosis in women. Biochemical markers can enable dynamic and rapid measurement of total body skeletal metabolism and will be clinically useful in the management of postmenopausal osteoporosis women (PMO) and also for assessing the effects of antiresorptive therapy. With this view, we planned to assess osteoclastic activity by determining urinary hydroxyproline in osteoporotic women. The aim of this study is to measure urinary hydroxyproline (expressed as mg of hydroxyproline/g of creatinine) and serum ascorbic acid in postmenopausal women with osteoporosis and without osteoporosis. These biochemical parameters were determined 3 months post antiresorptive therapy (alendronate + calcium + vitamin D) in postmenopausal osteoporosis patients. 60 postmenopausal women with osteoporosis in the age group 45-60 years and 60 healthy postmenopausal women (normal bone mineral density) in the same age group were included in the study. Urinary hydroxyproline levels were significantly increased (P < 0.001) in PMO at baseline level as compared to control group. These levels were decreased significantly (P < 0.001) post therapy in PMO patients. Serum vitamin C levels were significantly decreased (P < 0.001) in PMO patients at baseline level as compared to controls. No significant change occurred of serum vitamin C level post therapy. Raised excretion of hydroxyproline at the baseline level might be due to increased degradation of collagen type I from the bone matrix in osteoporosis. Breakdown of collagen seems to be lowered as reflected by lowering of hydroxyproline excretion post antiresorptive therapy. Alteration in the concentration of this marker can be very well utilized to monitor the effectiveness of therapy. Thus simple, direct urinary assay to measure bone resorption is very useful in monitoring the therapy in PMO and may become an integral part of the management of osteoporosis.

Antimony and sleep health outcomes: NHANES 2009-2016.

OBJECTIVES: Following an earlier National Health and Nutrition Examination Survey (NHANES) 2005-2008 analysis, we investigated the association between urine antimony and sleep health using more recent data, new measures of sleep health, and multiple measures of urine density adjustment in NHANES 2009-2016. DESIGN: A cross-sectional study. SETTING: United States, national population-based survey. MEASUREMENTS: Multinomial logistic regression (sleep duration) and a generalized linear model with log-binomial regression (OSA, daytime sleepiness, sleep problems) were used to analyze the association of urinary antimony with sleep health outcomes. Urine creatinine and osmolality were considered, combined with statistical adjustment and standardization to account for urine density. PARTICIPANTS: A total of 8133 adult participants over 20 years of age were used using NHANES 2009-2016. RESULTS: We did not observe associations between urine antimony and short sleep duration or sleep problems. We observed mixed results for long sleep duration; there was a negative association in NHANES 2015-2016 and no association in NHANES 2009-2014. For self-reported symptoms of OSA, which were only available in 2015-2016, we observed a positive association for upper quartile urine antimony compared with the first quartile (RR = 1.24; 95% CI: 1.03, 1.50) and a test for trend, P= .02. CONCLUSION: Urinary antimony was not consistently associated with short sleep duration, long sleep duration, or sleep problems, despite the findings from a relatively recent scientific article using earlier waves of NHANES. We observed a positive association between antimony and symptoms of OSA; this cross-sectional analysis requires confirmation.