Associations of air pollutant concentrations with longitudinal kidney function changes in patients with chronic kidney disease.

This longitudinal cohort study investigated the associations of air pollutant exposures, including CO, NO, NO2, NOx, O3, PM10, PM2.5, and SO2, with long-term kidney function changes in patients with chronic kidney disease (CKD). We enrolled 447 CKD patients who took part in a universal hospital pre-ESRD care program during 2011-2015. The daily average air pollutant exposures and temperature were estimated for each patient, with different levels of air pollutant concentrations defined by 5-knot and restricted cubic spline function. Predicted annual estimated glomerular filtration (eGFR) slope values by one mixed model were considered as the study outcome. The average age of the study population was 77.1 ± 12.6 years, and the median annual eGFR decreased by 2.1 ml/min/1.73 m2 per year from 30 ml/min/1.73 m2 at baseline during a mean follow-up time of 3.4 years. The univariable and multivariable analyses revealed no significant linear and non-linear associations between 5-knot air pollutant concentrations and annual eGFR slope. In addition, the visualized spline effect plots show insignificant variation patterns in annual eGFR slope values with increased air pollutant concentrations. These results encourage more extensive studies to clarify the causal relationships and mechanisms of long-term specific air pollutant exposures and longitudinal kidney function change, especially in CKD populations.

Reliability analysis of a novel measurement system for quantifying human skin color.

Background: Precision is crucial in determining the appropriate procedure for implementing further trials. We conducted a study to explore the reliability of a novel measuring system for human skin color. Methods: The novel skin color measuring system was used to capture the skin color of four volunteers (2 males and 2 females) from the same location on each subject by the same operator. The measurement was repeated for different poses and instrument factors (camera and shooting protocol) in the red, green, and blue (RGB) system. The average color depth in each image was calculated and converted from 0 to 255. The spread of measures and the Bland-Altman plot was displayed to determine each variance source's random error, with the interclass correlation coefficients applied to reflect the reliability. Result: The RGB color depth in the experiment ranged from 190, 152, and 122 to 208, 170, and 142. The 95% confidential interval of the differences from the means in RGB colors for the different protocols were ±2.8, ±2.6, and ±2.1, respectively. The largest variation in the replicate trials was observed when subjects were in a supine position (standard deviation: 2). The interclass correlation coefficients were greater than 90%, suggesting that the developed system is highly precise. Conclusion: This study demonstrated that the developed device could stably and reliably detect human skin color across different common sources of variation, and thus could be applied clinically to explore relationships between health/disease and skin color changes.

Effect of Nephrology Care on Mortality in Incident Dialysis Patients: A Population-Based Cohort Study.

Long-term and continuous nephrology care effects on post-dialysis mortality remain unclear. This study aims to systematically explore the causal effect of nephrology care on mortality for patients with dialysis initiation. We conducted a retrospective cohort study to include incident patients with dialysis for ≥ 3 months in Taiwan from 2004 through 2011. The continuous nephrology care of incident patients in the three years before their dialysis was measured every six months. Continuous nephrology care was determined by 0-6, 0-12, …, 0-36 months and their counterparts; and none, intermittent, 0-6 months, …, and 0-36 months. Simple and weighted hazards ratio (HR) and 95% confidence interval (CI) for one-year mortality were estimated after propensity score (PS) matching. We included a total of 44,698 patients (mean age 63.3 ± 14.2, male 51.9%). Receiving ≥ 1 year predialysis nephrology care was associated with a 22% lower post-dialysis mortality hazard. No different effects were found (ranges of PS matching HR: 0.77-0.80) when comparing the defined duration of nephrology care with their counterparts. Stepped survival benefits were newly identified in the intermittent care, which had slightly lower HRs (weighted HR: 0.88, 95% CI: 0.79-0.97), followed by reviving care over six months to two years (ranges of weighted HR: 0.60-0.65), and reviving care over two years (ranges of weighted HR: 0.48-0.52). There was no existing critical period of nephrology care effect on post-dialysis, but there were extra survival benefits when extending nephrology care to >2 years, which suggests that continuous and long-term care during pre-dialysis/chronic kidney disease phase is required.

Associations between Metabolic Syndrome and Obesity-Related Indices and Bone Mineral Density T-Score in Hemodialysis Patients.

Previous studies have reported inconsistent results regarding the associations between metabolic syndrome (MetS) and obesity-related indices and bone mineral density (BMD). However, no previous studies have reported these associations among hemodialysis (HD) patients. The aims of this study were to investigate associations between MetS and its components and BMD T-score in HD patients and also between obesity-related indices and BMD T-score in HD patients with and without MetS. MetS was defined according to the Adult Treatment Panel III for Asians, and BMD T-score was calculated using dual-energy X-ray absorptiometry. Eight obesity-related indices were evaluated, including lipid accumulation product (LAP), visceral adiposity index (VAI), body adiposity index, conicity index (CI), body roundness index (BRI), abdominal volume index (AVI), waist-to-height ratio (WHtR), waist-hip ratio, and body mass index (BMI). One hundred and sixty-four patients undergoing HD were enrolled, and the prevalence of MetS was 61.6%. MetS was significantly associated with high lumbar spine and total hip T-scores. Regarding the MetS components, abdominal obesity and low HDL-C were significantly associated with high lumbar spine, femoral neck, and total hip T-scores; hypertriglyceridemia was significantly associated with high lumbar spine and total hip T-scores; hyperglycemia was significantly associated with a high lumbar spine T-score, whereas high blood pressure was not associated with T-score at any site. In the patients with MetS, BMI, WHtR, AVI, and BRI were significantly associated with T-score at all sites, and high CI, VAI, and LAP were also related to a high lumbar T-score. However, these indices were not associated with T-score at any site in patients without MetS. This study demonstrated positive associations between MetS and its five components and BMD T-score among HD patients. MetS, abdominal obesity, hypertriglyceridemia, and low HDL-cholesterol were associated with low risk of osteoporosis among the HD patients. Furthermore, we found that some obesity-related indices were associated with BMD T-score among HD patients with MetS but not in those without MetS. Our study highlights the importance of BMI, WHtR, AVI, and BRI in predicting the risk of osteoporosis among HD patients with MetS. In clinical practice, they can be easily calculated through simple anthropometric measurements and routine laboratory examinations and be used to quickly and conveniently assess the risk of osteoporosis among HD patients.