Risk factors for chronic kidney disease in a community-based population: a 10-year follow-up study

Usefulness of the quantitative measurement of urine protein at a community-based health checkup: a cross-sectional study

BACKGROUND

The dipstick urinalysis for proteinuria has been used for chronic kidney disease (CKD) screening at community-based health checkups; however, it has major drawbacks in that the result is only semi-quantitative and is influenced by urine concentration.

METHODS

We conducted urine protein/creatinine ratio (UPCR) measurements of 590 participants who showed a result of more than trace proteinuria on a dipstick analysis and evaluated the usefulness of UPCR measurements in community-based health checkups.

RESULTS

The UPCR values increased in accordance with the severity of the dipstick test findings, but statistical significance was only obtained between (±) and (1+), between (±) and (2+), and between (±) and (3+) groups. When the participants with (±) proteinuria were subjected to CGA classification (a classification of CKD by cause, glomerular filtration rate category, and albuminuria category) according to their UPCR data, a significant proportion of subjects (277, 77.0%) moved from the A2 category into A1, which is a less severe category. Conversely, 21 subjects (5.8%) were reclassified into a more severe category (A3). Thus, a dipstick test may produce a non-negligible number of false negatives as well as a large number of false positives. Similarly, the classifications of more than half of the subjects with (1+) or more severe proteinuria were changed based on their UPCR results.

CONCLUSION

The dipstick urinalysis for proteinuria appears less reliable than expected, suggesting that the quantitative measurement of urine protein should be performed even during mass health checkups to ensure the early detection and prevention of CKD.

Association between alcohol intake and measures of incident CKD: An analysis of nationwide health screening data

To evaluate the association between alcohol intake and incident chronic kidney disease measures as well as the sex differences in this association, we analyzed health screening data of 14,190,878 adults who underwent health screening ≥3 times and had glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m² and normal proteinuria at baseline. eGFR was calculated with the Chronic Kidney Disease Epidemiology Collaboration equation. Proteinuria was defined as ≥1+ dipstick proteinuria and low eGFR as <60 mL/min/1.73 m². The risk of incident proteinuria and low eGFR was analyzed with an extended Cox model with alcohol intake level as a time-varying determinant and the annual change of eGFR with generalized linear model. A J-shape association of alcohol intake with the incident proteinuria was observed in men (adjusted hazard ratio [aHR], 0.961, 95% confidence interval [CI], 0.953–0.970 in men drinking alcohol <10 g/day; aHR 1.139, 95% CI, 1.123–1.154 in men drinking alcohol ≥40 g/day, compared with non-drinking men), and a positive association was seen in women (aHR, 1.034, 95% CI, 1.023–1.044 in women drinking alcohol <10 g/day; aHR, 1.094, 95% CI, 1.034–1.158 in women drinking alcohol ≥40 g/day, compared with non-drinking women). In both sexes, an inverse association of alcohol intake with the annual eGFR decline and incident low eGFR was observed. This study observed a beneficial effect of moderate alcohol intake on incident proteinuria in men and a protective effect of alcohol intake of any amount on the annual eGFR decline and incident low eGFR in both sexes. The long-term implications of these observations need to be elucidated with future studies.

Comparison of the effect of light alcohol consumption on Japanese men with and without fatty liver

Light and moderate drinking is associated with lower risk of metabolic syndrome (Mets)-related diseases in the general population. Non-alcoholic fatty liver disease (NAFLD) is considered to be a phenotype of Mets in the liver. Although there have been some reports of the association between NAFLD and light alcohol consumption (LAC), the association between Mets-related diseases and LAC in the subjects with and without fatty liver is unclear. Therefore, this study aimed to determine the influence of LAC on Mets-related diseases in individuals with and those without fatty liver. This study included 1,190 men who underwent regular health check-ups and consumed <20 g/day of alcohol. The subjects were divided into two groups, the non-fatty liver group and fatty liver group, and investigated the association between Mets-related diseases and LAC. Fatty liver was diagnosed by abdominal ultrasound. The effect of LAC was different between the non-fatty liver and fatty liver groups. In the non-fatty liver group, the odds ratio (OR) for hypertension was 1.73 (1.04-2.88;2 P=0.035). In the fatty liver group, the OR for each Mets-related diseases were as follows: Dyslipidemia, 0.64 (0.44-0.95, P=0.028); impaired glucose tolerance 0.57 (0.37-0.88; P=0.012); chronic kidney disease, 0.58 (0.36-0.94; P=0.029); and Mets by Japanese criteria, 0.63 (0.44-0.92; P=0.016). The influence of LAC on Mets-related diseases differs based on the presence of fatty liver. In individuals without fatty liver, light drinking is an independent risk factor for hypertension.

Chronic thrombotic microangiopathy secondary to antiphospholipid syndrome, presenting with severe hypertension and chronic renal impairment

A 42-year-old woman was referred from a primary care centre for severe hypertension, stage 3A chronic kidney disease and proteinuria. This was associated with a significant obstetric history of pre-eclampsia during her previous two pregnancies. Secondary hypertension was suspected and autoimmune workup was positive for anticardiolipin IgG and lupus anticoagulant. A renal biopsy showed evidence of chronic thrombotic microangiopathy, with electron microscopy features suggestive of fibrillar glomerulonephritis. The diagnosis of antiphospholipid syndrome with antiphospholipid-associated nephropathy was made. She was started on anticoagulation with warfarin, and her hypertension was controlled with lisinopril and amlodipine with subsequent improvement in proteinuria. She remains on regular follow-up to monitor for possible development of malignancy or connective tissue disease.

Factors associated with adherence to dietary prescription among adult patients with chronic kidney disease on hemodialysis in national referral hospitals in Kenya: a mixed-methods survey

Introduction

Adherence to dietary prescriptions among patients with chronic kidney disease is known to prevent deterioration of kidney functions and slow down the risk for morbidity and mortality. This study determined factors associated with adherence to dietary prescription among adult patients with chronic kidney disease on hemodialysis.

Methods

A mixed-methods study, using parallel mixed design, was conducted at the renal clinics and dialysis units at the national teaching and referral hospitals in Kenya from September 2018 to January 2019. The study followed a QUAN + qual paradigm, with quantitative survey as the primary method. Adult patients with chronic kidney disease on hemodialysis without kidney transplant were purposively sampled for the quantitative survey. A sub-sample of adult patients and their caregivers were purposively sampled for the qualitative survey. Numeric data were collected using a structured, self-reported questionnaire using Open Data Kit “Collect software” while qualitative data were collected using in-depth interview guides and voice recording. Analysis on STATA software for quantitative and NVIV0 12 for qualitative data was conducted. The dependent variable, “adherence to diet prescription” was analyzed as a binary variable. P values < 0.1 and < 0.05 were considered as statistically significant in univariate and multivariate logistic regression models respectively. Qualitative data were thematically analyzed.

Results

Only 36.3% of the study population adhered to their dietary prescriptions. Factors that were independently associated with adherence to diet prescriptions were “flexibility in the diets” (AOR 2.65, 95% CI 1.11–6.30, P 0.028), “difficulties in following diet recommendations” (AOR 0.24, 95% CI 0.13–0.46, P < 001), and “adherence to limiting fluid intake” (AOR 9.74, 95% CI 4.90–19.38, P < 0.001).

Conclusions

For patients with chronic kidney disease on hemodialysis, diet prescriptions with less restrictions and requiring minimal extra efforts and resources are more likely to be adhered to than the restrictive ones. Patients who adhere to their fluid intake restrictions easily follow their diet prescriptions. Prescribed diets should be based on the individual patient’s usual dietary habits and assessed levels of challenges in using such diets. Additionally, diet adherence messages should be integrated with fluid limitation messages. Further research on understanding patients’ adherence to fluid restriction is also suggested.

Lower Diastolic Blood Pressure was Associated with Higher Incidence of Chronic Kidney Disease in the General Population Only in those Using Antihypertensive Medications

BACKGROUND/AIMS

The association of diastolic blood pressure (DBP) with incidence of chronic kidney disease (CKD) in the general population is not well examined.

METHODS

Using national health check-up database from 2008 to 2011 in the general Japanese population aged 39-74 years, we evaluated the association between DBP and incidence of CKD 2 years later in 127,954 participants without CKD. DBP was categorized by every 5 mm Hg from the lowest (<60 mm Hg) to the highest category (>100 mm Hg) and was further stratified into those with and without antihypertensive medications (BP meds). We calculated the OR for estimating adjusted risk of incident CKD using logistic regression model.

RESULTS

Participants were 62% female and 25.9% with BP meds, mean age of 76 years with estimated glomerular filtration rate of 78.2 ± 13.4 and DBP of 76 ± 11 mm Hg. Two years later, 12,379 (9.7%) developed CKD. Compared to DBP 60-64 mm Hg without BP meds as reference, multivariate analysis showed no difference in CKD risk at any DBP category among those without BP meds. However, in those with BP meds, risk increased according to lower DBP from 95 to 60 mm Hg (p for trend 0.05) with OR 1.51 (95% CI 1.14-1.99) in DBP <60 mm Hg. In subgroup analysis within those with or without BP meds, CKD risk was lower at higher DBP (p for trend 0.02) only in those without BP meds.

CONCLUSION

Lower DBP was associated with higher risk of incident CKD only in the general population taking antihypertensive medication.

Comparison of HbA1c levels and body mass index for prevention of diabetic kidney disease: A retrospective longitudinal study using outpatient clinical data in Japanese patients with type 2 diabetes mellitus

AIM

This study examined the association among the onset of diabetic kidney disease (DKD), blood glucose levels (HbA1_C), and body mass index (BMI) in Japanese patients with type 2 diabetes mellitus.

METHODS

Patients eligible for this study included those with type 2 diabetes who visited the outpatient clinic at Kawasaki Medical School Hospital between 2000 and 2018 and were followed up for more than two years. The Cox proportional hazards model was used in four categories of subjects: at the beginning of the follow-up period, "controlled" or "uncontrolled" glycemic control based on HbA1c and "overweight" or "non-overweight" based on BMI.

RESULTS

After dividing the participants into four categories according to HbA1c (lower than 7.0% (C) or higher (U)), and BMI (25 kg/m² or higher (O) or lower (N)), hazard ratios for groups CO, UN, and UO were 1.40 (95% CI 1.03-1.90, P = 0.030), 1.40 (1.04-1.88, P = 0.027), and 1.54 (1.12-2.11, P = 0.008), respectively, compared with the CN reference group, after adjustment was made for age, sex, duration of diabetes, and medication for hypertension or dyslipidemia.

CONCLUSION

Maintenance of both an HbA1c level lower than 7.0% and a BMI lower than 25 kg/m² was important for the prevention of DKD in Japanese patients with type 2 diabetes mellitus. Both factors had a similar effect on DKD in this study.

Use of estimated glomerular filtration rate to predict incident chronic kidney disease in patients at risk of cardiovascular disease: a retrospective study

Background

Patients with cardiovascular disease are at an increased risk of chronic kidney disease (CKD). However, data on incident CKD in patients with multiple vascular comorbidities are insufficient. In this study, we identified the predictors of CKD stages 3–5 in patients at risk of cardiovascular disease and used their estimated glomerular filtration rate (eGFR) to construct a nomogram to predict the 5-year risk of incident CKD.

Methods

Ambulatory data on 622 adults with preserved kidney function and one or more cardiovascular disease risk factors who attended outpatient clinics at a tertiary care hospital in Al-Ain, United Arab Emirates were obtained retrospectively. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation and assessed every 3 months from baseline to December 12, 2017. Fine and Gray competing risk regression model was used to identify the independent variables and construct a nomogram to predict incident CKD at 5 years, which is defined as eGFR < 60 mL/min/1.73 m² for ≥3 months. Time-dependent area under the receiver operating characteristic curve (AUC) was used to evaluate the discrimination ability of the model. Calibration curves were applied to determine the calibration ability and adjusted for the competing risk of death. Internal validation of predictive accuracy was performed using K-fold cross-validation.

Results

Of the 622 patients, 71 had newly developed CKD stages 3–5 over a median follow-up of 96 months (interquartile range, 86–103 months). Baseline eGFR, hemoglobin A1c, total cholesterol, and history of diabetes mellitus were identified as significant predictors of CKD stages 3–5. The nomogram had good discrimination in predicting the disease stages, with a time-dependent AUC of 0.918 (95% confidence interval, 0.846–0.964) at 5 years, after internal validation by cross-validation.

Conclusions

This study demonstrated that incident CKD could be predicted with a simple and practical nomogram in patients at risk of cardiovascular disease and with preserved kidney function, which in turn could help clinicians make more informed decisions for CKD management in these patients.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1494-8) contains supplementary material, which is available to authorized users.

Risk of Kidney Dysfunction from Polypharmacy among Older Patients: A Nested Case-Control Study of the South Korean Senior Cohort

Polypharmacy, the concurrent use of multiple medicines, could increase the risk of kidney dysfunction among older adults because it likely burdens the aging kidneys to excrete multiple pharmaceutical ingredients and their metabolites. This study aimed to examine the relation between polypharmacy and kidney dysfunction among older patients. A nested case-control study was conducted using the National Health Insurance Service - Senior Cohort (NHIS-SC, 2009-2013), representative of the Korean senior population. It consisted of all health insurance claims linked to records of mandatory health examination. Kidney dysfunction was defined as having an eGFR lower than 60, with a decline rate of 10% or more compared to the baseline eGFR. Polypharmacy was defined based on daily counts of pharmaceutical ingredients during one year prior to the case's event date. It was classified into polypharmacy (five to 10 ingredients) and excessive polypharmacy (10 or more ingredients). After matching case and control groups based on a range of potential confounders, conditional logistic regression was performed incorporating adjustments on disease-specific, medication-specific, and lifestyle-related risk factors. The matching resulted in 14,577 pairs of cases and controls. Exposure to polypharmacy was significantly associated with increase in the risk of kidney dysfunction; i.e., crude model (polypharmacy: OR = 1.572, 95% CI = 1.492-1.656; excessive polypharmacy: OR = 2.069, 95% CI = 1.876-2.283) and risk adjustment model (polypharmacy: OR = 1.213, 95% CI = 1.139-1.292; excessive polypharmacy: OR = 1.461, 95% CI = 1.303-1.639). The significant associations were robust across different definitions of kidney dysfunction. These findings inform healthcare providers and policy makers of the importance of polypharmacy prevention to protect older adults from kidney dysfunction.

Dietary Care for ADPKD Patients: Current Status and Future Directions

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic nephropathy, and tolvaptan is the only therapy available. However, tolvaptan slows but does not stop disease progression, is marred by polyuria, and most patients worldwide lack access. This and recent preclinical research findings on the glucose-dependency of cyst-lining cells have renewed interest in the dietary management of ADPKD. We now review the current dietary recommendations for ADPKD patients according to clinical guidelines, the evidence base for those, and the potential impact of preclinical studies addressing the impact of diet on ADPKD progression. The clinical efficacy of tolvaptan has put the focus on water intake and solute ingestion as modifiable factors that may impact tolvaptan tolerance and ADPKD progression. By contrast, dietary modifications suggested to ADPKD patients, such as avoiding caffeine, are not well supported and their impact is unknown. Recent studies have identified a chronic shift in energy production from mitochondrial oxidative phosphorylation to aerobic glycolysis (Warburg effect) as a contributor to cyst growth, rendering cyst cells exquisitely sensitive to glucose availability. Therefore, low calorie or ketogenic diets have delayed preclinical ADPKD progression. Additional preclinical data warn of potential negative impact of excess dietary phosphate or oxalate in ADPKD progression.

Influence of Sex on the Progression of Chronic Kidney Disease

The role that sex plays in the development and progression of chronic kidney disease remains a subject of controversy. The lack of clarity in this important area reflects complex interactions between biological factors and cultural and socioeconomic influences that impact the relationship between sex and renal disease. Certainly, additional observational studies are indicated; however, innovative approaches are required to isolate biological processes from cultural influences. Despite these limitations, available data suggest that the progression of renal disease is slower in women than in men and that this sexual dimorphism is primarily due to direct actions of sex hormones on cellular metabolism. The extent to which differences in lifestyle factors between the sexes influence sexual dimorphism in the progression of chronic kidney disease remains to be elucidated.

Alcohol Drinking and the Risk of Chronic Kidney Damage: A Meta-Analysis of 15 Prospective Cohort Studies

The relationship between alcohol drinking and chronic kidney damage, mainly including declined glomerular filtration rate (GFR), proteinuria, and end-stage renal disease, was conflicting. Thus, a meta-analysis was conducted to investigate their potential associations. PubMed and Web of Science were searched to identify prospective studies assessing the associations between alcohol drinking and chronic kidney damage published up to March 2019. Random-effects model was employed to pool the relative risks (RR) with 95% confidence intervals (CIs). Subgroup meta-analyses stratified by the basic characteristics of subjects were performed. A total of 15 cohort studies were included in the present study, with 268,723 participants and 31,766 incident cases. Participants with low (<13 g/d), moderate (13 to 26 g/d), and high (26 to 60 g/d) dose of alcohol drinking had 12% (RR: 0.88, 95% CI: 0.83 to 0.93), 24% (RR: 0.76, 95% CI: 0.70 to 0.83), and 21% (RR: 0.79, 95% CI: 0.71 to 0.88) lower risk of chronic kidney damage compared with the reference group (non- or occasional drinkers), respectively. The lower risk for chronic kidney damage remained significant for the declined GFR, or in men, or for participants aged less than 55 yrs, or studies with longer than 8 yrs of follow-up, while severe alcohol drinking (≥60 g/d) insignificantly increased 7% risk of chronic kidney damage (RR: 1.07, 95% CI: 0.53 to 2.15). No obvious heterogeneity and no publication bias were observed. Based on our meta-analysis, participants with alcohol drinking less than 60 g/d were at lower risk of declined GFR, especially in men or participants aged less than 55 yrs. Much more prospective cohort studies are required to confirm our present findings.

Long-term Body Weight Gain After Maturity is Associated With the Incidence of Chronic Kidney Disease (CKD), Independent of Current Body Weight, in Middle-aged and Older Men

BACKGROUND

This study investigated the relationship between long-term body weight gain after maturity and the incidence of chronic kidney disease (CKD).

METHODS

The participants were 303 men without a history of cardiovascular and cerebrovascular diseases, kidney dysfunction, or dialysis treatment. Their body weight gain after maturity was examined using a standardized self-administered questionnaire. The participants were divided into two groups based on the presence/absence of a body weight gain of ≥10 kg since 20 years of age.

RESULTS

After a 6-year follow-up, the cumulative incidence of CKD was significantly higher in participants with a body weight gain of ≥10 kg than in participants without body weight a body weight gain of ≥10 kg since 20 years of age (log-rank test: P = 0.041). After adjusting for the age, body mass index, estimated glomerular filtration rate levels, smoking and drinking habits, and the presence of hypertension, dyslipidemia, and hyperglycemia at baseline, the normal body weight participants with a body weight gain of ≥10 kg since 20 years of age was significantly related to the incidence of CKD (hazard ratio 2.47; 95% confidence of interval, 1.02-6.01, P = 0.045).

CONCLUSIONS

These results suggest that long-term body weight gain after maturity in normal body weight participants may be associated with the incidence of CKD, independent of current body weight.

Prediction of Acute Glomerular Filtration Rate Reductions Following Renin-angiotensin System Blockade in Chronic Kidney Disease: A Possible Application of Ultrasonography in Clinical Practice

Objective Renal arteriolosclerosis is a risk factor for acute reductions in the glomerular filtration rate (GFR) when renin-angiotensin system (RAS) inhibitors are administered. Renal arteriolosclerosis can be detected by an increase in the resistive index (RI) on Doppler ultrasonography. The purpose of the present study is to determine whether or not the RI can predict acute GFR reductions following RAS blockade in chronic kidney disease (CKD). Methods We surveyed all CKD patients who were hospitalized in Otemae Hospital from January 2008 to December 2017. One hundred and eight patients who had been newly treated with RAS inhibitors were able to be followed for 14 weeks. The end point was an acute reduction in the GFR, defined as a decrease of ≥30%. Results Twenty-three of the 108 patients presented with acute GFR reductions. The cumulative probability of acute GFR reductions was 3.3% and 53% in patients with RI ≤0.70 and RI >0.70, respectively (p<0.001). A univariate Cox proportional-hazards analysis showed that the RI, age, GFR, systolic blood pressure, urinary protein excretion, diabetic kidney disease, coronary artery disease, and use of diuretics were significant variables. Multivariate hazard ratios were calculated from the RI and three established variables (age, GFR, diuretics), and the RI and use of diuretics were shown to be significant risk factors for acute GFR reductions. Conclusion These results suggest that an increase in the RI, as well as the use of diuretics, may be risk factors for acute GFR reductions following RAS blockade.

Analysis of 2897 hospitalization events for patients with chronic kidney disease: results from CKD-JAC study

BACKGROUND

Chronic kidney disease is a known risk factor for end-stage renal and cardiovascular diseases. However, data are limited on the causes of hospitalization in patients with chronic kidney disease of maintenance period. This study aimed to aggregate hospitalization data of CKD patients and to determine the high-risk population. In addition, we compared CKD population to general population.

METHODS

We conducted a post hoc analysis of the chronic kidney disease-Japan cohort study, a multicenter prospective cohort study of 2966 patients with chronic kidney disease with a median 3.9 years of follow-up. We examined the hospitalization reasons and analyzed the risk factors.

RESULTS

We found 2897 all-cause hospitalization events (252.3 events/1000 person-years), a hospitalization incidence 17.1-fold higher than that in an age- and sex-matched cohort from the general Japanese population. Kidney, eye and adnexa, and heart-related hospital admissions were the most common. All-cause hospitalization increased with chronic kidney disease stage and with the presence of diabetes. Patients with diabetes at enrollment had 345.7 hospitalization events/1000 person-years, which is considerably higher than 196.8 events/1000 person-years for those without diabetes. Survival analysis, using hospitalization as an event, showed earlier all-cause hospitalization with the progression of chronic kidney disease stage and diabetes. Cardiovascular disease hospitalizations were more strongly influenced by diabetes than chronic kidney disease stage.

CONCLUSIONS

Patients with chronic kidney disease and diabetes are highly vulnerable to hospitalization for a variety of diseases. These descriptive data can be valuable in predicting the prognosis of patients with chronic kidney disease.

Evidence of Blood and Muscle Redox Status Imbalance in Experimentally Induced Renal Insufficiency in a Rabbit Model

Chronic kidney disease (CKD) is accompanied by a disturbed redox homeostasis, especially in end-stage patients, which is associated with pathological complications such as anemia, atherosclerosis, and muscle atrophy. However, limited evidence exists about redox disturbances before the end stage of CKD. Moreover, the available redox literature has not yet provided clear associations between circulating and tissue-specific (muscle) oxidative stress levels. The aim of the study was to evaluate commonly used redox status indices in the blood and in two different types of skeletal muscle (psoas, soleus) in the predialysis stages of CKD, using an animal model of renal insufficiency, and to investigate whether blood redox status indices could be reflecting the skeletal muscle redox status. Indices evaluated included reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), catalase (CAT), total antioxidant capacity (TAC), protein carbonyls (PC), and thiobarbituric acid reactive substances (TBARS). Results showed that blood GSH was higher in the uremic group compared to the control (17.50 ± 1.73 vs. 12.43 ± 1.01, p = 0.033). In both muscle types, PC levels were higher in the uremic group compared to the control (psoas: 1.086 ± 0.294 vs. 0.596 ± 0.372, soleus: 2.52 ± 0.29 vs. 0.929 ± 0.41, p < 0.05). The soleus had higher levels of TBARS, PC, GSH, CAT, and GR and lower TAC compared to the psoas in both groups. No significant correlations in redox status indices between the blood and skeletal muscles were found. However, in the uremic group, significant correlations between the psoas and soleus muscles in PC, GSSG, and CAT levels emerged, not present in the control. Even in the early stages of CKD, a disturbance in redox homeostasis was observed, which seemed to be muscle type-specific, while blood levels of redox indices did not seem to reflect the intramuscular condition. The above results highlight the need for further research in order to identify the key mechanisms driving the onset and progression of oxidative stress and its detrimental effects on CKD patients.

Lipid Accumulation and Chronic Kidney Disease

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Identifying progressive CKD from healthy population using Bayesian network and artificial intelligence: A worksite-based cohort study

Identifying progressive early chronic kidney disease (CKD) patients at a health checkup is a good opportunity to improve their prognosis. However, it is difficult to identify them using common health tests. This worksite-based cohort study for 7 years in Japan (n = 7465) was conducted to evaluate the progression of CKD. The outcome was aggravation of the KDIGO prognostic category of CKD 7 years later. The subjects were male, 59.1%; age, 50.1 ± 6.3 years; and eGFR, 79 ± 14.4 mL/min/1.73 m2. The number of subjects showing CKD progression started to increase from 3 years later. Vector analysis showed that CKD stage G1 A1 was more progressive than CKD stage G2 A1. Bayesian networks showed that the time-series changes in the prognostic category of CKD were related to the outcome. Support vector machines including time-series data of the prognostic category of CKD from 3 years later detected the high possibility of the outcome not only in subjects at very high risks but also in those at low risks at baseline. In conclusion, after the evaluation of kidney function at a health checkup, it is necessary to follow up not only patients at high risks but also patients at low risks at baseline for 3 years and longer.

Associations of Circulating MicroRNAs (miR-17, miR-21, and miR-150) and Chronic Kidney Disease in a Japanese Population

Background

MicroRNAs (miRNAs) play crucial roles in the development of various diseases, including chronic kidney disease (CKD). Although previous studies in clinically severe patients have investigated associations between CKD and miRNAs, with particular attention on renal fibrosis, relationships in a general population have yet to be established. The aim of this study was to examine the relationship between expression level of circulating miRNAs and CKD in a middle-aged Japanese population.

Methods

A final total of 513 individuals (216 men and 297 women) who participated in the health check-up program in 2012 were included in our analysis. Quantitative real-time polymerase chain reaction was used to determine expression levels of 22 miRNAs. Estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine level, sex, and age. Participants with eGFR <60 mL/min/1.73 m² were defined as having CKD.

Results

Three different miRNAs (miR-17, miR-21, and miR-150) showed significant correlations with eGFR after Bonferroni correction and were selected for further analyses. Expression levels of miR-17, miR-21, and miR-150 miRNAs were positively associated with eGFR after adjusting for potential confounders (P = 0.004, 0.002, and 0.004, respectively). Logistic regression analyses showed significantly lower odds ratios for CKD (eGFR <60 mL/min/1.73 m²) in the highest tertile of all three miRNAs (miR-17, miR-21, and miR-150) compared with the lowest tertile (P = 0.003, 0.01, and 0.02, respectively).

Conclusions

We found that three circulating miRNAs were significantly associated with CKD in a general Japanese population, which suggested that these miRNAs may be biomarkers for CKD among general adults.

Increased Microalbuminuria Risk in Male Cigarette Smokers: Results from the “Olivetti Heart Study” after 8 Years Follow-Up

Background/Aims: Association between cigarette smoke and albuminuria (UA) was already demonstrated in cross-sectional studies and in selected population samples (i.e diabetic patients). This study aims to evaluate, prospectively, the relationship between cigarette smoke and UA in a male adult population sample, with basal normal kidney function, participating in the Olivetti Heart Study (OHS). Methods: Among 994 participants, examined in both 1994-95 and 2002-04, were selected those resulted in both visits smokers (n=221) and non-smokers (n=416) and with basal normal kidney function (GFR> 60 mL/min) and basal albumin/creatinine ratio (ACR< 30 mg/g). Results: At baseline, the prevalence of hypertension was 41%, diabetes affected 6.3% and obesity 17% of the whole sample. Smokers showed statistically significant lower levels of systolic (SBP) and diastolic blood pressure (DBP) and BMI (p< 0.001) compared to non-smokers. There were not basal differences in UA, GFR and metabolic profile. However, at follow-up examination, smokers showed a statistically significant increase in SBP and DBP (p< 0.05), but not in GFR and BMI. Moreover, smokers showed a higher risk compared to non-smokers to be in the higher median levels group of UA (OR: 2.17, C.I.95%: 1.51-3.13; p < 0.001), even after correction for major confounding factors. Further adjustment for basal antihypertensive and hypoglycemic treatment did not change these patterns of association. Conclusion: In a selected male adult population sample, cigarette smoke was independently associated with the development of higher levels of albuminuria over time.

Efficacy and safety of elbasvir/grazoprevir for Japanese patients with genotype 1b chronic hepatitis C complicated by chronic kidney disease, including those undergoing hemodialysis: A post hoc analysis of a multicenter study

BACKGROUND AND AIM

This study aimed to evaluate the efficacy and safety of elbasvir/grazoprevir in genotype 1b chronic hepatitis C Japanese patients with chronic kidney disease (CKD), including those undergoing hemodialysis.

METHODS

This post hoc analysis of a multicenter, retrospective study included patients who had received elbasvir/grazoprevir. CKD was defined by an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² . The sustained virologic response (SVR) rate and frequency of treatment-emergent adverse events were assessed in patients with CKD.

RESULTS

The study population comprised 155 men and 182 women. The median eGFR level at baseline was 69.6 mL/min/1.73 m² (range, 3.0-128.5 mL/min/1.73 m² ). Among the 337 patients, 109 (32.3%) had CKD: 72, 14, and 23 (including 20 hemodialysis) had CKD stages 3, 4, and 5, respectively. The SVR rates according to the baseline CKD stages were 98.1% (51/52) in stage 1, 98.3% (173/176) in stage 2, 93.9% (46/49) in stage 3a, 100% (23/23) in stage 3b, 100% (14/14) in stage 4, and 100% (23/23) in stage 5. All 20 patients undergoing hemodialysis achieved SVR. There was no significant decrease from baseline in the median eGFR level throughout the treatment period among the patients with CKD. The incidence of treatment-emergent adverse events was 6.4% (7/109) among the patients with CKD and 9.7% (22/228) among the patients without CKD (not significant, P = 0.323).

CONCLUSIONS

The present study demonstrated that elbasvir and grazoprevir are highly effective and safe for genotype 1b chronic hepatitis C Japanese patients with CKD, including those undergoing hemodialysis.

The Influence of Sport Participation on African American Youth Binge Drinking

Background: The many negative consequences and high rates of use associated with youth binge drinking make further study into its causes and correlates vital. Sport participation is a relevant factor in predicting drinking behaviors among youth in need of further research. Objectives: The current study tests the influence of specific types of sport participation on the binge drinking behaviors of African American youth through binary logistic regression. Study of this particular sample is vital as race and sport participation have been shown to be critical variables associated with variations in drinking behaviors. Results: Results indicated that various types of sport participation were uniquely associated with drinking behaviors. Conclusion/Importance: Results are framed through social learning, social bond, and the power sport hypothesis in accordance with previous research.

Normotensive non-dipping blood pressure profile does not predict the risk of chronic kidney disease progression

The lack of a decrease in nocturnal blood pressure is a risk factor for the progression of chronic kidney disease (CKD); however, it currently remains unknown whether it is a risk factor in normotensive CKD patients. We conducted a retrospective cohort study and enrolled 676 CKD patients who underwent ambulatory blood pressure monitoring (ABPM). According to their nocturnal blood pressure dipping pattern (>10%: dipper or <10%: non-dipper) and average 24-h systolic blood pressure (>130/80 mmHg: hypertension or <130/80 mmHg: normotension), patients were divided into four groups. The estimated glomerular filtration rate (eGFR) decline over 2 years and relevant clinical parameters were analyzed among groups. Among all participants, 82.7% were non-dippers and half of them were normotensive. The eGFR decline was the most rapid in hypertensive non-dipper patients (4.73 ± 0.45 ml/min/1.73 m²/2 years), and was not significantly different between normotensive non-dipper (1.31 ± 0.49 ml/min/1.73 m²/2 years) and dipper patients (1.69 ± 0.80 ml/min/1.73 m²/2 years). A multivariate regression analysis revealed that the amount of urinary protein (95% confidence interval (CI): 1.51-2.63), 24-h systolic blood pressure (95% CI 1.13-1.45), and eGFR (95% CI 1.02-1.44) were associated with a rapid eGFR decline. We conclude that, according to the ABPM-based analysis, a non-dipping blood pressure pattern in normotensive CKD patients does not predict the risk of a rapid decline in eGFR. This suggests that the control of blood pressure, rather than its circadian rhythm, is essential for the preservation of eGFR.

Associations between Water Quality Measures and Chronic Kidney Disease Prevalence in Taiwan

To determine the relationships between exposure to environmental contaminants in water and chronic kidney disease (CKD), we investigated the associations of 61 water attributes with the prevalence of CKD and End-Stage Renal Disease (ESRD) using data from 2005 to 2011 from all 22 counties and cities in the main island of Taiwan. We acquired patient information from the Taiwan Longitudinal Health Insurance Database to calculate the age-standardized CKD and ESRD prevalence rates and linked the patients’ residences to the water quality monitoring data, which were sampled periodically for a total of over 45,000 observations obtained from the Taiwan Environmental Water Quality Information Database. The association analysis adjusting for gender, age, and annual effects showed that the zinc (Zn), ammonia, chemical oxygen demand (COD), and dissolved oxygen in rivers were weakly correlated with CKD (τ = 0.268/0.250/0.238/−0.267, p = 6.01×10⁻⁶/2.52×10⁻⁵/6.05×10⁻⁵/3.30×10⁻⁵, respectively), but none for ESRD. The importances of Zn and COD in rivers were also demonstrated in a CKD regression model. Moreover, an unusually high CKD prevalence was related to arsenic contamination in groundwater. A further prospective cohort study would improve our understanding of what level of environmental water with risky properties could affect the development of CKD.

The potential of N-glycosylation profiles as biomarkers for monitoring the progression of Type II diabetes mellitus towards diabetic kidney disease

Background

On a global scale, type II diabetes mellitus (T2DM) remain a major health problem and it is the driver for chronic kidney disease (CKD). Despite this association, we still do not have sufficient biomarkers to anticipate better outcomes. N-glycosylation profiles are robust biomarkers and can be used for early monitoring of the progression of T2DM towards CKD.

Methods

In this cross-sectional study, we recruited 241 T2DM patients from January to May 2016. Demographic and anthropometric data were collected, following which fasting blood samples were collected for clinical analyses. Renal function decline was determined by estimation of glomerular filtration rate (eGFR) and N-glycosylation profiles were analysed by Ultra-performance liquid chromatography (UPLC).

Results

The prevalence of undiagnosed CKD was 31.53%. Compared to men, women had a statistically significantly higher HbA1c (p = 0.031), TG (p = 0.015), HDL-c (p < 0.0001), creatinine (<0.0001), urea (p < 0.028) and uric acid (p < 0.0001). T2DM patients with undiagnosed CKD had higher serum creatinine (145.75 ± 50.83 vs 88.59 ± 19.46, p < 0.0001), higher uric acid (361.10 ± 115.37 vs 294.54 ± 97.75; p < 0.0001) and higher urea (5.17 ± 2.35 vs 3.58 ± 1.19; p < 0.0001). After performing logistic regression and adjusting for age, sex and BMI, three N-glycan peaks [OR (95%CI): (GP12 (0.05(0.01-0.54), p = 0.013)); GP16 (0.61(0.43-0.87), p = 0.006)); GP22 (0.60(0.39-0.92), p = 0.018)) were associated with renal function.

Conclusion

There was an increased prevalence of undiagnosed CKD among T2DM patients. This prevalence is the consequence of uncontrolled modifiable risk factors, which collectively may lead to end stage renal disease (ESRD). Although, the identified N-glycans could not adequately predict incident CKD, our investigation indicates the potential role of N-glycosylation in renal function and that their inclusion may improve risk stratification for CKD.

Risk of developing type 2 diabetes according to blood pressure levels and presence or absence of hypertensive treatment: the Saku study

The aim was to investigate the risk of developing type 2 diabetes according to blood pressure (BP) levels and presence or absence of hypertensive treatment. This 5-year cohort study comprised 3508 Japanese adults aged 30-74 years without diabetes who had undergone a medical checkup including a 75-g oral glucose tolerance test (OGTT) between April 2008 and March 2009 at Saku Central Hospital. Participants receiving antihypertensive treatment were categorized into controlled hypertension ( < 140/90 mmHg) or uncontrolled hypertension ( ≥ 140/90 mmHg) groups. Participants not receiving antihypertensive treatment were categorized: optimal BP ( < 120/80 mmHg), normal BP (120-129/80-84 mmHg), high-normal BP (130-139/85-89 mmHg), grade I hypertension (140-159/90-99 mmHg), and grade II/III hypertension ( ≥ 160/100 mmHg). Hazard ratios and 95% confidence intervals for the incidence of type 2 diabetes as defined by the 75-g OGTT were estimated using multivariable-adjusted Cox proportional hazard models in reference to optimal BP. During an average of 4.4 years of follow-up, 295 participants developed type 2 diabetes. Those with high-normal BP, grade I hypertension, grade II/III hypertension, and uncontrolled hypertension were at significantly higher risk for developing type 2 diabetes, with hazard ratios (95% confidence intervals) of 1.53 (1.03-2.29), 1.53 (1.02-2.32), 2.19 (1.01-4.77), and 1.81 (1.10-2.99), respectively. In conclusion, compared with those with optimal BP, individuals with BP ≥ 130/85 mmHg not receiving antihypertensive treatment and uncontrolled hypertensives with BP ≥ 140/90 mmHg receiving antihypertensive treatment were at a significantly higher risk for developing type 2 diabetes.

Clinical Usefulness of the Cardio-Ankle Vascular Index as a Predictor of Primary Cardiovascular Events in Patients With Chronic Kidney Disease

Background

The cardio-ankle vascular index (CAVI) is a physiologic marker reflecting arterial function. There have been no prospective studies investigating the relationship between CAVI and cardiovascular events in patients with chronic kidney disease (CKD). The aim of this prospective study was to assess the clinical usefulness of CAVI as a predictor of primary cardiovascular events in patients with CKD.

Methods

The study enrolled 460 outpatients with CKD but no history of cardiovascular disease (152 men and 308 women; mean ± standard deviation age, 74 ± 12 years). Patients were assigned to one of three groups: low (L, CAVI < 9; n = 100), medium (M, CAVI 9 - 10; n = 199), or high (H, CAVI > 10; n = 161). The utility of the CAVI as a predictor of primary cardiovascular events was evaluated.

Results

During the follow-up period (median 60.1 months), major adverse cardiovascular events (MACE) occurred in 91 cases (L, 8 (8.0%); M, 31 (15.6%); H, 52 (32.3%); P < 0.001, log-rank test). On multivariate Cox regression analysis, the risk for a MACE was significantly higher in group H than in non-group H (hazard ratio, 2.04; 95% confidence interval, 1.31 - 3.02; P < 0.01). A CAVI cut-off of 9.7 yielded the largest area under the curve, 0.701 (95% confidence interval: 0.657 - 0.743, P < 0.001), indicating a sensitivity of 74.0% and a specificity of 59.6% for discriminating between those who did and did not experience a MACE during follow-up.

Conclusions

The results of this study showed that a high CAVI is a predictor of primary cardiovascular events in patients with CKD.

Urinary D-serine level as a predictive biomarker for deterioration of renal function in patients with atherosclerotic risk factors

BACKGROUND

D-serine, the enantiomer of L-serine, was identified in mammals 20 years ago. Although a close relationship between D-serine and renal dysfunction has been shown, the clinical implications of urinary D- and L-serine in humans are poorly understood. The aim of this study was to evaluate the relationship between urinary D- and L-serine with well-known renal biomarkers, and clarify the prognostic value of D- and L-serine for renal events.

METHODS

This cross-sectional, prospective study included 65 patients with atherosclerotic risk factors, who were followed up for a median of 16 months. The primary endpoint was a composite of end-stage renal disease and a decline in estimated glomerular filtration rate (eGFR) ≥ 25% from baseline.

RESULTS

Urinary D-serine concentrations showed a better correlation with eGFR than did urinary L-serine, whereas neither urinary D- nor L-serine correlated with tubular markers such as urinary liver-type fatty acid-binding protein and N-acetyl-beta-D-glucosaminidase. A Cox regression analysis revealed that low urinary D-serine levels were significantly associated with the primary endpoint after adjusting for confounding factors (hazard ratio 12.60; 95% confidence interval, 3.49-45.51).

CONCLUSIONS

Urinary D-serine is associated with glomerular filtration and can be a prognostic biomarker of renal dysfunction in patients with atherosclerotic risk factors.

The eNOS-NO pathway attenuates kidney dysfunction via suppression of inflammasome activation in aldosterone-induced renal injury model mice

Hypertension causes vascular complications, such as stroke, cardiovascular disease, and chronic kidney disease (CKD). The relationship between endothelial dysfunction and progression of kidney disease is well known. However, the relationship between the eNOS-NO pathway and chronic inflammation, which is a common pathway for the progression of kidney disease, remains unexplored. We performed in vivo experiments to determine the role of the eNOS-NO pathway by using eNOS-deficient mice in a hypertensive kidney disease model. All mice were unilateral nephrectomized (Nx). One week after Nx, the mice were randomly divided into two groups: the aldosterone infusion groups and the vehicle groups. All mice also received a 1% NaCl solution instead of drinking water. The aldosterone infusion groups were treated with hydralazine to correct blood pressure differences. After four weeks of drug administration, all mice were euthanized, and blood and kidney tissue samples were collected. In the results, NLRP3 inflammasome activation was elevated in the kidneys of the eNOS-deficient mice, and tubulointerstitial fibrosis was accelerated. Suppression of inflammasome activation by knocking out ASC prevented tubulointerstitial injury in the eNOS knockout mice, indicating that the eNOS-NO pathway is involved in the development of kidney dysfunction through acceleration of NLRP3 inflammasome in macrophages. We revealed that endothelial function, particularly the eNOS-NO pathway, attenuates the progression of renal tubulointerstitial injury via suppression of inflammasome activation. Clinically, patients who develop vascular endothelial dysfunction have lifestyle diseases, such as hypertension or diabetes, and are known to be at risk for CKD. Our study suggests that the eNOS-NO pathway could be a therapeutic target for the treatment of chronic kidney disease associated with endothelial dysfunction.

Identification of 13 novel susceptibility loci for early-onset myocardial infarction, hypertension, or chronic kidney disease

Early-onset cardiovascular and renal diseases have a strong genetic component. In the present study, exome-wide association studies (EWASs) were performed to identify genetic variants that confer susceptibility to early-onset myocardial infarction (MI), hypertension, or chronic kidney disease (CKD) in Japanese individuals. A total of 8,093 individuals aged ≤65 years was enrolled in the study. The EWASs for MI, hypertension, and CKD were performed in 6,926 subjects (1,152 cases, 5,774 controls), 8,080 subjects (3,444 cases, 4,636 controls), and 2,556 subjects (1,051 cases, 1,505 controls), respectively. Genotyping of single nucleotide polymorphisms (SNPs) was performed with Illumina Human Exome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The associations of allele frequencies for 31,245, 31,276, or 31,514 SNPs that passed quality control to MI, hypertension, and CKD, respectively, was examined with Fisher's exact test. Bonferroni's correction for statistical significance of association was applied to compensate for multiple comparisons of genotypes with MI, hypertension, or CKD. The EWASs of allele frequencies revealed that 25, 11, and 11 SNPs were significantly associated with MI (P<1.60×10⁻⁶), hypertension (P<1.60×10⁻⁶), or CKD (P<1.59×10⁻⁶), respectively. Multivariable logistic regression analysis with adjustment for covariates showed that all 25, 11, and 11 SNPs were significantly associated with MI (P<0.0005), hypertension (P<0.0011), or CKD (P<0.0011), respectively. On examination of the results from previous genome-wide association studies and linkage disequilibrium of the identified SNPs, 11 loci (TMOD4, COL6A3, ADGRL3-CXCL8-MARCH1, OR52E4, TCHP-GIT2, CCDC63, 12q24.1, OAS3, PLCB2-VPS33B, GOSR2, ZNF77), six loci (MOB3C-TMOD4, COL6A3, COL6A5, CXCL8-MARCH1, NFKBIL1-6p21.3-NCR3, PLCB2-VPS33B), and seven loci (MOB3C-TMOD4, COL6A3, COL6A5, ADGRL3-CXCL8-MARCH1, MUC17, PLCB2-VPS33B, ZNF77) were identified as novel loci significantly associated with MI, hypertension, and CKD, respectively. Furthermore, six genes (TMOD4, COL6A3, CXCL8, MARCH1, PLCB2, VPS33B) were significantly associated with MI, hypertension and CKD; two genes (ADGRL3, ZNF77) with MI and CKD; and two genes (COL6A5, MOB3C) with hypertension and CKD. Therefore, 13 novel loci (MOB3C-TMOD4, COL6A3, ADGRL3-CXCL8-MARCH1, OR52E4, TCHP- GIT2, CCDC63, 12q24.1, OAS3, PLCB2-VPS33B, ZNF77, COL6A5, NFKBIL1-NCR3, MUC17) were identified that confer susceptibility to early-onset MI, hypertension, or CKD. The determination of genotypes for the SNPs at these loci may provide informative for assessment of the genetic risk for MI, hypertension, or CKD.

The Association Between Metabolically Healthy Obesity and the Risk of Proteinuria: The Kansai Healthcare Study

Background

Metabolically healthy obesity seems to be a unique phenotype for the risk of cardiometabolic diseases. However, it is not known whether this phenotype is associated with the risk of proteinuria.

Methods

Study subjects were 9,185 non-diabetic Japanese male workers aged 40–55 years who had no proteinuria, an estimated glomerular filtration rate ≥60 mL/min/1.73 m², no history of cancer, and no use of antihypertensive or lipid-lowering medications at baseline. Obesity was defined as body mass index ≥25.0 kg/m². Metabolic health was defined as the presence of no Adult Treatment Panel III components of the metabolic syndrome criteria, excluding waist circumference, and metabolic unhealth was defined as the presence of one or more metabolic syndrome components, excluding waist circumference. “Consecutive proteinuria” was considered positive if proteinuria was detected twice consecutively as 1+ or higher on urine dipstick at annual examinations to exclude chance proteinuria as much as possible.

Results

During the 81,660 person-years follow-up period, we confirmed 390 cases of consecutive proteinuria. Compared with metabolically healthy non-obesity, metabolically healthy obesity was not associated with the risk of consecutive proteinuria (multiple-adjusted hazard ratio [HR] 0.86; 95% confidence interval [CI], 0.37–1.99), but metabolically unhealthy non-obesity with ≥2 metabolic syndrome components (HR 1.77; 95% CI, 1.30–2.42), metabolically unhealthy obesity with one component (HR 1.71; 95% CI, 1.12–2.61), and metabolically unhealthy obesity with ≥2 metabolic syndrome components (HR 2.77; 95% CI, 2.01–3.82) were associated with an increased risk of consecutive proteinuria.

Conclusions

Metabolically healthy obesity did not increase the risk of consecutive proteinuria in Japanese middle-aged men.

Self-Reported Tobacco, Alcohol, and Illicit Drug Use and Progression of Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

Previous studies suggest that tobacco, alcohol, and illicit drug use is associated with CKD. We examined the associations of substance use with CKD progression and all-cause mortality among patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Chronic Renal Insufficiency Cohort Study is a prospective, longitudinal cohort study among 3939 participants with CKD in the United States. Self-reported tobacco smoking, alcohol drinking, marijuana use, and hard illicit drug (cocaine, heroin, or methamphetamine) use were obtained at baseline and annual follow-up visits. CKD progression was defined as incident ESKD or halving of eGFR. Substance use was modeled as the cumulative average exposure to capture both recent and long-term use in multivariable time-dependent Cox regression.

RESULTS

Over a median 5.5-year follow-up, 1287 participants developed CKD progression, and 1001 died. Baseline proportions of tobacco smoking, alcohol drinking, marijuana use, and hard illicit drug use were 13%, 20%, 33%, and 12%, respectively. Compared with nonsmoking throughout follow-up, multivariable-adjusted hazard ratios for persistent tobacco smoking were 1.02 (95% confidence interval, 0.86 to 1.21) for CKD progression and 1.86 (95% confidence interval, 1.54 to 2.24) for all-cause mortality. Compared with nondrinking throughout follow-up, multivariable-adjusted hazard ratios for persistent alcohol drinking were 1.06 (95% confidence interval, 0.88 to 1.29) for CKD progression and 0.73 (95% confidence interval, 0.58 to 0.91) for all-cause mortality. Compared with nonuse throughout follow-up, multivariable-adjusted hazard ratios for persistent marijuana use were 0.94 (95% confidence interval, 0.82 to 1.07) for CKD progression and 1.11 (95% confidence interval, 0.96 to 1.30) for all-cause mortality. Compared with nonuse throughout follow-up, multivariable-adjusted hazard ratios for persistent hard illicit drug use were 1.25 (95% confidence interval, 1.00 to 1.55) for CKD progression and 1.41 (95% confidence interval, 1.10 to 1.81) for all-cause mortality.

CONCLUSIONS

Hard illicit drug use is associated with higher risk of CKD progression and all-cause mortality, tobacco smoking is associated with higher risk of all-cause mortality, and alcohol drinking is associated with lower risk of all-cause mortality among patients with CKD.

Chronic kidney disease in patients at high risk of cardiovascular disease in the United Arab Emirates: A population-based study

Chronic kidney disease has become an increasingly significant clinical and public health issue, accounting for 1.1 million deaths worldwide. Information on the epidemiology of chronic kidney disease and associated risk factors is limited in the United Arab Emirates. Therefore, this study aimed to evaluate the incidence and causes of chronic kidney disease stages 3-5 in adult United Arab Emirates nationals with or at high risk of cardiovascular disease. This retrospective study included 491 adults with or at high risk of cardiovascular disease (diabetes mellitus or associated clinical disease) who attended outpatient clinics at a tertiary care hospital in Al-Ain, United Arab Emirates. Estimated glomerular filtration rate was assessed every 3 months from baseline to June 30, 2017. Chronic kidney disease stages 3-5 were defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m2 for ≥ 3 months. Multivariable Cox's proportional hazards analysis was used to determine the independent risk factors associated with developing chronic kidney disease stages 3-5. The cumulative incidence of chronic kidney disease stages 3-5 over a 9-year period was 11.4% (95% confidence interval 8.6, 14.0). The incidence rate of these disease stages was 164.8 (95% confidence interval 121.6, 207.9) per 10,000 person-years. The independent risk factors for developing chronic kidney disease stages 3-5 were older age, history of coronary heart disease, history of diabetes mellitus, and history of smoking. These data may be useful to develop effective strategies to prevent chronic kidney disease development in high-risk United Arab Emirates nationals.

Efficacy and safety of ombitasvir/paritaprevir/ritonavir combination therapy for genotype 1b chronic hepatitis C patients complicated with chronic kidney disease

AIM

The aim of this study was to clarify the effects and safety of ombitasvir/paritaprevir/ritonavir (OBT/PTV/r) therapy in genotype 1b chronic hepatitis C patients with non-dialysis chronic kidney disease (CKD).

METHODS

This retrospective, multicenter study of 12-week OBT/PTV/r therapy included genotype 1b patients with non-dialysis CKD. Chronic kidney disease was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² . Virologic responses and treatment-emergent adverse events (TEAEs) in patients with CKD were compared with those in patients without CKD.

RESULTS

Two hundred and thirty-five patients with a median age of 67 years (range, 27-89 years) were enrolled, consisting of 181 patients without CKD and 54 patients with CKD. Overall, the rates of rapid virologic response (RVR), end of treatment response (ETR), and sustained virologic response (SVR) were 78.7%, 98.7%, and 98.7%, respectively. Among the 181 non-CKD patients, the rates were 77.3% (140/181), 98.9% (179/181), and 98.9% (179/181), respectively. Among the 54 CKD patients, the rates were 83.3% (45/54), 98.1% (53/54), and 98.1% (53/54), respectively. There were no significant differences in the virologic response rates between the two groups (P = 0.449 for RVR, 0.545 for ETR, and 0.545 for SVR). In the CKD group, the eGFR level did not significantly change throughout the treatment period. There was no significant difference in the incidence of TEAEs or treatment discontinuation due to TEAEs between the two groups.

CONCLUSION

The present study showed that the effects and safety of OBV/PTV/r therapy in genotype 1b chronic hepatitis C patients with non-dialysis CKD were not inferior to those in patients without CKD.

Associations between arsenic in drinking water and occurrence of end-stage renal disease with modifications by comorbidities: A nationwide population-based study in Taiwan

Arsenic may affect the function of proximal convoluted tubules and glomeruli, but epidemiological data on the association between arsenic ingestion and end-stage renal disease (ESRD) are limited. Therefore, we conducted a nationwide population-based study in Taiwan, where the incidence of ESRD is the highest in the world, to study the potential association. Using the National Health Insurance Database in Taiwan, we constructed a cohort of 362,505 members with age≥40years in 1998. We identified patients of ESRD newly diagnosed between January 1, 1998 and December 31, 2010 and performed Cox proportional hazard regressions to identify risk factors for ESRD and evaluate their effects. Arsenic levels in drinking water were assessed on the basis of a nationwide census survey conducted by the government, of which measurement reports were available for 311 townships. We identified 5442 new patient of ESRD during the study period and found that residents of areas with arsenic levels≥50μg/L in the drinking water had a hazard ratio (HR) of 1.14 (95% confidence interval [CI]: 1.08-1.21) for ESRD. After adjusting for sex, age, income, and comorbidities, we found an adjusted HR of 1.12 (95% CI: 1.06-1.19), which was still statistically significant. Furthermore, the effect was modified by comorbidities, with more prominent effects on patients with less than three comorbidities (adjusted HR=1.51; 95% CI: 1.22-1.86 for low comorbidity score). In conclusion, a high arsenic level in drinking water was a risk factor for ESRD, independent of other documented risk factors. Reducing high-risk comorbidities in patients with early-stage renal dysfunction is important for slowing the progression of the disease to ESRD, even in the endemic area of arsenic exposure.

Biomarkers for IgA nephropathy on the basis of multi-hit pathogenesis

IgA nephropathy (IgAN) is the most prevalent glomerular disease worldwide and is associated with a poor prognosis. Development of curative treatment strategies and approaches for early diagnosis is necessary. Renal biopsy is the gold standard for the diagnosis and assessment of disease activity. However, reliable biomarkers are needed for the noninvasive diagnosis of this disease and to more fully delineate the risk of progression. With regard to the pathogenesis of IgAN, the multi-hit hypothesis, including production of galactose-deficient IgA1 (Gd-IgA1; Hit 1), IgG or IgA autoantibodies that recognize Gd-IgA1 (Hit 2), and their subsequent immune complexes formation (Hit 3) and glomerular deposition (Hit 4), has been widely supported by many studies. Although the prognostic values of several biomarkers have been discussed, we recently developed a highly sensitive and specific diagnostic method by measuring serum levels of Gd-IgA1 and Gd-IgA1-containing immune complexes. In addition, urinary Gd-IgA1 may represent a disease-specific biomarker for IgAN. We also confirmed that there is a significant correlation between serum levels of these effector molecules and disease activity, suggesting that each can be considered a practical surrogate marker of therapeutic response. Thus, these disease-oriented specific serum and urine biomarkers may be useful for screening of potential IgAN with isolated hematuria, earlier diagnosis, disease activity, and eventually, response to treatment. In this review, we discuss these concepts, with a focus on potential clinical applications of these biomarkers.

Smoking Cessation Ameliorates Microalbuminuria With Reduction of Blood Pressure and Pulse Rate in Patients With Already Diagnosed Diabetes Mellitus

Background

Smoking cessation in newly diagnosed type 2 diabetes patients is reported to be associated with amelioration of metabolic parameters and blood pressure (BP), and the reduction of microalbuminuria. The aim of this study is to demonstrate changes in BP, pulse rate (PR), and microalbuminuria in already diagnosed diabetes patients who quit smoking.

Methods

We retrospectively evaluated diabetes outpatients who were habitual smokers, and who visited to our smoking cessation clinic. Patients were divided into two groups based on their smoking status at the termination of a 3-month smoking cessation program (smoking cessation group and smoking group), and analyzed systolic and diastolic BPs, PR, HbA1c, and body weight at the start date, and at 1, 3, 6, and 12 months thereafter. The urinary albumin-to-creatinine ratio was also measured at the start date and at 12 months.

Results

Thirty-five patients met our criteria. Mean diabetes duration was 12 years. Eighteen patients (52%) quit smoking. Success or failure of smoking cessation depended on nicotine dependence rather than good or bad glycemic control. Both BP and PR decreased significantly after 1 month or later in the smoking cessation group without worsening HbA1c, while both parameters did not show any changes in the smoking group. Microalbuminuria was also ameliorated significantly at 12 months compared with that at the start date in the smoking cessation group (95.8 ± 92.9 mg/gCr vs. 75.5 ± 96.3 mg/gCr, P = 0.0059), while it did not show a significant change in the smoking group. (61.9 ± 43.5 mg/gCr vs. 97.7 ± 90.4 mg/gCr, P = 0.1039).

Conclusions

Smoking cessation might cause a reduction in chronic kidney disease progression through ameliorating microalbuminuria without metabolic adverse effects in patients already diagnosed with diabetes mellitus.

Acid-suppressive drugs and risk of kidney disease: A systematic review and meta-analysis

BACKGROUND AND AIM

More concerns had been raised about the risk of kidney disease (KD) associated with acid-suppressive drugs. But whether they could directly increase such risk remained unclear. Meta-analysis was conducted to comprehensively investigate this relationship.

METHODS

PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and three Chinese databases were searched until April 2017 for observational studies investigating the associations between acid-suppressive drugs and KD. Pooled log (odds ratios [ORs]) or log (hazard ratios [HRs]) with standard errors for KD risk were calculated using the generic inverse variance method and random-effect model.

RESULTS

Ten studies involving 128 020 KD patients were included. Proton pump inhibitor (PPI) therapy was associated with higher risks of acute interstitial nephritis (OR, 2.78; 95% confidence interval [CI], 1.25-6.17), acute kidney injury (AKI) (HR, 1.85; 95% CI, 1.33-2.59), chronic kidney disease (CKD) (HR, 1.47; 95% CI, 1.03-2.09), and end-stage renal disease (ESRD) (HR, 1.61; 95% CI, 1.26-2.04) than non-PPI therapy. Additionally, PPI significantly increased the risks of AKI (HR, 1.32; 95% CI, 1.16-1.51), CKD (HR, 1.28; 95% CI, 1.24-1.33), and ESRD (HR, 1.96; 95% CI, 1.21-3.17) compared with histamine 2 receptor antagonist (H2 RA). Relationship between H2 RA therapy and AKI (OR, 0.98; 95% CI, 0.90-1.07) or CKD (OR, 1.00; 95% CI, 0.89-1.11) was not found.

CONCLUSIONS

Proton pump inhibitor therapy significantly increased the risks of acute interstitial nephritis, AKI, CKD, and ESRD. Similar risks were not identified for H2 RA therapy. More clinical trials are needed to confirm our findings.

Efficacy and safety of ledipasvir/sofosbuvir for genotype 1b chronic hepatitis C patients with moderate renal impairment

BACKGROUND/AIM

To evaluate the efficacy and safety of ledipasvir and sofosbuvir therapy for genotype 1b in chronic hepatitis C patients with chronic kidney disease (CKD) stage 3.

METHODS

In a multicenter collaborative retrospective study, 706 patients who have received ledipasvir which is NS5A inhibitor, and sofosbuvir 400 mg which is NS5B nucleoside polymerase inhibitor daily for 12 weeks between September 2015 and January 2017 were subjected to this analysis. Virologic response and adverse events in patients with CKD stage 3 were compared with those in patients with CKD stages 1 and 2.

RESULTS

The rates of sustained virologic response (SVR) were 97.0% in patients with CKD stage 1, 97.1% in patients with CKD stage 2, and 94.7% in patients with CKD stage 3, respectively. There were no significant differences in the SVR rates between CKD stages 1 and 2, and CKD stage 1 and stage 3. The incidence of adverse events over than grade 2 was 0% in patients with CKD stage 1, 0.5% in patients with CKD stage 2, and 3.0% in patients with CKD stage 3, respectively. For treatment and follow-up period, eGFR levels in the patients with CKD stage 3 were not worsened compared to those at baseline.

CONCLUSION

This study suggested that the virologic response of ledipasvir and sofosbuvir in patients with CKD stage 3 was not inferior to those with CKD stages 1 and 2. In addition, administration of ledipasvir and sofosbuvir did not affect eGFR levels in the patients with CKD stage 3.

Alcohol consumption and incidence of proteinuria: a retrospective cohort study

BACKGROUND

Previous studies report conflicting results of a dose-dependent association between alcohol consumption and incidence of chronic kidney disease. Only a few studies have assessed the clinical impact of > 45-65 g/day of critically high alcohol consumption.

METHODS

This retrospective cohort study included 88,647 males and 88,925 females with dipstick urinary protein ≤ ± and estimated glomerular filtration rate ≥ 60 mL/min/1.73 m² at their first annual health examinations between April 2008 and March 2010 in Japan. The exposure was the self-reported alcohol consumption. The outcome was proteinuria defined as dipstick urinary protein ≥ 1 + or ≥ 2 +.

RESULTS

During median 1.8 years (interquartile range 1.0-2.1) of the observational period, 5416 (6.1%) males and 3262 (3.7%) females developed proteinuria defined as dipstick urinary protein ≥ 1 +. In males, a U-shape association between alcohol consumption and proteinuria was observed in a multivariable-adjusted Poisson regression model [incidence rate ratio (95% confidence interval) of rare, occasional, and daily drinkers with ≤ 19, 20-39, 40-59, and ≥ 60 g/day: 1.00 (reference), 0.86 (0.79-0.94), 0.70 (0.64-0.78), 0.82 (0.75-0.90), 1.00 (0.90-1.11), and 1.00 (0.85-1.17), respectively], whereas a J-shape association was observed in females [1.00 (reference), 0.81 (0.75-0.87), 0.74 (0.64-0.85), 0.93 (0.78-1.11), 1.09 (0.83-1.44), and 1.45 (1.02-2.08), respectively]. Similar associations with dipstick urinary protein ≥ 2 + were shown in males and females.

CONCLUSIONS

Moderate alcohol consumption was associated with lower risk of proteinuria in both males and females. Females with ≥ 60 g/day of high alcohol consumption were at higher risk of proteinuria, whereas males were not. Females were more vulnerable to high alcohol consumption, than males.

Combined effect of body mass index and metabolic status on the risk of prevalent and incident chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE

The risk of chronic kidney disease (CKD) differs in the normal weight, overweight, and obese individuals owing to metabolic abnormality. We aimed to determine the combined effects of body mass index (BMI) and metabolic status on the risk of the prevalence and incidence of CKD.

METHODS

Pubmed, Scopus, Web of science, and abstracts from recently relevant meetings prior to April 2016 were searched to identify eligible studies. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated using a random effects model.

RESULTS

Eight cross-sectional studies and four longitudinal follow-up studies with a total of 14787 and 166718 participants were separately included in present study. Compared with metabolically healthy normal weight individuals, metabolically healthy obese individuals showed increased risk for CKD, with RR of 1.235 (95%CI: 1.027 to 1.484), while metabolically health overweight individuals still presented in a healthy pattern, RR=1.094(95%CI: 0.774 to 1.547). In addition, metabolically abnormal groups had much higher risk for CKD, with RR of 1.572 (95%CI: 1.373 to 1.801), 1.652(95%CI: 1.139 to 2.397) and 1.898(95%CI: 1.505 to 2.395) across metabolically unhealthy normal weight, overweight and obese individuals respectively.

CONCLUSION

Individuals with abnormal metabolic status are at a significantly elevated risk for CKD, regardless of BMI. For metabolically healthy individuals, CKD risk increases with the growth of BMI, and obese persons eventually have a higher risk.

Uric acid-lowering and renoprotective effects of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia: a randomized, double-blind, placebo-controlled, parallel-group study (UPWARD study)

BACKGROUND

Hyperuricemia is supposed to be an independent risk factor for kidney dysfunction in diabetic patients. We attempted to examine the uric acid-lowering effect and the renoprotective effect of topiroxostat, a selective xanthine oxidoreductase inhibitor, in patients with diabetic nephropathy and hyperuricemia in this pilot study.

METHODS

The study design was randomized, double-blind, placebo-controlled, parallel-group study. A total of 65 patients with hyperuricemia and diabetic nephropathy with microalbuminuria were enrolled and assigned to either the topiroxostat group or the placebo group. Topiroxostat (stepwise dosing from 40 to 160 mg/day) or matching placebo was administered BID for 28 weeks. The primary endpoint was a change in the urinary albumin-to-creatinine ratio in the first-morning-void urine sample. Secondary endpoints were changes in the estimated glomerular filtration rate and the serum uric acid level.

RESULTS

At 28 weeks, there was no significant difference in the percent change from baseline in the urinary albumin-to-creatinine ratio between the two groups (topiroxostat: 0 vs. placebo: 17%, p = 0.3206), but the changes in the estimated glomerular filtration rate (- 0.2 vs. - 4.0 mL/min/1.73 m², p = 0.0303) and the serum uric acid level (- 2.94 vs. - 0.20 mg/dL, p < 0.0001) were significantly different between the topiroxostat and placebo groups. Gouty arthritis occurred in 1 patient in the placebo group and no patients in the topiroxostat group.

CONCLUSION

These findings support that diabetic nephropathy combined with hyperuricemia may be associated with kidney dysfunctions. Topiroxostat provides strict control of the serum uric acid level preventing decline of eGFR in these patients.

Serum chemerin levels are inversely associated with renal function in a general population

OBJECTIVE

Chemerin has been found to be highly expressed in the kidneys of rodents and has been suggested to affect metabolic syndrome (MetS)-related phenotypes which are in turn related to kidney damage. Only few clinical studies have addressed the relation between circulating chemerin and renal function in humans, and no population-based analyses have yet been performed. The potential influence of MetS-related phenotypes on the assumed association has been largely neglected. We aimed to investigate the association of serum chemerin with renal function in a general population with special regard to possible interactions between chemerin and metabolic phenotypes.

DESIGN, PATIENTS AND MEASUREMENTS

Linear and logistic regression models were applied to analyse data from 4082 subjects of the German Study of Health in Pomerania. Main outcomes included estimated glomerular filtration rate (eGFR), serum creatinine and cystatin C and chronic kidney disease.

RESULTS

Inverse associations of chemerin with eGFR were observed. The components of the MetS emerged as modulating factors in this relation and enhanced the association. Logistic regression models confirmed the relation between chemerin and eGFR and revealed that each increase in chemerin per 25 ng/mL was associated with an about threefold higher odds of chronic kidney disease [odds ratio 2.72 (95% confidence interval 2.26-3.29)].

CONCLUSIONS

Our results demonstrate a strong inverse association between serum chemerin levels and renal function. This association might be explained by MetS-related phenotypes, which lead to renal damage and are associated with increased chemerin levels and/or an impaired renal elimination of chemerin by diseased kidneys.

Validity of a Risk Prediction Equation for CKD After 10 Years of Follow-up in a Japanese Population: The Ibaraki Prefectural Health Study

BACKGROUND

Chronic kidney disease (CKD) is an important health problem for which risk equations have been developed for Western populations. This study aimed to develop and validate a risk prediction equation for CKD in a Japanese population.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

The study included 135,007 participants who completed an annual health checkup in 1993 to 1996 in the Ibaraki Prefecture in Japan. Participants were initially free of CKD (defined as stage 3, 4, or 5 CKD or proteinuria [2+ or 3+] by dipstick). Follow-up information was available from health checkups 10 years after the initial evaluation. We used data from 40,963 women and 17,892 men in the northern region of the prefecture for the development of risk prediction equations and 53,042 women and 23,110 men in the southern region for external validation.

PREDICTORS

Age, estimated glomerular filtration rate (eGFR), body mass index, proteinuria, hematuria, hypertension, diabetes mellitus, smoking, and drinking.

OUTCOME

Occurrence of CKD (defined as eGFR<60mL/min/1.73m² and/or proteinuria [2+ or 3+] by dipstick).

ANALYTICAL APPROACH

Logistic regression analysis to estimate risk for CKD stratified by sex.

RESULTS

During follow-up, 7,500 cases of CKD developed in the northern region and 8,964, in the southern region. Older age, proteinuria (1+), higher systolic blood pressure, medication for hypertension, and current smoking were associated with increased risk for CKD in both sexes, whereas higher eGFR and daily alcohol intake were associated with lower risk. C statistics of risk estimation equations for CKD at 10 years were >0.8 for both the development and external validation populations, and discrimination of the risk estimation was fairly good in women and men.

LIMITATIONS

Fluctuations in variables were not evaluated because the study used annual health checkups. This study excluded a large number of people for whom a 10-year health checkup was not available.

CONCLUSIONS

Estimations of risk for CKD after 10 years of follow-up in a general Japanese population can be achieved with a high level of validity.

Associations of smoking with cardiometabolic profile and renal function in a Romanian population-based sample from the PREDATORR cross-sectional study

BACKGROUND

The impact of smoking on morbidity is well known, but in Romania, limited data are available regarding the smoking prevalence and relationship with cardiometabolic profile and kidney function.

OBJECTIVES

To assess the association of smoking with cardiometabolic traits and kidney function, in a Romanian population-based sample from the PREDATORR study.

METHODS

PREDATORR was an epidemiological cross-sectional study. Between 2012 and 2014, participants were randomly selected from the lists of general practitioners and enrolled if they were aged 20 to 79 years, born and living in the past 10 years in Romania. Sociodemographic and lifestyle characteristics were collected through interviewer-administered questionnaires.

RESULTS

Overall, 2704 participants were included in the analysis, 18% of them being current smokers and 30.8% former smokers. Current smokers compared to non-smokers had higher total cholesterol (220.6 ± 50.4 versus 213.9 ± 86.8 mg/dl, P = 0.017), LDL-cholesterol (137.8 ± 45.2 versus 130.7 ± 83.7 mg/dl, P = 0.004) and glomerular filtration rate (96.9 ± 16.8 versus 90.7 ± 19.1 ml/min/1.73 m2, P <0.001) in women and higher triglycerides (170.7 ± 129.8 versus 144.3 ± 94.2 mg/dl, P = 0.007), glomerular filtration rate (97.6 ± 17 versus 90.3 ± 18 ml/min/1.73 m2, P < 0.001) and lower HDL-cholesterol (48 ± 15.5 versus 50.4 ± 14.1 mg/dl, P = 0.002) in men. Active smoking was associated with hypercholesterolaemia [OR: 1.40 (95% CI: 1.01-1.96), P = 0.04] and low HDL-cholesterolaemia [OR: 1.39 (95% CI: 1.01-1.91), P = 0.04] and negatively associated with overweight/obesity [OR: 0.67 (95% CI: 0.48-0.94), P = 0.02]. Male former smokers had higher prevalence of abdominal obesity (82.4% versus 76.4%, P = 0.02), hypertriglyceridaemia (43.6% versus 35.6%, P = 0.01), hypertension (64% versus 56.4%, P = 0.01) and ischaemic vascular disease (40.5% versus 30.9%, P = 0.003) than male non-smokers.

CONCLUSION

The PREDATORR study showed a high prevalence of smoking in the adult Romanian population providing data on the association of smoking with cardiometabolic traits.

Application of survival tree analysis for exploration of potential interactions between predictors of incident chronic kidney disease: a 15-year follow-up study

Background

Chronic kidney disease (CKD) is a growing public health challenges worldwide. Various studies have investigated risk factors of incident CKD; however, a very few studies examined interaction between these risk factors. In an attempt to clarify the potential interactions between risk factors of CKD, we performed survival tree analysis.

Methods

A total of 8238 participants (46.1% men) aged > 20 years without CKD at baseline [(1999–2001) and (2002–2005)], were followed until 2014. The first occurrence of CKD, defined as the estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m², was set as the main outcome. Multivariable Cox proportional hazard (Cox PH) regression was used to identify significant independent predictors of CKD; moreover, survival tree analysis was performed to gain further insight into the potential interactions between predictors.

Results

The crude incidence rates of CKD were 20.2 and 35.2 per 1000 person-years in men and women, respectively. The Cox PH identified the main effect of significant predictors of CKD incidence in men and women. In addition, using a limited number of predictors, survival trees identified 12 and 10 subgroups among men and women, respectively, with different survival probability. Accordingly, a group of men with eGFR > 74 ml/min/1.73 m², age ≤ 46 years, low level of physical activity, waist circumference ≤ 100 cm and FPG ≤ 4.7 mmol/l had the lowest risk of CKD incidence; while men with eGFR ≤ 63.4 ml/min/1.73 m², age > 50 years had the highest risk for CKD compared to men in the lowest risk group [hazard ratio (HR), 70.68 (34.57–144.52)]. Also, a group of women aged ≤ 45 years and eGFR > 83.5 ml/min/1.73 m² had the lowest risk; while women with age > 48 years and eGFR ≤ 69 ml/min/1.73 m² had the highest risk compared to low risk group [HR 27.25 (19.88–37.34)].

Conclusion

In this post hoc analysis, we found the independent predictors of CKD using Cox PH; furthermore, by applying survival tree analysis we identified several numbers of homogeneous subgroups with different risk for incidence of CKD. Our study suggests that two methods can be used simultaneously to provide new insights for intervention programs and improve clinical decision making.

Renoprotective Effect of Dipeptidyl Peptidase-4 Inhibitors in Patients with Type 2 Diabetes Mellitus

Diabetic nephropathy is one of three major complications of diabetes mellitus, often leading to chronic renal failure requiring dialysis. Recently developed dipeptidyl peptidase-4 (DPP-4) inhibitors may exhibit renoprotective effects in addition to antihyperglycemic effects. In this study, we retrospectively investigated temporal changes in the renal function index of patients with type 2 diabetes mellitus (DM) and examined the influence of DPP-4 inhibitors on renal function. Patients with type 2 DM (>18 years old) prescribed hypoglycemic agents at Gifu Municipal Hospital for ≥3 months between March 2010 and April 2014 were included in the study. Renal function was evaluated as estimated the decline in 12-month glomerular filtration rate from the baseline in patients receiving and not receiving DPP-4 inhibitors. Patient data from the DPP-4 inhibitor-treated (501 patients, 58.6%) and untreated (354, 41.4%) groups were analyzed using multiple logistic regression analysis, as well as Cox proportional-hazards regression analysis (616, 55.6% and 491, 44.4%, for DPP-4 inhibitors-treated and untreated groups). Multiple logistic regression analysis indicated that DPP-4 inhibitors significantly lowered the estimated glomerular filtration rate (eGFR) decline [20% over 12 months; odds ratio (OR), 0.626; 95% confidence interval [CI], 0.409–0.958; P = 0.031]. Similar results were obtained using Cox proportional-hazards regression analysis (hazard ratio [HR], 0.707; 95% CI, 0.572–0.874; P = 0.001). These findings suggest that DPP-4 inhibitors suppress the decrease of estimated glomerular filtration rate in patients with type 2 DM and show a renoprotective effect.