The prevalence and risk factors of microalbuminuria in normoglycemic, normotensive adults

Differential Association of Vitamin D Deficiency With Albuminuria by Sex in the Korean General Population: A Cross-sectional Study of the Korea National Health and Nutrition Examination Survey 2011-2012

Objectives

Albuminuria has emerged as a biomarker for several medical conditions, and vitamin D has received attention due to its associations with various disorders. We evaluated the association between low serum vitamin D levels and prevalent albuminuria by sex in the Korean general population.

Methods

We analyzed 9823 participants (4401 males, 5422 females) from the Korea National Health and Nutrition Examination Survey 2011-2012 (KNHANES V-2), and categorized them as having a normal range of vitamin D levels, vitamin D insufficiency, or vitamin D deficiency. A multivariable logistic regression model was used to compare the risk of albuminuria across these groups. Stratified analyses were conducted by smoking status, obesity, and renal function.

Results

Albuminuria was found in 325 of the 4401 male participants (7.4%) and in 455 of the 5422 female participants (8.4%). Among the males, vitamin D deficiency was associated with an odds ratio (OR) for albuminuria of 1.78 (95% confidence interval [CI], 1.07 to 2.97, p<0.05). However, such an association was not found in females. The association was stronger in male current smokers (OR, 3.54; 95% CI, 1.47 to 8.50; p=0.005).

Conclusions

The findings of this study suggest that sex differences exist in the association between serum vitamin D deficiency and albuminuria. Additionally, we observed that the association was stronger in current smokers than in the overall male population, but was not seen in non-smokers. Therefore, different approaches by sex and smoking status might be needed when considering using vitamin D as a biomarker for renal function.

A multicenter cohort study of primary hypertension in Korea: study design and interim analysis of the Korean registry of target organ damage in hypertension (KorHR)

BACKGROUND

The Korean Registry of Target Organ Damage in Hypertension aims to evaluate the clinical characteristics and prevalence of subclinical target organ damage in Korean hypertensive patients.

METHOD

This is a prospective, observational, multicenter cohort study in which 23 university hospitals participated. Since May 2013, we have enrolled 1,318 consecutive hypertensive patients without known cardiovascular disease who met the following inclusion criteria: 1) age older than 30 years and 2) the first visit to the participating hospitals was within the last 5 years.

RESULTS

The mean age was 52 ± 12 years; 62.1% were male, and 41.3% were incident hypertensives. Patients with diabetes mellitus accounted for 7.8% of the population and 43.8% had hyperlipidemia or were on statins at baseline. The mean office blood pressures were 152 ± 20/96 ± 14 mmHg for incident hypertensive patients and 129 ± 13/78 ± 10 mmHg for patients on treatment. Patients with electrocardiographic and echocardiographic left ventricular hypertrophy accounted for 18.9 and 25.6%, respectively. The mean brachial-ankle pulse wave velocity (PWV) was 1564 ± 293 m/s and 19.5% had PWV values of more than 1750 cm/s. Patients with microalbuminuria and chronic kidney disease accounted for 21 and 4%, respectively. The first prescribed class of antihypertensive medications was angiotensin converting enzyme inhibitors in 2.9%, angiotensin receptor blockers (ARBs) in 57.5%, diuretics in 7.6%, calcium channel blockers (CCBs) in 61.0%, beta blockers in 17.3%, and fixed dose combination pill in 27.8%.

CONCLUSION

Our interim analysis shows that subclinical target organ damage in hypertension is considerably present for incident or treated hypertensive patients. CCBs and ARBs were the most commonly prescribed classes of antihypertensive medications and fixed dose combination pills were actively used in Korea.

TRIAL REGISTRATION

NCT01861080. Registered 16 May 2013.

Safety and Efficacy of Fondaparinux in Renal Impairment

Objective: To evaluate the cumulative evidence regarding the efficacy and safety of using fondaparinux in renal impairment, manifested by preventing new or recurrent thrombosis and the incidence of bleeding, respectively. Data Sources: We searched the MEDLINE and Cochrane databases for relevant studies from 1966 until November 2014, using the terms "fondaparinux" and "renal failure" or "dialysis." Additional references were identified from review of literature citations. Study Selection and Data Extraction: Inclusion criteria were articles in English language and patients with creatinine clearance (CrCl) less than 50 mL/min. Exclusion criteria were using fondaparinux as an anticoagulant for dialyzer circuit patency, abstracts, case reports, case series, pediatrics (<18 years), and pharmacokinetic studies with no clinical efficacy and safety results. Data Synthesis: Our search retrieved 4 cohort studies, 1 clinical trial, and 1 randomized clinical trial (RCT) subgroup analysis. A total of 3237 patients received fondaparinux with a dose ranging from 1.25 mg to 2.5 mg daily. Three studies investigated fondaparinux as a prophylactic agent, 2 as a treatment agent, and 1 study investigated both. The only study with control group was the RCT subgroup analysis, which compared fondaparinux to enoxaparin. A total of 470 patients developed thromboembolic complications or death and 169 developed major bleeding. The composite outcome of safety and efficacy in the RCT subgroup analysis was significantly lower in fondaparinux group compared with the enoxaparin group (P = .001). Conclusions: Current evidence regarding the safety and efficacy of fondaparinux in renally impaired patients is limited and does not support its use in such population.

The relationship between serum fetuin-A, cystatin-C levels, and microalbuminuria in patients with metabolic syndrome

BACKGROUND

The metabolic syndrome, syndrome X, is a group of metabolic disorders in which insulin resistance plays a pivotal role. The MS is an important risk factor for subsequent development of type 2 diabetes and cardiovascular disease. Fetuin-A is a liver derived blood protein that acts as effective inhibitor of soft tissue calcification. Cystatin C is a useful marker in measuring glomerular filtration rate. Moreover, recently it has been suggested that cystatin C may be a potential biomarker for detecting microalbuminuria. Microalbuminuria (MA) is a strong indicator of morbidity related to cardiovascular disorders, and is currently considered a novel diagnostic criterion for MS. It has been also demonstrated that the increased serum fetuin-A levels is associated with several parameters of MS. In this study, we attempted to investigate the relationship between serum fetuin-A, cystatin-C levels and microalbuminuria in patients with MS.

METHODS

A total of 50 patients with MS and 25 control were included in this study. We defined MS by the NCEP criteria among nondiabetic outpatients. Patients with MS were further divided into two groups based on MA status. Overall 25 of the participants with MS did not have MA (group I), while the remaining 25 had MA (group II). None of the subjects in the healthy control group (group III) had laboratory findings supporting the presence of MA. The serum fetuin-A and cystatin-C levels were measured using ELISA.

RESULTS

Age, distributions of sex, BP and LDL cholesterol levels were similar among all groups. BMI, Waist/hip ratio, FBG, HOMA-IR, total cholesterol, trigliserid, CRP levels were significantly higher in group I and group II compared to control. In group II, the cystatin-C and fetuin levels were higher than control. While the cystatin-C levels were higher in group II compared to group I, the fetuin levels did not different. Morever, the fetuin A and cystatin-C concentrations were positively correlated with microalbuminuria (r = 0.26, p = 0.02; r = 0.50, p = 0.0001, respectively).

CONCLUSION

In our study, we found that MS patients with microalbuminuria had high levels of fetuin-A and cystatin-C. In conclusion, we suggest that determination of fetuin-A and cystatin C levels could be useful marker as an early indicator of renal injury in patients with MS.

Prevalence of and factors associated with albuminuria in the Korean adult population: the 2011 Korea National Health and Nutrition Examination Survey

BACKGROUND

Microalbuminuria is associated with increased risk of renal disease and cardiovascular diseases even in non-diabetic subjects. High incidence rates of microalbuminuria have been found in a number of population-based studies. However, the prevalence and risk factors associated with microalbuminuria in the general population in Korea are unclear.

OBJECTIVES

The present study was performed to estimate the prevalence of microalbuminuria and investigate the associated risk factors in the general adult population using the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V-2) data from 2011.

METHODS

A total of 5,202 participants (mean age, 45.6 years; men, 2,337; women, 2,865) were included in the analysis. Microalbuminuria was evaluated in participants of KNHANES V-2 based on the urine albumin-creatinine ratio. Estimated glomerular filtration rate was calculated using the Modification of Diet in Renal Disease study equation.

RESULTS

The weighted prevalence of microalbuminuria was 5.2% (95% CI, 4.4-6.1) in the general population. The prevalence of albuminuria is increased with age. After adjustment for age and sex, the presence of albuminuria was associated with increased waist circumference, systolic and diastolic blood pressure, aspartate aminotransferase, triglyceride, fasting plasma glucose, and the presence of hypertension and diabetes. In logistic regression analyses, older age, female sex, diabetes, hypertension, and serum aspartate aminotransferase were independently associated with the presence of albuminuria.

CONCLUSION

The prevalence of microalbuminuria was found to be 5.2%, and conventional risk factors for cardiovascular diseases are closely related to the presence of microalbuminuria in Korea. Microalbuminuria may be a useful marker to identify individuals with increased risk of cardiovascular disease.

Early detection of chronic kidney disease: results of the PolNef study

BACKGROUND

Continuous increase in the number of patients with end-stage renal disease demands early detection of chronic kidney disease (CKD). The aim of the present study was to diagnose CKD in its earliest stages in a randomly selected population using a diagnostic algorithm developed by the working group.

METHODS

An algorithm for the diagnostic procedure was created to identify patients with CKD requiring further nephrological care. Randomly chosen adult inhabitants of a city with a population of 60,000 were invited to participate in this study. Screening procedures included a microalbuminuria dipstick test accompanied by blood pressure measurement and medical questionnaire. In further diagnosis of CKD, estimated glomerular filtration rate (eGFR), albumin concentration in urine, urinalysis and ultrasound examination were used according to the algorithm. Multivariate logistic regression was performed to identify associations between participants' characteristics and albuminuria.

RESULTS

Out of 9,700 invited subjects, 2,471 individuals participated in the PolNef study. Albuminuria was detected in 15.6% of the investigated population using the dipstick test and thereafter confirmed in 11.9% by the turbidimetric method. The modeling of multivariate logistic regression indicated the following independent predictors of albuminuria: male sex, diabetes, nocturia and hypertension. For people without diabetes and without hypertension, nocturia independently predicted detection of albuminuria. 481 people received a consultation with a nephrologist, and 96% of them were recognized as having CKD. At least 9% of patients with CKD had eGFR by MDRD <60 ml/min/1.73 m(2). Six persons were referred for further treatment because of newly diagnosed kidney tumor.

CONCLUSIONS

CKD in early stages occurs frequently in the studied population. The proposed diagnostic algorithm seems to be a powerful tool to identify subjects at risk of CKD. The role of nocturia as an independent predictor of albuminuria, both in the general population and in people without diabetes or hypertension, should be further examined.

Airborne particulate matter exposure and urinary albumin excretion: the Multi-Ethnic Study of Atherosclerosis

OBJECTIVES

Understanding mechanistic pathways linking airborne particle exposure to cardiovascular health is important for causal inference and setting environmental standards. We evaluated whether urinary albumin excretion, a subclinical marker of microvascular function which predicts cardiovascular events, was associated with ambient particle exposure.

METHODS

Urinary albumin and creatinine were measured among members of the Multi-Ethnic Study of Atherosclerosis at three visits during 2000-2004. Exposure to PM(2.5) and PM(10) (microg/m(3)) was estimated from ambient monitors for 1 month, 2 months and two decades before visit one. We regressed recent and chronic (20 year) particulate matter (PM) exposure on urinary albumin/creatinine ratio (UACR, mg/g) and microalbuminuria at first examination, controlling for age, race/ethnicity, sex, smoking, second-hand smoke exposure, body mass index and dietary protein (n = 3901). We also evaluated UACR changes and development of microalbuminuria between the first, and second and third visits which took place at 1.5- to 2-year intervals in relation to chronic PM exposure prior to baseline using mixed models.

RESULTS

Chronic and recent particle exposures were not associated with current UACR or microalbuminuria (per 10 microg/m(3) increment of chronic PM(10) exposure, mean difference in log UACR = -0.02 (95% CI -0.07 to 0.03) and relative probability of having microalbuminuria = 0.92 (95% CI 0.77 to 1.08)) We found only weak evidence that albuminuria was accelerated among those chronically exposed to particles: each 10 microg/m(3) increment in chronic PM(10) exposure was associated with a 1.14 relative probability of developing microalbuminuria over 3-4 years, although 95% confidence intervals included the null (95% CI 0.96 to 1.36).

CONCLUSIONS

UACR is not a strong mechanistic marker for the possible influence of air pollution on cardiovascular health in this sample.

Lipoprotein metabolism in chronic renal insufficiency

Chronic renal insufficiency (CRI) is associated with a characteristic dyslipidemia. Findings in children with CRI largely parallel those in adults. Moderate hypertriglyceridemia, increased triglyceride-rich lipoproteins (TRL) and reduced high-density lipoproteins (HDL) are the most usual findings, whereas total and low-density lipoprotein cholesterol (LDL-C) remain normal or modestly increased. Qualitative abnormalities in lipoproteins are common, including small dense LDL, oxidized LDL, and cholesterol-enriched TRL. Measures of lipoprotein lipase and hepatic lipase activity are reduced, and concentrations of apolipoprotein C-III are markedly elevated. Still an active area of research, major pathophysiological mechanisms leading to the dyslipidemia of CRI include insulin resistance and nonnephrotic proteinuria. Sources of variability in the severity of this dyslipidemia include the degree of renal impairment and the modality of dialysis. The benefits of maintaining normal body weight and physical activity extend to those with CRI. In addition to multiple hypolipidemic pharmaceuticals, fish oils are also effective as a triglyceride-lowering agent, and the phosphorous binding agent sevelamer also lowers LDL-C. Emerging classes of hypolipidemic agents and drugs affecting sensitivity to insulin may impact future treatment. Unfortunately, cardiovascular benefit has not been convincingly demonstrated by any trial designed to study adults or children with renal disease. Therefore, it is not possible at this time to endorse general recommendations for the use of any agent to treat dyslipidemia in children with chronic kidney disease.