Microalbuminuria, cardiovascular risk factors and cardiovascular morbidity in a British population: The EPIC-Norfolk Population-based Study

Evaluation of microalbuminuria as a prognostic indicator after a TIA or minor stroke in an outpatient setting: the prognostic role of microalbuminuria in TIA evolution (ProMOTE) study

OBJECTIVE

Transient ischaemic attacks (TIA) and minor strokes are important risk factors for further vascular events. We explored the role of albumin creatinine ratio (ACR) in improving risk prediction after a first event.

SETTING

Rapid access stroke clinics in the UK.

PARTICIPANTS

2202 patients attending with TIA or minor stroke diagnosed by the attending stroke physician, able to provide a urine sample to evaluate ACR using a near-patient testing device.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome was major adverse cardiac events (MACE: recurrent stroke, myocardial infarction or cardiovascular death) at 90 days. The key secondary outcome was to determine whether urinary ACR could contribute to a risk prediction tool for use in a clinic setting.

RESULTS

151 MACE occurred in 144 participants within 90 days. Participants with MACE had higher ACR than those without. A composite score awarding a point each for age >80 years, previous stroke/TIA and presence of microalbuminuria identified those at low risk and high risk. 90% of patients were at low risk (scoring 0 or 1). Their 90-day risk of MACE was 5.7%. Of the remaining 'high-risk' population (scoring 2 or 3) 12.4% experienced MACE over 90 days (p<0.001 compared with the low-risk population). The need for acute admission in the first 7 days was twofold elevated in the high-risk group compared with the low-risk group (3.23% vs 1.43%; p=0.05). These findings were validated in an independent historic sample.

CONCLUSION

A risk score comprising age, previous stroke/TIA and microalbuminuria predicts future MACE while identifying those at low risk of a recurrent event. This tool shows promise in the risk stratification of patients to avoid the admission of low-risk patients.

Microalbuminuria and cardiorenal risk: old and new evidence in different populations

Since the association of microalbuminuria (MAU) with cardiovascular (CV) risk was described, a huge number of reports have emerged. MAU is a specific integrated marker of CV risk and targets organ damage in patients with hypertension, chronic kidney disease (CKD), and diabetes and its recognition is important for identifying patients at a high or very high global CV risk. The gold standard for diagnosis is albumin measured in 24-hour urine collection (normal values of less than 30 mg/day, MAU of 30 to 300 mg/day, macroalbuminuria of more than 300 mg/day) or, more practically, the determination of urinary albumin-to-creatinine ratio in a urine morning sample (30 to 300 mg/g). MAU screening is mandatory in individuals at risk of developing or presenting elevated global CV risk. Evidence has shown that intensive treatment could turn MAU into normoalbuminuria. Intensive treatment with the administration of an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker, in combination with other anti-hypertensive drugs and drugs covering other aspects of CV risk, such as mineralocorticoid receptor antagonists, new anti-diabetic drugs, and statins, can diminish the risk accompanying albuminuria in hypertensive patients with or without CKD and diabetes.

Use of a proximity extension assay proteomics chip to discover new biomarkers associated with albuminuria

Background The underlying mechanisms for the development of albuminuria and the increased cardiovascular risk in patients with elevated albuminuria levels are incompletely understood. We therefore investigated the associations between 80 cardiovascular proteins and the urinary albumin to creatinine ratio (ACR). Methods We used a discovery/replication approach in two independent community-based cohorts of elderly patients: the Uppsala Longitudinal Study of Adult Men ( n = 662; mean age 78 years) and the Prospective Investigation of the Vasculature in Uppsala Seniors ( n = 757; mean age 75 years; 51% women). A proteomic chip with a panel of 80 plasma proteins associated with different aspects of cardiovascular disease was analysed. In the discovery cohort, we used a false discovery rate of 5% to take into account the multiple statistical testing. Nominal p values were used in the replication. Results Higher levels of T-cell immunoglobulin mucin-1, placenta growth factor, growth/differentiation factor-15, urokinase plasminogen activator surface receptor and kallikrein-11 were robustly associated with a higher ACR in both cohorts in multivariable linear regression models adjusted for sex, established cardiovascular risk factors, antihypertensive treatment, prevalent cardiovascular disease and glomerular filtration rate ( p < 0.02 for all). All associations were also significant in separate analyses of patients without diabetes. Conclusions We discovered and replicated associations between ACR and five cardiovascular proteins involved in tubular injury, atherosclerosis, endothelial function, heart failure, inflammation, glomerulosclerosis and podocyte injury. Our findings put forward multiplex proteomics as a promising approach to explore novel aspects of the complex detrimental interplay between kidney function and the cardiovascular system.

Subclinical Kidney Damage in Hypertensive Patients: A Renal Window Opened on the Cardiovascular System. Focus on Microalbuminuria

The kidney is one of the major target organs of hypertension.Kidney damage represents a frequent event in the course of hypertension and arterial hypertension is one of the leading causes of end-stage renal disease (ESRD).ESRD has long been recognized as a strong predictor of cardiovascular (CV) morbidity and mortality. However, over the past 20 years a large and consistent body of evidence has been produced suggesting that CV risk progressively increases as the estimated glomerular filtration rate (eGFR) declines and is already significantly elevated even in the earliest stages of renal damage. Data was supported by the very large collaborative meta-analysis of the Chronic Kidney Disease Prognosis Consortium, which provided undisputable evidence that there is an inverse association between eGFR and CV risk. It is important to remember that in evaluating CV disease using renal parameters, GFR should be assessed simultaneously with albuminuria.Indeed, data from the same meta-analysis indicate that also increased urinary albumin levels or proteinuria carry an increased risk of all-cause and CV mortality. Thus, lower eGFR and higher urinary albumin values are not only predictors of progressive kidney failure, but also of all-cause and CV mortality, independent of each other and of traditional CV risk factors.Although subjects with ESRD are at the highest risk of CV diseases, there will likely be more events in subjects with mil-to-moderate renal dysfunction, because of its much higher prevalence.These findings are even more noteworthy when one considers that a mild reduction in renal function is very common in hypertensive patients.The current European Society of Hypertension (ESH)/European Society of Cardiology (ESC) guidelines for the management of arterial hypertension recommend to sought in every patient signs of subclinical (or asymptomatic) renal damage. This was defined by the detection of eGFR between 30 mL/min/1.73 m² and 60 mL/min/1.73 m² or the presence of microalbuminuria (MAU), that is an amount of albumin in the urine of 30-300 mg/day or an albumin/creatinine ratio, preferentially on morning spot urine, of 30-300 mg/g.There is clear evidence that urinary albumin excretion levels, even below the cut-off values used to define MAU, are associated with an increased risk of CV events. The relationships of MAU with a variety of risk factors, such as blood pressure, diabetes and metabolic syndrome and with several indices of subclinical organ damage, may contribute, at least in part, to explain the enhanced CV risk conferred by MAU. Nonetheless, several studies showed that the association between MAU and CV disease remains when all these risk factors are taken into account in multivariate analyses. Therefore, the exact pathophysiological mechanisms explaining the association between MAU and CV risk remain to be elucidated. The simple search for MAU and in general of subclinical renal involvement in hypertensive patients may enable the clinician to better assess absolute CV risk, and its identification may induce physicians to encourage patients to make healthy lifestyle changes and perhaps would prompt to more aggressive modification of standard CV risk factors.

Cardiovascular disease screening

Cardiovascular disease is the leading cause of death amongst women worldwide. Cardiovascular risk assessment and primary prevention are important strategies to improve morbidity and mortality. In additional to the traditional risk factors, pregnancy complications such as pre-eclampsia and gestational diabetes increment future risk of developing cardiovascular complications. Additionally, several serum biomarkers are valuable measures for both risk assessment and predictors of clinical outcomes in women. The purpose of this review is to describe current risk stratification schemes as well as outline the role of obstetric history and serum biomarkers in adjusting risk stratification in women.

Prediabetes is not independently associated with microalbuminuria in Korean general population: the Korea National Health and Nutrition Examination Survey 2011-2012 (KNHANES V-2,3)

We investigated the association between microalbuminuria and prediabetes in Korean population using data from the KNHANES 2011-2012. Prevalence of microalbuminuria was significantly increased in prediabetes group. However, the odds ratio became insignificant after adjustment for blood pressure, and the prevalence of microalbuminuria was not increased in prediabetic subjects without hypertension.

Serum uric acid level is associated with the development of microalbuminuria in Korean men

BACKGROUND

Elevated serum uric acid (UA) could be a risk factor for hypertension, type 2 diabetes mellitus and cardiovascular disease. In addition, elevated serum UA may be associated with impaired renal function. However, it is unclear whether elevated serum UA is a cause of microalbuminuria or not. Therefore, we performed a prospective cohort study of the temporal relationship between baseline elevated serum UA and the development of microalbuminuria in Korean men.

DESIGN AND METHODS

A microalbuminuria-free cohort of 1743 healthy Korean men, who had their urine albumin-creatinine ratio (UACR) calculated for a medical check-up programme in 2005, was followed until 2010. Microalbuminuria was defined as a urine albumin-creatinine ratio between 30 and 300 μg/mg. Cox proportional hazards model was performed.

RESULTS

During 5884.6 person-years of follow-up, 96 incident cases of microalbuminuria developed between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95% confidence intervals) for incident microalbuminuria when comparing the second tertile to the third tertile of serum UA levels vs. the first tertile were 1.52 (0.86-2.70) and 2.27 (1.30-3.98), respectively (P for trend = 0.005).

CONCLUSION

Elevated serum UA level was independent risk factor for the development of microalbuminuria during a 5-year follow-up in Korean men.

High normal urine albumin-to-creatinine ratio predicts development of hypertension in Korean men

BACKGROUND

Microalbuminuria is known as a risk factor for hypertension. Recently it was suggested that urine albumin-to-creatinine ratio (UACR), even within the normal range, can be associated with hypertension, but the temporal relationship between normal range UACR and hypertension was not confirmed. Therefore the aim of this study was to verify an association between normal range UACR and the development of hypertension in Korean men.

METHODS AND RESULTS

This prospective cohort study was performed on 1,284 initially non-hypertensive Korean men. The total follow-up period was 4,109.5 person-years and the mean follow-up period was 3.2±1.51 years. Cox proportional hazards model was used to estimate the hazard ratios (HR) for the risk of hypertension development. After adjusting for multiple covariates, the HR (95% confidence interval [CI]) for incident hypertension, comparing the second to the fourth quartiles of UACR level to the first quartile, were 1.35 (95% CI: 0.93-1.97), 1.55 (95% CI: 1.07-2.25) and 1.89 (95% CI: 1.31-2.71), respectively (P for trend=0.001).

CONCLUSIONS

High UACR within the normal range was significantly associated with hypertension development. Furthermore, this association remained significant after adjusting for multiple baseline covariates. 

Prevalence of microalbuminuria among middle-aged population of China: a multiple center cardiovascular epidemiological study

We assessed the prevalence of microalbuminuria (MAU) and the relationships with other cardiovascular (CV) risk factors among a middle-aged Chinese population. Data from 10 313 participants were included in our cross-sectional survey. Microalbuminuria was defined as the urine albumin to creatinine ratio of 30:300 mg/g from a single-spot morning urine sample. Microalbuminuria was found to be common in males and females (15.04% vs 10.09%) aged 35 to 64 years in this Chinese general population, especially in those with obesity, hypertension, and diabetes. Multivariate analysis found that body mass index, triglyceride, high-sensitivity C-reactive protein, alcohol consumption, hypertension, and diabetes were independently associated with MAU. Microalbuminuria may be a useful indicator for risk of CV disease in general populations.

Serum phosphorus as a predictor of low-grade albuminuria in a general population without evidence of chronic kidney disease

BACKGROUND

High levels of serum phosphorus, even within the normal range, have been associated with cardiovascular (CV) morbidity. Low-grade albuminuria (LGA) was demonstrated to be related to increased CV events in various study populations. The present study aimed to investigate the association between serum phosphorus levels and LGA in the general population.

METHODS

We examined the individuals who had undergone health inspections. We evaluated the correlation between serum phosphorus and LGA in 8953 participants (mean age, 47.4 years) with estimated glomerular filtration rates (eGFRs)≥60 mL/min/1.73 m2 and urinary albumin-to-creatinine ratios (UACRs)<30 mg/g. Participants who underwent a colonoscopy were excluded.

RESULTS

The mean UACR was significantly higher in the uppermost quartile group of serum phosphorus concentrations than in other quartile groups. In the multivariate regression analysis, serum phosphorus remained an independent predictor of increased UACR (B=0.610, P<0.001). Subgroup analyses showed that this association was maintained irrespective of age, gender, presence of hypertension or diabetes, body mass index and eGFR.

CONCLUSIONS

In our population-based study, higher serum phosphorus was independently related to LGA in individuals without evidence of renal dysfunction. Further investigations are warranted to clarify the precise mechanism of the association between serum phosphorus and LGA.

Vitamin D and racial disparity in albuminuria: NHANES 2001-2006

Background

National data show unexplained racial disparity in albuminuria. We assessed whether low serum vitamin D status contributes to racial disparity in albuminuria.

Methods

We examined the association between race and albuminuria (spot urinary albumin/creatinine ratio (ACR) ≥30) among non-Hispanic black and white nonpregnant adults who were free of renal impairment in the National Health and Nutrition Examination Survey (NHANES) from 2001–2006. We conducted analyses without and with serum 25(OH)D. We adjusted for age, sex, education level, smoking, body mass index (BMI), diabetes, diagnosis of hypertension, and use of antihypertensive medication.

Results

Albuminuria was present in 10.0% of non-Hispanic blacks and 6.6% in non-Hispanic whites. Being black (odds ratio (OR) 1.46; 95% confidence interval (CI) 1.23–1.73) was independently associated with albuminuria. There was a graded, inverse association between 25(OH)D level and albuminuria. Notably, the association between race and albuminuria was no longer significant (OR 1.19; 95% CI 0.97–1.47) after accounting for participants' serum 25(OH)D. Similar results were observed when participants with macroalbuminuria (ACR ≥300 mg/g) or elevated parathyroid hormone (>74 pg/ml) were excluded or when a continuous measure of 25(OH)D was substituted for the categorical measure. There were no interactions between race and vitamin D status though racial disparity in albuminuria was observed among participants with the highest 25(OH)D levels.

Conclusion

Suboptimal vitamin D status may contribute to racial disparity in albuminuria. Randomized controlled trials are needed to determine whether supplementation with vitamin analogues reduces risk for albuminuria or reduce racial disparity in this outcome.

Microalbuminuria in the paediatric age: current knowledge and emerging questions

The prevalence of microalbuminuria (MA) in children and adolescents differs from the one in adults, and it is estimated to be about 5.7-7.3% in boys and 12.7-15.1% in girls. The percentage is greater in smaller age group, whereas a positive association is found between albumin excretion rate and pubertal development stage in nondiabetic subjects. The data so far suggest that impairment of glucose metabolism, obesity-related proatherosclerotic pathways and the impact of haemodynamic load constitute major determinants of albuminuria development in the early years of life. In everyday practice if persistent MA is present at a young age, especially in the setting of diabetes, further investigation of cardiovascular risk factors, a more careful follow-up and dietary/lifestyle interventions are needed.

CONCLUSION

Although the significance of MA in paediatric essential hypertension has yet to be determined, its role in diabetic children and adolescents is established and albuminuria assessment has been utilized as a screening test for the presence of diabetes-related kidney disease.

Angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and combined therapy in patients with micro- and macroalbuminuria and other cardiovascular risk factors: a systematic review of randomized controlled trials

BACKGROUND

A recent clinical trial showed harmful renal effects with the combined use of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-II receptor blockers (ARB) in people with diabetes or vascular disease. We examined the benefits and risks of these agents in people with albuminuria and one or more cardiovascular risk factors.

METHODS

MEDLINE, EMBASE and Renal Health Library were searched for trials comparing ACEI, ARB or their combination with placebo or with one another in people with albuminuria and one or more cardiovascular risk factor.

RESULTS

Eighty-five trials (21,708 patients) were included. There was no significant reduction in the risk of all-cause mortality or fatal cardiac-cerebrovascular outcomes with ACEI versus placebo, ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. There was a significant reduction in the risk of nonfatal cardiovascular events with ACEI versus placebo but not with ARB versus placebo, ACEI versus ARB or with combined therapy with ACEI + ARB versus monotherapy. Development of end-stage kidney disease and progression of microalbuminuria to macroalbuminuria were reduced significantly with ACEI versus placebo and ARB versus placebo but not with combined therapy with ACEI + ARB versus monotherapy.

CONCLUSIONS

ACEI and ARB exert independent renal and nonfatal cardiovascular benefits while their effects on mortality and fatal cardiovascular disease are uncertain. There is a lack of evidence to support the use of combination therapy. A comparative clinical trial with ACE, ARB and its combination in people with albuminuria and a cardiovascular risk factor is warranted.

Urinary nitric oxide metabolites and individual blood pressure progression to overt hypertension

Baseline blood pressure (BP) is the strongest known determinant of progression to hypertension, but for an individualized prediction of the incidence of hypertension, the identification of additional biomarkers is crucial. In animal models of hypertension, renal nitric oxide (NO) handling modifies the systemic BP responses prior to the development of hypertension. This study aimed to evaluate whether urinary NO metabolites (NOx) predict the progression of hypertension in normotensive subjects. Among 62 participants enrolled in the Flemish Study on Environment, Genes and Health Outcomes, we assessed progression to hypertension over 4.6 years. In a case-control design, 49 normotensive subjects including 10 subjects with high-normal blood pressure were enrolled of whom 25 remained normotensive (controls), whereas 24 'progressed' to hypertension (progressors). Thirteen hypertensive patients served as negative controls. Urinary NOx concentration, renal function and the urinary excretion of electrolytes were assessed at baseline and follow-up. At baseline, progressors showed higher BP values than controls and urinary NOx concentration was significantly lower in progressors as compared to the normotensive controls (p < 0.01). In all initially normotensive subjects baseline urinary NOx concentration was associated with follow-up BP (r = -0.55, p < 0.001) and the relative increase of BP over time (r = -0.47, p < 0.001). In progressors baseline urinary NOx was associated with follow-up BP (r = -0.52, p < 0.009) and the relative increase of BP over time (r = -0.44, p = 0.033). Baseline urinary NOx and BP were independent predictors for the relative BP increase. A urinary NOx threshold of <130.5 mg/L predicted 75% of all progressors. In context with high-normal baseline BP, 87.5% of all progressors were identified. These findings indicate that urinary NO metabolites are associated with BP development in normotensive subjects. Moreover, urinary NOx predicts the progression to hypertension independent of baseline BP suggesting urinary NOx as a biomarker for individual new-onset hypertension.

Association and prognostic impact of heart rate and micro- albuminuria in patients with type 2 diabetes and cardiovascular disease: results from the PROactive trial

AIM

Microalbuminuria (MAU) and heart rate are established predictors of an adverse cardiovascular outcome. Recently, heart rate was described as an independent predictor of MAU in hypertensive patients, raising the question of a causal link.

METHODS

In post-hoc analysis of the PROactive trial we examined the association of the baseline heart rate and MAU in diabetic patients with cardiovascular disease (n = 5,110, mean age 62 ± 8, 66% male) using logistic regression. Cox regression analysis was used to examine the independent impact of heart rate and MAU on the composite endpoint of all-cause mortality, myocardial infarction and stroke.

RESULTS

Baseline heart rate was not associated with a significantly increased risk for MAU at baseline (OR 1.01 per 10 bpm, 95% CI 0.97-1.06, p = 0.48) or MAU at the final visit (OR per 10 bpm 1.04, 95% CI 0.98-1.11, p = 0.20). Similar results were observed in subgroups of patients with hypertensive blood pressure at baseline (OR 0.98 per 10 bpm, 95% CI 0.93-1.03, p = 0.42) or patients with a history of hypertension (OR 1.02 per 10 bpm, 95% CI 0.98-1.07, p = 0.31), respectively. Stratification by use of an ACE inhibitor/AT1-receptor blocker did also not change the results. In multivariate analysis, both heart rate and MAU were significantly predictive of a cardiovascular outcome.

CONCLUSION

There was no evidence of an association between heart rate and MAU in diabetic patients with cardiovascular disease, independently of whether hypertension was present or not, but both markers were independently predictive of a cardiovascular outcome. These results do not support a causal link between heart rate and MAU.

Proteinuria and clinical outcomes in hypertensive patients

This narrative review focuses on outcomes related to proteinuria in hypertension (HT), and also examines the role of current and future therapeutic strategies. Proteinuria is an independent marker of renal and cardiovascular (CV) disease in hypertensive populations, particularly in high-risk groups such as diabetic patients. Effective blood pressure (BP) control and proteinuria management are associated with significant improvements in the risk of key adverse outcomes, although a causative relationship needs careful assessment. Available antihypertensives have varying effects on proteinuria reduction. Drugs affecting the renin system offer antiproteinuric and renoprotective effects that are probably at least partially independent of their BP effects. Economic evaluations of these interventions confirm their cost-saving benefits relative to other antihypertensives, but outcomes-based research is needed in some settings.

Clinical Use and Pathogenetic Basis of Laboratory Tests for the Evaluation of Primary Arterial Hypertension

This review focuses on the laboratory biochemical tests that are useful in the diagnostic approach to the hypertensive patient. A "minimal" diagnostic laboratory work-up, including a small number of tests that are simple and relatively inexpensive, is first described. Because these tests provide basic information on the presence of major cardiovascular (CV) risk factors and target organ damage, and might give some clues to the presence of a secondary form of hypertension (HT), they should be performed on all patients presenting with HT. Other tests that are aimed at assessing the overall CV risk, a major determinant of prognosis that dictates the therapeutic strategy in the individual HT patient, are then discussed. They allow identification of major CV risk factors and associated clinical conditions which, if present, lead to a substantial change of therapeutic strategy. The role of C-reactive protein as a marker of atherosclerosis and its predictive value for CV events are also discussed. Finally, a section is devoted to tests that are currently confined to research purposes, such as markers of endothelial function including endothelin-1, homocysteine and genetic analysis.

Importance of low-grade albuminuria

The well-described association between chronic kidney disease and cardiovascular disease is typically thought to originate from loss of renal function, as estimated by the glomerular filtration rate. However, recent data suggest that urinary albumin excretion has an important role in this association. Albuminuria is a marker of underlying vascular dysfunction and has been correlated with structural and functional integrity of the vasculature. Although the traditional upper limit of normal daily albumin excretion has been 30 mg/d, recent epidemiologic data suggest that levels in the general population are actually much lower. Further, within this range of low-grade albuminuria (LGA), increasing excretion rates are associated with increasing risk of cardiovascular disease. This association is independent of renal function, and in the earliest stages of chronic kidney disease, LGA seems to be a more important determinant than the glomerular filtration rate. This emerging association underscores the complexity of albumin excretion, in which subtle changes in albumin excretion reflect widespread vascular processes. Using the key words albuminuria, low-grade albuminuria, and microalbuminuria in a PubMed search of literature from January 1, 1995, to February 29, 2008, this review summarizes the most recent data on LGA and its association with cardiovascular and renal disease.

Cross-sectional association between fish consumption and albuminuria: the European Prospective Investigation of Cancer-Norfolk Study

BACKGROUND

Studies have shown a potential beneficial role for fish and fish oil consumption in the management of diabetes and its complications. The aim of this study is to examine the association between fish consumption and albuminuria in individuals with and without diabetes.

STUDY DESIGN

A cross-sectional analysis conducted in the European Prospective Investigation of Cancer-Norfolk population-based cohort study.

SETTING & PARTICIPANTS

22,384 men and women from general practices in the city of Norwich and vicinity, of whom 517 had diabetes by self-report and 21,867 did not report diabetes.

PREDICTORS

Fish consumption was measured in a validated semiquantitative food frequency questionnaire and categorized as less than 1, 1 to 2, and more than 2 portions/wk. Interaction between fish intake and diabetes status was hypothesized a priori.

OUTCOMES & MEASUREMENTS

Microalbuminuria and macroalbuminuria were defined as urinary albumin-creatinine ratio of 2.5 or greater to 24.9 and 25 mg/mmol or greater, respectively. Log-transformed albumin-creatinine ratio was used as a continuous variable.

RESULTS

Prevalences of microalbuminuria were 22.6% in participants with diabetes and 11.4% in participants without diabetes. Prevalences of macroalbuminuria were 8.3% and 0.6%, respectively. Fish consumption was associated with a lower risk of macroalbuminuria in participants with diabetes (odds ratio, 0.22, >2 versus <1 portion/wk; 95% confidence interval, 0.07 to 0.70; P for trend = 0.009) after adjustment for confounding. This association was not observed in participants with diabetes with microalbuminuria or in the nondiabetic population. There was a significant interaction between diabetes status and fish consumption of 1 to 2 portions/wk (P = 0.03) and more than 2 portions/wk (P = 0.007) for risk of macroalbuminuria.

LIMITATIONS

Cross-sectional nature of study. Self-report of fish intake and diabetes status.

CONCLUSIONS

Greater fish intake was associated with a lower risk of macroalbuminuria in a self-defined diabetic population. These findings merit confirmation in prospective studies and intervention trials and suggest that fish intake may be beneficial for albuminuria in people with diabetes.

A population-based screening for microalbuminuria among relatives of CKD patients: the Kidney Evaluation and Awareness Program in Sheffield (KEAPS)

BACKGROUND

Microalbuminuria has been used to detect subjects at risk of cardiovascular disease and chronic kidney disease (CKD) in patients with diabetes, those with hypertension, and the general population. However, relatives of patients with CKD have not been investigated for microalbuminuria in the United Kingdom.

STUDY DESIGN

A cross-sectional study evaluating the prevalence of microalbuminuria in relatives of patients with CKD compared with the general population of Sheffield, England.

SETTING & PARTICIPANTS

Participants in the Kidney Evaluation and Awareness Program in Sheffield, a population-based screening program for microalbuminuria. 274 relatives of patients with CKD were studied and compared with an age- and sex-matched control group from the general population.

PREDICTOR

Family history of CKD.

MEASUREMENT & OUTCOMES

Screening tools included a questionnaire collating information for demographics, lifestyle, and medical and family history of diabetes, hypertension, and CKD. Urine samples were collected for microalbuminuria estimation. Microalbuminuria measurements were obtained by using immunonephelometry. Microalbuminuria thresholds were defined using albumin-creatinine ratio.

RESULTS

The prevalence of microalbuminuria was 9.5% in those with a family history of CKD. This was significantly greater than the prevalence of 1.4% in the age- and sex-matched control group with no family history of CKD (P = 0.001). Independent determinants of microalbuminuria in the study population in an adjusted logistic regression model were family history of diabetes (odds ratio [OR], 2.88; 95% confidence interval, 1.17 to 7.04), obesity (OR, 3.29; 95% confidence interval, 1.61 to 6.69), and family history of CKD (OR, 6.96; 95% confidence interval, 3.48 to 13.92).

LIMITATIONS

Cross-sectional snapshot analysis, microalbuminuria measured once.

CONCLUSIONS

The prevalence of microalbuminuria in relatives of patients with CKD is greater than in an age- and sex-matched control group from the general population. The prognostic value of microalbuminuria in this category of at-risk population remains to be determined in longitudinal studies.

Proteinuria increases oxylipid concentrations in VLDL and HDL but not LDL particles in the rat

We previously established that proteinuria alters the apolipoprotein content of lipoproteins. This study was conducted to establish whether proteinuria also alters the concentrations of oxidized lipids within lipoprotein density fractions. To this end, we induced passive Heymann nephritis in Sprague Dawley rats and measured an array of alkaline-stable oxylipids in VLDL, LDL, and HDL particles. Proteinuria increased the total oxylipid amounts in the HDL and VLDL fractions. More importantly, these levels were increased when expressed per unit lipoprotein protein, indicating that the oxidized lipid load per particle was increased. Epoxides and diols increased approximately 2-fold in HDL and approximately 5-fold in VLDL, whereas LDL showed approximately 2-fold decreases. The hydroxyeicosatetraenoic acids and hydroxyoctadecadienoic acids (HODEs) increased >4-fold in HDL and >20-fold in VLDL, whereas LDL showed approximately 2-fold decreases in the HODEs. Therefore, nephrotic syndrome alters the lipoprotein oxylipid composition independently of an increase in total lipoprotein levels. These proteinuria-induced changes may be associated with the cardiovascular risk of lipoprotein oxidation.

Current Trends in Pharmacy Benefit Designs: A Threat to Disease Management in Chronic Complex Diseases

With a focus on those patients who are candidates for treatment with biologic agents, we review the impact that current pharmacy benefit trends have on patients with chronic complex diseases and how they affect opportunities for disease management in this unique patient population. Dramatic increases in health care costs have led to a variety of strategies to manage cost. Many of these strategies either limit access to care or increase the patient's responsibility for choosing and paying for care, especially for medications. These strategies have a disproportionate impact on patients with chronic complex diseases, particularly those who require the use of biologic medications. A fundamental prerequisite of disease management has been coverage of disease-modifying therapies. If current pharmacy benefit trends continue, unintended consequences will likely occur including lost opportunities for disease management. Current pharmacy benefit trends could adversely impact disease management, particularly for patients requiring the use of biologic agents. Health plans should consider innovative benefit designs that reflect an appropriate level of cost sharing across all key stake-holders, ensuring appropriate access to needed therapies. Additional research is needed to clarify the value of newer approaches to therapies or benefit design changes.

Microalbuminuria: what is it? Why is it important? What should be done about it? An update

Microalbuminuria (MA) is defined as a persistent elevation of albumin in the urine of >30 to <300 mg/d (>20 to <200 microg/min). Use of the morning spot urine test for albumin-to-creatinine measurement (mg/g) is recommended as the preferred screening strategy for all patients with diabetes and with the metabolic syndrome and hypertension. MA should be assessed annually in all patients and every 6 months within the first year of treatment to monitor the impact of antihypertensive therapy. It is an established risk marker for the presence of cardiovascular disease and predicts progression of nephropathy when it increases to frank microalbuminuria>300 mg/d. Data support the concept that the presence of MA is the kidney's warning that there is a problem with the vasculature. The presence of MA is a marker of endothelial dysfunction and a predictor of increased cardiovascular risk. MA can be reduced, and progression to overt proteinuria prevented, by aggressive blood pressure reduction, especially with a regimen based on medications that block the renin-angiotensin-aldosterone system, and control of diabetes. The National Kidney Foundation recommends that blood pressure levels be maintained at or below 130/80 mm Hg in anyone with diabetes or kidney disease.

Abdominal obesity, systolic blood pressure, and microalbuminuria in normotensive and euglycemic Korean men

OBJECTIVES

To evaluate the relationship between abdominal obesity and microalbuminuria (MA) in normotensive, euglycemic Korean men.

DESIGN

A cross-sectional study at a health screening center.

SUBJECTS

A total of 1321 healthy, normotensive Korean men, aged 20-78 years, with a fasting plasma glucose level <100 mg/dl.

MEASUREMENTS

Height, weight, and waist; systolic blood pressure (SBP); diastolic blood pressures (DBP); urinary albumin to creatinine ratio (ACR); fasting glucose, insulin, lipids, C-reactive protein (CRP), and white blood cell count. Waist circumference (WC) was used to indicate abdominal obesity and a single measurement of ACR was used to estimate MA. We also calculated body mass index (BMI) based on weight and height.

RESULTS

Mean BMI, WC, and SBP were significantly higher in subjects with MA than in those without (24.8+/-4.1 vs 23.8+/-2.7 kg/m2, 86+/-9 vs 83+/-8 cm, and 115+/-5 vs 112+/-7 mmHg, respectively). Multiple logistic regression analyses showed that only WC and SBP were independent predictors of MA.

CONCLUSION

WC and SBP were positively associated with MA in normotensive and euglycemic Korean men.

Riesgo coronario y prevalencia de cardiopatías en pacientes hipertensos con afectación renal en asistencia primaria

INTRODUCTION AND OBJECTIVES

The presence of renal disease significantly alters the cardiovascular risk of patients with high blood pressure. However, few studies have examined renal parameters in primary care patients. The objectives of this study were to investigate cardiovascular risk and the factors influencing it in hypertensive patients with renal disease and to compare the findings with those in hypertensive patients without renal disease.

METHODS

The CORONARIA study involved primary care patients with hypertension from all regions of Spain and included two groups with different degrees of renal disease.

RESULTS

In total, 703 patients (9.8%) had renal disease. Hypertensive patients with renal disease had a worse cardiovascular risk profile than other hypertensives. The prevalence of diabetes was double in patients with renal disease. Moreover, the risk of a coronary event was significantly higher in those with renal disease. One-third of hypertensives with renal disease had another previously diagnosed cardiovascular disease. In addition, they more frequently had a history of angina, were twice as likely to have had a myocardial infarction, and were more than twice as likely to have undergone revascularization or to have peripheral vascular disease or cerebrovascular disease. Heart failure was four times more frequent in these patients with renal disease than in other hypertensives.

CONCLUSIONS

Patients with hypertension and renal disease have a higher risk of cardiovascular disease, exhibit an increased prevalence of diabetes, and suffer from more extensive target organ damage.

Dementia before death in ageing societies--the promise of prevention and the reality

BACKGROUND

Dementia and severe cognitive impairment are very closely linked to ageing. The longer we live the more likely we are to suffer from these conditions. Given population increases in longevity it is important to understand not only risk and protective factors for dementia and severe cognitive impairment at given ages but also whether protection affects cumulative risk. This can be explored by examining the effect on cumulative risk by time of death of factors found consistently to reduce risk at particular ages, such as education and social status.

METHODS AND FINDINGS

In this analysis we report the prevalence of dementia and severe cognitive impairment in the year before death in a large population sample. In the Medical Research Council Cognitive Function and Ageing Study (a 10-y population-based cohort study of individuals 65 and over in England and Wales), these prevalences have been estimated by age, sex, social class, and education. Differences have been explored using logistic regression. The overall prevalence of dementia at death was 30%. There was a strong increasing trend for dementia with age from 6% for those aged 65-69 y at time of death to 58% for those aged 95 y and above at time of death. Higher prevalences were seen for severe cognitive impairment, with similar patterns. People with higher education and social class had significantly reduced dementia and severe cognitive impairment before death, but the absolute difference was small (under 10%).

CONCLUSIONS

Reducing risk for dementia at a given age will lead to further extension of life, thus cumulative risk (even in populations at lower risk for given ages) remains high. Ageing of populations is likely to result in an increase in the number of people dying with dementia and severe cognitive impairment even in the presence of preventative programmes. Policy development and research for dementia must address the needs of individuals who will continue to experience these conditions before death.

Glomerular volume and renal histology in obese and non-obese living kidney donors

The link between obesity and renal disease is unclear, and there is no consensus as to whether obese individuals are at increased risk for kidney disease after living kidney donation if they otherwise meet acceptance criteria. We retrospectively studied time-zero (implantation) biopsies in 49 obese (body mass index (BMI) > or = 30 kg/m2) and 41 non-obese (BMI < 30 kg/m2) renal donors that met acceptance criteria. We found that our obese donor population had higher systolic blood pressure (P < 0.001 vs non-obese) and higher absolute iothalamate clearance (P = 0.001 vs non-obese) before donation. The obese donors had larger glomerular planar surface area compared to non-obese controls (P = 0.017), and this parameter correlated with patient weight and urinary microalbumin excretion. Detailed examination of the biopsies revealed that although most histologic findings were similar between groups, the obese donors had more tubular dilation (P = 0.01), but less tubular vacuolization (P = 0.02) than the non-obese controls. There was also a trend toward more arterial hyalinosis in the obese patients than controls (P = 0.08). From these data, our studies detected subtle differences in donor organs obtained from obese compared to non-obese individuals. Further studies should be carried out to quantify the long-term impact of these findings.

What is the evidence that microalbuminuria is a predictor of cardiovascular disease events?

PURPOSE OF REVIEW

This review describes recently published studies evaluating the association between microalbuminuria and the development of cardiovascular disease events either in the presence of diabetes or hypertension, or in the population as a whole.

RECENT FINDINGS

Prospective studies confirm that microalbuminuria is predictive, independently of classical risk factors, of cardiovascular disease events and all-cause mortality within groups of patients with diabetes or hypertension and in the general population. However, these studies suggest that levels of albuminuria below the conventional cutoff point definition of microalbuminuria are significantly associated with cardiovascular morbidity and mortality. The pathophysiological mechanism underyling this association is still uncertain. Data from recent intervention studies suggest that treatment with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, as well as intensive multi-factorial intervention including behaviour modification and targeted pharmacotherapy in patients with microalbuminuria, offers significant reduction in cardiovascular and renal morbidity in people with albuminuria.

SUMMARY

Future absolute risk prediction scores for primary cardiovascular events could include microalbuminuria as a modifiable risk factor. The association between levels of albuminuria and cardiovascular outcomes in individuals within the normoalbuminuric range questions the current categorical definition of microalbuminuria. Intensive multifactorial interventions, including the use of agents that affect the renin-angiotensin pathway, are effective in reducing cardiovascular risk in patients with microalbuminuria and diabetes or hypertension.

Graded effects of proteinuria on HDL structure in nephrotic rats

Nephrotic syndrome is characterized by increased triglycerides resulting from decreased clearance of VLDL and chylomicrons. These triglyceride-rich lipoproteins are structurally altered by interaction with HDL derived from animals with proteinuria and not as a consequence of hypoalbuminemia. HDL isolated from rats with massive proteinuria is depleted in apolipoprotein E (apoE). It is unknown at what threshold of urinary albumin loss HDL structure is altered, and it is unknown what effects proteinuria has on apolipoproteins other than apoE. Two models of albuminuria were used in Sprague-Dawley rats: Adriamycin and passive Heymann nephritis (HN). The adriamycin group was divided into minimal albumin excretion (MAE) and intermediate albumin excretion (MAE, 1 to 40; intermediate albumin excretion, 60 to 210 mg/d per 100 g body wt). Urinary albumin excretion exceeded 300 mg/d per 100 g body wt in the HN rats. HDL apolipoprotein composition was analyzed with SDS-PAGE densitometry and liquid chromatography-time of flight mass spectrometer mass spectrometry. HDL apoA-IV content relative to apoA-I was reduced at all levels of albuminuria (P < 0.0001). ApoE was not reduced in MAE but was significantly reduced in IAE (72%; P < 0.001). By contrast, apoA-II and apoC-III were each significantly increased with increasing UAE. ApoA-IV and apoE were decreased to approximately 10% of control in HDL isolated from rats with HN, whereas apoA-II, apoC-II, and apoC-III were each significantly increased relative to apoA-I. HDL is structurally altered by levels of albuminuria that are insufficient to change serum albumin levels and is progressively altered as albuminuria increases.