Albuminuria in chronic heart failure: prevalence and prognostic importance

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.

Tubular damage in chronic systolic heart failure is associated with reduced survival independent of glomerular filtration rate

BACKGROUND

The prognostic impact of reduced glomerular filtration rate (GFR) in chronic heart failure (CHF) is increasingly recognised, but little is known about tubular damage in these patients.

OBJECTIVE

To investigate the prevalence of tubular damage, and its association with GFR, and prognosis in patients with CHF.

METHODS AND RESULTS

In 90 patients with CHF, GFR and effective renal plasma flow (ERPF) were measured ([(125)I]iothalamate and [(131)I]hippuran clearances). The tubular markers neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-beta-D-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1) as well as urinary albumin excretion were determined in 24 h urine collections. Mean GFR was 78+/-26 ml/min/1.73 m(2). Urinary NGAL (175 (70-346) microg/g creatinine (gCr)), NAG (12 (6-17) U/gCr) and KIM-1 (277 (188-537) ng/gCr) levels were increased compared with 20 healthy controls (all p<0.001). Urinary NAG, but not NGAL or KIM-1 correlated with GFR (r=-0.34, p=0.001) and ERPF (r=-0.29, p=0.006). Both NAG (r=0.21, p=0.048) and KIM-1 (r=0.23, p=0.033) correlated with plasma N-terminal pro-brain natriuretic peptide levels. Both urinary KIM-1 (HR=1.15 (95% CI 1.02 to 1.30) per 100 ng/gCr increase, p=0.025) and NAG (HR=1.42 (95% CI 1.02 to 1.94) per 5 U/gCr increase, p=0.039), were associated with an increased risk of death or heart failure hospitalisations, independent of GFR.

CONCLUSION

Tubular damage, as indicated by increased urinary concentrations of NGAL, NAG and KIM-1 is common in patients with CHF and mildly reduced GFR. Both urinary KIM-1 and NAG showed prognostic information additional to GFR. These findings suggest an important role for tubular damage and tubular markers in cardiorenal interaction in heart failure.

Kidney function, albuminuria, and all-cause mortality in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study

BACKGROUND

Chronic kidney disease and albuminuria are associated with increased risk of all-cause mortality.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

17,393 participants (mean age, 64.3 ± 9.6 years) in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study.

PREDICTOR

Estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (ACR).

OUTCOME

All-cause mortality (710 deaths); median duration of follow-up, 3.6 years. MEASUREMENTS & ANALYSIS: Categories of eGFR (90 to <120, 60 to <90, 45 to <60, 30 to <45, and 15 to <30 mL/min/1.73 m(2)) and urinary ACR (<10 mg/g or normal, 10 to <30 mg/g or high normal, 30 to 300 mg/g or high, and >300 mg/g or very high). Cox proportional hazards models were adjusted for demographic factors, cardiovascular covariates, and hemoglobin level.

RESULTS

The background all-cause mortality rate for participants with normal ACR, eGFR of 90 to <120 mL/min/1.73 m(2), and no coronary heart disease was 4.3 deaths/1,000 person-years. Higher ACR was associated with an increased multivariable-adjusted HR for all-cause mortality within each eGFR category. Decreased eGFR was associated with a higher adjusted HR for all-cause mortality for participants with high-normal (P = 0.01) and high (P < 0.001) ACRs, but not those with normal or very high ACRs.

LIMITATIONS

Only 1 laboratory assessment for serum creatinine and ACR was available.

CONCLUSIONS

Increased albuminuria was an independent risk factor for all-cause mortality. Decreased eGFR was associated with increased mortality risk in those with high-normal and high ACRs. The mortality rate was low in the normal-ACR group and increased in the very-high-ACR group, but did not vary with eGFR in these groups.

Should targeting albuminuria be part of a cardiovascular risk reduction paradigm?

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States as well as the rest of the world. Chronic kidney disease (CKD) is considered a CVD risk equivalent. The development of albuminuria has been identified as an additional possible risk marker that is almost unique to patients with CKD and a marker for predicting CVD risk. This review focuses on clinical and epidemiologic evidence regarding the role of albuminuria in the context of CVD development. It reviews the association of albuminuria with other comorbidities associated with increased cardiovascular risk and the modalities aimed at the reduction of albuminuria and maximizing of cardiovascular risk reduction.

Cardio-Kidney-Damage: a unifying concept

The perceived global rise in chronic kidney disease (CKD) has been met with apprehension and skepticism. It has been argued by some that we are facing a CKD 'epidemic' and by others that the high prevalence of CKD observed in different communities may be the result of flawed screening methods and tools. Both estimation of glomerular filtration rate and determination of microalbuminuria as markers of CKD have been criticized. Also, many commented that CKD, as currently defined, was primarily a disease of elderly people with reduced kidney function. Some described this as a physiological age-related decline in kidney function while others consider it to be pathological, warranting the label of a disease. In this review, an attempt is made to reconcile different views by examining some of the available evidence and to conclude that the high prevalence of 'CKD' in the elderly population is likely to reflect the underlying high prevalence of overt and subclinical atherosclerosis and cardiovascular disease. This leads to the conclusion that CKD is a reflection of diffuse and age-related Cardio-Kidney-Damage (C-K-D) that may not warrant the label of disease but certainly justifies attention with reduction of lifelong cardiovascular risks and careful evaluation and treatment.

Candesartan cilexetil/hydrochlorothiazide treatment in high-risk patients with type 2 diabetes mellitus and microalbuminuria: the CHILI T2D study

BACKGROUND

Arterial hypertension complicated by the presence of diabetes mellitus and microalbuminuria is a particularly hazardous risk-factor combination. Blockers of the renin-angiotensin system have been shown to be beneficial with respect to these risk factors in randomized clinical trials.

OBJECTIVES

To provide proof of effectiveness for a fixed-dose combination such as candesartan cilexetil 16 mg/hydrochlorothiazide (HCTZ) 12.5 mg in clinical practice within the context of a variety of concomitant diseases and medications.

METHODS

CHILI T2D was a non-interventional, open-label, non-controlled, multicentre study in clinical practice that evaluated 4110 patients with type 2 diabetes, uncontrolled hypertension and microalbuminuria who were being prescribed a fixed-dose combination of candesartan cilexetil 16 mg/HCTZ 12.5 mg (Blopress). Documented outcomes included blood pressure (BP) reductions, metabolic changes, changes in albuminuria, and adverse events throughout the 12-week treatment period.

RESULTS

Patients had a mean +/- SD age of 64.0 +/- 10.3 years, 54.0% were male and the mean +/- SD body mass index was 29.6 +/- 5.8 kg/m2. Coronary heart disease (34.3%), diabetic neuropathy (23.8%), retinopathy (18.6%) and heart failure (20.2%) were frequent co-morbidities. The use of candesartan cilexetil 16 mg/HCTZ 12.5 mg in patients with a mean +/- SD baseline BP of 158.5 +/- 14.2/92.5 +/- 9.1 mmHg resulted in a substantial further reduction of office BP by a mean +/- SD of -27.1 +/- 14.4/-13.1 +/- 9.5 mmHg (p < 0.001). The reduction was particularly pronounced in patients with severe hypertension (mean reduction of -44.7/-19.9 mmHg). Glucose (glycosylated haemoglobin [HbA(1c)], fasting blood glucose) as well as lipid parameters (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides) were significantly improved (p < 0.001). Microalbuminuria, indicative of renal and cardiovascular risk, was significantly reduced by 28.8% (p < 0.001). Tolerability was excellent with only 16 out of 4110 patients experiencing any adverse event, of which six were considered to be serious.

CONCLUSIONS

The fixed-dose combination of candesartan cilexetil 16 mg/HCTZ 12.5 mg is highly effective in lowering blood pressure in type 2 diabetic patients with all stages of hypertension and microalbuminuria. The data indicate that low-dose HCTZ can safely be added to an existing drug regimen in this patient group to increase the BP-lowering effect, without compromising tolerability and the favourable metabolic profile of candesartan cilexetil monotherapy.

Aldosterone: effects on the kidney and cardiovascular system

Aldosterone, a steroid hormone with mineralocorticoid activity, is mainly recognized for its action on sodium reabsorption in the distal nephron of the kidney, which is mediated by the epithelial sodium channel (ENaC). Beyond this well-known action, however, aldosterone exerts other effects on the kidney, blood vessels and the heart, which can have pathophysiological consequences, particularly in the presence of a high salt intake. Aldosterone is implicated in renal inflammatory and fibrotic processes, as well as in podocyte injury and mesangial cell proliferation. In the cardiovascular system, aldosterone has specific hypertrophic and fibrotic effects and can alter endothelial function. Several lines of evidence support the existence of crosstalk between aldosterone and angiotensin II in vascular smooth muscle cells. The deleterious effects of aldosterone on the cardiovascular system require concomitant pathophysiological conditions such as a high salt diet, increased oxidative stress, or inflammation. Large interventional trials have confirmed the benefits of adding mineralocorticoid-receptor antagonists to standard therapy, in particular to angiotensin-converting-enzyme inhibitor and angiotensin II receptor blocker therapy, in patients with heart failure. Small interventional studies in patients with chronic kidney disease have shown promising results, with a significant reduction of proteinuria associated with aldosterone antagonism, but large interventional trials that test the efficacy and safety of mineralocorticoid-receptor antagonists in chronic kidney disease are needed.