Prognostic significance of hypertension and albuminuria for early mortality after acute myocardial infarction

CYP1A2 Genetic Variation, Coffee Intake, and Kidney Dysfunction

IMPORTANCE

Caffeine is detoxified by cytochrome P450 1A2 (CYP1A2), and genetic variation in CYP1A2 impacts the rate of caffeine clearance. Factors that may modify the association between coffee intake and kidney disease remain unclear.

OBJECTIVE

To assess whether CYP1A2 genotype modifies the association between coffee intake and kidney dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

The Hypertension and Ambulatory Recording Venetia Study (HARVEST) was a prospective cohort study of individuals with stage 1 hypertension in Italy; HARVEST began on April 1, 1990, and follow-up is ongoing. The current study used data from April 1, 1990, to June 30, 2006, with follow-up of approximately 10 years. Blood pressure and biochemical data were collected monthly during the first 3 months, then every 6 months thereafter. Data were analyzed from January 2019 to March 2019. Participants were screened and recruited from general practice clinics. The present study included 1180 untreated participants aged 18 to 45 years with stage 1 hypertension; those with nephropathy, diabetes, urinary tract infection, and cardiovascular disease were excluded.

EXPOSURES

Coffee intake and CYP1A2 genotype rs762551 were exposures analyzed over a median follow-up of 7.5 (IQR, 3.1-10.9) years.

MAIN OUTCOMES AND MEASURES

Albuminuria (defined as an albumin level of ≥30 mg/24 h) and hyperfiltration (defined as an estimated glomerular filtration rate of ≥150 mL/min/1.73 m2) were the primary outcomes as indicators of kidney dysfunction.

RESULTS

Among 1180 participants, genotyping, lifestyle questionnaires, and urine analysis data were obtained from 604 individuals (438 [72.5%] male) with a mean (SD) age of 33.3 (8.5) years and a mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 25.4 (3.4). A total of 158 participants (26.2%) consumed less than 1 cup of coffee per day, 379 (62.7%) consumed 1 to 3 cups per day, and 67 (11.1%) consumed more than 3 cups per day. Genotype frequencies for rs762551 (260 participants [43.1%] with genotype AA, 247 participants [40.8%] with genotype AC, and 97 participants [16.1%] with genotype CC) did not differ between coffee intake categories. The level of risk of developing albuminuria, hyperfiltration, and hypertension, assessed by Cox regression and survival analyses, was not associated with coffee intake in the entire group or among fast metabolizers. The risks of albuminuria (adjusted hazard ratio [aHR], 2.74; 95% CI, 1.63-4.62; P < .001), hyperfiltration (aHR, 2.11; 95% CI, 1.17-3.80; P = .01), and hypertension (aHR, 2.81; 95% CI, 1.51-5.23; P = .001) increased significantly among slow metabolizers who consumed more than 3 cups per day.

CONCLUSIONS AND RELEVANCE

In this study, the risks of albuminuria, hyperfiltration, and hypertension increased with heavy coffee intake only among those with the AC and CC genotypes of CYP1A2 at rs762551 associated with slow caffeine metabolism, suggesting that caffeine may play a role in the development of kidney disease in susceptible individuals.

Urinary albumin concentration and long-term cardiovascular risk in acute coronary syndrome patients: a PROVE IT-TIMI 22 substudy

Albuminuria has been shown to be associated with mortality and cardiovascular events, independent of traditional cardiovascular risk factors. This suggests that albuminuria may not just represent glomerular damage, but may be a marker of more diffuse endothelial dysfunction. We investigated the relationship between urinary albumin levels after an acute coronary syndrome and cardiovascular outcomes in statin treated subjects after acute coronary syndromes (ACS). Furthermore we assessed the effect of intensive statin treatment on albuminuria among patients in the PROVE IT-TIMI 22 trial, in which patients who had been hospitalized with ACS were randomized to pravastatin 40 mg (standard therapy) or atorvastatin 80 mg daily (intensive therapy). In univariate analyses, increasing urine albumin concentration was associated with increased risk of myocardial infarction, stroke, heart failure, and composite of death, myocardial infarction and stroke at 2 years. However, in a multivariable model containing traditional cardiovascular risk factors, albuminuria was not an independent predictor of the primary PROVE IT endpoint of death, myocardial infarction, unstable angina, revascularization and stroke, and was only an independent predictor of all-cause mortality at urinary albumin concentration >300 mcg/ml. There was no significant change in urinary albumin concentration from enrolment to end of study in either the standard or intensive statin therapy groups, and no significant difference between treatment groups. Our results suggest that after an acute coronary syndrome in statin treated patients, microalbuminuria may reflect traditional cardiovascular risk factor burden and offer little prognostic information independent of those factors.

Prevalence, predictors and prognostic significance of microalbuminuria in acute cardiac patients: a single center experience

The objective of this study was to prospectively assess the prevalence, predictors and prognostic significance of microalbuminuria in a large cohort of consecutive acute cardiac patients, admitted to an intensive cardiac care unit from 1 January 2008 to 30 June 2009. In 815 acute cardiac patients, microalbuminuria is detectable in 39.3%. Microalbuminuria shows a significant negative correlation with left ventricular ejection fraction (Spearman's ρ = -0.228; p < 0.001), while it is positively correlated with C-reactive protein (Spearman's ρ = 0.239; p < 0.001), NT-pro-BNP (Spearman's ρ = 0.306; p < 0.001) and glycemia (Spearman's ρ = 0.191; p < 0.001). Microalbuminuria is an independent predictor for in-hospital mortality (1 μg/min step) (OR 1.015; 95% CI 1.008-1.023; p < 0.001). In the acute phase of cardiac patients, microalbuminuria is a common finding, and it represents an independent predictor for early mortality. It is strictly linked to the inflammatory activation (as indicated by C-reactive protein) and to acute glucose values, thus suggesting that it may be part of the acute response to stress.

Hypertension and acute myocardial infarction: an overview

History of hypertension is a frequent finding in patients with acute myocardial infarction (AMI) and its recurring association with female sex, diabetes, older age, less frequent smoking and more frequent vascular comorbidities composes a risk profile quite distinctive from the normotensive ischemic counterpart.Antecedent hypertension associates with higher rates of death and morbid events both during the early and long-term course of AMI, particularly if complicated by left ventricular dysfunction and/or congestive heart failure. Renin-angiotensin-aldosterone system blockade, through either angiotensin-converting enzyme inhibition, angiotensin II receptor blockade or aldosterone antagonism, exerts particular benefits in that high-risk hypertensive subgroup.In contrast to the negative implications carried by antecedent hypertension, higher systolic pressure at the onset of chest pain associates with lower mortality within 1 year from coronary occlusion, whereas increased blood pressure recorded after hemodynamic stabilization from the acute ischemic event bears inconsistent relationships with recurring coronary events in the long-term follow-up.Whether antihypertensive treatment in post-AMI hypertensive patients prevents ischemic relapses is uncertain. As a matter of fact, excessive diastolic pressure drops may jeopardize coronary perfusion and predispose to new acute coronary events, although the precise cause-effect mechanisms underlying this phenomenon need further evaluation.

Comparison of C-reactive protein and albumin excretion as prognostic markers for 10-year mortality after myocardial infarction

BACKGROUND

C-reactive protein (CRP) is an established prognostic marker in the setting of acute coronary syndromes. Recently, albumin excretion rate also has been found to be associated with adverse outcomes in this clinical setting. Our aim was to compare the prognostic power of CRP and albumin excretion rate for long-term mortality following acute myocardial infarction (AMI).

HYPOTHESIS

To determine whether albumin excretion rate is a better predictor of long-term outcome than CRP in post-AMI patients.

METHODS

We prospectively studied 220 unselected patients with definite AMI (median [interquartile] age 67 [60-74] y, female 26%, heart failure 39%). CRP and albumin-to-creatinine ratio (ACR) were measured on day 1, day 3, and day 7 after admission in 24-hour urine samples. Follow-up duration was 10 years for all patients.

RESULTS

At survival analysis, both CRP and ACR were associated with increased risk of 10-year all-cause mortality, also after adjusting for age, hypertension, diabetes mellitus, prehospital time delay, creatine kinase-MB isoenzyme peak, heart failure, and creatinine clearance. CRP and ACR were associated with nonsudden cardiovascular (non-SCV) mortality but not with sudden death (SD) or noncardiovascular (non-CV) death. CRP was not associated with long-term mortality, while ACR was independently associated with outcome both in short- and long-term analyses. At C-statistic analysis, CRP did not improve the baseline prediction model for all-cause mortality, while it did for short-term non-SCV mortality. ACR improved all-cause and non-SCV mortality prediction, both in the short and long term.

CONCLUSIONS

ACR was a better predictor of long-term mortality after AMI than CRP.

The prevalence and outcome of hypertension in patients with acute coronary syndrome in six Middle-Eastern countries

AIMS

The aim was to report the prevalence and significance of hypertension (HTN) in patients with acute coronary syndrome (ACS).

METHODS AND MAJOR FINDINGS

Over a 6-month period in 2007, 8171 consecutive patients (49.4% hypertensive and 50.6% non-hypertensive) presenting with ACS were enrolled in a prospective, multicenter study from six Middle Eastern adjacent countries. Patients with HTN were older (59.2 vs 53.1 years, p<0.001), and more likely to be female (34% vs 14.4%, p<0.001) when compared with patients without HTN. Patients with HTN were also more likely to have diabetes mellitus, hyperlipidemia, cerebrovascular disease, prior history of coronary artery disease, peripheral artery disease but less likely to be cigarette smokers. At admission, HTN patients had higher Killip class, heart rate and GRACE risk scoring. In-hospital mortality was higher in hypertensive patients with ST-elevation myocardial infarction (STEMI) but not in patients with non-STEMI or unstable angina. The incidence of heart failure complications was significantly higher among patients with HTN in overall ACS type (OR = 1.2, 95% CI 1.001-1.338, p= 0.04).

MAIN CONCLUSION

In this large cohort of patients with ACS, HTN was an independent predictor of heart failure and was associated with an increased rate of in-hospital mortality in STEMI only.

Microalbuminuria in the intensive care unit: Clinical correlates and association with outcomes in 431 patients*

OBJECTIVE

Comparison of urine albumin within 6 hrs of intensive care unit (ICU) admission with demography, clinical classification, outcome, inotrope/vasopressor requirement, clinical assessment of mortality risk, and Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) II scores.

DESIGN

Urine albumin-creatinine ratio (ACR) was measured on ICU admission (ACR 1) and after 4-6 hrs (ACR 2).

SETTING

A 17-bed general ICU in a university teaching hospital.

PATIENTS

Unselected medical (206) and surgical (225) patients recruited prospectively.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Bedside urine ACR was measured by nurses using a Bayer DCA 2000 analyzer and expressed in mg/mmol (reference range <2.3). ACR 1 in medical and surgical patients was 15.5 (12.4-19.5) and 8.2 (5.9-11.1) mg/mmol, respectively (p = .0002), and ACR 2 was 9.0 (5.8-12.5) and 4.6 (3.6-5.3), respectively (p < .0001). For all patients, median (95% confidence interval) ACR fell from 11.2 (8.7-13.2) to 5.4 (4.7-6.8) mg/mmol 4-6 hrs after ICU admission (p < .0001). ACR 1 for nonsurvivors (n = 90) and survivors (n = 341) was 16.1 (11.2-21.3) and 8.8 (6.9-11.9), respectively (p = .0002) and ACR 2, 12.4 (8.2-18.9) and 4.8 (3.9-5.4), respectively (p < .0001). In both medical and surgical patients who died on the ICU, median ACR failed to decrease significantly following admission. ACR1 and ACR 2 were higher in patients who required inotropic or vasopressor support and correlated with duration of therapy. ACR 1 and 2 were inversely correlated with mean Po2/Fio2 ratio 48 hrs after ICU admission and positively correlated with duration of mechanical ventilation and ACR 1 with ICU stay. ACR 2 predicted mortality and ACR 1 inotrope requirement independent of clinical mortality risk assessment and APACHE II and SOFA scores.

CONCLUSIONS

Urine albumin changes rapidly within the first 6 hrs following ICU admission and predicts ICU mortality and inotrope requirement as well as or better than APACHE II and SOFA scores. Serial urine albumin measurement may provide a means of monitoring the microvascular effects of systemic inflammation.

Does microalbuminuria predict illness severity in critically ill patients on the intensive care unit? A systematic review

CONTEXT

Studies assessing the accuracy of microalbuminuria to predict illness severity on the intensive care unit have produced inconsistent results.

OBJECTIVE

To determine the diagnostic accuracy of microalbuminuria to predict illness severity in critically ill patients on the intensive care unit.

DATA SOURCE

MEDLINE (1951 to September 2004) and EMBASE (1980 to September 2004) electronic databases were searched for relevant studies. Reference lists of all abstracts were manually searched to identify studies not included in the electronic database.

STUDY SELECTION

Studies that prospectively evaluated the accuracy of microalbuminuria to predict illness severity and/or mortality probability in adult patients on the intensive care unit were selected.

DATA EXTRACTION

We included nine studies in the review. Data to evaluate methodological quality and results were abstracted.

DATA SYNTHESIS

The methodological quality of a number of studies was poor. Significant heterogeneity in the design and conduct of the studies circumvented the data being subjected to meta-analysis. Studies also differed in the timing of the index test, in the methods of quantifying microalbuminuria, and in the cutoff values used.

CONCLUSIONS

This descriptive analysis reveals that microalbuminuria may hold promise as a predictor of illness severity and mortality on the intensive care unit. However, future epidemiologic studies need to be conducted to determine the optimal timing as well as the threshold reference value for the urine albumin creatinine ratio in the adult intensive care unit population. Thereafter, multiple-center prospective epidemiologic studies must be conducted to confirm and validate the findings of these preliminary studies. Future studies should conform to the Standards for Reporting of Diagnostic Accuracy checklist in terms of study design, conduct, and reporting. Presently there is no evidence to warrant the use of this tool on the intensive care unit.

Microalbuminuria: a strong predictor of 3-year adverse prognosis in nondiabetic patients with acute myocardial infarction

BACKGROUND

The aim of this study is to evaluate the significance of microalbuminuria (MA) as a 3-year prognostic index in nondiabetic patients with acute myocardial infarction (AMI).

METHODS

One hundred seventy-five patients with AMI were followed prospectively for 3 years. The study end point was cardiac death or rehospitalization for an acute coronary event.

RESULTS

Forty-two patients (24%) developed a new cardiac event during the follow-up. Microalbuminuria (P < .001), pulmonary edema during initial hospitalization (P < .001) and postinfarction angina (P = .0364), advanced age (P = .001), severe atherosclerosis (high Gensini score) (P = .036), ejection fraction <50% (P = .0013), history of bypass surgery (P = .0265), and early conservative management (P = .0214) were all associated with adverse prognosis. Cox proportional hazards regression analysis showed that MA was an independent predictor of 3-year adverse prognosis in all the models tested, with an adjusted relative risk for the development of a cardiac event ranging from 2.1 to 4.3.

CONCLUSIONS

In nondiabetic patients with AMI, MA is a strong and independent predictor of an adverse cardiac event within the next 3 years.

Left Ventricular Remodeling after Myocardial Infarction in Antecedent Hypertensive Patients

Antecedent hypertension adversely affects mortality and heart failure after myocardial infarction (MI). In addition, accelerated ventricular remodeling is a contributor to the increased mortality observed after MI. The purpose of this study was to assess the relationship of antecedent hypertension to ventricular remodeling after MI. Ninety-four patients presenting with a first acute MI who were treated with reperfusion therapy within 12 h of their symptom onset were enrolled in this study. All of them underwent left ventriculography immediately after reperfusion therapy and again at 6 months after the occurrence of MI. Patients were divided into two groups: a hypertensive group and a normotensive group. End-diastolic volume index (EDVI), end-systolic volume index (ESVI), and ejection fraction (EF) values in the acute phase were compared to those at 6 months after acute MI in either group. The hypertensive group showed a significant increase in both EDVI and ESVI after 6 months, whereas the normotensive group did not. In addition, there was no change in EF in the hypertensive group, whereas EF increased significantly after 6 months in the normotensive group. As a result, the percent changes in ESVI and EF were significantly different between the hypertensive group and normotensive group. The results demonstrated that antecedent hypertension interacts with ventricular cavity dilatation after MI.

Is it time to measure microalbuminuria in hypertension?

Former guidelines on hypertension never made a commitment to the detection of microalbuminuria for screening or follow-up of hypertensive patients. On the other hand, growing evidence support the contributory role of microalbuminuria in the prediction of absolute cardiovascular risk in hypertension and document the potential relevance of this parameter to the initial choice of antihypertensive treatment. Upcoming new guidelines and diagnostic algorithms in hypertension need to underscore the clinical positioning of microalbuminuria for stratification of risk and follow-up purposes.

Microalbuminuria in hypertension

A body of evidence indicates that microalbuminuria is a well-recognized marker of cardiovascular complications and increased cardiovascular risk in hypertension. However, the prognostic significance of microalbuminuria remains controversial because only the results of a few prospective studies performed in small groups of hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of microalbuminuria in hypertension including age, sex, race, severity of the disease, and concomitant risk factors. This accounts for the large differences in the prevalence of microalbuminuria that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 46%. The main determinant of albumin excretion rate in subjects with mild hypertension and no cardiovascular complications seems to be the hemodynamic load, whereas in subjects with more severe hypertension and associated target organ damage, the augmented urinary albumin leak is probably the consequence of glomerular damage. Inhibition of the renin-angiotensin system with angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists is particularly effective at reducing the albumin excretion rate, but whether these classes of drugs are more beneficial in patients with microalbuminuria remains to be determined. There is general consensus that evaluation of microalbuminuria is useful for the assessment of overall cardiovascular risk in hypertension, since albumin excretion rate appears to be a cost-effective way to identify patients at higher risk for whom additional preventive and therapeutic measures are advisable.

Microalbuminuria, cardiovascular, and renal risk in primary hypertension

Microalbuminuria is defined as abnormal urinary excretion of albumin between 30 and 300 mg/d. It can be measured accurately by several widely available and sensitive methods. This abnormality can be found in 8 to 15% of nondiabetic patients with primary hypertension, although its prevalence varies greatly in the literature, likely due to differences in the methods used to detect it and to the criteria applied in the selection of patients. The pathogenetic mechanisms leading to the development of microalbuminuria are still not completely known. BP load and increased systemic vascular permeability, possibly due to early endothelial damage, seem to play a major role. Increased urinary albumin excretion has been associated with several unfavorable metabolic and nonmetabolic risk factors and subclinical hypertensive organ damage. In fact, a higher prevalence of concentric left ventricular hypertrophy and subclinical impairment of left ventricular performance, as well as the presence of carotid atherosclerosis, have been reported in patients with microalbuminuria. These associations might per se justify a greater incidence of cardiovascular events. Long-term longitudinal studies have recently confirmed the unfavorable prognostic significance of microalbuminuria in hypertensive patients. It has also been hypothesized that microalbuminuria might be a forerunner of overt renal damage in primary hypertension. Clinical studies, however, have shown conflicting results, and this hypothesis has to be considered tempting but speculative at present. In conclusion, microalbuminuria is a specific, integrated marker of cardiovascular risk and target organ damage in primary hypertension and one that is suitable for identifying patients at higher global risk. A wider use of this test in the diagnostic work-up of hypertensive patients is recommended.

Antecedent hypertension and heart failure after myocardial infarction

OBJECTIVES

We sought to assess the relationship of antecedent hypertension to neurohormones, ventricular remodeling and clinical heart failure (HF) after myocardial infarction (MI).

BACKGROUND

Heart failure is a probable contributor to the increased mortality observed after MI in those with antecedent hypertension. Hence, neurohormonal activation, adverse ventricular remodeling and a higher incidence of clinical HF may be expected in this group. However, no previous report has documented serial postinfarction neurohumoral status, serial left ventricular imaging and clinical outcomes over prolonged follow-up in a broad spectrum of patients with and without antecedent hypertension.

METHODS

Inpatient events were documented in 1,093 consecutive patients (436 hypertensive and 657 normotensive) with acute MI. In 68% (282 hypertensive, 465 normotensive) serial neurohormonal sampling and radionuclide ventriculography were performed one to four days and three to five months after infarction. Clinical outcomes were recorded over a mean follow-up of two years.

RESULTS

Plasma neurohormones were significantly higher in hypertensives than in normotensives one to four days and three to five months after infarction. From similar initial values, left ventricular volumes increased significantly in hypertensives, compared with normotensives. Left ventricular ejection fraction rose significantly in normotensive but not hypertensive patients. Together with higher inpatient (8.1% vs. 4.4%, p < 0.002) and post-discharge mortality (9.5% vs. 5.5%, p = 0.043), hypertensive patients incurred more inpatient HF (33% vs. 24%, p < 0.001) and more late HF requiring readmission to hospital (12.4% vs. 5.5%, p < 0.001). Antecedent hypertension predicted late HF in patients >64 years of age with neurohormonal activation and early left ventricular dilation.

CONCLUSIONS

Antecedent hypertension interacts with age, neurohumoral activation and early ventricular remodeling to confer greater risk of HF after MI.

Microalbumin measurement alone or calculation of the albumin/creatinine ratio for the screening of hypertension patients?

BACKGROUND

Spot urine sampling seems to be a reliable screening method for the detection of microalbuminuria in hypertensive patients. It remains unclear whether microalbumin measurement alone or calculation of the albumin/creatinine ratio (ACR) are more reliable for the detection of microalbuminuria in non-selected hypertensive patients.

METHODS

Following collection of a spot, midstream urine sample, urine was collected for 24 h for the measurement of microalbumin in 264 hypertensive patients. We compared microalbumin concentration in the spot urine with microalbumin measured in the 24-h urine sample and examined the utility of the ACR in evaluating microalbuminuria in hypertensive patients. Pathologic microalbuminuria was assumed when the microalbumin concentration exceeded 30 mg/l in the 24-h urine sample. Diagnostic performance is expressed in terms of specificity, sensitivity, positive (PPV) and negative predictive value (NPV), and area under receiver operating characteristics curve (AUC).

RESULTS

A total of 47 samples (17.8%) showed pathologic microalbuminuria in the 24-h urine sample. The diagnostic performance expressed as AUC was 0.94 (95% CI 0.90-0.98) for microalbumin measurement alone and 0.94 (95% CI 0.89-0.97) for ACR. The PPV and NPV were 44.2 and 97.9% for microalbumin measurement alone. ACR revealed a PPV of 29.3% and a NPV of 96.2% for males and 42.9 and 98% for females, if a cut-off value of 2.5 mg/mmol for males and of 4.0 mg/mmol for females was used.

CONCLUSIONS

The ACR did not provide any advantage compared with microalbumin measurement alone, but requires an additional determination of creatinine and the use of gender-specific cut-off values. Therefore, measurement of microalbuminuria alone in the spot urine sample is more convenient in daily clinical practice and should be used as the screening method for hypertensive patients.

Predictive value of microalbuminuria in medical ICU patients: results of a pilot study

STUDY OBJECTIVES

To evaluate the predictive value of microalbuminuria in the development of acute respiratory failure (ARF) and multiple organ failure (MOF) in ICU patients.

DESIGN

Prospective, observational study.

SETTING

A 31-bed, mixed medicosurgical ICU in a university hospital.

PATIENTS

All adult medical patients admitted to the ICU over a 2-month period, except those receiving nephrotoxic drugs, or those with urologic trauma resulting in frank hematuria or urinary infection, or with existing chronic renal disease (serum creatinine level > or 2.0 mg/dL).

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Urinary samples for microalbumin measurement were collected at hospital admission and at 8, 24, 48, 72, 96, and 120 h after hospital admission. The severity of illness was assessed by the APACHE (acute physiology and chronic health evaluation) II score calculated on the first ICU day, and the degree of organ dysfunction was assessed using the sequential organ failure assessment (SOFA) score. Acute respiratory failure (ARF) was defined as a SOFA respiratory score > or = 3. Patients were separated into two groups according to the trend in microalbuminuria levels over the first 48 h: patients in group 1 had increasing microalbuminuria levels, and patients in group 2 had decreasing microalbuminuria levels. Group 1 included 14 patients in whom microalbuminuria levels increased from 5.2 +/- 2.0 to 19.0 +/- 3.0 mg/dL. Group 2 included 26 patients in whom microalbuminuria levels decreased from 16.4 +/- 4.0 to 7.8 +/- 3.0 mg/dL. The hospital mortality rate was 43% in group 1 and 15% in group 2 (p < 0.05). The APACHE II score and the SOFA score were higher in group 1 than in group 2. The negative predictive value of increasing microalbuminuria was 100% for the development of ARF and 96% for MOF; the positive predictive value of increasing microalbuminuria was 57% for the development of ARF and 50% for MOF.

CONCLUSIONS

Accurate identification of patients destined for ARF and MOF development may enable therapeutic strategies to be applied to limit the disease process. Trend analysis of urinary albumin excretion over the first 48 h of an ICU admission may provide a useful means of identifying such patients. Additional studies need to be performed in larger, mixed patient populations to confirm these findings.

Non-diabetic microalbuminuria, endothelial dysfunction and cardiovascular disease

Subclinical increases in albuminuria (microalbuminuria) predict morbid events, but the reasons for that are still not understood in full. This paper reviews the existing evidence regarding the relationships of non-diabetic microalbuminuria and cardiovascular disease, the underlying assumption being that endothelial dysfunction contributes both to atherosclerotic macrovascular disease and renal microvascular disease of which albuminuria is a marker. Much data support that concept, and suggest a preferential link with endothelial activation in response to acute and subclinical inflammatory stimulation, although further studies are needed to establish the exact cause-effect mechanisms. Epidemiological studies also show associations with cardiovascular events, and some recent prospective results also indicate the power of microalbuminuria to predict risk independently from conventional atherogenic factors. Thus, microalbuminuria might be considered as an integrated marker of cardiovascular risk sensitive to systemic vascular status in addition to other parameters such as blood pressure levels, glucose metabolism, smoking habits, a profile rather unique among the prognostic predictors available to stratify risk in hypertensive patients.

Proteinuria after renal transplantation affects not only graft survival but also patient survival

BACKGROUND

Proteinuria is associated with an increased risk of renal failure. Moreover, proteinuria is associated with an increased death risk in patients with diabetes mellitus or hypertension and even in the general population.

METHODS

One year after renal transplantation, we studied the influence of the presence of proteinuria on the risk of either graft failure or death in all 722 recipients of a kidney graft in our center who survived at least 1 year with a functioning graft. Proteinuria was analyzed both as a categorical variable (presence versus absence) and as a continuous variable (quantification of 24 hr urine). Other variables included in this analysis were: donor/recipient age and gender, original disease, race, number of HLA-A and HLA-B mismatches, previous transplants, postmortal or living related transplantation, and transplantation year. At 1 year after transplantation, we included: proteinuria, serum cholesterol, serum creatinine, blood pressure, and the use of antihypertensive medication.

RESULTS

In the Cox proportional hazards analysis, proteinuria at 1 year after transplantation (both as a categorical and continuous variable) was an important and independent variable influencing all endpoints. The influence of proteinuria as a categorical variable on graft failure censored for death showed no interaction with any of the other variables. There was an adverse effect of the presence of proteinuria on the graft failure rate (RR=2.03). The influence of proteinuria as a continuous variable showed interaction with original disease. The presence of glomerulonephritis, hypertension, and systemic diseases as the original disease significantly increased the risk of graft failure with an increasing amount of proteinuria at 1 year. The influence of proteinuria as a categorical variable on the rate ratio for patient failure was significant, and there was no interaction with any of the other significant variables (RR=1.98). The death risk was almost twice as high for patients with proteinuria at 1 year compared with patients without proteinuria. The influence of proteinuria as a continuous variable was also significant and also without interaction with other variables. The death risk increased with increasing amounts of proteinuria at 1 year. Both the risks for cardiovascular and for noncardiovascular death were increased.

CONCLUSION

Proteinuria after renal transplantation increases both the risk for graft failure and the risk for death.

Clinical value of microalbuminuria in hypertension

Microalbuminuria (MA) is a well recognized marker of cardiovascular complications in hypertension, but whether MA can predict adverse outcome in this clinical condition is still a subject for debate. The fact that in hypertensive cohorts those patients who showed an increase in albumin excretion rate also manifested an increased incidence of morbid events indicates that the presence of MA in hypertension may carry an increased cardiovascular risk. However, the prognostic significance of MA remains controversial because no results of prospective studies performed in hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of MA in hypertension, including severity of the disease, selection procedures, concomitant risk factors, degree of obesity, age, and sex distribution. This accounts for the large differences in the prevalence of MA that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 40%. There is still conflict over whether MA in hypertension is due to increased intraglomerular pressure or to glomerular damage. The data from the literature suggest that in subjects with mild hypertension the main determinant of albumin excretion rate is the haemodynamic load. In subjects with more severe hypertension and hypertensive complications, the augmented urinary albumin leak is probably the consequence of a systemic microvascular disturbance which involves the glomeruli. In this respect, the insulin resistance state often associated to high blood pressure appears as one of the main pathogenetic factors. Whether management of hypertensive populations may be improved by monitoring of albumin excretion rate and whether antihypertensive drugs which are more effective in decreasing urinary albumin can be more beneficial in patients with MA remains to be determined.

Microalbuminuria in essential hypertension

Urinary excretion of albumin exceeds normal values in 10 to 25% of patients with essential hypertension. The level of albuminuria is highly correlated with arterial pressure, and more closely with ambulatory arterial pressure. The interaction between albuminuria and arterial pressure is enhanced by overweight, smoking, protein intake, insulin resistance, lipid abnormalities, and possibly genotypes of the components of the renin-angiotensin system. The renal mechanisms of microalbuminuria are not well elucidated. Notably, an increase in filtration fraction suggestive of intraglomerular hypertension was observed in patients with hyperfiltration. Microalbuminuria may be a marker of diffuse vascular abnormalities predisposing to cardiovascular disease and/or hypertensive renal disease heralding future renal failure, but its predictive value needs to be tested in more long-term follow-up studies. Antihypertensive treatment has a varied influence on albuminuria; angiotensin-converting enzyme inhibitors may correct this abnormality (at least partially) better than other agents.