Long-Term Impact of Systolic Blood Pressure and Glycemia on the Development of Microalbuminuria in Essential Hypertension

Interaction effect of blood glucose and pressure on the risk of chronic kidney disease: a population-based prospective cohort study

OBJECTIVE

To evaluate the interaction effect of blood glucose and blood pressure on the risk of chronic kidney disease (CKD).

METHODS

31,165 subjects were selected without CKD at baseline and had completed the first follow-up from "Jinchang cohort". Cox regression model and restricted cubic splines functions were used to evaluate the effects of blood glucose or pressure on the incidence of CKD and dose-response relationship after adjusting for confounding covariates. Synergic effect was assessed by the multiplicative or additive interaction scale.

RESULTS

Among 31,165 subjects, 1307 new-onset CKD were observed during 68905.78 person-years follow-up, and the incidence density was 18.97 per 1000 person-years. The risk of CKD gradually increased with the increase of blood pressure in diabetes, pre-diabetes and normal groups (P_trend < 0.05). And, the risk was greatest when SBP/DBP reached ≥150/≥110 mmHg in three groups, and HRs (95% CI) were 1.610 (1.070-2.422), 2.142 (1.396-3.288) and 2.455 (1.941-3.106), respectively. Additionally, among hypertension, pre-hypertension and normal groups, the risk of CKD increased by 16.0%, 14.3% and 25.2% for each 1 mmol/L of FPG. When FPG level was more than 9.0 mmol/L, the risk was greatest and adjusted HRs (95% CI) were 2.856 (2.176-3.748), 2.979 (1.828-4.854) and 7.520 (4.517-12.519). Furthermore, the risk was highest when hypertension was accompanied by diabetes (HR = 4.915, 95% CI: 3.923-6.157). This analysis supported a less than multiplicative effect (HR = 0.634, 95% CI: 0.417-0.964) for the interaction term of diabetes and hypertension, while there was no additive interaction towards CKD in all interaction term.

CONCLUSIONS

Blood glucose and pressure were independent risk factors in incidence of CKD, but there was only a negative multiplicative interaction between hypertension and diabetes, but no additive interaction effect between them.

Development and Validation of Prediction Models for Hypertensive Nephropathy, the PANDORA Study

Importance

Hypertension is a leading cause of end-stage renal disease (ESRD), but currently, those at risk are poorly identified.

Objective

To develop and validate a prediction model for the development of hypertensive nephropathy (HN).

Design, Setting, and Participants

Individual data of cohorts of hypertensive patients from Kailuan, China served to derive and validate a multivariable prediction model of HN from 12, 656 individuals enrolled from January 2006 to August 2007, with a median follow-up of 6.5 years. The developed model was subsequently tested in both derivation and external validation cohorts.

Variables

Demographics, physical examination, laboratory, and comorbidity variables.

Main Outcomes and Measures

Hypertensive nephropathy was defined as hypertension with an estimated glomerular filtration rate (eGFR) &lt; 60 ml/min/1.73 m2 and/or proteinuria.

Results

About 8.5% of patients in the derivation cohort developed HN after a median follow-up of 6.5 years that was similar in the validation cohort. Eight variables in the derivation cohort were found to contribute to the risk of HN: salt intake, diabetes mellitus, stroke, serum low-density lipoprotein, pulse pressure, age, hypertension duration, and serum uric acid. The discrimination by concordance statistics (C-statistics) was 0.785 (IQR, 0.770-0.800); the calibration slope was 1.129, the intercept was –0.117; and the overall accuracy by adjusted R2 was 0.998 with similar results in the validation cohort. A simple points scale developed from these data (0, low to 40, high) detected a low morbidity of 7% in the low-risk group (0–10 points) compared with &gt;40% in the high-risk group (&gt;20 points).

Conclusions and Relevance

A prediction model of HN over 8 years had high discrimination and calibration, but this model requires prospective evaluation in other cohorts, to confirm its potential to improve patient care.

Hypertension in Women: A South-Asian Perspective

Introduction

Hypertension is an important contributor to cardiovascular disease related morbidity and mortality. Despite the magnitude of its negative impact on cardiovascular outcomes, treatment and control of hypertension remain suboptimal in both men and women.

Materials and Methods

Numerous databases, i.e., PubMed, ScienceDirect, etc., were searched using keywords to identify relevant studies to our narrative review. The findings from the most pertinent articles were summarized and integrated into our narrative review on hypertension in women.

Results

The pathophysiology of essential hypertension is still being delineated in both men and women; there are multiple sex specific factors in association with the development of hypertension in women, including age, combined oral contraceptives (COCs), polycystic ovarian syndrome (PCOS), preeclampsia, etc. There are several sex specific considerations in antihypertensives drug choices.

Discussion

Despite the magnitude of its negative impact on cardiovascular outcomes, treatment and control of hypertension remain suboptimal in women. Medical treatment and adherence is uniquely challenging for South Asian women due to a variety of socio-cultural-economic factors. Further research is warranted to identify optimal sex-specific treatment options that will improve the control of hypertension and decrease the risk of subsequent cardiovascular disease in both genders.

An Observational Registry to Assess Urinary Albumin Evolution in Saudi Hypertensive Patients with the Current Treatment Local algorithm: Results of the RATIONAL Study

Introduction

Hypertension causes microalbuminuria, which if left uncontrolled could progress to kidney damage. Antihypertensive treatment primarily aims at controlling blood pressure (BP), but is also shown to control urine albumin excretion. This renoprotective role of antihypertensive medications consists of halting or reverting albuminuria progression.

Patients and Methods

A national Kingdom of Saudi Arabia (KSA), multicenter, observational, longitudinal study (RATIONAL), evaluated the correlation between BP control and microalbuminuria evolution over 1 year. Adult hypertensive patients with kidney damage were enrolled, after giving written consent.

Results

Of 409 patients, 60% had uncontrolled BP at baseline, down to 34% at 12 months. Over 80% of patients were on mono or double antihypertensive therapy, and angiotensin-receptor blockers (ARB) topped the list of medication classes. Albumin–creatinine ratio (ACR) significantly decreased throughout the study, indicating that BP control is paramount to prevent target organ damage. BP change most strongly correlated with ACR change upon triple therapy (ARB + calcium channel blocker + β-blocker). Importantly, 25% (at 6 months) and 38% (at 12 months) of patients reverted back to normoalbuminuria, mostly upon renin-angiotensin system blockers. Around 80% of study patients had also diabetes, a common condition in KSA, which significantly hindered achievement of normoalbuminuria at 12 months.

Conclusion

A modest but solid correlation between BP control and ACR reduction was identified. Results underline proper BP management in KSA and success of antihypertensive treatment in reverting microalbuminuria or delaying its progress. The study duration might be insufficient to reflect conclusively the beneficial effect of longer-term BP control on microalbuminuria evolution.

Bidirectional and Temporal Association Between Hypertension and Microalbuminuria: A Longitudinal Study in Chinese Adults

Background Although hypertension and microalbuminuria are closely interrelated, the magnitude and temporal sequence of the bidirectional association between hypertension and microalbuminuria are largely unknown. We aimed to delineate the bidirectional and temporal relationship between hypertension and microalbuminuria. Methods and Results Leveraging a longitudinal cohort of Chinese adults who had blood pressure and urinary albumin measured twice 4 years apart, we examined the temporal association between hypertension and microalbuminuria by bidirectional and cross-lagged panel analysis. All participants were free of cardiovascular disease and chronic kidney disease at baseline. Bidirectional association analysis found that baseline microalbuminuria predicted the risk of incident hypertension (odds ratio=1.75, P=0.028), and baseline blood pressure also significantly predicted the risk of microalbuminuria (odds ratios=1.27 and 1.21 for a per-SD increase in systolic and diastolic blood pressure, respectively; all P<0.05). Cross-lagged panel analysis demonstrated a bottom-line significant relationship of baseline systolic blood pressure to follow-up urinary albumin ( P=0.079), which is significantly weaker than the other direction of the relationship of baseline urinary albumin to follow-up blood pressures (all P<0.001). Conclusions These findings indicate a significant bidirectional association between microalbuminuria and hypertension in Chinese adults. Elevated urinary albumin excretion is more likely to precede hypertension. The causality between microalbuminuria and hypertension needs further investigation.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Study of ambulatory blood pressure in diabetic children: prediction of early renal insult

Background

Hypertension is a highly prevalent risk factor for cardiovascular disease in patients with type 1 diabetes mellitus. Elevated blood pressure (BP) promotes the development and progression of microvascular complications, eg, nephropathy and retinopathy. The purpose of this study was to identify and detect early BP changes in diabetic children and adolescents, aiming for the early prediction of future renal and cardiovascular disease risk during childhood.

Methods and materials

Ambulatory BP monitoring was undertaken for 40 normotensive type 1 diabetic children with mean age of 11.56±2.82 years, and 24 healthy children as control group with matched age and sex. Albumin/creatinine ratio and glycated hemoglobin were tested. BP indices and standard deviation scores were calculated using reference standards. The data were analyzed by SPSS software version 20 using mean and standard deviations for descriptive data. Correlation and regression analysis tests were used to study relations between BP indices and diabetic parameters.

Results

All parameters of BP z-scores were highly significantly increased in diabetic patients compared with controlled group (P<0.0001). The frequency of non-dipping was greater and highly significant in microalbuminuric diabetic patients (P<0.0001). Regression analysis revealed that BP parameters were significantly related to albumin/creatinine ratio, glycated hemoglobin, insulin dose, and body mass index.

Conclusion

Our observation revealed a clear link between the nocturnal BP and microalbuminuria which mandates BP follow-up via ambulatory BP monitoring with therapeutic intervention to prevent renal and cardiovascular diabetic complications in adulthood.

Prognostic Value of Microalbuminuria During Antihypertensive Treatment in Essential Hypertension

Whether changes over time of urinary albumin excretion have prognostic value is a matter of discussion. The objective was to assess the prognostic value of changes in urinary albumin excretion over time in cardiovascular risk during antihypertensive treatment. Follow-up study of 2835 hypertensives in the absence of previous cardiovascular disease (mean age 55 years, 47% men, BP 138/80 mm Hg, 19.1% diabetics, and calibrated systemic coronary risk estimation 5 or >10.6%). Usual-care of antihypertensive treatment was implemented to maintain blood pressure <140/90 mm Hg. Urinary albumin excretion was assessed yearly, and the values were expressed as the creatinine ratio. Incidence of cardiovascular events, fatal and nonfatal, was recorded during the follow-up. During a median follow-up of 4.7 years (17 028 patients-year), 294 fatal and first nonfatal cardiovascular events were recorded (1.73 CVD per 100 patients/year). Independently of blood pressure, estimated glomerular filtration rate, level of cardiovascular risk, and antihypertensive treatment, microalbuminuria at baseline and at any time during the follow-up resulted in higher risk for events, hazard ratio (HR) 1.35 (95% confidence interval [CI], 1.08–1.79) and HR 1.49 (95% CI, 1.14–1.94), respectively. Likewise, development of microalbuminuria (HR 1.60; 95% CI, 1.04–2.46) or persistence from the beginning (1.53; 95% CI, 1.13–2.06) had a significantly higher rate of events than if remained normoalbuminuric (HR 1) or regress to normoalbuminuria (HR 1.37; 95% CI, 0.92–2.06) with an 18%, 18%, 8%, and 11% events, respectively, P <0.001. The study supports the value of urinary albumin excretion assessment as a prognostic factor for cardiovascular risk, but also opens the way to consider it as an intermediate objective in hypertension.

Regression of left ventricular hypertrophy and microalbuminuria changes during antihypertensive treatment

OBJECTIVE

The objective of the present study was to assess the regression of left ventricular hypertrophy (LVH) during antihypertensive treatment, and its relationship with the changes in microalbuminuria.

INDIVIDUALS AND METHODS

One hundred and sixty-eight previously untreated patients with echocardiographic LVH, 46 (27%) with microalbuminuria, were followed during a median period of 13 months (range 6-23 months) and treated with lifestyle changes and antihypertensive drugs. Twenty-four-hour ambulatory blood pressure monitoring, echocardiography and urinary albumin excretion were assessed at the beginning and at the end of the study period.

RESULTS

Left ventricular mass index (LVMI) was reduced from 137 [interquartile interval (IQI), 129-154] to 121 (IQI, 104-137) g/m (P < 0.001). Eighty-nine patients (53%) had a reduction in LVMI of at least 17.8 g/m, and an LVH regression rate of 43.8 per 100 patient-years [95% confidence interval (CI) 35.2-53.9]. The main factor related to LVH regression was the reduction in SBP24 h [multivariate odds ratio (ORm) 4.49; 95% CI 1.73-11.63; P = 0.005, highest tertile compared with lower tertiles]. Male sex (ORm 0.39; 95% CI 0.17-0.90; P = 0.04) and baseline glomerular filtration rate less than 90 ml/min per 1.73 m (ORm 0.39; 95% CI 0.17-0.90; P = 0.03) were associated with a lower probability of LVH regression. Patients with microalbuminuria regression (urinary albumin excretion reduction >50%) had the same odds of achieving regression of LVH as patients with normoalbuminuria (ORm 1.1; 95% CI 0.38-3.25; P = 0.85). However, those with microalbuminuria at baseline, who did not regress, had less probability of achieving LVH regression than the normoalbuminuric patients (OR 0.26; 95% CI 0.07-0.90; P = 0.03) even when adjusted for age, sex, initial LVMI, GFR, blood pressure and angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) treatment during the follow-up.

CONCLUSION

Patients who do not have a significant reduction in microalbuminuria have less chance of achieving LVH regression, independent of blood pressure reduction.

The prevalence and risk factors of microalbuminuria in hypertensive patients under current medical treatment

OBJECTIVE

A link between urinary albumin excretion and an increased incidence of cardiovascular mortality has already been demonstrated. However, the reported prevalence of microalbuminuria (MAU) in patients with hypertension is highly variable. We therefore aimed to conduct a cross-sectional multicenter study to investigate the prevalence of urinary albumin excretion in treated hypertensive patients in our current practice.

METHODS

A total of 1,258 hypertensive patients were enrolled in this study. Patients with macroalbuminuria were excluded. The concentrations of urinary microalbumin and creatinine were measured. Urinary albumin excretion was expressed as the ratio of albumin to creatinine excretion.

RESULTS

The mean systolic and diastolic blood pressures were 130.9±12.7 mmHg and 74.7±8.9 mmHg, respectively. The overall prevalence of MAU was 42.8%, and it was observed in 35.8% of patients treated with a single medication. Patients with polyvascular disease exhibited a higher prevalence of MAU compared with patients with monovascular disease. The factors related to the presence of MAU included the estimated glomerular filtration rate (eGFR), systolic blood pressure, and glycated hemoglobin (HbA1c) level (odds ratios [ORs] of 0.988, 1.026, and 1.371, respectively).

CONCLUSION

The present study showed that the prevalence of MAU among hypertensive patients was 42.8%, even in patients whose blood pressure was relatively well controlled. Additionally, the eGFR, systolic blood pressure, and HbA1c level are risk factors for the development of MAU. These findings suggest that a substantial number of hypertensive patients have MAU and highlight the importance of strictly controlling these factors to improve patient prognosis.

High-normal diastolic blood pressure is a risk for development of microalbuminuria in the general population: the Watari study

OBJECTIVE

Although hypertension is a well known risk factor for microalbuminuria, it is unclear whether blood pressure less than 140/90 mmHg could be a risk for microalbuminuria. We assessed the relationship between baseline blood pressure and the future onset of microalbuminuria in the general population.

METHODS

We studied 2603 town inhabitants of Watari, located in the southeastern part of Miyagi prefecture, Japan. Demographic data, medical history, sitting blood pressure, fasting blood chemistry, and urinary albumin-creatinine ratio were measured at baseline and were followed annually during the next 3 years.

RESULTS

Among 2338 individuals who were normoalbuminuric at baseline (albumin-creatinine ratio <30 mg/g Cr), 161 developed microalbuminuria (albumin-creatinine ratio 30-299 mg/g Cr) during a mean follow-up period of 2.4 years. Incident microalbuminuria patients were older (63.7 ± 8.6 vs. 61.4 ± 10.5 years; P < 0.01), included fewer men (31.1 vs. 40.1%; P < 0.05), had a greater BMI (23.8 ± 3.6 vs. 23.1 ± 3.1 kg/m²; P < 0.01), higher blood pressures (133.5 ± 18.1/75.8 ± 11.9 vs. 127.6 ± 18.1/73.4 ± 11.0 mmHg; P < 0.01 for both systolic and diastolic), higher triglycerides (median 1.18 vs. 1.02 mmol/l; P < 0.01), higher fasting blood glucose (median 5.05 vs. 4.94 mmol/l; P < 0.01), higher urinary albumin excretion (median 13.0 vs. 5.9 mg/g Cr; P < 0.001), and lower serum creatinine concentrations (59.2 ± 12.8 vs. 61.4 ± 13.2 μmol/l; P < 0.05) compared to persistent normoalbuminuric individuals. Multivariate Cox proportional hazards analysis including all covariates revealed that only baseline urinary albumin excretion was an independent predictor for future microalbuminuria, whereas high-normal DBP, triglyceride, and fasting blood glucose concentrations were all significant predictors in the model excluding urinary albumin excretion.

CONCLUSIONS

High-normal DBP associated with metabolic disorders could initiate glomerular damage, leading to future microalbuminuria.

Pre-hypertension as a significant predictor of chronic kidney disease in a general population: the Ohasama Study

BACKGROUND

Hypertension is associated with an increased risk of development of chronic kidney disease (CKD). However, it is unclear whether pre-hypertension is related to the incidence of CKD.

METHODS

The incidence of CKD defined as positive proteinuria or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) was examined in 2150 inhabitants without pre-existing CKD from the general Japanese population. The association of blood pressure and CKD incidence was examined using a Cox regression model adjusted for age, sex, habitual smoking and drinking, obesity, history of cardiovascular disease, diabetes mellitus or hypercholesterolemia, eGFR at baseline, number of follow-up examinations and year of baseline examination. Participants were categorized according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure.

RESULTS

Participants were categorized into normotension (n = 586, 27.3 % ), pre-hypertension (n = 815, 37.9 % ), Stage 1 hypertension (n = 386, 18.0 % ) and Stage 2 hypertension (n = 363, 16.9 % ). During a mean follow-up of 6.5 years (14 023 person-years), 461 incidences of CKD were recorded. Compared to normotension, adjusted hazard ratios of CKD were significantly higher for pre-hypertension (1.49, P < 0.003), Stage 1 (1.83, P < 0.001) and Stage 2 (2.55, P < 0.001) hypertension. The population-attributable fraction of pre-hypertension (12.1 % ) was considered to be compatible to that of Stage 1 (8.6 % ) and Stage 2 (14.9 % ) hypertension.

CONCLUSION

This was the first study to demonstrate that pre-hypertension was significantly associated with an increased risk of CKD and was one of the considerable causes of CKD in the general population.

Premenopausal women have increased risk of hypertensive target organ damage compared with men of similar age

BACKGROUND

The impact of high blood pressure (BP) on target organs (TO) in premenopausal women is not well known. The purpose of this study was to describe gender differences in TO involvement in a cohort of young-to-middle-aged subjects screened for stage 1 hypertension and followed for 8.2 years.

METHODS

Participants were 175 women and 451 men with similar age (range 18-45 years). Ambulatory BP at entry was 127.5±12.5/83.7±7.2 mm Hg in women and 131.9±10.3/81.0±7.9 mm Hg in men. Ambulatory BP, albumin excretion rate (AER), and echocardiographic data (n=489) were obtained at entry, every 5 years, and before starting antihypertensive treatment.

RESULTS

Female gender was an independent predictor of final AER (p=0.01) and left ventricular mass index (LVMI) (p<0.001). At follow-up end, both microalbuminuria (13.7% vs. 6.2%, p=0.002) and left ventricular hypertrophy (LVH) (26.4% vs. 8.8%, p<0.0001) were more common among women than men. In a multivariable Cox analysis, after adjusting for age, lifestyle factors, body mass, ambulatory BP, heart rate, and parental hypertension, female gender was a significant predictor of time to development of microalbuminuria (p=0.002), with a hazard ratio (HR) of 3.06, (95% confidence interval [CI] 1.48-6.34) and of LVH (p=0.004), with an HR of 2.50 (1.33-4.70). Inclusion of systolic and diastolic BP changes over time in the models only marginally affected these associations, with HRs of 3.13 (1.50-6.55) and 3.43 (1.75-6.70), respectively.

CONCLUSIONS

These data indicate that premenopausal women have an increased risk of hypertensive TO damage (TOD) and raise the question about whether early antihypertensive treatment should be considered in these patients.

Urine albumin excretion, within normal range, reflects increasing prevalence of metabolic syndrome in patients with essential hypertension

Microalbuminuria is a prognostic marker of cardiovascular disease and is related to metabolic syndrome (MetS). For this purpose, the authors examined the relationship of low grade albuminuria to MetS, using 4 current definitions and a MetS score. They studied 6650 consecutive, nondiabetic, hypertensive patients with normal microalbumin excretion. MetS was defined by Adult Treatment Panel III, American Heart Association, World Heart Organization, International Diabetes Federation criteria, and MetS Gruppo Italiano per lo Studio della Streptochinasi nell'Infarcto Miocardico (GISSI) score. Urine microalbumin concentration was measured after a 24-hour urine collection by immunonephelometry. By all definitions, hypertensive patients with MetS had higher microalbumin levels. Significantly higher microalbumin levels were observed as the number of metabolic components rose. After adjustment for systolic blood pressure, the strength of this association was reduced to a nonsignificant level. Microalbumin levels, within normal range, are increased in patients with MetS, irrespective of the definition criteria.

Predictors of incident albuminuria in the Framingham Offspring cohort

BACKGROUND

Predictors for incident albuminuria are not well known in population-based cohorts. The purpose of this study is to identify predictors of incident albuminuria in an unselected middle-aged population.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Framingham Offspring Study participants who attended both the sixth (baseline; 1995-1998) and eighth (2005-2008) examination cycles.

PREDICTORS

Standard clinical predictors were used. Predictors of incident albuminuria were identified using stepwise logistic regression analysis with age and sex forced into the model.

OUTCOMES & MEASUREMENTS

Albuminuria was defined as urine albumin-creatinine ratio (UACR) ≥ 17 mg/g (men) or ≥ 25 mg/g (women). Individuals with albuminuria at baseline were excluded.

RESULTS

1,916 participants were available for analysis (mean age, 56 years; 54% women). Albuminuria developed in 10.0% of participants (n = 192) during 9.5 years. Age (OR, 2.09; P < 0.001), baseline diabetes (OR, 1.93; P = 0.01), smoking (OR, 2.09; P < 0.001), and baseline log UACR (OR per 1-SD increase in log UACR, 1.56; P < 0.001) were associated with incident albuminuria in a stepwise model. An inverse relationship with female sex (OR, 0.53; P < 0.001) and high-density lipoprotein (HDL) cholesterol level (OR, 0.80; P = 0.007) also was observed. Results were similar when participants with baseline chronic kidney disease (n = 102), defined as estimated glomerular filtration rate <60 mL/min/1.73 m(2), were excluded from the model. Age, male sex, low HDL cholesterol level, smoking, and log UACR continued to be associated with incident albuminuria when baseline diabetes (n = 107) was excluded. Age, male sex, and log UACR correlated with incident albuminuria after participants with baseline hypertension were excluded (n = 651).

LIMITATIONS

Causality may not be inferred because of the observational nature of the study. One-third of participants did not return for follow-up, potentially attenuating the observed risks of albuminuria.

CONCLUSIONS

The known cardiovascular risk factors of increasing age, male sex, diabetes, smoking, low HDL cholesterol level, and albuminuria within the reference range are correlates of incident albuminuria in the general population.

Determinants of urinary albumin excretion within the normal range in patients with type 2 diabetes: the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study

AIMS/HYPOTHESIS

In contrast to microalbuminuric type 2 diabetic patients, the factors correlated with urinary albumin excretion are less well known in normoalbuminuric patients. This may be important because even within the normoalbuminuric range, higher rates of albuminuria are known to be associated with higher renal and cardiovascular risk.

METHODS

At the time of screening for the Randomised Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) Study, the urinary albumin/creatinine ratio (UACR) was 0.44 mg/mmol in 4,449 type 2 diabetic patients. The independent correlates of UACR were analysed.

RESULTS

Independent correlates of UACR during baseline were (in descending order): night-time systolic BP (r(s) = 0.19); HbA(1c) (r(s) = 0.18); mean 24 h systolic BP (r(s) = 0.16); fasting blood glucose (r(s) = 0.16); night-time diastolic BP (r(s) = 0.12); office systolic BP, sitting (r(s) = 0.11), standing (r(s) = 0.10); estimated GFR (r(s) = 0.10); heart rate, sitting (r(s) = 0.10); haemoglobin (r(s) = -0.10); triacylglycerol (r(s) = 0.09); and uric acid (r(s) = -0.08; all p <or= 0.001). Significantly higher albumin excretion rates were found for the following categorical variables: higher waist circumference (more marked in men); presence of the metabolic syndrome; smoking (difference more marked in males); female sex; antihypertensive treatment; use of amlodipine; insulin treatment; family history of diabetes; and family history of cardiovascular disease (more marked in women).

CONCLUSIONS/INTERPRETATION

Although observational correlations do not prove causality, in normoalbuminuric type 2 diabetic patients the albumin excretion rate is correlated with many factors that are potentially susceptible to intervention.

TRIAL REGISTRATION

ClinicalTrials.gov ID no.: NCT00185159

FUNDING

This study was sponsored by Daichii-Sankyo.

Microalbuminuria and obesity: impact on cardiovascular disease and mortality

OBJECTIVE

Microalbuminuria and obesity are both associated with cardiovascular disease (CVD). The aim of this study was to determine the association between obesity (measured by body mass index, waist-to-hip ratio, waist circumference) and different levels of microalbuminuria. We also aimed to determine the risk of death and CVD at different levels of microalbuminuria and obesity.

DESIGN

Population-based observational study based on 2696 men and women, 30-70 years of age. Urinary albumin excretion (UAE), body mass index, waist-to-hip ratio, waist circumference and other cardiovascular risk factors were measured during the years 1992-1994 at the Copenhagen City Heart Study. End-points were registered until 1999-2000 with respect to CVD and until 2004 with respect to death.

RESULTS

There was a strong association between microalbuminuria and obesity. Microalbuminuria and obesity had additive effects on the relative risk of death independently of other risk factors. In contrast there was no statistically significant association between microalbuminuria and risk of CVD when stratified by obesity.

CONCLUSIONS

Microalbuminuria (UAE > 5 microg/min) confers increased risk of death and to a similar extent as obesity. This effect is independent of concomitant obesity. We suggest microalbuminuria to be included in health examinations besides measurements of obesity.

Spironolactone and doxazosin treatment in patients with resistant hypertension

INTRODUCTION AND OBJECTIVES

The aim of this study was to evaluate the use of spironolactone and doxazosin as treatment for patients with resistant hypertension.

METHODS

This retrospective study involved 181 outpatients with resistant hypertension (defined as a failure of blood pressure [BP] control despite treatment with three drugs, one of which was a diuretic) who received additional spironolactone (n=88) or doxazosin (n=93).

RESULTS

Mean systolic BP in the spironolactone group fell by 28 mmHg (95% confidence interval [CI], 24-32 mmHg; P< .001) and mean diastolic BP fell by 12 mmHg (95% CI, 9-14 mmHg; P< .001). The corresponding falls in the doxazosin group were 16 mmHg (95% CI, 13-20 mmHg; P< .001) and 7 mmHg (95% CI, 5-9 mmHg; P< .001), respectively. The decrease was significantly greater with spironolactone for both systolic (P< .001) and diastolic (P=.003) pressures. At the end of follow-up, 30% of all patients had achieved BP control, with control being more frequent with spironolactone (39%) than doxazosin (23%; P=.02). Multivariate logistic regression analysis showed that the only factors that significantly influenced the achievement of BP control were diabetes (odds ratio=0.17; 95% CI, 0.08-0.39; P< .001) and baseline systolic BP <165 mmHg (odds ratio=2.56; 95% CI, 1.11-5.90; P=.03).

CONCLUSIONS

In patients with resistant hypertension, the addition of either spironolactone or doxazosin resulted in a significant decrease in BP, though the decrease appeared to be greater with spironolactone. The presence of diabetes complicated BP control.

Arterial hypertension determined by ambulatory blood pressure profiles: contribution to microalbuminuria risk in a multicenter investigation in 2,105 children and adolescents with type 1 diabetes

OBJECTIVE

Arterial hypertension is a key player in the development of diabetes complications. We used a nationwide database to study risk factors for abnormal 24-h blood pressure regulation and microalbuminuria in children and adolescents with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Ambulatory blood pressure monitoring was performed in 2,105 children and adolescents from 195 pediatric diabetes centers in Germany and Austria. Individual least median squares (LMS)-SD scores were calculated for diurnal and nocturnal systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressure according to normalized values of a reference population of 949 healthy German children. The nocturnal blood pressure reduction (dipping) was calculated for SBP as well as DBP.

RESULTS

In diabetic children, nocturnal blood pressure in particular was significantly elevated (SBP +0.51, DBP +0.58, MAP +0.80 LMS-SD) and dipping of SBP DBP, and MAP was significantly reduced (P < 0.0001). Age, diabetes duration, sex BMI, A1C, and insulin dose were related to altered blood pressure profiles; dipping, however, was only affected by age, female sex, and A1C. The presence of microalbuminuria was associated with nocturnal DBP (P < 0.0001) and diastolic dipping (P < 0.01).

CONCLUSIONS

Our observations revealed a clear link between the quality of metabolic control and altered blood pressure regulation even in pediatric patients with short diabetes duration. Nocturnal blood pressure in particular seems to mainly contribute to diabetes complications such as microalbuminuria.

Relation of albuminuria to left ventricular mass (from the HyperGEN Study)

Although albuminuria has been associated with a larger left ventricular (LV) mass in hypertensive and diabetic populations, little is known about this association in normotensive adults. We hypothesized that albuminuria is positively associated with LV mass in normotensive and hypertensive subjects. We analyzed data from 3,445 participants of the Hypertension Genetic Epidemiology Network (HyperGEN) Study (mean age 48.6 +/- 13.7 years, range 18 to 87, 57% women). LV parameters were obtained by echocardiography. Urinary albumin was estimated using standard methods. From the lowest to highest quartile of albuminuria, multivariable adjusted means of LV mass indexed to body surface area were 71.9, 73.3, 74.0, and 76.5 g/m2, respectively (p for trend = 0.002) in normotensive participants. Corresponding values for hypertensive subjects were 87.4, 89.3, 92.3, and 94.9 g/m2, respectively (p for trend <0.0001). Similar results were observed for LV mass indexed to height2.7. In secondary analyses, we found similar associations for men and women and after exclusion of subjects with diabetes. Furthermore, positive associations were observed between albuminuria and LV wall thickness in hypertensive and normotensive subjects. Albuminuria was negatively related to ejection fraction only in hypertensive subjects. In conclusion, these results suggest that albuminuria is positively associated with LV mass in normotensive subjects as it is in hypertensive subjects.

Microalbuminuria screening in patients with hypertension: recommendations for clinical practice

INTRODUCTION

Correlations between renal and cardiovascular (CV) pathologies in advanced kidney or heart disease are well characterised, but less clearly defined in the early stages. Microalbuminuria, in addition to being an early sign of kidney damage, is often found in patients with essential hypertension, suggesting that it may reflect early vascular abnormalities.

EVIDENCE FROM LITERATURE

Studies have shown that even very low levels of microalbuminuria strongly correlate with CV risk: albumin excretion rates as low as 4.8 microg/min, well below the microalbuminuria thresholds stated in current clinical guidelines, are associated with increased risk of CV and cerebrovascular disease, independent of the presence of other risk factors. Increased microalbuminuria indicates endothelial dysfunction or developing atherosclerosis and predicts end-organ damage, major cardio or cerebrovascular events and death.

CLINICAL ASPECTS

Available tests for screening microalbuminuria are sensitive, reliable and accessible; current European and US guidelines advocate annual screening in patients with diabetes and wherever possible in non-diabetic patients with hypertension. Early identification of high-risk patients through detection of microalbuminuria allows selection of aggressive treatment to slow disease progression.

THERAPEUTIC IMPLICATIONS

Antihypertensive agents providing angiotensin II blockade are recommended for the treatment of hypertensive patients with microalbuminuria, regardless of diabetes and/or early or overt nephropathy. Treatment with angiotensin II receptor blockers provides effective reduction of microalbuminuria and blood pressure, and long-term prevention of CV events beyond blood pressure reduction. In addition, pharmacoeconomic studies have shown that these long-term benefits translate into a substantially reduced burden on healthcare resources.

Microalbuminuria and the metabolic syndrome and its components in the Chinese population

BACKGROUND

Microalbuminuria and the metabolic syndrome (MetS) have both been linked to chronic kidney disease and cardiovascular disease. This study investigated the association between urinary albumin-to-creatinine ratio (ACR) and MetS and its components.

MATERIALS AND METHODS

A total of 2311 subjects aged 40 years and over were recruited in 2004 in a metropolitan city in Taiwan. The biochemical indices, such as fasting glucose levels, urinary albumin, urinary creatinine and anthropometric indices, were measured. We defined microalbuminuria as a urinary ACR ranging from 30 to 300 mg g(-1) creatinine. MetS was defined using the American Heart Association and the National Heart, Lung and Blood Institute (AHA/NHLBI) and the International Diabetes Federation (IDF) definitions. The relationship between MetS and microalbuminuria was examined using multiple logistical regression analysis.

RESULTS

Subjects with microalbuminuria had higher age, body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose, triglycerides, total cholesterol (TCHOL)/high-density lipoprotein cholesterol (HDL-C) ratio, prevalence of diabetes mellitus and hypertension and lower HDL-C than subjects with normoalbuminuria. After adjusting for age and BMI, microalbuminuria was associated with the individual components of MetS, except in central obesity in women and elevated fasting glucose in men. After adjusting for age, BMI, smoking and alcohol consumption status, multiple logistical regressions revealed that microalbuminuria is strongly associated with MetS in both genders and according to both definitions. The odds ratio of having MetS using the AHA/NHLBI and IDF definition was 1.76 (1.16-2.67) and 1.73 (1.06-2.83) in men and 2.19 (1.38-3.50) and 2.09 (1.24-3.51) in women, respectively.

CONCLUSIONS

Microalbuminuria was strongly associated with MetS and its components. There is an increased likelihood of having MetS if subjects have microalbuminuria.

Differential impacts of adiponectin on low-grade albuminuria between obese and nonobese persons without diabetes

The goal of this study was to examine the association between adiponectin and low-grade albuminuria in nondiabetic persons and whether it differed between obese and nonobese individuals. Urinary albumin excretion (UAE) was assessed by overnight collection in 157 participants. Overall, as anticipated, 24-hour systolic blood pressure and fasting glucose levels were independent determinants of UAE (beta=0.254 and 0.176, respectively, P<.05). In obese persons (body mass index [BMI] >/=25 kg/m(2); n=63), adiponectin value was a significant negative determinant of UAE (beta=-0.256, P<.05) independent of blood pressure and glucose levels, whereas in nonobese participants (n=94) it was not. In an analysis of BMI and the median value of adiponectin (9.9 microg/mL), UAE was found to be significantly higher in obese persons with low adiponectin levels than in obese persons with high adiponectin levels (9.20 vs 5.11 microg/min; P<.05), even after adjustment for age, sex, blood pressure level, and glucose level. There was an inverse association between adiponectin and low-grade albuminuria in obese nondiabetic persons.

Nueva definición del síndrome metabólico: ¿mismo riesgo cardiovascular?

OBJECTIVE

The International Diabetes Federation (IDF) has recently published the new criteria for the diagnosis of metabolic syndrome. The aim of this study was to compare the clinical characteristics and cardiovascular risk of the new patients with MS compared to the previous National Cholesterol Education Program ATP III definition, its differential characteristics and cardiovascular risk.

PATIENTS AND METHODS

Cross sectional study in a hypertension clinic. Coronary risk was calculated (Framingham function NCEP-ATP III) and other cardiovascular markers, urinary albumin excretion (UAE in mg/24 hours) and high sensitivity C-reactive protein (CRP) were assessed.

RESULTS

A total 2,404 patients were evaluated, 1,901 non-diabetic and 503 diabetic hypertensive subjects. The non-diabetics 726 (38.2%) had MS with the previous NCEP ATP-III definition, the number increasing sharply to 1,091 (57.4%) with the new IDF definition. The proportion did not increase in diabetics (93% vs. 92%). Concordance in the diagnosis was 78% in non-diabetics and 91% in diabetics. The new patients had a similar coronary risk (Framingham) but lower values of other cardiovascular markers: logUAE 1.00 (0.49) mg/24 hours vs. 1.06 (0.55) mg/24 hours (p = 0.003), and CRP 1.9 (2.7) mg/L vs. 2.5 (3.2) mg/L (median, interquartile range; p < 0.001).

CONCLUSIONS

The new IDF definition of MS increases the number of patients with MS. The new patients have a similar coronary risk (Framingham) but the new parameters used to assess cardiovascular risk (UAE and CRP) were lower. The relationship of the new definition of MS and cardiovascular risk remains to be defined.

Determinants of urinary albumin excretion reduction in essential hypertension: A long-term follow-up study

OBJECTIVE

The objective of the present study was to assess factors related to long-term changes in urinary albumin excretion (UAE) of nondiabetic microalbuminuric (n = 252) or proteinuric hypertensive individuals (n = 58) in a prospective follow-up.

METHOD

After enrollment, patients were placed on usual care including nonpharmacological treatment and/or treatment with an antihypertensive drug regime to achieve blood pressure < 135/85 mmHg. Periodic UAE measurements were performed until regression or significant reduction (defined when UAE dropped > 50% from the initial values, plus reduction of UAE to < 30 mg/24 h for microalbuminuric patients and < 300 mg/24 h for proteinuric patients).

RESULTS

Among the microalbuminuric patients, 113 (44.8%) significantly reduced UAE after a mean follow-up of 18 months (range 12-69 months), 20.3/100 patients per year. Among the proteinuric patients, 29 (50%) significantly reduced UAE after a mean follow-up of 25 months (range 12-51 months), 20.2/100 patients per year. The baseline glomerular filtration rate, diastolic blood pressure and fasting glucose during follow-up were independent factors related to the regression or significant reduction in a Cox proportional hazard model. Regression of UAE was independently related to initial estimated glomerular filtration rate < or = 60 ml/min per 1.73 m (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001) and DBP > or = 90 mmHg achieved during the follow-up (hazard ratio, 0.57; 95% confidence interval, 0.38-0.86; P = 0.001), even when adjusted for age, gender, body mass index, fasting glucose, presence of treatment at the beginning of the study and treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers during the follow-up.

CONCLUSIONS

The reduction of urinary albumin excretion was linked to the preserved glomerular filtration rate and to adequate blood pressure control.

Waist circumference and the metabolic syndrome predict the development of elevated albuminuria in non-diabetic subjects: the DESIR Study

OBJECTIVE

Metabolic determinants of microalbuminuria remain poorly understood in non-diabetic individuals and particularly in women. We investigated in both sexes whether an elevated waist circumference (WC) or the presence of the metabolic syndrome (MetS) predict the development of elevated albuminuria at 6 years.

DESIGN AND PATIENTS

We studied 2738 subjects from the DESIR cohort without microalbuminuria or diabetes at baseline and who were followed up for 6 years.

RESULTS

At 6 years, 254 individuals [9.3%; 95% confidence interval (CI) 8.2-10.4%] had developed elevated albuminuria (> or = 20 mg/l), which was significantly and positively associated with WC and blood pressure, but not with fasting glucose, lipids or body mass index in either sex. In both sexes, subjects with a high WC or with MetS at baseline were more likely to develop elevated albuminuria at 6 years compared with those with a normal WC or absence of MetS. In multivariate logistic analysis, WC as a continuous variable or a WC of 94 cm or greater for men and a WC greater than 88 cm for women were predictive of the development of elevated albuminuria, after adjusting for age, hypertension, the use of angiotensin-converting enzyme inhibitors, fibrinogen and glycaemia. MetS was a risk factor for elevated albuminuria in men (odds ratio 1.87; 95% CI 1.25-2.81), with differences according to the MetS definition.

CONCLUSION

Abdominal adiposity is related to the development of elevated albuminuria in both sexes, suggesting that the measurement of WC may improve the identification of non-diabetic individuals at risk of developing microalbuminuria and emphasizing the interest of screening for albuminuria among those with MetS.

Development of microalbuminuria in essential hypertension

During the past few years, microalbuminuria has become a prognostic marker for cardiovascular and/or renal risk in diabetic and nondiabetic subjects. In essential hypertensives, an increased transglomerular passage of albumin may result from several mechanisms--hyperfiltration, glomerular basal membrane abnormalities, endothelial dysfunction, and nephrosclerosis. Cross-sectional studies have demonstrated that the main factors related to microalbuminuria are blood pressure (BP) values and hyperinsulinemia, as an expression of insulin resistance. Genetics, obesity, and smoking, however, have also been implicated as determinants of microalbuminuria in some of the studies. Follow-up studies support the role of BP values and subtle alterations in glucose metabolism, although contributing roles need to be assessed in further studies. It seems that the significance of microalbuminuria in essential hypertension is much broader than expected, and several factors may influence the presence of microalbuminuria. Thus, to reverse microalbuminuria, and to reduce urine albumin excretion and cardiovascular and renal risk, a strategy of multiple approaches may be needed. Whether or not the multiple approaches need to be implemented from the beginning or step by step in an individual approach should be established in the near future.

The Japan Morning Surge-1 (JMS-1) Study: Protocol Description

Morning blood pressure is reported to be more closely related to hypertensive organ damages such as left ventricular mass index, microalbuminuria and silent cerebral infarcts, than blood pressure at other times of the day. Morning blood pressure may play an important role in the pathogenesis of hypertensive target organ damage. Increased sympathetic nerve activity is reported to be one of the mechanisms of morning hypertension; however, there are no available data that show whether strict home blood pressure control, especially in the morning period, can reduce target organ damage. The Japan Morning Surge-1 (JMS-1) study includes hypertensive outpatients with elevated morning systolic blood pressure (>or=135 mmHg) as assessed by self-measured blood pressure monitoring at home. All enrolled patients are under stable antihypertensive medication status. Exclusion criteria are arrhythmia, chronic inflammatory disease, and taking alpha-blockers or beta-blockers. The target number of patients to be enrolled in the JMS-1 study is 600, and the aim is to evaluate differences in the markers of hypertensive target organ damage, such as brain natriuretic peptide and the urinary albumin excretion/creatinine ratio. All of the patients are randomized to an experimental group or a control group, with randomization to be carried out by telephone interviews with the patients' physicians. In the experimental group, patients begin taking additional antihypertensive medication just before going to bed. This consists of doxazosin 1 mg/day, which then is increased to 2 mg/day and 4 mg/day, with a beta-blocker added after a 1-month interval until the morning systolic blood pressure is controlled to less than 135 mmHg. Patients in the control group continue the treatment they are receiving at the enrollment for 6 months. Blood pressure levels, adverse effects, and hypertensive target organ damage before and after the study are evaluated. In the JMS-1 study, we will evaluate whether strict morning blood pressure control by sympathetic nervous system blockade using an alpha-blocker, doxazosin, and with the addition of a beta-blocker if needed, can reduce hypertensive target organ damage.

Brachial-Ankle Pulse Wave Velocity Is an Independent Risk Factor for Microalbuminuria in Patients with Essential Hypertension-A Japanese Trial on the Prognostic Implication of Pulse Wave Velocity (J-TOPP)

Brachial-ankle pulse wave velocity is a new measure of arterial stiffness. The clinical significance of brachial-ankle pulse wave velocity as a measure of early vascular damage remains unclear. We examined the hypothesis that higher brachial-ankle pulse wave velocity is associated with a much greater risk of albuminuria by employing a cohort of 718 never-treated hypertensive patients registered in a prospective study. The 718 patients consisted of 500 patients with normoalbuminuria (69.6%), 191 patients with microalbuminuria (26.6%) and 27 patients with macroalbuminuria (3.8%). The prevalence of microalbuminuria increased with a graded increase in brachial-ankle pulse wave velocity (17.6, 22.8, 28.2 and 39.6%, p < 0.0001). The prevalence of macroalbuminuria remained constant until the third grade group of the brachial-ankle pulse wave velocity but increased significantly in the highest grade group compared with the lower grade groups (2.3, 3.2, 2.3, 9.9%, p < 0.0001). Age, systolic and diastolic blood pressure, pulse pressure, heart rate, and fasting glucose concentration were also significantly increased with an increase in brachial-ankle pulse wave velocity (p < 0.0001 for all). Multiple logistic regression analysis has shown that systolic blood-pressure, fasting blood glucose, and brachial-ankle pulse wave velocity are significant risk factors for microalbuminuria. After adjusting for other risk factors, the odds ratio for an increase of 200 cm/s in brachial-ankle pulse wave velocity was 1.192 (95% confidence interval: 1.022-1.365; p < 0.05). These data suggest that brachial-ankle pulse wave velocity is an independent risk factor for microalbuminuria and could be used as a marker for early vascular damage in never-treated hypertensive patients.