Microalbuminuria is more frequent in South Asian than in European origin populations: a comparative study in Newcastle, UK

Ethnic differences in kidney function in childhood: the Born in Bradford Cohort Renal Study

Background: Endstage kidney failure rates are higher in South Asians than in White Europeans. Low birth weight is associated with adult chronic kidney disease and is more common in South Asians. Foetal kidney size was smaller in South Asians in the Born in Bradford (BiB) birth cohort. As part of BiB follow up, we aimed to investigate if there were ethnic differences in kidney function and blood pressure in early childhood and whether this was different by foetal kidney size. Methods: Serum creatinine, cystatin C, urea, and urinary albumin to creatinine ratio (ACR), protein to creatinine ratio (PCR) and retinol binding protein (RBP) were analysed in blood and urine samples from those who participated in the BiB follow-up at 7-11 years. Ethnicity was categorised by parental self-report as White European and South Asian. Estimated glomerular filtration rate (eGFR) was calculated using Schwartz, and cystatin C Zappitelli and Filler equations. Linear regression was used to examine the association between ethnicity and eGFR, PCR and blood pressure. Results: 1591 children provided blood (n=1403) or urine (n=625) samples. Mean eGFR was 92 ml/min/1.73m 2 (standard deviation (SD) 9) using Schwartz (n=1156) and 94 (SD 11) using Zappitelli (n=1257). CKD prevalence was rare (1 with eGFR <60 ml/min/1.73m 2, 14 (2.4%) had raised ACR (>2.5 mg/mmol in boys/3.5 mg/mmol in girls). Diastolic blood pressure was higher in South Asian children (difference 2.04 mmHg, 95% CI 0.99 to 3.10) but was not significant in adjusted analysis. There was no evidence of association in adjusted models between ethnicity and any eGFR or urinary measure at this age. Conclusions: There was no evidence of significant ethnic differences in kidney function at pre-pubertal age despite differences in kidney volume at birth. Longitudinal follow-up is required to track ethnic patterns in kidney function and blood pressure as children develop through puberty.

Risk Amplifiers for Vascular Disease and CKD in South Asians: When Intrinsic β-Cell Dysfunction Meets a High-Carbohydrate Diet

South Asians, comprising almost one fourth of the world population, are at higher risk of type 2 diabetes mellitus, hypertension, cardiovascular disease, and CKD compared with other ethnic groups. This has major public health implications in South Asia and in other parts of the world to where South Asians have immigrated. The interplay of various modifiable and nonmodifiable risk factors confers this risk. Traditional models of cardiometabolic disease progression and CKD evaluation may not be applicable in this population with a unique genetic predisposition and phenotype. A wider understanding of dietary and lifestyle influences, genetic and metabolic risk factors, and the pitfalls of conventional equations estimating kidney function in this population are required in providing care for kidney diseases. Targeted screening of this population for metabolic and vascular risk factors and individualized management plan for disease management may be necessary. Addressing unhealthy dietary patterns, promoting physical activity, and medication management that adheres to cultural factors are crucial steps to mitigate the risk of cardiovascular disease and CKD in this population. In South Asian countries, a large rural and urban community-based multipronged approach using polypills and community health workers to decrease the incidence of these diseases may be cost-effective.

South Asian ethnicity: What can we do to make this risk enhancer a risk equivalent?

South Asians account for around 25% of the global population and are the fastest-growing ethnicity in the US. This population has an increasing burden of atherosclerotic cardiovascular disease (ASCVD) which is also seen in the diaspora. Current risk prediction equations underestimate this risk and consider the South Asian ethnicity as a risk-enhancer among those with borderline-intermediate risk. In this review, we discuss why the South Asian population is at a higher risk of ASCVD and strategies to mitigate this increased risk.

Diversity in Alzheimer's disease drug trials: The importance of eligibility criteria

INTRODUCTION

To generalize safety and efficacy findings, it is essential that diverse populations are well represented in Alzheimer's disease (AD) drug trials. In this review, we aimed to investigate participant diversity in disease-modifying AD trials over time, and the frequencies of participant eligibility criteria.

METHODS

A systematic review was performed using Medline, Embase, the Cochrane Library, and Clinicaltrials.gov, identifying 2247 records.

RESULTS

In the 101 included AD trials, participants were predominantly White (median percentage: 94.7%, interquartile range: 81.0-96.7%); and this percentage showed no significant increase or decrease over time (2001-2019). Eligibility criteria such as exclusion of persons with psychiatric illness (78.2%), cardiovascular disease (71.3%) and cerebrovascular disease (68.3%), obligated caregiver attendance (80.2%), and specific Mini-Mental State Examination scores (90.1%; no significant increase/decrease over time) may have led to a disproportionate exclusion of ethnoracially diverse individuals.

DISCUSSION

Ethnoracially diverse participants continue to be underrepresented in AD clinical trials. Several recommendations are provided to broaden eligibility criteria.

A study on the status of normoalbuminuric renal insufficiency among type 2 diabetes mellitus patients: A multicenter study based on a Chinese population

BACKGROUND

Patients with normoalbuminuria and a reduced estimated glomerular filtration rate (eGFR) account for a considerable proportion of type 2 diabetes patients. The aim of this research was to investigate the epidemiological and clinical characteristics of normoalbuminuric kidney disease in a Chinese population.

METHODS

We included 8131 diabetic patients from a multicenter prospective study in China. Based on eGFR and urinary albumin-to-creatinine ratio (UACR), participants were stratified into four groups-normal albuminuria, albuminuria, normoalbuminuria with eGFR < 60 mL/min/1.73 m² , and albuminuria with eGFR < 60 mL/min/1.73 m² . Clinical parameters and characteristics of patients with normoalbuminuria and eGFR < 60 mL/min/1.73 m² were retrospectively analyzed.

RESULTS

A total of 1060 out of 8131 individuals with diabetes had decreased eGFR (<60 mL/min/1.73 m² ). Normoalbuminuria accounted for 63.3% of participants with eGFR < 60 mL/min/1.73 m² , and microalbuminuria and macroalbuminuria accounted for 30.1% and 6.3%, respectively. Patients with normoalbuminuria and reduced eGFR were more frequently male, older, and had higher levels of triglycerides than patients with normal albuminuria and eGFR. We also detected a correlation between lower extremity arterial disease, newly diagnosed diabetes, and normoalbuminuria-reduced eGFR. Compared with participants with both albuminuria and eGFR decline, those with normoalbuminuria had better metabolic indicators, including systolic blood pressure and glycosylated hemoglobin, and shorter diabetes duration. Even in the normal range, UACR has a significant correlation with the risk of eGFR insufficiency.

CONCLUSIONS

Normoalbuminuric renal insufficiency, characterized by male sex, older age, a higher level of triglyceride levels, and a higher risk of lower extremity arterial disease, accounted for a dominant proportion of diabetic patients with eGFR decline.

Prevalence of chronic kidney disease in Bangladesh: a systematic review and meta-analysis

BACKGROUND

Worldwide, chronic kidney disease (CKD) is a major public health issue, with a leading cause of death and disability. The aim of our study to estimate the prevalence of CKD in the Bangladeshi population based on existing data of previous studies.

METHODS

In this systematic review and meta-analysis study, electronic search engines of PubMed, Google Scholar, Scopus, and the national journal databases were used to find relevant published articles until December 31, 2019. Based on predefined inclusion/exclusion criteria, nine studies were included, and RevMan V5.0 statistical software was used for meta-analysis.

RESULTS

The outcomes of the included studies (nine studies, a total of 225,206 participants) based on meta-analysis showed an overall prevalence of CKD in Bangladeshi people of 22.48%, which was higher than the global prevalence of CKD. The prevalence of CKD in females was higher with high heterogeneity (I² 90%) in contrast to male participants (25.32% vs. 20.31%).

CONCLUSION

Above all, this study revealed a higher rate of prevalence of CKD in Bangladeshi people. So, it needs more attention to concern public health policymakers and the government to control and reduce the high-risk of disability due to CKD.

Impact of Kidney Function on Cardiovascular Risk and Mortality: A Comparison of South Asian and European Cohorts

BACKGROUND

Evidence is limited on ethnic differences in associations between kidney function markers and mortality or cardiovascular disease (CVD).

METHODS

Baseline cross-sectional analysis and longitudinal follow-up study of a UK population-based cohort of 1,116 Europeans and 1,104 South Asians of predominantly Indian descent, age 52 ± 7 years at baseline (1988-1991). Kidney function was estimated using Cystatin C and creatinine-based chronic kidney disease (CKD) Epidemiology Collaboration estimated glomerular filtration rate (eGFR) equations, and urinary albumin-creatinine ratio (ACR). Mortality was captured at 27 years, and incident CVD at 22 years, from death certification, medical records and participant report. Longitudinal associations between eGFR/ACR and mortality/incident CVD were examined using Cox models.

RESULTS

eGFRcys was lower and ACR higher in South Asians than Europeans. eGFRcys and -eGFRcreat were more strongly associated with outcomes in Europeans than South Asians. Conversely, associations between ACR and outcomes were greater in South Asians than Europeans, for example, for CVD mortality: HRs (95% CI) adjusted for CVD risk factors and ACR/eGFRcys as appropriate, p for ethnicity interaction: eGFRcys: Europeans: 0.76 (0.62-0.92), South Asians: 0.92 (0.78-1.07), p = 0.05, eGFRcreat: Europeans 0.81 (0.67-0.99), South Asians 1.18 (0.97-1.41), p = 0.002, ACR: -Europeans: 1.24 (1.08-1.42), South Asians: 1.39 (1.25-1.57), p= 0.23. Addition of all CKD measures to a standard CVD risk factor model modestly improved prediction capability in -Europeans; in South Asians only ACR contributed to improvement.

CONCLUSIONS

Strong associations between ACR and outcomes in South Asians of predominantly Indian origin, and null associations for eGFRcys and eGFRcreat, suggest that ACR may have greater utility in CVD risk prediction in South Asians. Further work is needed to validate these -findings.

Prevalence and progression of diabetic nephropathy in South Asian, white European and African Caribbean people with type 2 diabetes: A systematic review and meta-analysis

AIMS

To conduct a systematic review and meta-analysis of published observational evidence to assess the difference in the prevalence and progression of diabetic nephropathy, and the development of end-stage renal disease (ESRD) in people from three different ethnic groups with type 2 diabetes (T2DM).

MATERIALS AND METHODS

Relevant studies were identified in a literature search of MEDLINE, EMBASE and reference lists of relevant studies published up to May 2018. We decided a priori that there were no differences in the prevalence and progression of diabetic nephropathy, and the development of ESRD in the three ethnicities with T2DM. Pooled relative risks of microalbuminuria by ethnicity were estimated by fitting three random effects meta-analyses models. A narrative synthesis of the nephropathy progression in the studies was carried out. The review was registered in PROSPERO (CRD42018107350).

RESULTS

Thirty-two studies with data on 153 827 unique participants were eligible for inclusion in the review. The pooled prevalence ratio of microalbuminuria in South Asian compared with white European participants was 1.14 (95% confidence interval [CI] 0.99, 1.32; P = 0.065), while for African Caribbean vs South Asian participants the pooled prevalence ratio was 1.08 (95% CI 0.93, 1.24; P = 0.327). Results for renal decline were inconsistent, with preponderance towards a high rate of disease progression in South Asian compared with white participants. The estimated pooled incidence rate ratio (IRR) for ESRD was significantly higher in African Caribbean vs white European participants: 2.75 (95% CI 2.01, 3.48; P < 0.001).

CONCLUSION

The results of this review did not show a significant link between ethnicity (South Asian, white European and African Caribbean) and the prevalence of microalbuminuria; however, the IRR for ESRD in African Caribbean compared with white European participants was significantly higher. Further research is needed to explore the potential non-albuminuric pathways of progression to ESRD.

Prevalence of chronic kidney disease in South Asia: a systematic review

Background

Chronic kidney disease (CKD) is becoming a major public health problem around the world. But the prevalence has not been reported in South Asian region as a whole. This study aimed to systematically review the existing data from population based studies in this region to bridge this gap.

Methods

Articles published and reported prevalence of CKD according to K/DOQI practice guideline in eight South Asian countries between December 1955 and April 2017 were searched, screened and evaluated from seven electronic databases using the PRISMA checklist. CKD was defined as creatinine clearance (CrCl) or GFR less than 60 ml/min/1.73 m².

Results

Sixteen population-based studies were found from four South Asian countries (India, Bangladesh, Pakistan and Nepal) that used eGFR to measure CKD. No study was available from Sri Lanka, Maldives, Bhutan and Afghanistan. Number of participants ranged from 301 in Pakistan to 12,271 in India. Majority of the studies focused solely on urban population. Different studies used different equations for measuring eGFR. The prevalence of CKD ranged from 10.6% in Nepal to 23.3% in Pakistan using MDRD equation. This prevalence was higher among older age group people. Equal number of studies reported high prevalence among male and female each.

Conclusions

This systematic review reported high prevalence of CKD in South Asian countries. The findings of this study will help pertinent stakeholders to prepare suitable policy and effective public health intervention in order to reduce the burden of this deadly disease in the most densely populated share of the globe.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1072-5) contains supplementary material, which is available to authorized users.

Predictors of diastolic dysfunction in ethnic groups: observations from the Hypertensive Cohort of The Ethnic-Echocardiographic Heart of England Screening Study (E-ECHOES)

The study aimed to establish a relationship of ethnicity to diastolic dysfunction in subjects of African-Caribbean and South Asian origins and the impact of diastolic dysfunction and ethnicity on all-cause and cardiovascular mortality.

Hypertensive subjects with ejection fraction ≥55% and no history of ischemic heart disease/valve pathology (n=1546, 830 South Asians and 716 African-Caribbeans) were identified from the Ethnic - Echocardiographic Heart of England Screening Study (E-ECHOES). Diastolic function and cardiac remodelling were measured by echocardiography.

African-Caribbean ethnicity was associated with lower prevalence of having diastolic dysfunction (odds ratio 0.67, 95% confidence interval 0.51-0.87, p=0.003) and increased left ventricular filling pressure (odds ratio 0.48, 95% confidence interval 0.34-0.69, p<0.001) as well as lower left atrial index (p<0.001). This was the case despite the fact that African-Caribbean ethnicity was independently associated with higher left ventricular mass index (p<0.001). Ninety-two deaths (6%) occurred during 68±21 months follow up. On Cox regression analysis, South Asian ethnicity (p=0.024) was predictive of all-cause death before adjustment for parameters of diastolic dysfunction, but it was no longer predictive of death after accounting for these variables.

South Asian ethnicity is independently associated with worse parameters of diastolic function in hypertension, despite African-Caribbeans having more prominent hypertrophy.

Validity and reliability of the Urdu version of the 5D itching scale to assess pruritus among patients with chronic kidney disease in Pakistan

Background

Chronic kidney disease (CKD) has become a major public health issue worldwide in the past few years. Pruritus is a common, well-recognized complication often seen in patients with chronic renal failure. For assessment of pruritus, different tools are used but these tools are unable to identify the changes and variations in the severity of pruritus. The aim of our study was to validate the Urdu-version of the Urdu-version of the 5D itch scale among patients suffering from chronic kidney disease in Pakistan.

Method

The 5D itch scale was translated from English into Urdu following translation guidelines for translation. Face and content validity was determined by a panel of experts and piloted. For retest, the Urdu version of the 5D itch scale was administered at baseline and two weeks.

Results

A total of 50 participants with end stage renal disease were recruited, and of these, 64% were males. Exploratory factor analysis revealed that the 5D–IS had 2-factor loadings: “Pattern and activity” and “Distribution” with Kaiser–Mayer–Olkin (KMO) = 0.802, Bartlett’s test of sphericity was significant (df = 28, p < 0.001). At test re-test, Cronbach’s alpha was 0.914, while the intra class correlation was 0.9160 (95% confidence interval 0.941–0.975), which is a highly significant correlation (p < 0.0001).

Conclusion

The Urdu version of the 5D itch scale was found to be a valid and reliable instrument for assessing pruritus and its severity in patients with chronic kidney disease in Pakistan.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0717-0) contains supplementary material, which is available to authorized users.

Association Between Obesity and Chronic Kidney Disease, Defined by Both Glomerular Filtration Rate and Albuminuria, in Korean Adults

BACKGROUND

Chronic kidney disease (CKD) has often been defined based on glomerular filtration rate (GFR) alone. The Kidney Disease: Improving Global Outcomes guideline highlights albuminuria in the CKD definition. Thus, we investigated the association between obesity and CKD, as defined by both GFR and albuminuria, in Korean adults.

METHODS

We used Korea National Health and Nutrition Examination Survey 2011-2014 data (N = 19,331, ≥19 years old) representing the national Korean population. CKD was classified by (1) estimated GFR (eGFR) < 60 mL/min/1.73 m² (CKD_GFR); (2) albumin-to-creatinine ratio (ACR) ≥30 mg/gram (CKD_ACR); and (3) eGFR < 60 mL/min/1.73 m² or ACR ≥30 mg/gram (CKD_Risk). Associations between obesity and each CKD category were evaluated using multivariate logistic regression analysis.

RESULTS

The prevalence rates of CKD_GFR, CKD_ACR, and CKD_Risk were 2.2%, 6.7%, and 8.1%, respectively. Compared with the normal body mass index (BMI; 18.5-22.9 kg/m²) group, men with BMI ≥ 25 kg/m² had 1.88 times greater risk of CKD_GFR in the adjusted model [95% confidence interval (CI), 1.26-2.80; P = 0.002]; BMI was not significantly associated with CKD_GFR in women. In contrast, both men and women with BMI ≥ 25 kg/m² had 1.58 and 1.40 times higher risk of CKD_ACR (95% CI, 1.21-2.07 and 1.08-1.81, respectively, both P < 0.01). Obese men and women had 1.65 and 1.38 times higher risk of CKD_Risk (95% CI, 1.29-2.12 and 1.09-1.75, respectively, both P < 0.01).

CONCLUSIONS

Obesity was significantly associated with an increased ACR-based CKD risk. Longitudinal studies are needed to investigate the role of overweight and obesity in the development and progression of CKD.

Low Rice Intake Is Associated with Proteinuria in Participants of Korea National Health and Nutrition Examination Survey

Little is known about the risk factors of proteinuria in the Asian population. On the basis of the association between rice intake patterns and chronic diseases, we hypothesized that rice intake patterns are associated with proteinuria in the Asian population. Data, including data regarding rice intake frequency and dipstick urinalysis results, from the Korea National Health and Nutrition Examination Survey in 1998, 2001, 2005, and 2007 were analyzed. The study involved 19,824 participants who were older than 20 years of age. Low rice intake was defined as consumption of rice ≤ 1 time/day. Proteinuria was defined as dipstick urinalysis protein ≥ 1 positive. Among the 19,824 participants, the prevalence of low rice intake and proteinuria were 17.3% and 2.9%, respectively. The low rice intake group showed a higher rate of proteinuria than the non-low rice intake group did (3.8% vs. 2.7%, P < 0.001). In multivariate logistic regression analysis, the odds ratio (OR) of low rice intake for proteinuria was 1.54 (95% confidence interval (CI): 1.25-1.89; P < 0.001). Low rice intake was also independently associated with high blood pressure (OR: 1.43, 95% CI: 1.31-1.56; P < 0.001) and diabetes (OR: 1.43, 95% CI: 1.27-1.62; P < 0.001). In conclusion, low rice intake was found to be independently associated with proteinuria in the Asian population, which might have been affected by the associations of low rice intake with high blood pressure and diabetes. Future prospective studies are needed to confirm the results of this study.

Review: Diabetes and cardiac disease in South Asians

South Asians have a higher prevalence of diabetes, coronary heart disease and cardiovascular death. Their predisposition to insulin resistance partly explains this excess risk. After immigration, the adoption of a western diet allied to increased sedentary behaviour leads to weight gain, hypertension and hyperlipidaemia, factors which in turn combine to amplify the chances of getting heart disease. Further contributory factors are increased sub-clinical inflammation, increased thrombogenic tendency and higher serum homocysteine levels. South Asians with diabetes might do as well as White people with respect to intensive glycaemic and blood pressure control. However, there is little evidence for measures to reduce cardiovascular risk as South Asians have not been included as a subgroup in most large trials. Future prospective studies, including studies on the prevention of diabetes and cardiovascular disease in this high-risk population, are therefore urgently required.

Hypertension, diabetes and cardiovascular risk in ethnic minorities in the UK

Mortality from coronary heart disease (CHD), stroke and end-stage renal failure (ESRF) is high in South Asian (Indo-Asian) migrants in the UK. This is associated with a high prevalence of diabetes and hypertension.

Mortality from stroke and ESRF is also high in migrants to the UK of black African origin. However, CHD mortality is low in this group. This pattern of mortality is also associated with a high prevalence of hypertension and diabetes.

Conventional risk factors, such as cigarette smoking and hypercholesterolaemia, are less prevalent in ethnic minority populations in the UK and unlikely to explain the differences seen between groups, although each risk factor is likely to contribute to the variation in vascular disease within each group.

Smaller kidney size at birth in South Asians: findings from the Born in Bradford birth cohort study

BACKGROUND

Rates of advanced chronic kidney disease and renal replacement therapy are higher in South Asian than in white British populations. Low birth weight is also more frequent in South Asian populations and has been associated with increased risks of kidney disease, perhaps due to a reduced nephron endowment.

METHODS

Using ultrasound scans at 34 weeks of gestation, we measured fetal kidney dimensions (transverse and anteroposterior diameters, length and circumference) and derived volume in a random sample of 872 white British and 715 South Asian participants in the Born in Bradford cohort study. Kidney measurements were compared between ethnic groups.

RESULTS

Birth weight for gestational age at 40 weeks was 200 g less in South Asian babies compared with white British babies. The mean kidney volume for gestational age was 16% lower in South Asian than in white British babies [8.79 versus 10.45 cm(3), difference 1.66 cm(3) (95% confidence interval 1.40-1.93, P < 0.001)]. The difference was robust after adjustment for maternal age, socio-economic factors, marital status, body mass index, smoking and alcohol use in pregnancy, parity, baby's gender and birth weight for gestational age [adjusted difference 1.38 cm(3) (0.97-1.84), P < 0.001]. There were smaller reductions in other fetal measures.

CONCLUSION

South Asian babies have smaller kidneys compared with white British babies, even after adjusting for potential confounders including birth weight. This finding may contribute to increased risks of adult kidney disease in South Asian populations.

South Asian Ethnicity and Cardiovascular Risk

South Asians (SAs), in their countries or after migration, are at high risk of coronary artery disease (CAD) and mortality compared to other ethnic groups. It has been shown that >90% of CAD global risk could be attributed to 9 modifiable risk factors (RFs) worldwide. However, these conventional RFs may not fully explain this high risk of CAD among SAs. Therefore, attention has been directed toward nonconventional RFs. In this narrative review, we evaluate the conventional and emerging cardiovascular RFs characterizing SAs. These factors may explain the high morbidity and mortality among SAs. Further prospective studies are urgently needed to set algorithms for the optimal management of these RFs in high-risk populations like SAs.

Prevalence, determinants, and management of chronic kidney disease in Karachi, Pakistan - a community based cross-sectional study

BACKGROUND

Chronic kidney disease (CKD) is increasing being recognized as a global public health problem. However, there is dearth of information on the prevalence, determinants, and management of CKD from low- and middle-income countries. The objectives of the study were to determine the 1) prevalence of CKD; 2) socio-demographic and clinical factors associated with CKD; and 3) the existing management of these patients with regards to blood pressure control, and use of antihypertensive medications.

METHODS

We conducted a cross-sectional study on 2873 participants aged ≥ 40 years in 12 representative communities in Karachi, Pakistan. The primary outcome was clinically significant CKD defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 estimated by CKD-EPI (CKD Epidemiology Collaboration) Pakistan equation (0.686 × CKD-EPI1.059) or urinary albumin to creatinine ratio ≥ 3 mg/mmol (i.e. KDOQI CKD stage G3, A2 or worse).

RESULTS

The overall prevalence (95% CI) of CKD was 12.5% (11.4 - 13.8%). The factors independently associated with CKD were older age, hypertension, diabetes, elevated systolic blood pressure, raised fasting plasma glucose, raised triglycerides, and history of stroke (p<0.05 for each). About 267 (74.4%, 69.5 - 78.8%) adults with CKD had concomitant hypertension. Of these, 130 (48.7%, 42.6 - 54.9%) were on antihypertensive medications, and less than 20% had their BP controlled to conventional target of ≤ 140/90 mm Hg, and only 16.9% (12.6 - 21.9%) were on blockers of renin-angiotensin system alone or in combination with other drugs.

CONCLUSIONS

Clinically significant CKD is common among Pakistani adults. The conventional risk factors for CKD and poor control of blood pressure among patients with CKD highlight the need to integrate CKD prevention and management in the primary care infrastructure in Pakistan, and possibly neighbouring countries.

Microcirculatory rarefaction in South Asians - a potential mechanism for increased cardiovascular risk and diabetes

People of South Asian descent have an increased risk of cardiovascular disease (CVD) and diabetes, but little is known about the microcirculation in South Asian people despite evidence that this plays an important role in the aetiology of CVD. We compared the retinal microcirculation in a population-based sample of 287 middle-aged adults (144 European 143 South Asian) matched for age and sex. Retinal photographs were taken and analysed using a validated semi-automated program and microvascular measures were compared. Blood pressure, anthropometry and fasting bloods were also measured. South Asians had significantly fewer arteriolar and venular vessels and bifurcations. Arterioles and venules were longer and venules were also more tortuous in South Asians. These differences were not explained by adjustment for traditional risk factors including blood pressure, body mass index, diabetes or measures of insulin resistance. People of South Asian descent have rarefaction of the retinal microcirculation compared to age-sex matched individuals of European descent. Reduced microvascular density could contribute to the elevated risk of CVD and impaired glucose tolerance in South Asian people.

Smoking and risk of kidney failure in the Singapore Chinese health study

Background

The relationship between smoking and risk of kidney failure, especially in people of Chinese origin, is not clear. We analyzed data from the Singapore Chinese Health Study to investigate whether smoking increases the risk of kidney failure.

Methods

The Singapore Chinese Health Study is a population-based cohort of 63,257 Chinese adults enrolled between 1993 and 1998. Information on smoking status was collected at baseline. Incidence of kidney failure was identified via record linkage with the nationwide Singapore Renal Registry until 2008. Kidney failure was defined by one of the following: 1) serum creatinine level of more than or equal to 500 µmol/l (5.7 mg/dl), 2) estimated glomerular filtration rate of less than 15 ml/min/1.73 m², 3) undergoing hemodialysis or peritoneal dialysis, 4) undergone kidney transplantation. Cox proportional hazard regression analysis was performed for the outcome of kidney failure after adjusting for age, education, dialect, herbal medications, body mass index, sex, physician-diagnosed hypertension and diabetes mellitus.

Results

The mean age of subjects was 55.6 years at baseline, and 44% were men. Overall 30.6% were ever smokers (current or former) at baseline. A total of 674 incident cases of kidney failure occurred during a median follow-up of 13.3 years. Among men, smokers had a significant increase in the adjusted risk of kidney failure [hazard ratio (HR): 1.29; 95% CI: 1.02–1.64] compared to never smokers. There was a strong dose-dependent association between number of years of smoking and kidney failure, (p for trend = 0.011). The risk decreased with prolonged cessation (quitting ≥10 years since baseline). The number of women smokers was too few for conclusive relationship.

Limitation

Information on baseline kidney function was not available.

Conclusions

Cigarette smoking is associated with increased risk of kidney failure among Chinese men. The risk appears to be dose- and duration-dependent and modifiable after long duration of cessation.

Ethnic differences in the association between waist-to-height ratio and albumin-creatinine ratio: the observational SUNSET study

BACKGROUND

Ethnic differences in the association between central obesity and raised albumin-creatinine ratio (ACR) have not been investigated. Our aim was to determine whether the association between central obesity, defined by the waist-to-height ratio (WHtR), and ACR differed between subjects of Hindustani-Surinamese, African-Surinamese and Dutch origin.

METHODS

In total, 334 Hindustani-Surinamese (~South Asian), 589 African-Surinamese (~African), and 493 Dutch (~European) men and women, aged 35-60 years, randomly selected from the municipal register of Amsterdam, participated in an interview and physical examination.We calculated the WHtR by dividing the waist circumference by height and the log ACR (logACR, log mg/mmol) by log-transforming the albumin concentration by the creatinine concentration in urine. The association between WHtR and logACR was studied in the total population and stratified by ethnicity. We also tested for interaction.

RESULTS

In the total population, a higher WHtR was associated with a higher logACR, after adjustment for sex, age, and smoking, body mass index and the presence of type 2 diabetes or hypertension. Among the Hindustani-Surinamese, the adjusted association between WHtR and logACR appeared somewhat stronger than among the other ethnic groups: for every 0.1 increase in the WHtR, the log-ACR increased by 0.522 (0.096-0.949) log mg/mmol among the Hindustani-Surinamese, by 0.334 (0.047-0.622) among the African-Surinamese and by 0.356 (-0.010-0.721) among the Dutch. However, the interaction was not statistically significant.

CONCLUSIONS

WHtR was associated with a higher ACR among populations of Hindustani-Surinamese, African-Surinamese and Dutch origin. Our study seems to support global use of WHtR in relation to ACR across ethnic groups. However, although not significant, the association appeared slightly stronger among the Hindustani-Surinamese than among the other ethnic groups. If confirmed, this could have implications for use of the WHtR across ethnic groups.

Systolic heart failure in South Asians

Heart failure (HF) is a common condition leading to an unfavourable prognosis and impaired quality of life. In this review, we provide an overview of published literature on possible epidemiological and pathophysiological differences between patients with systolic HF of South Asian origin and those from other ethnic groups (mainly White). Systolic HF tends to manifest earlier among South Asians and with frequent hospital admissions. However, survival for such patients appears to be significantly better compared with the White group, which might be associated with different patterns of HF. For example, this could be attributed to a lower prevalence of left ventricular systolic dysfunction in South Asian subjects. Indeed, the high prevalence of hypertension and diabetes among South Asians may predispose to diastolic HF with preserved systolic function. In addition, because of underrepresentation of South Asians in clinical trials, there are little data on optimal management of this ethnic group.

Impaired post-ischaemic microvascular hyperaemia in Indian Asians is unexplained by diabetes or other cardiovascular risk factors

OBJECTIVE

People of Indian Asian descent have an increased risk of cardiovascular disease (CVD) that cannot be explained by diabetes and other established CVD risk factors. We investigated if microcirculatory function was impaired in a population-based sample of people of Indian Asian descent compared with Europeans in the UK and whether any differences could be accounted for by diabetes or other CVD risk factors.

RESEARCH DESIGN AND METHODS

Cutaneous microvascular function was assessed using laser Doppler fluximetry in response to heating to 42 °C (maximum hyperaemia) and 3 min arterial occlusion (post occlusive reactive hyperaemia: PORH) in 148 Indian Asians and 147 Europeans. Blood pressure, anthropometry and fasting bloods were also measured.

RESULTS

Maximum hyperaemia and minimum resistance did not differ significantly by ethnicity. Resting flux and PORH were lower in Indian Asians and time to peak of PORH was prolonged. Diabetes was associated with reduced maximum hyperaemia and PORH. Adjustment for diabetes accounted for differences in resting flux and time to peak but not differences in PORH (Europeans = 45.0 (40.3, 50.1)au, Indian Asians = 35.6 (31.9, 39.7)au, mean (95% confidence interval); p = 0.008 after adjustment). Differences in conventional CVD risk factors did not account for interethnic differences in microvascular responses.

CONCLUSIONS

People of Indian Asian descent have impaired post-occlusive reactive hyperaemia unexplained by diabetes, dysglycaemia or other CVD risk factors. Abnormal microvascular function in response to ischaemia could represent a novel mechanism contributing to the elevated risk of CVD in Indian Asians.

Association between GFR, proteinuria, and adverse outcomes among White, Chinese, and South Asian individuals in Canada

BACKGROUND

We investigated the association between proteinuria, estimated glomerular filtration rate (eGFR), and risk of mortality and kidney failure in white, Chinese, and South Asian populations.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

Participants from Alberta, Canada, with a serum creatinine and urine protein dipstick measurement from January 1, 2005, to December 31, 2005.

PREDICTOR

White, Chinese, or South Asian ethnicity.

OUTCOMES

Prevalence of proteinuria by level of eGFR (estimated using the MDRD [Modification of Diet in Renal Disease] Study equation) and the association between eGFR, proteinuria, and all-cause mortality and kidney failure.

MEASUREMENTS

Rates of all-cause mortality and kidney failure per 1,000 person-years were calculated using Poisson regression by ethnicity, eGFR level, and proteinuria level while adjusting for sociodemographic variables and comorbid conditions.

RESULTS

Of 491,729 participants, 5.3% were Chinese and 4.7% were South Asian. For participants with eGFR <60 mL/min/1.73 m(2), the prevalence of heavy proteinuria was higher in Chinese and South Asians compared with whites. Compared with whites, adjusted rates of death were significantly lower for Chinese and South Asian populations (rate ratios, 0.67 [95% CI, 0.56-0.80] and 0.73 [95% CI, 0.59-0.88], respectively); these rate ratios did not vary by eGFR and proteinuria levels.

LIMITATIONS

Using surname to identify ethnicity has the potential for misclassification due to name changes and identical last names from different ethnic groups. Also, to be eligible for inclusion, participants had to have a measurement of serum creatinine and urine dipstick proteinuria.

CONCLUSIONS

Although increasing proteinuria and lower eGFR predicted mortality and progression to kidney failure in all 3 ethnic groups, both Chinese and South Asian populations experienced a lower risk of death and similar risk of kidney failure compared with whites at all eGFR and proteinuria levels. Studies exploring this association further are required.

Comparative risk of microalbuminuria and proteinuria in UK residents of south Asian and white European ethnic background with type 2 diabetes: a report from UKADS

OBJECTIVE

This study investigated and compared the prevalence of microalbuminuria and overt proteinuria and their determinants in a cohort of UK resident patients of white European or south Asian ethnicity with type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS

A total of 1978 patients, comprising 1486 of south Asian and 492 of white European ethnicity, in 25 general practices in Coventry and Birmingham inner city areas in England were studied in a cross-sectional study. Demographic and risk factor data were collected and presence of microalbuminuria and overt proteinuria assessed.

TRIAL REGISTRATION NUMBER

ISRCTN 38297969.

MAIN OUTCOME MEASURES

Prevalences of microalbuminuria and overt proteinuria.

RESULTS

Urinary albumin:creatinine measurements were available for 1852 (94%) patients. The south Asian group had a lower prevalence of microalbuminuria, 19% vs. 23% and a higher prevalence of overt proteinuria, 8% vs. 3%, χ(2) = 15.85, 2df, P = 0.0004. In multiple logistic regression models, adjusted for confounding factors, significantly increased risk for the south Asian vs. white European patients for overt proteinuria was shown; OR (95% CI) 2.17 (1.05, 4.49), P = 0.0365. For microalbuminuria, an interaction effect for ethnicity and duration of diabetes suggested that risk for south Asian patients was lower in early years following diagnosis; OR for SA vs. WH at durations 0 and 1 year were 0.56 (0.37, 0.86) and 0.59 (0.39, 0.89) respectively. After 20 years' duration, OR = 1.40 (0.63, 3.08).

LIMITATIONS

Comparability of ethnicity defined groups; statistical methods controlled for differences between groups, but residual confounding may remain. Analyses are based on a single measure of albumin:creatinine ratio.

CONCLUSIONS

There were significant differences between ethnicity groups in risk factor profiles and microalbuminuria and overt proteinuria outcomes. Whilst south Asian patients had no excess risk of microalbuminuria, the risk of overt proteinuria was elevated significantly, which might be explained by faster progression of renal dysfunction in patients of south Asian ethnicity.

Which factors are associated with higher rates of chronic kidney disease recording in primary care? A cross-sectional survey of GP practices

The prevalence of chronic kidney disease (CKD) at stage 3-5 is estimated at 8.5% in the UK, but the recorded rate of CKD from Quality and Outcomes Framework (QOF) registers in 2007-2008 was 2.9%. This study aimed to identify practice or patient characteristics associated with recorded rates of CKD. Demographic and QOF data for 230 general practices were combined into a database for cross-sectional analysis. Regression analyses investigated factors associated with CKD recording; deprivation, location in Leicester city or Northamptonshire, and low recording of hypertension and stroke were associated with low CKD recording.

Salt sensitivity, insulin resistance, and public health in India

OBJECTIVE

To provide a current overview of the worldwide prevalence and pattern of cardiovascular disease and discuss the role of sodium intake and salt sensitivity, with a focus on the Asian Indian population.

METHODS

An extensive search of the literature from PubMed and the Cochrane Library was undertaken. Moreover, the pathophysiologic basis of the relationship between sodium intake and insulin sensitivity in various populations was reviewed.

RESULTS

High blood pressure is the most common cause of cardiovascular disease and mortality globally. Although salt sensitivity is a frequent determinant of hypertension, a strong link between salt sensitivity and cardiovascular disease associated with insulin resistance has not received adequate attention. This may be particularly relevant to the public health challenges of increasing prevalences of obesity, diabetes, and cardiometabolic syndrome in India where, according to recent estimates, approximately 60% of the world's cases of cardiovascular disease occur and the salt consumption is among the highest in any large population.

CONCLUSION

There is evidence for a strong link between increased salt sensitivity and insulin resistance leading to metabolic syndrome and cardiovascular disease. This relationship may be particularly relevant to the escalating epidemic of cardiovascular disease in the southern Asian Indian population. A broad-based community action to achieve at least a modest restriction of salt intake can yield important health benefits and is urgently needed.

South Asian ethnicity as a risk factor for major adverse cardiovascular events after renal transplantation

BACKGROUND AND OBJECTIVES

South Asians (SAs) comprise 25% of all Canadian visible minorities. SAs constitute a group at high risk for cardiovascular disease in the general population, but the risk in SA kidney transplant recipients has never been studied.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cohort study of 864 kidney recipients transplanted from 1998 to 2007 and followed to June 2009, we identified risk factors including ethnicity associated with major cardiac events (MACEs, a composite of nonfatal myocardial infarction, coronary intervention, and cardiac death) within and beyond 3 months after transplant. Kaplan-Meier methodology and multivariate Cox regression analysis were used to determine risk factors for MACEs.

RESULTS

There was no difference among SAs (n = 139), whites (n = 550), blacks (n = 65), or East Asians (n = 110) in baseline risk, including pre-existing cardiac disease. Post-transplant MACE rate in SAs was 4.4/100 patient-years compared with 1.31, 1.16, and 1.61/100 patient-years in whites, blacks, and East Asians, respectively (P < 0.0001 versus each). SA ethnicity independently predicted MACEs along with age, male gender, diabetes, systolic BP, and prior cardiac disease. SAs also experienced more MACEs within 3 months after transplant compared with whites (P < 0.0001), blacks (P = 0.04), and East Asians (P = 0.006). However, graft and patient survival was similar to other groups.

CONCLUSIONS

SA ethnicity is an independent risk factor for post-transplant cardiac events. Further study of this high-risk group is warranted.

Screening for type 2 diabetes in a multiethnic setting using known risk factors to identify those at high risk: a cross-sectional study

Introduction

Screening enables the identification of type 2 diabetes mellitus (T2DM) during its asymptomatic stage and therefore allows early intervention which may lead to fewer complications and improve outcomes. A targeted screening program was carried out in a United Kingdom (UK) multiethnic population to identify those with abnormal glucose tolerance.

Methods

A sample of individuals aged 25–75 years (40–75 white European) with at least one risk factor for T2DM were invited for screening from 17 Leicestershire (UK) general practices or through a health awareness campaign. All participants received a 75 g oral glucose tolerance test, cardiovascular risk assessment, detailed medical and family histories and anthropometric measurements.

Results

In the 3,225 participants who were screened. 640 (20%) were found to have some form of abnormal glucose tolerance of whom 4% had T2DM, 3% impaired fasting glucose (IFG), 10% impaired glucose tolerance (IGT) and 3% both IFG and IGT. The odds of detecting IGT was approximately 60% greater (confounder-adjusted odds ratios [OR] 1.67 [1.22–2.29]) in the South Asian population.

Conclusions

Around one in five people who had targeted screening have IGT, IFG or T2DM, with a higher prevalence in those of South Asian origin. The prevalence of undetected T2DM is lower in South Asians compared to previously published studies and maybe due to increased awareness of this group being at high risk.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Prevalence and risk factors of microalbuminuria in Thai nondiabetic hypertensive patients

PURPOSE

To assess the prevalence and risk factors of microalbuminuria in nondiabetic hypertensive patients in Thailand.

PATIENTS AND METHODS

A cross-sectional study was performed during January to December 2007 at outpatients departments of Bhumibol Adulyadej hospital. Nondiabetic hypertensive patients without a history of pre-existing kidney diseases participated in this study. A questionnaire was used for collecting information on demographics, lifestyle, and family history of cardiovascular and kidney disease. Spot morning urine samples were collected for albuminuria estimation. Albuminuria thresholds were evaluated and defined using albumin-creatinine ratio (ACR).

RESULTS

A total of 559 hypertensive patients (283 males, 276 females), aged 58.0 +/- 11.6 years were enrolled in this study. Microalbuminuria (ACR 17 to 299 mg/g in males and 25 to 299 mg/g in females) was found in 93 cases (16.6%) [15.0%-18.2%]. The independent determinants of elevated urinary albumin excretion in a multiple logistic regression model were; body mass index > or =30 (odds ratio (OR) = 2.24, 95% confidence intervals (CI): 1.33-3.76) and dihydropyridine calcium channel blockers (DCCB) use (OR = 1.92, 95% CI: 1.22-3.02).

CONCLUSION

In Thai nondiabetic hypertensive patients, microalbuminuria was not uncommon. Obesity and use of dihydropyridine calcium channel blocker were found to be the important predictors. Prognostic value of the occurrence of microalbuminuria in this population remains to be determined in prospective cohort studies.

Prevalence of microalbuminuria among patients with type 2 diabetes mellitus--a hospital-based study from north India

BACKGROUND

Asian ethnicity is said to be a risk factor for microalbuminuria. Prevalence studies in native Asians, especially Indians, are scarce. The aim was to study the prevalence of microalbuminuria in patients with type 2 diabetes mellitus and to identify the associated risk factors.

METHODS

Eight hundred consecutive patients attending the endocrine outpatient clinic were screened. Six hundred seventy patients were eligible for microalbuminuria screening. Urinalysis was done in a random spot urine sample using dipsticks. History, physical examination, and metabolic data were recorded.

RESULTS

The mean age and body mass index of the study population were 52.13 +/- 9.9 years and 26.19 +/- 4.34 kg/m(2), respectively. The median duration of diabetes was 5 years. Microalbuminuria was found in 25.5% (95% confidence interval, 22.4-29%) and macroproteinuria in 16.2% (95% confidence interval, 13.5-19.1%). In patients with duration of diabetes less than 1 year, the prevalence of microalbuminuria was 24.7%, and that of macroproteinuria was 6.2%. The risk factors associated with microalbuminuria and macroproteinuria were glycated hemoglobin, retinopathy, and calcium channel blocker intake. However, waist circumference was negatively associated with macroproteinuria but not with microalbuminuria. This difference in the risk factors supports the newer concept that microalbuminuria and diabetic nephropathy are pathophysiologically different and may not be inextricably linked.

CONCLUSIONS

The high proportion of patients who present with albuminuria within the first year of diagnosis probably indicates longer duration of prior undiagnosed diabetes. Screening for asymptomatic diabetes and defining newer risk factors to identify those at risk for complications are essential to reduce the socioeconomic burden of diabetes.

Attenuation of microvascular function in those with cardiovascular disease is similar in patients of Indian Asian and European descent

Background

Indian Asians are at increased risk of cardiovascular death which does not appear to be explained by conventional risk factors. As microvascular disease is also more prevalent in Indian Asians, and as it is thought to play a role in the development of macrovascular disease, we decided to determine whether impaired microcirculation could contribute to this increased cardiovascular risk in Indian Asians.

Methods

Forearm skin laser Doppler fluximetry in response to heating and ischaemia was assessed in 83 Europeans (41 with angiographically confirmed atherosclerotic coronary artery disease (CAD) and 42 from the general population) and 84 Indian Asians (41 with CAD). Explanations for differences in microvascular function were sought using multivariate analysis including conventional cardiovascular risk factors.

Results

Compared to ethnically matched control populations both Europeans and Indian Asians with CAD had poorer microvascular responses to heating than those without (117(95% CI 105-131) vs. 142(130-162) arbitrary units, (au) for Europeans and 111(101-122) vs. 141(131-153)au for Indian Asians) and to ischaemia (44(38-50) vs. 57(49-67)au & 39(34-45) vs. 49(43-56)au respectively). These differences were not accounted for by conventional cardiovascular risk factors. There was no ethnic difference in the attenuation of microvascular function associated with CAD.

Conclusion

Patients of European and Indian Asian descent with symptomatic CAD have poorer microvascular maximal tissue perfusion and reactive hyperaemia in the skin compared to ethnically matched asymptomatic control populations. Despite the increased cardiovascular risk in Indian Asians, the attenuation of microvascular function associated with CAD was equivalent in the ethic groups. This suggests that in Indian Asians microcirculation does not explain the increased susceptibility to CAD.

Prevalence of microalbuminuria and associated electrocardiographic abnormalities in an Indo-Asian population

BACKGROUND

Microalbuminuria (MA) is a known predictor of cardiovascular disease (CVD) in European origin populations, but such data are lacking in native Indo-Asian populations, where CVD risks are high. Major electrocardiographic (ECG) changes are predictive of cardiovascular mortality. We determined the association of MA with major ECG changes in the general population of Pakistan.

METHODS

A total of 3143 subjects aged >or=40 years from 12 randomly selected communities in Karachi participated. MA was defined as the urine albumin to creatinine (ACR) ratio of < 300 mg/g creatinine and >or=17 mg/g in men and >or=25 mg/g in women from a single-spot morning urine sample. Major changes on ECG were coded in duplicate using Minnesota classification.

RESULTS

The mean age of subjects was 51.5 (10.7) years. The median (25-75 percentile) ACR was 4.2 (2.9-7.9) mg/g in men and 6.0 (3.9-10.8) mg/g in women (P < 0.001). The overall prevalence (95% CI) of MA was 12.3% (11.1-13.5%), and 20.3% in those with major ECG changes. In a multivariable model, major ECG changes (OR, 95% CI) (1.50, 1.10-2.00), diabetes (3.57, 2.93-4.35), hypertension (2.30, 1.85-2.86), female sex (0.61, 0.53-0.69), age (1.09, 1.05-1.13, for each 5-year increase) and eGFR (0.80, 0.78-0.81, for each 10 mg/g increase) were independently associated with MA. The presence of MA increased the prevalence of major ECG changes from 21 to 31% in those with hypertension (44.9%), 15 to 28% among those with diabetes (21.4%), 14 to 26% among those with overweight or obesity (68.4%) and 14 to 26% among current users of tobacco (38.7%) (P < 0.001) each.

CONCLUSIONS

The strong association between MA and major ECG changes underscores the importance of screening Indo-Asian subjects for MA for unmasking underlying CVD, especially those with hypertension, diabetes, obesity, and tobacco users.

Microalbuminuria in nondiabetic and nonhypertensive systolic heart failure patients

The American Diabetes Association and the National Kidney Foundation define microalbuminuria as an albumin (microg)/creatinine (mg) ratio (ACR) between 30 and 300 microg/mg regardless of sex. Microalbuminuria is associated with increased cardiovascular risk. The authors evaluated the prevalence of microalbuminuria in nondiabetic and nonhypertensive systolic heart failure (SHF) patients. Twenty-seven SHF patients, 18 years and older, with New York Heart Association functional classes II through IV and left ventricular ejection fraction < or =40%, who were nondiabetic and nonhypertensive and not receiving angiotensin-converting enzyme inhibitors, were selected. Twenty-seven healthy individuals, paired according to sex, ethnicity, and age, were used as controls. Early-morning midstream urine was used. Data are expressed as medians. Excretion of albumin in SHF patients (39 microg/mL urine) was significantly higher than in controls (26 microg/mL urine). Creatinine excretion was not significantly different between patients and controls. ACR was significantly higher in patients (54 microg/mg) than in controls (24 microg/mg). The results indicate that microalbuminuria was significantly present in nondiabetic and nonhypertensive SHF patients.

Prevalence of albuminuria and cardiovascular risk profile in a referred cohort of patients with type 2 diabetes: an Asian perspective

BACKGROUND

Microalbuminuria (MA) is a risk marker for diabetic nephropathy and cardiovascular (CV) disease (CVD) in patients with diabetes. This study aimed to describe the prevalence of albuminuria, CV risk factors, and treatments for renal and CV protection in an Asian population with type 2 diabetes.

METHODS

This cross-sectional study conducted in eight Asian countries enrolled normotensive/hypertensive adults with type 2 diabetes without known proteinuria and/or non-diabetic kidney disease. Exclusion criteria were type 1 diabetes, menstruation, pregnancy, and acute fever. A single random urinary albumin/creatinine test was carried out in all patients.

RESULTS

Of 8,561 patients, 14% had diabetic retinopathy, and 17% and 21% had history of CV disease and smoking, respectively. Normoalbuminuria was seen in 44%, MA in 44%, and macroalbuminuria in 12%. Target glycosylated hemoglobin (HbA1c) (<7%) was reached in only 37% of 3,834 patients with available values. Diabetes was managed by diet alone in 6%, while others received oral hypoglycemic drugs and/or insulin. In total, 75% did not reach target blood pressure (BP) of <or=130/80 mm Hg. Antihypertensive drugs were prescribed to 52%, with the number of drugs increasing as the level of systolic BP increased. Drugs blocking the renin-angiotensin system were most commonly prescribed, followed by calcium channel blockers. Lipid-lowering drugs and anticoagulant/antiplatelet agents were used in about 30% and 25% of patients, respectively.

CONCLUSIONS

Asian patients with type 2 diabetes had a high prevalence of MA and reduced kidney function. Furthermore, BP and HbA1c control was only achieved in a minority of patients. Aggressive risk management by administration of reno- and cardioprotective treatments is urgently needed.

Prevalence of metabolic syndrome and associated risk factors in Asian Indians

OBJECTIVE

This study examined the association between metabolic syndrome, lifestyle behaviors, and perception and knowledge of current health and cardiovascular disease (CVD) among Asian Indians in the US.

METHOD

The sample comprised of 143 adult Asian Indians recruited through health fairs for survey and bioclinical measures.

RESULTS

The prevalence of metabolic syndrome was 32%, much higher than other ethnic groups, did not vary by gender but increased with age. Respondents had high physical inactivity and poor knowledge of CVD risk factors. Dietary behavior, age, number of years lived in the US, self-rated physical and mental health and BMI were significant predictors and explained 40.1% of variance in metabolic syndrome score. Poorer physical health status had the greatest predictive influence on metabolic syndrome.

CONCLUSION

Asian Indians are a high risk group for CVD.

Ethnic diversity in type 2 diabetes

BACKGROUND AND METHODS

The present review assesses published data relating to the main ethnic groups in the UK Prospective Diabetes Study (UKPDS), namely White Caucasians (WC; 82% of the cohort), Indian-Asians (IA; 10%) and Afro-Caribbeans (AC; 8%).

RESULTS

At entry, the IA patients were younger than WC and AC patients, had a greater waist-hip ratio and more sedentary lifestyle, but had the lowest prevalence of hypertension and current smoking. The AC patients had the poorest glycaemic control but the most favourable lipid profile. The differences in modifiable vascular risk factors did not change over 9 years of follow-up. Consistent with UKPDS exclusion criteria, few patients had complications at baseline and there were no between-group differences. An interim analysis of incident fatal/non-fatal myocardial infarction (median follow-up 8.7 years) showed that the AC patients had a 70% lower risk than WC after adjustment for explanatory variables and that IA patients had a similar risk to WC. An analysis of complete albuminuria and renal failure data (median follow-up 15 years) showed that IA ethnicity was independently associated with an increased risk.

CONCLUSIONS

There are sustained ethnic differences in the nature of diabetes, including vascular risk factors. AC patients had a substantially reduced risk of myocardial infarction that was not explained by their more favourable lipid profile, while IA patients were more likely to develop nephropathy than WC and IA patients. Longer follow-up is needed to determine whether the increased macrovascular risk observed in IA patients in other studies is replicated in the UKPDS cohort.

Estimation of glomerular filtration rate in South Asian healthy adult kidney donors

AIM

We evaluated the performance of serum creatinine based equations to estimate glomerular filtration rate (GFR) in South Asian healthy renal donors.

METHODS

GFR by 99mTc-diethylenetriamine pentaacetic acid (DTPA) renogram (mGFR) in 599 renal donors was measured. GFR was estimated using a six variable modification of diet in renal disease formula (MDRD1), a four variable MDRD formula (MDRD2), Cockcroft-Gault creatinine clearance (CG CrCl), Cockcroft-Gault glomerular filtration rate (CG GFR) and the Mayo Clinic formula (Mayo GFR). The performance of various prediction equations was compared for global bias, precision (R(2)) and accuracy (percentage of estimated GFR (eGFR) falling within 15% and 30% of mGFR).

RESULTS

The mean age was 37.4 +/- 11 years and 48.2% were male. The mGFR was 95.5 +/- 11.6 mL/min per 1.73 m(2). The bias (mL/min per 1.73 m(2)) was 7.5 +/- 0.9, -9.0 +/- 0.75, 13.1 +/- 0.9, 7.5 +/- 0.9 and 23.4 +/- 0.76 for CG CrCl, CG GFR, MDRD1, MDRD2 and Mayo GFR, respectively. R(2) was 0.082 for CG CrCl and MDRD1, 0.081 for CG GFR and MDRD2 and 0.045 for Mayo GFR. The percentages of eGFR falling within 15% and 30% of mGFR were 50.5 and 80.1 for CG CrCl, 65.8 and 84 for CG GFR, 50 and 74 for MDRD1, 54.3 and 80.1 for MDRD2 and 32 and 63.4 for Mayo GFR. Overall CG GFR performed better in estimating GFR in all subjects.

CONCLUSION

The CG GFR equation was better than other equations to estimate GFR in South Asian healthy renal donors. We propose a new equation derived from the regression model in our study population to estimate GFR in a South Asian healthy adult population.

Insulin resistance phenotypes and coronary artery disease in a native Pakistani cohort

OBJECTIVE

To determine the relationship between insulin resistance (IR) and atheroma burden in Pakistanis.

METHODS

A prospective case-control study of 400 patients selected for the presence/absence of angiographic disease. Coronary atheroma burden was quantified and IR and cardiovascular risk factors were measured.

RESULTS

The patients were divided into two groups by QuickI score. Waist circumference (90 +/- 10 vs. 90 +/- 9 cm; p = 0.7) was similar but the groups differed in body mass index (26.5 +/- 3.7 vs. 24.2 +/- 3.5 kg/m(2); p < 0.001) and waist:hip ratio (0.94 +/- 0.09 vs. 0.90 +/- 0.06; p < 0.001). Lipid parameters showed similar high-density lipoprotein cholesterol (HDL-C) (0.77 +/- 0.23 vs. 0.82 +/- 0.22 mmol/l; p = 0.1) differences in triglycerides [1.32 (0.08-3.98) vs. 1.12 (0.37-3.61) mmol/l; p = 0.01], but no difference in low-density lipoprotein cholesterol (LDL-C) (2.75 +/- 1.00 vs. 2.90 +/- 0.94 mmol/l; p = 0.14). In insulin-resistant patients C-reactive protein (CRP) [6.8 (0.3-175.1) vs. 3.9 (0.2-57.9) mg/l: p < 0.001], sialic acid (82 +/- 14 vs. 77 +/- 15 mg/l; p < 0.001) aspartate transaminase [24 (7-171) vs. 21 (7-83) IU/l; p < 0.001] and gamma-glutamyl transferase [27 (8-482) vs. 21 (7-168) IU/l; p = 0.005] levels were increased. In insulin-resistant patients (n = 187), coronary artery disease (CAD) burden correlated (r = 0.55) with age (beta = 1.62; p < 0.001), HDL-C (beta = -53.2; p < 0.001), lipoprotein (a) (beta = 11.4; p = 0.007), smoking (beta = 7.98; p = 0.004), CRP (beta = 6.06; p = 0.03) and QuickI index (beta = -146; p = 0.04). In contrast in insulin-sensitive patients (n = 178) CAD burden (r = 0.46) correlated with LDL-C (beta = 10.0; p = 0.02), CRP (beta = 7.13; p = 0.03), HDL-C (beta = -38.1; p = 0.03), and weakly with age (beta = 0.73; p = 0.07) and smoking (beta = 5.52; p = 0.09).

CONCLUSIONS

Indian Asians show a dichotomous insulin-resistance phenotype. Atheroma is associated with low HDL-C and inflammation associated in all but LDL-C is a factor in the insulin sensitive in contrast to age and extent of IR in the insulin resistant.

Disparities in renal endowment: causes and consequences

In humans, nephrogenesis is completed by 36 weeks of gestation. Thus, human kidney development is complete at the time of birth in full-term infants. Those infants born before 36 weeks of gestation are still undergoing nephrogenesis for several weeks after their preterm birth and, accordingly, may be exposed to medications that impact the kidney during its final stages of renal development. The ultimate nephron number (nephron endowment) may influence future response to kidney injury, should it occur. The concept that nephron number may strongly influence blood pressure as well as susceptibility to kidney disease in later life developed in parallel with that of perinatal programming, which holds that the perinatal milieu causes changes that permanently alter organ structure and function, preordaining adult physiology to some extent. Both concepts together may help elucidate, at least in part, the pathogenesis of not only primary but secondary hypertension. This article summarizes human data on nephron number and its evaluation and considers the circumstances, implication, and management of persons born with or acquiring a decreased complement of nephrons early in life. Insufficient data exist to predict outcome or guide management. However, a common-sense approach of avoiding nephrotoxins and minimizing renal stress is indicated.

Microalbuminuria in Thai essential hypertensive patients

Essential hypertensive patients (176 males and 329 females), aged 58.0+/-11.2 years were enrolled in a cross-sectional study conducted from February to March 2006 to investigate the prevalence and risk factors for microalbuminuria in hypertensive patients attending the Outpatient Department of Siriraj Hospital, Bangkok, Thailand. Macroalbuminuria was detected in 11 (2.2%) patients and microalbuminuria in 94 (18.6%) patients. Only male aged>or=45 years or female aged>or=55 years correlated significantly with a high occurrence of microalbuminuria, while calcium channel blocker and statin users were protected against microalbuminuria. The presence of microalbuminuria was not associated with age>or=60 years, male gender, current/previous smokers, hypertension duration>or=10 years, lack of blood pressure normalization, metabolic syndrome, use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and multi-drug use. Risk factor recognition for microalbuminuria will enable physicians to identify cases that should be screened for microalbuminuria.

Vascular risk factors in South Asians

South Asians originate from the Indian sub-continent (India, Pakistan, Bangladesh, Sri Lanka and Nepal) and represent one fifth of the world's population. Several studies suggested that South Asians have an increased risk of developing coronary heart disease (CHD) when compared with European populations. We review the role of traditional and emerging risk factors in the increased CHD risk in South Asians. The high prevalence of insulin resistance and type 2 diabetes mellitus in South Asians may be a major cause for their elevated vascular risk. However, other established and emerging risk factors are also overrepresented in South Asians. Large-scale prospective studies could determine the relative contribution of established and emerging vascular risk factors in South Asians. There is an urgent need for trials in South Asians that will evaluate clinical outcomes following treatment of these risk factors.

Central obesity is an independent risk factor for albuminuria in nondiabetic South Asian subjects

OBJECTIVE

South Asians have a high prevalence of central obesity. When the diagnosis of diabetes is made, they have a very high risk of developing renal failure. In the current study, we explored the hypothesis that central obesity is associated with the development of renal injury, before the manifestation of diabetes.

RESEARCH DESIGN AND METHODS

We invited first-degree nondiabetic relatives of South Asian type 2 diabetic patients for investigation of microalbuminuria and diabetes. Subjects who used antihypertensive or antidiabetic medication were excluded. We performed a glucose tolerance test according to the classic World Health Organization criteria. A total of 205 subjects were normoglycemic; we excluded 25 subjects because of impaired glucose tolerance, and 30 subjects were excluded because of de novo diabetes. Central obesity was measured by waist-to-hip ratio (WHR). Albuminuria was measured as albumin-to-creatinine ratio (ACR) in the early-morning urine.

RESULTS

Central obesity was independently related with albuminuria in the 205 normoglycemic subjects. We found no relation of fasting blood glucose or systolic blood pressure with albuminuria. Multivariate analysis for the presence of increased albuminuria (median ACR >0.31 mg/mmol) showed a relative risk of 4.1 for the highest versus the lowest tertile of WHR (P = 0.002).

CONCLUSIONS

Central obesity is an early and independent risk factor for increased albuminuria in normoglycemic South Asian subjects. This could explain the high incidence of diabetic renal disease in South Asians, probably by the mechanism of insulin resistance and endothelial dysfunction in the pre-diabetic state.

Type 2 diabetes and cardiovascular risk in the UK south Asian community

A popular hypothesis for the greater prevalence of type 2 diabetes and cardiovascular disease in UK south Asians is that they have an increased susceptibility of developing insulin resistance in response to certain environmental factors, including obesity and adoption of a sedentary lifestyle. Insulin resistance is postulated as a central feature of the metabolic syndrome, culminating in type 2 diabetes, atherosclerotic vascular disease and CHD; a pathway potentially accelerated by migration/urbanisation. We describe and compare the prevalence of type 2 diabetes, cardiovascular disease and their associated risk factors in UK south Asian and white Caucasian populations to determine possible reasons for the increased preponderance of these diseases in south Asians, and highlight key evidence for optimal risk factor management. Finally, we describe a UK community-based programme that attempts to reduce the morbidity and mortality from type 2 diabetes and cardiovascular disease in south Asians through a new approach to management.