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43.
44.
45.
46.
of GFR in health and in chronic kidney disease. J Am Soc Nephrol 2005; 16: 459–466 Ma YC, Zuo L, Chen JH et al. Modified glomerular filtration rate estimating equation for Chinese patients with chronic kidney disease. J Am Soc Nephrol 2006; 17: 2937–2944 Imai E, Horio M, Nitta K et al. Modification of the Modification of Diet in Renal Disease (MDRD) study equation for Japan. Am J Kidney Dis 2007; 50: 927–937 Quinn MP, Rainey A, Cairns KJ et al. The practical implications of using standardized estimation equations in calculating the prevalence of chronic kidney disease. Nephrol Dial Transplant 2008; 23: 542– 548 Glassock RJ, Winearls C. An epidemic of chronic kidney disease: fact or fiction? Nephrol Dial Transplant 2008; 23: 1117–1121
1205 47. Chronic Kidney Disease in Adults. UK Guidelines for Identification, Management and Referral. http:\\www.renal.org/CKDguide/ full/CKDprintedfullguide.pdf. 48. Couser WG. Chronic kidney disease—the promise and the perils. J Am Soc Nephrol 2007; 18: 2803–2805 49. Perkovic V, Algert C, Arima H et al. Predictive ability of different measures of kidney function: data from the PROGRESS study. J Am Soc Nephrol 2006; 17: 401A 50. Cirillo M, Anastasio P, De Santo NG. Relationship of gender, age and body mass index to errors in predicted kidney function. Nephrol Dial Transplant 2005; 20: 1791–1798 51. Vassallotti JA, Stevens LA, Levey AS. Testing for chronic kidney disease: a position statement from the national kidney foundation. Am J kidney Dis 2007; 50: 169–180 Received for publication: 28.3.08 Accepted in revised form: 29.9.08
Nephrol Dial Transplant (2009) 24: 1205–1212 doi: 10.1093/ndt/gfn604 Advance Access publication 24 October 2008
Prevalence and risk factors associated with chronic kidney disease in an adult population from southern China Wei Chen1 , Weiqing Chen2 , Hui Wang2 , Xiuqing Dong1 , Qinghua Liu1 , Haiping Mao1 , Jiaqing Tan1 , Jianxiong Lin1 , Feiyu Zhou1 , Ning Luo1 , Huijuan He1 , Richard J. Johnson3 , Shu-Feng Zhou4 and Xueqing Yu1 1
Department of Nephrology, The First Affiliated Hospital, 2 Department of Epidemiology and Preventive Medicine, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China, 3 Division of Nephrology, Hypertension and Renal Transplantation, University of Florida, Gainesville, FL 32610-0224, USA and 4 School of Health Sciences, RMIT University, Victoria 3108, Australia
Abstract Background. Population-based studies evaluating the prevalence of kidney damage in different communities have been limited in developing countries. We conducted a population-based screening study in the southern Chinese city of Guangzhou that aimed to identify the prevalence and associated risk factors of chronic kidney disease (CKD) in southern Chinese populations. Methods. We interviewed 6311 residents (>20 years) from six districts of Guangzhou from July 2006 to June 2007 and tested for haematuria, albuminuria and reduced renal function. Associations between age, gender, smoking, diabetes mellitus, hypertension, hyperuricaemia and kidney damage were examined. Results. There were 6311 subjects enrolled in this study. After adjustment for age and gender, the prevalence of albuminuria, haematuria and reduced estimated glomerular filtration rate (eGFR) was 6.6% [95% confidence interval (CI): 5.5–7.6%], 3.8% (95% CI: 3.4%, 4.3%) and 3.2% (95% CI: 2.4%, 3.3%), respectively. Approximately 12.1%
(95% CI: 11.3%, 12.9%) of the sample population had at least one indicator of kidney damage. Age, diabetes mellitus, hypertension, central obesity, hyperlipidaemia and use of nephrotoxic medications were independently associated with albuminuria; hyperuricaemia, age, gender, hypertension and use of nephrotoxic medications were independently associated with reduced eGFR, and female gender was independently associated with haematuria. Conclusions. In the general adult population from southern China, 12.1% has either proteinuria, haematuria and/or reduced eGFR, indicating the presence of kidney damage, with an awareness of only 9.6%. The high prevalence and low awareness of CKD in this population suggest an urgent need for CKD prevention programmes in China.
Correspondence and offprint requests to: Xueqing Yu, Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China. Tel: +8620-87766335; Fax: +862087769673; E-mail:
[email protected]
The prevalence of chronic kidney disease (CKD) is increasing rapidly worldwide, and is now recognized as a global public health problem. In addition, end-stage renal disease
Keywords: chronic kidney disease; epidemiology; screening
Introduction
C The Author [2008]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please e-mail:
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(ESRD) is at epidemic levels and has become an important health-threatening condition just behind cardiovascular disease, cerebrovascular disease, cancer and diabetes. In the United States and Australia, ∼11–16% of the general population is affected by various renal diseases [1,2]. Studies from Europe have also shown a high prevalence of CKD in the general population [3]. The incidence of ESRD is increasing, with a doubling in the number of patients treated for ESRD in Europe and the United States over the past decade [4,5]. The burden of renal disease is likely to escalate since both population age and prevalence of diabetes are projected to increase dramatically. However, studies examining the prevalence of CKD and its associated factors in developing countries, especially in Chinese populations, remain limited. The prevalence of CKD in China, which has the largest world population, will have a vital influence on global CKD epidemiology. Nevertheless, there have been only a few epidemiological studies that examined CKD prevalence in China. In 2005, Chen et al. [6] reported that the prevalence of decreased kidney function was 2.53% in a nationwide representative population of Chinese; however, other indicators of renal injury were not reported. Zhang et al. [7] showed that the prevalence of CKD in Chinese aged 40 years or older was 9.4% in a district of Beijing. A more recent study found that the prevalence of CKD in adult Chinese of Beijing was 13.0% [8]. Importantly, the awareness of CKD prevalence among these patients was 1.1 million) from July 2006 to June 2007. Subjects were local residents aged 20 years or older who had lived in the region for 5 years or longer. Participants were selected using a stratified, multistage sampling method. In the first stage,
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a total of six districts were sampled from the entire city, consisting of four randomly selected districts from older suburbs and two districts from recently developed suburbs. In the second stage, seven street offices were randomly chosen from each selected district. In the third stage, 12 communities were randomly selected. In the final stage, a simple randomized method was used to select households. In the selected households, all subjects fulfilling the inclusion criteria were selected, until the required number of subjects for each age group was reached. Using this method, a total of 6311 subjects aged 20 years or older were selected from 12 primary sampling units and were enrolled into the study; of these subjects, 6101 completed the entire survey with a response rate of 96.7%. The study was approved by the Human Ethics Committees of Sun Yat-sen University (Guangzhou, China). Written informed consent was obtained from all participants of this study. Screening protocol and evaluation criteria All Staff participating in this study including clinical doctors and medical students received intensive training on proper methods for screening. Data were collected at local health stations or community clinics. A questionnaire documenting socio-demographic status (e.g. age, sex, income and education level), personal and family health history (e.g. hypertension, diabetes and kidney disease) and lifestyle behavior (e.g. smoking) was completed by each subject. History of taking medications with nephrotoxic potential (including non-steroidal anti-inflammatory drugs and herbs containing aristolochic acid) was also recorded. Anthropometric measurements were obtained using standard protocols and techniques. After removal of shoes and heavy clothing, each subject underwent body weight and height measurements, using a calibrated scale. The body mass index (BMI) was calculated as weight (in kilograms) divided by height squared (in square meters). Venous blood was collected after an overnight fast of at least 10 h for measurements of various biomarkers. A clean-catch, midstream, morning urine specimen was collected for dipstick urinalysis (Roche Diagnostics, Mannheim, Germany) and microscopic analysis. All blood and urine samples were tested in the laboratory of The First Affiliated Hospital, Sun Yat-sen University. Albuminuria. Urinary albumin and creatinine were measured from a morning urine sample using an automatic analyser (COBAS INTEGRA 400 plus, Roche, Basel, Switzerland). Creatinine was measured by Jaffe’s kinetic method and albumin by the immunoturbidimetic method. Urinary ACR (mg/g) was calculated. Microalbuminuria and macroalbuminuria were defined as an increase in ACR between 30 and 299 mg/g and 300 mg/g or greater, respectively, according to the guideline of American Diabetes Association. The term ‘albuminuria’ is used to describe the presence of either microalbuminuria or macroalbuminuria. Estimated glomerular filtration rate (eGFR). Blood was collected by venous puncture after overnight fasting. Serum creatinine (Scr) was measured using the same method as
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that for urinary creatinine determination. The eGFR was calculated using the MDRD equation, which was modified for data from Chinese CKD patients [10]. As part of this, 38 serum samples with a creatinine range of 0.5–15 mg/dL were sent to the central laboratory of Peking University First Hospital where the modified equation was developed [10]. The resulting calibration equation was (R2 = 0.999): Calibrated Scr (mg/dL) = 0.893 × Scr (mg/dL) + 0.39. Reduced renal function was defined as an eGFR 10 mmHg, in which case the mean of the two closest of the three readings was used. Hypertension was defined as systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or use of anti-hypertensive medication in the previous 2 weeks irrespective of BP or self-reported diagnosis of high BP and use of anti-hypertensive medication. Diabetes status. Fasting blood glucose was measured enzymatically with a glucose oxidase method (COBAS INTEGRA 400 plus, Roche, Basel, Switzerland). Diabetes was defined as the use of insulin or oral hypoglycaemic agents or a fasting plasma glucose ≥7.0 mmol/L (126 mg/dL) and/or 2-h post-prandial plasma glucose ≥11.1 mmol/L (200 mg/dL). Other measurements. Serum total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and uric acid were measured by an autoanalyser (COBAS INTEGRA 400 plus, Roche). Hyperuricaemia was defined as a serum uric acid level >7.0 mg/dL. Cardiovascular diseases were reported by subjects from diagnoses originating from doctors or other health professionals, and included congestive heart failure, coronary heart disease, angina, stroke or heart attack. The metabolic syndrome was defined according to the National Cholesterol Education Programme Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATP III) criteria.
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Statistical analysis Data entry and management were performed using Epidata software, version 3.0 (Epidata Association, Odense, Denmark). All analyses and calculations were performed using SPSS software, version 10.0 (SPSS, Inc., Chicago, IL USA). Data are presented as means ± standard error for continuous variables and as proportions for categorical variables. Quantitative variables were summarized as means and 95% confidence intervals (CI). Differences between subjects were analysed by two-tailed unpaired Student’s t tests for continuous data and by χ2 tests for categorical data. Univariate and multivariate logistic regression analyses were used to estimate odds ratios (OR) and CIs by comparing associated risk factors on CKD occurrence. P
