ESRD incidence is much lower in. The relative risk for progression from CKD stages 3 or 4 to ESRD in US white patients compared with Norwegian patients was 2.5. This was only modestly modified by adjustment for age, gender, and diabetes. Age and GFR at start of dialysis were similar, hypertension and cardiovascular mortality in the populations were comparable, but US white patients were referred later to a nephrologist and had higher prevalence of obesity and diabetes. In conclusion, CKD prevalence in Norway was similar to that in the United States, suggesting that lower progression to ESRD rather than a smaller pool of individuals at risk accounts for the lower incidence of ESRD in Norway.J Am Soc Nephrol 17: 2275 -2284, 2006 . doi: 10.1681 T here has been a dramatic rise in the number of patients with ESRD in both Europe and North America during the past decades. There is significant disparity, however, in ESRD incidence rates between the two continents: Incidence rates are three times higher in the United States compared with Norway and Great Britain (1,2). Data on the prevalence of chronic kidney disease (CKD) in Europe are limited, making it unclear whether the higher ESRD incidence in the United States reflects a higher burden of all stages of CKD (3,4).The relationship between the prevalence of earlier stages of CKD and the incidence of ESRD is complex (5-9): US CKD prevalence has been relatively stable in the past decade, whereas ESRD incidence has increased significantly, and US black patients have a three times higher incidence of ESRD despite similar prevalences of CKD. This can be due to differences in other mechanisms, such as more rapid progression or greater initiation of dialysis. Early stages of CKD also result in a higher risk for complications, cardiovascular disease, and mortality, which pose a larger absolute risk than ESRD. Furthermore, identifying and treating individuals with early stages of CKD is increasingly proposed for prevention of ESRD and cardiovascular disease (9,10). This requires solid documentation of a high prevalence of preclinical disease. Thus far, European studies on CKD prevalence have been hampered by selection bias or incomplete data for defining CKD stages (11-13).Therefore, there is a need for more information on the prevalence of CKD in European populations as well as a better understanding of the relationship of CKD prevalence to ESRD incidence. The second Health Survey of Nord-Trondelag County (HUNT II) is a large, population-based, cross-sectional study that was conducted in central Norway with a high participation rate (14). We used HUNT II data to assess the prevalence of CKD using calibrated serum creatinine values and repeated measurements of albuminuria. Combining these prevalence estimates with available information on ESRD, health care, and population characteristics, we also examined the extent to which the low incidence of ESRD in Norway compared with the United States reflects a difference in the earlier stages of CKD between the two countries. Material...

CKD prevalence estimation is central to CKD management and prevention planning at the population level. This study estimated CKD prevalence in the European adult general population and investigated international variation in CKD prevalence by age, sex, and presence of diabetes, hypertension, and obesity. We collected data from 19 general-population studies from 13 European countries. CKD stages 1-5 was defined as eGFR,60 ml/min per 1.73 m 2 , as calculated by the CKD-Epidemiology Collaboration equation, or albuminuria .30 mg/g, and CKD stages 3-5 was defined as eGFR,60 ml/min per 1.73 m 2 .CKD prevalence was age-and sex-standardized to the population of the 27 Member States of the European Union (EU27). We found considerable differences in both CKD stages 1-5 and CKD stages 3-5 prevalence across European study populations. The adjusted CKD stages 1-5 prevalence varied between 3.31% (95% confidence interval [95% CI], 3.30% to 3.33%) in Norway and 17.3% (95% CI, 16.5% to 18.1%) in northeast Germany. The adjusted CKD stages 3-5 prevalence varied between 1.0% (95% CI, 0.7% to 1.3%) in central Italy and 5.9% (95% CI, 5.2% to 6.6%) in northeast Germany. The variation in CKD prevalence stratified by diabetes, hypertension, and obesity status followed the same pattern as the overall prevalence. In conclusion, this large-scale attempt to carefully characterize CKD prevalence in Europe identified substantial variation in CKD prevalence that appears to be due to factors other than the prevalence of diabetes, hypertension, and obesity.

Despite the high prevalence of chronic kidney disease (CKD), relatively few individuals with CKD progress to ESRD. A better understanding of the risk factors for progression could improve the classification system of CKD and strategies for screening. We analyzed data from 65,589 adults who participated in the Nord-Trøndelag Health (HUNT 2) Study (1995 to 1997) and found 124 patients who progressed to ESRD after 10.3 yr of follow-up. In multivariable survival analysis, estimated GFR (eGFR) and albuminuria were independently and strongly associated with progression to ESRD: Hazard ratios for eGFR 45 to 59, 30 to 44, and 15 to 29 ml/min per 1.73 m 2 were 6.7, 18.8, and 65.7, respectively (P Ͻ 0.001 for all), and for micro-and macroalbuminuria were 13.0 and 47.2 (P Ͻ 0.001 for both). Hypertension, diabetes, male gender, smoking, depression, obesity, cardiovascular disease, dyslipidemia, physical activity and education did not add predictive information. Time-dependent receiver operating characteristic analyses showed that considering both the urinary albumin/creatinine ratio and eGFR substantially improved diagnostic accuracy. Referral based on current stages 3 to 4 CKD (eGFR 15 to 59 ml/min per 1.73 m 2 ) would include 4.7% of the general population and identify 69.4% of all individuals progressing to ESRD. Referral based on our classification system would include 1.4% of the general population without losing predictive power (i.e., it would detect 65.6% of all individuals progressing to ESRD). In conclusion, all levels of reduced eGFR should be complemented by quantification of urinary albumin to predict optimally progression to ESRD.

Background:The cardiovascular risk implications of a combined assessment of reduced kidney function and microalbuminuria are unknown. In elderly persons, traditional cardiovascular risk factors are less predictive, and measures of end organ damage, such as kidney disease, may be needed for improved cardiovascular mortality risk stratification.Methods: The glomerular filtration rate was estimated from calibrated serum creatinine, and the urine albumincreatinine ratio (ACR) was measured in 3 urine samples in 9709 participants of the second Nord-Trøndelag Health Study (HUNT II), a Norwegian community-based health study, followed for 8.3 years with a 71% participation rate.Results: An estimated glomerular filtration rate (EGFR) at levels of less than 75 mL/min/1.73 m 2 was associated with higher cardiovascular mortality risk, whereas a higher ACR was associated with higher risk with no lower limit. Low EGFR and albuminuria were synergistic cardiovascular mortality risk factors. Compared with subjects with an EGFR greater than 75 mL/min/1.73 m 2 and ACR below the sex-specific median who were at the lowest risk, subjects with an EGFR of less than 45 mL/min/1.73 m 2 and microalbuminuria had an adjusted incidence rate ratio of 6.7 (95% confidence interval, 3.0-15.1; P Ͻ.001). The addition of ACR and EGFR improved traditional risk models: 39% of subjects with intermediate risk were reclassified to low-or high-risk categories with corresponding observed risks that were 3-fold different than the original category. Age-stratified analyses showed that EGFR and ACR were particularly strong risk factors for persons 70 years or older.Conclusions: Reduced kidney function and microalbuminuria are risk factors for cardiovascular death, independent of each other and traditional risk factors. The combined variable improved cardiovascular risk stratification at all age levels, but particularly in elderly persons where the predictive power of traditional risk factors is attenuated.

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Background: There is strong biologic plausibility to support change in albuminuria as a surrogate endpoint for progression of chronic kidney disease (CKD), but empirical evidence to supports its validity in epidemiologic studies is lacking. Methods: We analyzed 28 cohorts including 693,816 individuals (80% with diabetes) and 7,461 end-stage kidney disease (ESKD) events, defined as initiation of kidney replacement therapy. Percent change in albuminuria was quantified during a baseline period of 1, 2 and 3 years using linear regression. Associations with subsequent ESKD were quantified using Cox regression in Coresh et al.

Background Acute kidney injury (AKI) is a serious global public health problem. We aimed to quantify the risk of AKI associated with estimated glomerular filtration rate (eGFR), albuminuria (albumin-creatinine ratio [ACR]), age, sex, and race (African American and Caucasian). Study Design Collaborative meta-analysis. Setting & Population 8 general population cohorts (1,285,049 participants) and 5 chronic kidney disease (CKD) cohorts (79,519 participants). Selection Criteria for Studies Available eGFR, ACR, and ≥50 AKI events. Predictors Age, sex, race, eGFR, urine ACR, and interactions. Outcome Hospitalized with or for AKI, using Cox proportional hazards models to estimate HRs of AKI and random effects meta-analysis to pool results. Results 16,480 (1.3%) general population cohort participants had AKI over a mean follow-up of 4 years; 2,087 (2.6%) CKD participants had AKI over mean follow-up of 1 year. Lower eGFR and higher ACR were strongly associated with AKI. Compared with eGFR 80 ml/min/1.73 m2, the adjusted HR of AKI at eGFR 45 ml/min/1.73 m2 was 3.35 (95% CI, 2.75–4.07). Compared with ACR 5 mg/g, the risk of AKI at ACR 300 mg/g was 2.73 (95% CI, 2.18–3.43). Older age was associated with higher risk of AKI, but this effect was attenuated in lower eGFR or higher ACR. Male sex was associated with higher risk of AKI, with a slight attenuation in lower eGFR but not in higher ACR. African Americans had higher AKI risk at higher levels of eGFR and most levels of ACR. Limitations Only 2 general population cohorts could contribute to analyses by race; AKI identified by diagnostic code. Conclusions Reduced eGFR and increased ACR are consistent, strong risk factors for AKI whereas the associations of AKI with age, sex, and race may be weaker in more advanced stages of CKD.

Objective To estimate the high risk group for cardiovascular disease in a well defined Norwegian population according to European guidelines and the systematic coronary risk evaluation system. Design Modelling study. Setting Nord-Tröndelag health study 1995-7 (HUNT 2), Norway. Participants 5548 participants of the Nord-Tröndelag health study 1995-7, aged 40, 50, 55, 60, and