***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: INTRODUCTION Chronic kidney disease ( CKD ) is an independent cardiovascular risk factor . The knowledge of prevalence in general population may help to early detection of CKD and prevent or delay its progression . METHODS  Sociodemographic , baseline characteristics , and CKD prevalence ( measured by  central ized serum creatinine and MDRD equation )  were evaluated in a r and omly selected sample of general population aged 20 years or older , collected in all Spanish regions and stratified by habitat , age and sex according to 2001 census ( n=2746 ) .  Univariate and multivariate logistic regression analyses were used to evaluate associations with CKD risk factors . RESULTS Mean age was 49.5 years . The overall prevalence of Kidney Disease Outcomes Quality Initiative grade s 3 - 5 CKD was 6.8 % , with a 95 % confidence interval ( CI ) of 5.4 to 8.2 ( 3.3 % for age 40 - 64 years and 21.4 % for age > 64 years ) . The prevalence estimates of CKD stages were : 0.99 % for stage 1 ( glomerular filtration rate [ GFR ] > or=90 ml/min per 1.73 m2 with proteinuria ) ; 1.3 % for stage 2 ( GFR 60 - 89 ) ; 5.4 % for stage 3a ( GFR 45 - 59 ) ; 1.1 % for stage 3b ( GFR 30 - 44 ) ; 0.27 % for stage 4 ( GFR 15 - 29 ) ; and 0.03 % for stage 5 ( GFR < 15 ) . An important prevalence of classical cardiovascular risk factors was observed : dyslipemia ( 29.3 % ) , obesity ( 26.1 % ) , hypertension ( 24.1 % ) , diabetes ( 9.2 % ) and current smoking ( 25.5 % ) . The independent predictor factors for CKD were age , obesity and previously diagnosed hypertension . CONCLUSION The prevalence of CKD at any stage in general population from Spain is relatively high , especially in the elderly , and similar to countries of the same geographical area . Independently of age , two modifiable risks factors , hypertension and obesity , are associated with an increased prevalence of CKD Background . The prognostic value of reduced glomerular filtration rate ( GFR ) was examined in a community-based cohort of British women . Methods . Serum creatinine measurements were available for 90 % ( n = 3851 ) of a representative r and om sample of 4286 women aged 60 - 79 years . GFR was estimated using the Modification of Diet in Renal Disease equation . Hazard ratios ( HR ) were calculated using Cox regression with outcomes of all-cause and cardiovascular disease ( CVD ) mortality . Results . Eight hundred and thirty-two women ( 21.6 % ) had a GFR < 60 ml/min/1.73 m(2 ) . Over a median follow-up of 5.6 years , there were 318 deaths ( 100 CVD deaths ) . Women with GFR < 60 ml/min/1.73 m(2 ) compared to all others showed only a borderline increased risk of all-cause mortality [ HR 1.35 ( 95 % confidence intervals : 0.99 , 1.85 ) ] and CVD mortality [ 1.34 ( 0.97 , 1.85 ) ] . Adjustment for conventional CVD risk factors had little impact . The association with CVD mortality was attenuated in women with pre-existing CVD [ adjusted HR : 0.51 ( 0.24 , 1.04 ) ] . Only the subset of women without CVD at baseline were at risk for later CVD death [ adjusted HR : 1.80 ( 1.13 , 2.88 ) ] . Conclusions . A substantial proportion of older British women have GFR < 60 ml/min/1.73 m(2 ) without strong evidence for statistical association with all-cause mortality . The effect on CVD mortality is partly explained by existing CVD and its risk factors . GFR measurement appears only to play a useful role in the subset of older women without pre-existing CVD who are at higher risk of premature CVD death BACKGROUND In older adults , current equations to estimate glomerular filtration rate ( GFR ) are not vali date d and may misclassify elderly persons in terms of their stage of chronic kidney disease . OBJECTIVE To derive the Berlin Initiative Study ( BIS ) equation , a novel estimator of GFR in elderly participants . DESIGN Cross-sectional . Data were split for analysis into 2 sets for equation development and internal validation . SETTING R and om community-based population of a large insurance company . PARTICIPANTS 610 participants aged 70 years or older ( mean age , 78.5 years ) . INTERVENTION Iohexol plasma clearance measurement as gold st and ard . MEASUREMENTS GFR , measured as the plasma clearance of the endogenous marker iohexol , to compare performance of existing equations of estimated GFR with measured GFR of the gold st and ard ; estimation of measured GFR from st and ardized creatinine and cystatin C levels , sex , and age in the learning sample ; and comparison of the BIS equations ( BIS1 : creatinine-based ; BIS2 : creatinine- and cystatin C-based ) with other estimating equations and determination of bias , precision , and accuracy in the validation sample . RESULTS The new BIS2 equation yielded the smallest bias followed by the creatinine-based BIS1 and Cockcroft-Gault equations . All other equations considerably overestimated GFR . The BIS equations confirmed a high prevalence of persons older than 70 years with a GFR less than 60 mL/min per 1.73 m2 ( BIS1 , 50.4 % ; BIS2 , 47.4 % ; measured GFR , 47.9 % ) . The total misclassification rate for this criterion was smallest for the BIS2 equation ( 11.6 % ) , followed by the cystatin C equation 2 ( 15.1 % ) proposed by the Chronic Kidney Disease Epidemiology Collaboration . Among the creatinine-based equations , BIS1 had the smallest misclassification rate ( 17.2 % ) , followed by the Chronic Kidney Disease Epidemiology Collaboration equation ( 20.4 % ) . LIMITATION There was no validation by an external data set . CONCLUSION The BIS2 equation should be used to estimate GFR in persons aged 70 years or older with normal or mild to moderately reduced kidney function . If cystatin C is not available , the BIS1 equation is an acceptable alternative . PRIMARY FUNDING SOURCE Kuratorium für Dialyse und Nierentransplatation ( KfH ) Foundation of Preventive Medicine Background The prevalence of  chronic kidney disease ( CKD ) using available estimating equations with the Republic of Irel and is unknown . Methods A r and omly selected population based cross-sectional study of 1,098 adults aged 45 years and older was conducted using data from the 2007 Survey of Lifestyle , Attitudes and Nutrition ( SLÁN ) . Estimated Glomerular Filtration Rate ( eGFR ) was calculated from a single IDMS aligned serum creatinine using the CKD-EPI and the MDRD equations , and albumin to creatinine ratio was based on a single r and om urine sample . Results The sample clinical characteristics and demography was similar to middle and older age adults in the general Irish population , though with an underrepresentation of subjects > 75 years and of males . All results are based on subjects with available blood and urine sample s. Applying weighting to obtain survey based population estimates , using Irish population census data , the estimated weighted prevalence of CKD-EPI eGFR<60 mL/min/1.73m2 was 11.6 % , ( 95 % confidence interval ; 9.0 , 14.2 % ) , 12.0 % ( 9.0 , 14.2 % ) of men and 11.2 % ( 7.3 , 15.2 % ) of women . Unweighted prevalence estimates were similar at 11.8 % ( 9.9 , 13.8 % ) . Albuminuria increased with lower CKD-EPI eGFR category . 10.1 % of all subjects had albuminuria and an eGFR≥60 mL/min/1.73 m2 giving an overall weighted estimated prevalence of National Kidney Foundation ( NKF ) defined CKD 21.3 % ( 18.0 , 24.6 % ) , with the unadjusted estimate of 21.9 % ( 19.5 , 24.4 % ) . MDRD related estimates for eGFR < 60 mL/min/1.73 m2 , and NFK defined CKD were higher than CKD-EPI and differences were greater in younger and female subjects . Conclusions CKD is highly prevalent in middle and older aged adults within the Republic of Irel and . In this population , there is poor agreement between CKD-EPI and MDRD equations especially at higher GFRs . CKD is associated with lower educational status and poor self rated health BACKGROUND We investigate whether the urinary proteome refines the diagnosis of renal dysfunction , which affects over 10 % of the adult population . METHODS We measured  serum creatinine , estimated glomerular filtration rate ( eGFR ) and 24-h albuminuria  in 797 people r and omly recruited from a population . We applied capillary electrophoresis coupled with mass spectrometry to measure multi-dimensional urinary proteomic classifiers developed for renal dysfunction ( CKD273 ) or left ventricular dysfunction ( HF1 and HF2 ) . Renal function was followed up in 621 participants and the incidence of cardiovascular events in the whole study population . RESULTS In multivariable-adjusted cross-sectional analyses , higher biomarker levels analysed separately or combined by principal component analysis into a single factor ( SF ) , correlated ( P ≤ 0.010 ) with worse renal function . Over 4.8 years , higher HF1 and SF predicted ( P ≤ 0.014 ) lowering of eGFR ; higher HF2 predicted ( P ≤ 0.049 ) increase in serum creatinine and decrease eGFR . HF1 , HF2 and SF predicted progression from CKD Stages 2 or ≤2 to Stage ≥3 , with risk estimates for a 1-SD increment in the urinary biomarkers ranging from 38 to 71 % ( P ≤ 0.039 ) . HF1 , HF2 and SF yielded a net reclassification improvement of 31 - 51 % ( P ≤ 0.029 ) . Over 6.1 years , 47 cardiovascular events occurred . HF2 and SF , independent of baseline eGFR , 24-h albuminuria and other covariables were significant predictors of cardiovascular complications with risk estimates for 1-SD increases ranging from 32 to 41 % ( P ≤ 0.047 ) . CONCLUSIONS The urinary proteome refines the diagnosis of existing or progressing renal dysfunction and predicts cardiovascular complications Background Increasing evidence suggests a mechanistic link between the glycemic environment and renal and cardiovascular events , even below the threshold for diabetes . We aim ed to assess the association between HbA1c and chronic kidney disease ( CKD ) and cardiovascular disease ( CVD ) . Methods A cross-sectional study involving a r and om representative sample of 2270 adults from southern Spain ( Malaga ) was undertaken . We measured  HbA1c , serum creatinine and albuminuria in fasting blood and urine sample s. Results Individuals without diabetes in the upper HbA1c tertile had an unfavorable cardiovascular and renal profile and shared certain clinical characteristics with the patients with diabetes . Overall , a higher HbA1c concentration was strongly associated with CKD or CVD after adjustment for traditional risk factors . The patients with known diabetes had a 2-fold higher odds of CKD or CVD . However , when both parameters were introduced in the same model , the HbA1c concentration was only significantly associated with clinical endpoints ( OR : 1.4 , 95 % CI , 1.1 - 1.6 , P = 0.002 ) . An increase in HbA1c of one percentage point was associated with a 30 % to 40 % increase in the rate of CKD or CVD . This relationship was apparent in persons with and without known diabetes . ROC curves illustrated that a HbA1c of 37 mmol/mol ( 5.5 % ) was the optimal value in terms of sensitivity and specificity for predicting endpoints in this population . Conclusion HbA1c levels were associated with a higher prevalence of CKD and CVD cross-sectionally , regardless of diabetes status . These data support the value of HbA1c as a marker of cardiovascular and renal disease in the general population BACKGROUND national policy is focused on early identification , referral and management of chronic kidney disease ( CKD ) to prevent both progression to endstage renal failure and cardiovascular disease . However , the significance of identifying CKD in older people is unclear . OBJECTIVE to determine the frequency of CKD in older people using estimated glomerular filtration rate ( eGFR ) , and its associations with morbidity and functional measures . DESIGN observational cross-sectional analysis of baseline data from a large cluster r and omised trial of health and social assessment of older people in the community . 
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Conclusions The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence .
These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies , which will enhance comparability of study results