***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*** 
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    Input: Objective To quantify the psychological impact of primary care based stepwise screening for type 2 diabetes . Design Controlled trial and comparative study embedded in a r and omised controlled trial . Setting 15 practice s ( 10 screening , five control ) in the ADDITION ( Cambridge ) trial in the east of Engl and . Participants 7380 adults ( aged 40 - 69 ) in the top fourth for risk of having undiagnosed type 2 diabetes ( 6416 invited for screening , 964 controls ) . Interventions Invited for screening for type 2 diabetes or not invited ( controls ) , incorporating a comparative study of subgroups of screening attenders . Attenders completed question naires after a r and om blood glucose test and at 3 - 6 months and 12 - 15 months later . Controls were sent question naires at corresponding time points . Non-attenders were sent question naires at 3 - 6 months and 12 - 15 months . Main outcome measures State anxiety ( Spielberger state anxiety inventory ) , anxiety and depression ( hospital anxiety and depression scale ) , worry about diabetes , and self rated health . Results No significant differences were found between the screening and control participants at any time — for example , difference in means ( 95 % confidence intervals ) for state anxiety after the initial blood glucose test was −0.53 , −2.60 to 1.54 , at 3 - 6 months was 1.51 ( −0.17 to 3.20 ) , and at 12 - 15 months was 0.57 , −1.11 to 2.24 . After the initial test , compared with participants who screened negative , those who screened positive reported significantly poorer general health ( difference in means −0.19 , −0.25 to −0.13 ) , higher state anxiety ( 0.93 , −0.02 to 1.88 ) , higher depression ( 0.32 , 0.08 to 0.56 ) , and higher worry about diabetes ( 0.25 , 0.09 to 0.41 ) , although effect sizes were small . Small but significant trends were found for self rated health across the screening subgroups at 3 - 6 months ( P=0.047 ) and for worry about diabetes across the screen negative groups at 3 - 6 months and 12 - 15 months ( P=0.001 ) . Conclusions Screening for type 2 diabetes has limited psychological impact on patients . Implementing a national screening programme based on the stepwise screening procedure used in the ADDITION ( Cambridge ) trial is unlikely to have significant consequences for patients ' psychological health . Trial registration Current Controlled Trials IS RCT N99175498 Background Uncertainty exists regarding the optimal method to estimate glomerular filtration rate ( GFR ) for disease detection and monitoring . Widely used GFR estimates have not been vali date d in British ethnic minority population s. Methods / design Iohexol measured GFR will be the reference against which each estimating equation will be compared . The estimating equations will be based upon serum creatinine and /or cystatin C. The eGFR-C study has 5 components:1 ) A prospect i ve longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference ( measured ) GFR and test ( estimated GFR [ eGFR ] and urinary albumin-to-creatinine ratio ) measurements at baseline and 3 years . Test measurements will also be undertaken every 6 months . The study population will include a representative sample of South-Asians and African-Caribbeans . People with diabetes and proteinuria ( ACR ≥30 mg/mmol ) will comprise 20 - 30 % of the study cohort.2 ) A sub- study of patterns of disease progression of 375 people ( 125 each of Caucasian , Asian and African-Caribbean origin ; in each case containing subjects at high and low risk of renal progression ) . Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3 ) A biological variability study to establish reference change values for reference and test measures .4 ) A modelling study of the performance of monitoring strategies on detecting progression , utilising estimates of accuracy , patterns of disease progression and estimates of measurement error from studies 1 ) , 2 ) and 3).5 ) A comprehensive cost data base for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy .The performance of the estimating equations will be evaluated by assessing bias , precision and accuracy . Data will be modelled as a linear function of time utilising all available ( maximum 7 ) time points compared with the difference between baseline and final reference values . The percentage of participants demonstrating large error with the respective estimating equations will be compared . Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline . Discussion The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice .Trial registration IS RCT N42955626 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 OBJECTIVES Chronic kidney disease is , increasingly , both a contributor to premature deaths and a financial burden to the health system , and is estimated to affect between 10 % and 15 % of the adult population in Western countries . Hypertension and , in particular diabetes , are significant contributors to the global burden of chronic kidney disease . Although it might increase costs , screening for , and improved management of , persons at increased risk of progressive kidney disease could improve health outcomes . We therefore sought to estimate the costs and health outcomes of alternative strategies to prevent end-stage kidney disease , compared with usual care . METHODS A Markov model comparing : 1 ) intensive management versus usual care for patients with suboptimally managed diabetes and hypertension ; and 2 ) screening for and intensive treatment of diabetes , hypertension , and proteinuria versus usual care was developed . Intervention effectiveness was based on published meta-analyses and r and omized controlled trial data ; costs were measured from a central health-care funder perspective in 2008 Australian dollars ( $ A ) , and outcomes were reported in quality -adjusted life-years ( QALYs ) . RESULTS Intensive treatment of inadequately controlled diabetes was both less costly ( an average lifetime saving of $ A133 ) and more effective ( with an additional 0.075 QALYs per patients ) than conventional management . Intensive management of hypertension had an incremental cost-effectiveness ratio ( ICER ) $ A2588 per QALY gained . Treating all known diabetics with angiotensin-converting enzyme ( ACE ) inhibitors was both less costly ( an average lifetime saving of $ A825 per patient ) and more effective than current treatment ( result ing in 0.124 additional QALYs per patient ) . Primary care screening for 50- to 69-year-olds plus intensive treatment of diabetes had an ICER of $ A13,781 per QALY gained . Primary care screening for hypertension ( between ages 50 and 69 years ) plus intensive blood pressure management had an ICER of $ A491 per QALY gained . Primary care screening for proteinuria ( between ages 50 and 69 years ) combined with prescription of an ACE inhibitor for all persons showing proteinuria and all known diabetics had an ICER of $ A4793 per QALY gained . CONCLUSIONS Strategies combining primary care screening of 50- to 69-year-olds for proteinuria , diabetes , and hypertension followed by the routine use of ACE inhibitors , and optimal treatment of diabetes and hypertension , respectively , have the potential to reduce death and end-stage kidney disease and are likely to represent good value for money Diabetes mellitus is the most common cause of  end-stage renal disease ( ESRD ) . In 1996 , 42 % of new cases of ESRD were caused by diabetes . Two thirds of these cases occurred in patients with type 2 diabetes ( 1 , 2 ) . Although tight control of blood sugar and hypertension might slow the development and progression of nephropathy in type 2 diabetes ( 3 ) , the most promising approach has been angiotensin-converting enzyme ( ACE ) inhibitor therapy ( 4 , 5 ) . Current recommendations emphasize identification and treatment of patients with incipient diabetic nephropathy by screening for microalbuminuria ( 6 ) . Because this test is not uniformly available ( and , until recently , sample s had to be sent to specialized laboratories ) , some physicians screen only for gross proteinuria with a dipstick or urinalysis . Others undoubtedly do not screen at all , either because they are unaware of the recommendations or they forget to do so ( 7 ) . Thus , some patients who might benefit from ACE inhibitors are not prescribed them ( 8) . Treating all patients with diabetes might be a simpler strategy , but patients who take ACE inhibitors may experience significant side effects ( 9 , 10 ) and may not comply with treatment ( 11 - 14 ) . The opportunity to avoid [ or delay ] ESRD in a few patients must be weighed against the cost of treating many patients with ACE inhibitors . Unfortunately , this issue is unlikely to be settled in clinical trials because a large number of patients and a very long follow-up would be required . For this reason , we used a decision model to simulate costs and clinical outcomes associated with three strategies for preserving renal function in patients with newly diagnosed type 2 diabetes : 1 ) treating all patients with ACE inhibitors , 2 ) screening for microalbuminuria , and 3 ) screening for gross proteinuria . Methods Decision Model We constructed a Markov model ( by using DATA 3.0 [ TreeAge Software , Inc. , Williamstown , Massachusetts ] ) to evaluate the cost-effectiveness of three clinical strategies for managing type 2 diabetes . Input data on the effectiveness of ACE inhibitors were obtained from three r and omized trials ( 15 - 17 ) , each of which examined treatment in a different stage of proteinuria . As shown in Figure 1 , we used four health states to model the progression of diabetic nephropathy : normoalbuminuria ( albumin excretion<30 mg/d ) , microalbuminuria ( excretion , 30 to 300 mg/d ) , gross proteinuria ( excretion>300 mg/d ) , and ESRD . The health states were further subdivided to reflect detection ( whether or not patients have been screened ) and treatment ( whether or not patients are receiving ACE inhibitors ) . Figure 1 . Health states and clinical strategies in the Markov model . With each cycle of the model , patients may progress to the next health state or to death , based on a specific transition probability . To simulate the typical screening interval , we used a cycle length of 1 year . We assumed that nephropathy does not regress and that progression is sequential ( that is , no states are skipped ) . However , patients may make the transition to death at any time . By following a large cohort of identical patients through time until all are in the death state , the model calculates average lifetime cost , life expectancy , quality -adjusted life expectancy , and marginal cost-effectiveness ( the additional cost per additional quality -adjusted life-year [ QALY ] compared with next best strategy ) for each strategy . Clinical Strategies We assessed three competing strategies . In the treat-all strategy , patients are not screened and all patients start receiving ACE inhibitor therapy at the time of diagnosis of diabetes mellitus . Screening adherence is not relevant to this strategy , but our modeling of side 
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The full impact of inaccurate test results was frequently not considered in economic evaluations in this setting as a societal perspective was rarely adopted .
The impact of false positive tests on patients in terms of the costs incurred in re-attending for repeat testing , and the anxiety associated with a positive test was almost always overlooked .