Identification of persons at high risk for kidney disease via targeted screening: the NKF Kidney Early Evaluation Program

Projecting the clinical burden of chronic kidney disease at the patient level (Inside CKD): a microsimulation modelling study

Background

Chronic kidney disease (CKD) is a global concern that presents significant challenges for disease management. Several factors drive CKD prevalence, including primary risk factors, such as type 2 diabetes and hypertension, and an ageing population. Inside CKD is an international initiative that aims to raise awareness of the substantial burden incurred by CKD.

Methods

Using a peer-reviewed microsimulation method, the clinical burden of CKD was estimated from 2022 to 2027. Demographic data from the Americas, Europe, and Asia-Pacific/Middle East were used to generate virtual populations and to project the prevalence of CKD, kidney replacement therapy, associated cardiovascular complications, comorbid conditions, and all-cause mortality in the CKD population over the modelled time frame.

Findings

Across the 31 participating countries/regions, the total prevalence of CKD was projected to rise to 436.6 million cases by 2027 (an increase of 5.8% from 2022), with most cases (∼80%) undiagnosed. Inside CKD projected a mean of 8859 cases of heart failure, 10,244 of myocardial infarction, and 7797 of stroke per 100,000 patients with CKD by 2027.

Interpretation

The clinical impact of CKD is substantial and likely to increase; the high prevalence of undiagnosed cases and associated complications may benefit from the implementation of health policy interventions that promote screening, earlier diagnosis, and interventions to improve outcomes.

Funding

AstraZeneca.

Targeted screening in the UK: A narrow concept with broad application

A recent report on screening in the UK proposed that the responsibility for recommendations on population and targeted screening programmes should be held by one new integrated advisory body. There is no wide international consensus on the definition of targeted screening. Our review identified and compared the defining components of screening terms: targeted, population, selective, and cascade screening, and case finding. Definitions of targeted screening and population screening were clearly demarcated by the eligible population; targeted and selective screening were found to be conceptually interchangeable; cascade screening, whilst conceptually similar to targeted screening across several components, was only used within the context of genetic diseases. There was little consensus between different definitions of case finding. These comparisons contributed to an updated definition of targeted screening. Considerable overlap between definition components across terms implies that a broad range of disease areas may fall into the remit of the new advisory body.

A simple questionnaire to detect chronic kidney disease patients from Long An province screening data in Vietnam

BACKGROUND

The prevalence of chronic kidney disease (CKD) in rural Vietnam is unknown. We wished to determine the prevalence of CKD and determine whether a simple questionnaire was able to detect individuals at high risk of CKD before expensive confirmatory laboratory testing.

METHODS

A cross sectional study was performed. We recruited 2037 participants from 13 communes of Long An province, Vietnam, for CKD screening with urine albumin/creatinine ratio (ACR) measured by immunoturbidimetric method and serum creatinine to estimate glomerular filtration rate (eGFR). CKD was defined as either ACR ≥ 30 mg/g or eGFR MDRD < 60 ml/min/1.73 m2. A two page questionnaire with 23 variables was administered to each participant with queries postulated to be correlated with risk of CKD.

RESULTS

Of the 2037 participants, 260 (12.76%) were found to have CKD. Five questionnaire variables (age more than 50, measured hypertension, history of diabetes, history of hypertension, and history of a low salt diet) were correlated with CKD, and used to construct a risk score for CKD.

CONCLUSIONS

CKD is common in Vietnam. Our questionnaire and risk score tool can be used to detect individuals with a higher likelihood of CKD, and who can then be more economically screened with routine laboratory confirmatory tests.

Opportunistic in-hospital screening for kidney disease using the Kidney Health Check

BACKGROUND

Chronic kidney disease (CKD) is a major public health issue and early detection may prevent morbidity and mortality. Screening for CKD is simply assessed using the Kidney Health Check (KHC), a compilation of blood pressure (BP), estimated glomerular filtration rate (eGFR) and urinalysis (UA). KHC screening of high risk hospital inpatients is recommended, but its implementation and cost-effectiveness is unknown.

AIMS

We aimed to determine the proportion of patients currently tested for all components of the KHC during an acute hospital admission, and to compare the estimated costs of screening and subsequent follow-up with other screening programs.

METHODS

A retrospective audit was conducted of consecutively admitted adult patients, and the frequency of BP, eGFR and UA testing recorded. Using published data, the likely costs and benefits of components of the KHC were estimated.

RESULTS

Two hundred patients (median age 75 years, range 20-98) were assessed. All had a documented BP and eGFR, and 55% had a UA, representing a complete KHC. Of the total, 141 (71%) had one or more abnormalities detected, and of 71 with an eGFR <60 mL/min per 1.73 m(2) , only 22 (31%) had a recorded diagnosis of CKD. Estimated costs of opportunistic in-hospital KHC screening are below those of current Australian screening programs.

CONCLUSIONS

Hospital in-patients frequently have a full KHC and most have abnormalities detected. Opportunistic inpatient KHC screening would have little impact on hospital costs, but may result in significant health benefits. The KHC should be included in routine discharge documentation.

Investigation of urinary abnormalities and risk factors for kidney disease in the World Kidney Day campaigns in Northeast Brazil

Objective: chronic kidney disease (CKD) is an increasing common problem in the world due to the exponential growth of diabetes mellitus, hypertension and other risk factors. The aim of this study is to investigate urinary abnormalities and risk factors for kidney disease in the general population. Methods: this study was performed from data collected during the annual World Kidney Day (WKD) campaigns, in Fortaleza, Ceará, Brazil, between 2009 and 2012. The population sought assistance spontaneously in stands placed in high people-traffic areas. Results: among 2,637 individuals interviewed, the mean age was 50.7±15.7 years and 53% were male. The main risk factors found were sedentarism (60.7%), obesity (22.7%) and smoking (19.8%). Blood pressure (BP) > 140x90 mmHg was found in 877 (33%). Increased BP was found for the first time in 527 cases (19.9%). Cardiovascular diseases were reported in 228 (8.6%). Diabetes was related by 343 (13%). Capillary blood glucose > 200 mg/dL was found in 127 (4.8%) and it was > 200 mg/dL for the first time in 30 (1.13%). Urinalysis was performed in 1,151 people and found proteinuria in 269 (23.3%). Proteinuria was most frequent in hypertension people (77.3% vs. 55.8%, p=0.0001), diabetes mellitus (22.7% vs. 15.2%, p=0.005) and elderly (42.1% vs. 30.7%, p=0.0007). Conclusion: risk factors for CKD are frequent in the general population. Many individuals had hypertension and diabetes and did not know this. It is important to regularly perform actions like WKD in order to early detect potential candidates for CKD.

Lessons from the profile of kidney diseases among Afghan refugees

BACKGROUND

Due to a paucity of research on the profile of kidney diseases among refugee populations, specifically Afghan refugees in Iran, this study aimed to illustrate the pattern of kidney disease among Afghan refugees in Iran and create a database for evaluating the performance of future health services.

MATERIAL AND METHODS

This was a retrospective cross sectional study, in which we collected the demographics and profile of kidney diseases among Afghan refugees between 2005 and 2010 from referrals to the United Nations High Commissioner for Refugees (UNHCR) offices in Iran.

RESULTS

The total number of referrals in this group of diseases was 3193 out of 23 152 with 41.5% female and 58.5% male. Regarding age distribution, 10.5% were 0-14 years of age, 78% were 15-59, and 11.5% were ≥60. The most common health referral for females and males (0-14) was end-stage renal disease (ESRD), accounting for 34.6%. This was also the main reason of referrals for females and males aged 15-59, accounting for 73.5% and 66.6%, respectively, and in both sexes in the ≥60 age range it was 63.1%.

CONCLUSIONS

The pattern of our renal clinic referrals may gradually change to ESRD, which is associated with a huge economic burden. The need to provide health insurance to everyone or reform the health care system to provide coverage for more of the population can be justified and would improve cost effectiveness.

The association of parathyroid hormone with ESRD and pre-ESRD mortality in the Kidney Early Evaluation Program

CONTEXT

Studies have suggested that PTH may influence mortality and progression of chronic kidney disease. However, the development of either event may influence the development of the other as a competing risk.

OBJECTIVE

The objective of the study was to examine the association of PTH with end-stage renal disease (ESRD) and pre-ESRD death using a competing risk survival model.

DESIGN, SETTING, AND PATIENTS

A total of 10,823 participants in the Kidney Early Evaluation Program with chronic kidney disease (estimated glomerular filtration rate < 60 ml/min per 1.73 m(2)) were examined from 2005 to 2010.

MAIN OUTCOME MEASURES

The association of PTH levels with ESRD and pre-ESRD mortality was ascertained by linking Kidney Early Evaluation Program data to the Social Security Administration Death Master File and the U.S. Renal Data System.

RESULTS

Among the cohort, the incidence of ESRD and pre-ESRD mortality was 6.4 and 20.1 events per 1000 person-years. Higher PTH levels were associated with increasing age, black race, lack of a high school education, cardiovascular disease, hypertension, and lower glomerular filtration rate. The incidence of ESRD and pre-ESRD mortality was lowest among participants in the second PTH quintile. After multivariate adjustment, as compared with the second quintile, the risk of pre-ESRD mortality was higher in the third [subhazard ratio (SHR) 1.52 (95% confidence interval 1.04-2.22)], fourth [SHR 1.73 (95% confidence interval 1.19-2.52)], and fifth [SHR 1.86 (1.28-2.52)] quintiles, respectively. Conversely, PTH was not associated with ESRD after multivariate adjustment. The association was not modified by diabetic status, gender, race, or glomerular filtration rate status.

CONCLUSIONS

Elevated PTH levels are associated with increased pre-ESRD mortality but not with ESRD.

Association of physician care with mortality in Kidney Early Evaluation Program (KEEP) participants

BACKGROUND

People with or at high risk of chronic kidney disease (CKD) are at increased risk of premature morbidity and mortality. We sought to examine the effect of care provided by a primary care physician (PCP) on survival for all participants in the National Kidney Foundation's Kidney Early Evaluation Program (KEEP) and the effect of care provided by a nephrologist on survival for KEEP participants with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2).

METHODS

Provision of care by a PCP (n = 138,331) or nephrologist (n = 10,797) was defined using self-report of seeing that provider within the past year. Survival was ascertained by linking KEEP data to the Social Security Administration Death Master File. Multivariable Cox proportional hazards models examining the relationship between primary care and nephrologist provider status adjusted for age, sex, race, smoking status, education, health insurance, diabetes, cardiovascular disease, hypertension, cancer, albuminuria, body mass index, baseline eGFR, and hemoglobin level, with nephrology models further adjusting for calcium, phosphorus, and parathyroid hormone levels.

RESULTS

Of all participants, 70.9% (98,050 of 138,331) reported receiving PCP care; older age and female sex were associated with this care. During a median follow-up of 4.2 years, 4,836 deaths occurred. After multivariable adjustment, receiving PCP care and mortality were not associated (HR, 0.94; 95% CI, 0.86-1.03; P = 0.2). Of participants with eGFR <60 mL/min/1.73 m(2), 10.1% (1,095 of 10,797) reported receiving nephrology care; younger age and male sex were associated with receipt of nephrology care. During a mean follow-up of 2.2 years, 558 deaths occurred. After multivariable adjustment, nephrologist care was not associated with mortality (HR, 1.01; 95% CI, 0.75-1.36; P = 0.9). These associations were not modified by other specialist care (endocrinologist or cardiologist).

CONCLUSIONS

For all KEEP participants, neither PCP nor nephrology care was associated with improved survival. These results highlight the need to explore the connection between access to health care and outcomes in persons at high risk of or with CKD.

Association of family history of ESRD, prevalent albuminuria, and reduced GFR with incident ESRD

BACKGROUND

The contribution of albuminuria to the increased risk of incident end-stage renal disease (ESRD) in individuals with a family history of ESRD has not been well studied.

STUDY DESIGN

Prospective cohort study. STUDY SETTING & PARTICIPANTS: We analyzed data for family history of ESRD collected from 19,409 participants of the Renal REGARDS (Reasons for Geographic and Racial Differences in Stroke) cohort study.

PREDICTOR

Family history of ESRD was ascertained by asking "Has anyone in your immediate family ever been told that he or she had kidney failure? This would be someone who is on or had been on dialysis or someone who had a kidney transplant."

STUDY OUTCOMES

Incidence rate for ESRD.

MEASUREMENTS

Morning urine albumin-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR). Incident cases of ESRD were identified through the US Renal Data System.

RESULTS

A family history of ESRD was reported by 11.1% of participants. Mean eGFRs for those with and without a family history of ESRD were 87.5 ± 22.2 (SD) and 86.5 ± 19.3 mL/min/1.73 m(2), respectively (P = 0.05) and the respective geometric mean ACRs were 12.2 and 9.7 mg/g (P < 0.001). ESRD incidence rates for those with and without a family history of ESRD were 244.3 and 106.1/100,000 person-years, respectively. After adjusting for age, sex, and race, the ESRD HR for those with versus those without a family history of ESRD was 2.13 (95% CI, 1.18-3.83). Adjustment for comorbid conditions and socioeconomic status attenuated this association (HR, 1.82; 95% CI, 1.00-3.28), and further adjustment for baseline eGFR and ACR completely attenuated the association between family history of ESRD and incident ESRD (HR, 1.12; 95% CI, 0.69-1.80).

LIMITATIONS

The report of a family history of ESRD was not validated.

CONCLUSION

Family history of ESRD is common in older Americans and the increased risk of ESRD associated with a family history reflects lower GFR, higher albuminuria, and comorbid conditions.

The Association between Parathyroid Hormone Levels and the Cardiorenal Metabolic Syndrome in Non-Diabetic Chronic Kidney Disease

AIMS

The relationship between parathyroid hormone (PTH) and the cardiorenal metabolic syndrome was examined among non-diabetic persons with chronic kidney disease (CKD).

METHODS

In a cross-sectional analysis, the relationship between PTH levels and the cardiorenal metabolic syndrome was investigated in 3,215 non-diabetic participants in the National Kidney Foundation-Kidney Early Evaluation Program (KEEP 2.0) found to have CKD (eGFR <60 ml/min/1.73 m2).

RESULTS

In unadjusted analyses, the prevalence of the cardiorenal metabolic syndrome increased along increasing PTH quartiles (31.7, 33.8, 37.3, and 48.7%, respectively, p for trend <0.0001). After multivariate adjustment, as compared to the first PTH quartile, odds of the cardiorenal metabolic syndrome were 16% (p = 0.18), 35% (p = 0.006), and 80% (p < 0.0001) higher for the second, third, and fourth quartiles, respectively. When taken as a continuous predictor, each standard deviation increase of natural log transformed PTH was associated with 26% (p < 0.0001) higher odds of the cardiorenal metabolic syndrome. The association of PTH with the cardiorenal metabolic syndrome was not modified by age or gender (p for interaction was not significant for both modifiers).

CONCLUSIONS

Among an outpatient non-diabetic population with CKD, higher PTH levels were associated with a higher prevalence of the cardiorenal metabolic syndrome.

Population based screening for chronic kidney disease: cost effectiveness study

OBJECTIVE

To determine the cost effectiveness of one-off population based screening for chronic kidney disease based on estimated glomerular filtration rate.

DESIGN

Cost utility analysis of screening with estimated glomerular filtration rate alone compared with no screening (with allowance for incidental finding of cases of chronic kidney disease). Analyses were stratified by age, diabetes, and the presence or absence of proteinuria. Scenario and sensitivity analyses, including probabilistic sensitivity analysis, were performed. Costs were estimated in all adults and in subgroups defined by age, diabetes, and hypertension.

SETTING

Publicly funded Canadian healthcare system.

PARTICIPANTS

Large population based laboratory cohort used to estimate mortality rates and incidence of end stage renal disease for patients with chronic kidney disease over a five year follow-up period. Patients had not previously undergone assessment of glomerular filtration rate.

MAIN OUTCOME MEASURES

Lifetime costs, end stage renal disease, quality adjusted life years (QALYs) gained, and incremental cost per QALY gained.

RESULTS

Compared with no screening, population based screening for chronic kidney disease was associated with an incremental cost of $C463 (Canadian dollars in 2009; equivalent to about £275, €308, US $382) and a gain of 0.0044 QALYs per patient overall, representing a cost per QALY gained of $C104 900. In a cohort of 100 000 people, screening for chronic kidney disease would be expected to reduce the number of people who develop end stage renal disease over their lifetime from 675 to 657. In subgroups of people with and without diabetes, the cost per QALY gained was $C22 600 and $C572 000, respectively. In a cohort of 100 000 people with diabetes, screening would be expected to reduce the number of people who develop end stage renal disease over their lifetime from 1796 to 1741. In people without diabetes with and without hypertension, the cost per QALY gained was $C334 000 and $C1 411 100, respectively.

CONCLUSIONS

Population based screening for chronic kidney disease with assessment of estimated glomerular filtration rate is not cost effective overall or in subgroups of people with hypertension or older people. Targeted screening of people with diabetes is associated with a cost per QALY that is similar to that accepted in other interventions funded by public healthcare systems.

Chronic kidney disease awareness, screening and prevention: rationale for the design of a public education program

Design principles for a chronic kidney disease (CKD) screening program start with the general population at increased risk of CKD. Simple risk factor analysis demonstrates diabetes, hypertension, cardiovascular disease and older age as significant associated conditions. More comprehensive risk factor analysis shows only diabetes and hypertension as risk factors in people aged less than 50-60 years, and that anyone aged older than 50-60 years is at risk. Assessment of the relationship between CKD stage and cardiovascular risk factors shows early stage CKD to be associated with poor blood pressure control, which should be addressed. Other risk factors should be more completely assessed to determine if participants and their physicians are adequately addressing factors amenable to treatment to reduce high adverse event rates, premature death and progression to end-stage renal disease (ESRD). Such assessment is needed to reduce the high burden of ESRD on national health-care systems, which can only be addressed by early screening and active treatment.

Obesity is associated with increased parathyroid hormone levels independent of glomerular filtration rate in chronic kidney disease

The objective of the study was to examine the relationship of obesity and parathyroid hormone (PTH) levels among persons with chronic kidney disease (CKD). This was a cross-sectional analysis of 4551 participants in the National Kidney Foundation-Kidney Early Evaluation Program found to have CKD (estimated glomerular filtration rate <60 mL/[min 1.73 m(2)]) examining the relationship of body mass index (BMI) and PTH levels. In unadjusted analysis, PTH levels increased with increasing BMI quartiles. After adjustment for age, race, sex, diabetes, calcium, phosphorus, estimated glomerular filtration rate, and presence of microalbuminuria, PTH levels were 7.3% (P = .008), 11.9% (P < .0001), and 18.1% (P < .0001) higher in the second, third, and fourth BMI quartiles, respectively, as compared with the first quartile. In a companion analysis, higher BMI was associated with increased odds of having an elevated PTH measurement (>70 pg/mL). Compared with the first quartile, odds ratios for elevated PTH were 1.26 (95% confidence interval, 1.06-1.50; P = .01), 1.38 (1.15-1.65, P = .0005), and 1.66 (1.37-2.00, P < .0001) for the second, third, and fourth quartiles, respectively. We found no effect modification by race, diabetes, or presence of microalbuminuria. Therefore, in a large community-dwelling population with CKD, the presence of obesity and of increasing BMI is associated with higher PTH levels independent of measured confounders and may be an additional target in the management of secondary hyperparathyroidism in CKD.

Screening populations at increased risk of CKD: the Kidney Early Evaluation Program (KEEP) and the public health problem

The epidemiological characteristics of the US end-stage renal disease population growth and increased costs in the late 1980s framed the public health agenda for the development of a community-based chronic kidney disease (CKD) screening program. Development of the National Kidney Foundation Kidney Early Evaluation Program (KEEP) included 2 preliminary screening programs, the Computerized Assessment of Risk and Education and the KEEP pilot, which was organized around the African American Study of Kidney Diseases clinical centers. The current KEEP program, launched in August 2000, targets individuals with diabetes, hypertension, or a family history of diabetes or hypertension or CKD. The screening includes informed consent, health screening questionnaire, diagnostic panel, and physician consultation. Participants are followed up by telephone and mail. Of 100,000 KEEP participants screened, 28.7% have CKD and 6.7% self-reported CKD stages 1 to 5. Conversely, National Health and Nutrition Examination Survey 1999-2002 results show 13.1% CKD prevalence; 2.9% of women and 17.9% of men with an estimated glomerular filtration rate less than 60 mL/min/1.73 m(2) self-report CKD. CKD prevalences in KEEP by stage are 3.1% for stage 1; 4.8%, stage 2; 19.7%, stage 3; and 1.1%, stages 4 and 5, confirming the ability of this targeted screening program to detect CKD early. In addition to identifying individuals at increased risk of kidney disease, KEEP's structured data collection provides an opportunity to advance knowledge about kidney disease and advance the CKD public health agenda.

Comprehensive public health strategies for preventing the development, progression, and complications of CKD: report of an expert panel convened by the Centers for Disease Control and Prevention

Chronic kidney disease (CKD) is a public health threat in the United States, with increasing prevalence, high costs, and poor outcomes. More widespread effort at the prevention, early detection, evaluation, and management of CKD and antecedent conditions could prevent complications of decreased kidney function, slow the progression of kidney disease to kidney failure, and reduce cardiovascular disease risk. In 2006, the Centers for Disease Control and Prevention (CDC) launched an initiative on CKD. As part of this initiative, the CDC convened an expert panel to outline recommendations for a comprehensive public health strategy to prevent the development, progression, and complications of CKD in the United States. The panel adapted strategies for primary, secondary, and tertiary prevention for chronic diseases to the conceptual model for the development, progression, and complications of CKD; reviewed epidemiological data from US federal agencies; and discussed ways of integrating public health efforts from various agencies and organizations. The panel recommended a 10-point plan to the CDC to improve surveillance, screening, education, and awareness directed at 3 target populations: people with CKD or at increased risk of developing CKD; providers, hospitals, and clinical laboratories; and the general public. Cooperation among federal, state, and local governmental and private organizations will be necessary to carry out these recommendations.

Iron deficiency anemia

The most severe consequence of iron depletion is iron deficiency anemia (IDA), and it is still considered the most common nutrition deficiency worldwide. Although the etiology of IDA is multifaceted, it generally results when the iron demands by the body are not met by iron absorption, regardless of the reason. Individuals with IDA have inadequate intake, impaired absorption or transport, physiologic losses associated with chronological or reproductive age, or chronic blood loss secondary to disease. In adults, IDA can result in a wide variety of adverse outcomes including diminished work or exercise capacity, impaired thermoregulation, immune dysfunction, GI disturbances, and neurocognitive impairment. In addition, IDA concomitant with chronic kidney disease or congestive heart failure can worsen the outcome of both conditions. In this review, the prevalence of IDA related to confounding medical conditions will be described along with its diverse etiologies. Distinguishing IDA from anemia of chronic disease using hematologic measures is reviewed as well. In addition, current diagnostic strategies that are inclusive of clinical presentation, biochemical tests, and differential diagnosis will be outlined, followed by a discussion of treatment modalities and future research recommendations.

Trends in mineral metabolism: Kidney Early Evaluation Program (KEEP) and the National Health and Nutrition Examination Survey (NHANES) 1999-2004

BACKGROUND

Chronic kidney disease (CKD) is associated with mineral metabolism dysregulation, cardiovascular disease, and premature mortality. No study specifically examined mineral metabolism trends in a generalizable sample of patients at increased CKD risk.

METHODS

This cross-sectional analysis from November 1, 2005, to December 31, 2006, of calcium, phosphorus, and parathyroid hormone (PTH) includes 2,646 individuals with estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m(2) in the National Kidney Foundation Kidney Early Evaluation Program (KEEP), a community-based health-screening program targeting individuals 18 years and older with diabetes, hypertension, or family history of kidney disease, diabetes, or hypertension. A parallel analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2004 data was performed.

RESULTS

In KEEP, as eGFR decreased from 55 to less than 60 mL/min/1.73 m(2) to less than 30 mL/min/1.73 m(2), calcium level decreased (9.55 +/- 0.47 to 9.34 +/- 0.62 mg/dL; P < 0.001), phosphorus level increased (3.70 +/- 0.59 to 4.15 +/- 0.80 mg/dL; P < 0.001), and PTH level increased (66.3 +/- 36.3 to 164 +/- 109 pg/mL; mean, 80.8 +/- 57.0 pg/mL; P < 0.001). NHANES 1999-2004 showed similar trends, with PTH values not as high. Individuals within opinion-based Kidney Disease Outcomes Quality Initiatives targets from the highest to the lowest eGFR group were as follows: calcium, 93.0% to 92.3% (KEEP) and 97.4% to 89.6% (NHANES); phosphorus, 90.4% to 90.3% (KEEP) and 91.6% to 87.1% (NHANES); and PTH, 46.1% to 31.2% (KEEP) and 56.4% to 36.1% (NHANES).

CONCLUSIONS

In a community-based CKD screening population, increased PTH level occurs early in patients with stage 3, typically with normal calcium and phosphorus levels. These findings support the importance of including PTH with calcium and phosphorus monitoring for individuals with eGFR less than 60 mL/min/1.73 m(2).

Applying an expanded set of cognitive design principles to formatting the Kidney Early Evaluation Program (KEEP) longitudinal survey

BACKGROUND

The National Kidney Foundation Kidney Early Evaluation Program (KEEP) is a free community-based health-screening program targeting populations at greatest risk of chronic kidney disease (CKD), those with high rates of diabetes and hypertension, and a high proportion of racial/ethnic minorities. The KEEP Longitudinal Survey will adopt methods similar to those used in KEEP to gather follow-up data to measure CKD-related heath status and gauge program effectiveness for repeated KEEP participants with evidence of CKD stages 3 to 5. KEEP has defined objectives to enhance follow-up survey response rates and target vulnerable populations who bear the greatest CKD risk-factor burdens.

METHODS

The KEEP Follow-up Form was assessed for adherence to 6 cognitive design principles (simplicity, consistency, organization, natural order, clarity, and attractiveness) considered to summate the techniques guiding good survey development and for the additional cognitive design principles of readability and variation of readability across survey items.

RESULTS

The KEEP Follow-up Form was found to include violations of each cognitive design principle and readability principle, possibly contributing to item nonresponse and low follow-up rates in KEEP. It was revised according to empirically substantiated formatting techniques guided by these principles and found during qualitative assessment to be more user friendly, simpler, better organized, more attractive, and easier to read. Subsequent development of the KEEP Longitudinal Survey form also was guided by these principles.

CONCLUSION

To ensure ease of use by populations with limited literacy skills, poor health literacy, and limited survey literacy, survey researchers must apply cognitive design principles to survey development to improve participation and response rates.

CKD in the United States: Kidney Early Evaluation Program (KEEP) and National Health and Nutrition Examination Survey (NHANES) 1999-2004

BACKGROUND

The prevalence of chronic kidney disease (CKD) is increasing in the United States, caused in part by older age and increasing prevalences of hypertension and type 2 diabetes. CKD is silent and undetected until advanced stages. The study of populations with earlier stages of kidney disease may improve outcomes of CKD.

METHODS

The Kidney Early Evaluation Program (KEEP), a National Kidney Foundation program, is a targeted community-based health-screening program enrolling individuals 18 years and older with diabetes, hypertension, or family history of kidney disease, diabetes, or hypertension. Participants who had received transplants or were on regular dialysis treatment were excluded from this analysis. The National Health and Nutrition Examination Survey (NHANES) 1999-2004 was a nationally representative cross-sectional survey; participants were interviewed in their homes and/or received standardized medical examinations in mobile examination centers.

RESULTS

Of the 61,675 KEEP participants, 16,689 (27.1%) were found to have CKD. In the NHANES sample of 14,632 participants, 2,734 (15.3%) had CKD. Older age, smoking, obesity, diabetes, hypertension, and cardiovascular disease were associated significantly with CKD in both KEEP and NHANES (P < 0.05 for all). Of note, the likelihood for CKD in African Americans differed between KEEP (odds ratio, 0.81; P < 0.001) and NHANES (odds ratio, 1.10; P = 0.2).

CONCLUSION

A greater prevalence of CKD was detected in the KEEP screening than in the NHANES data. KEEP has the limitations common to population-screening studies and conclusions for population-attributable risk may be limited. The targeted nature of the KEEP screening program and the large sample size with clinical characteristics comparable to NHANES validates KEEP as a valuable cohort to explore health associations for the CKD and at-risk-for-CKD populations in the United States.

Chronic kidney disease prevention in Singapore

In consideration of the epidemiologic basis for screening and surveillance, a comprehensive program for chronic kidney disease prevention was initiated in Singapore by the National Kidney Foundation Singapore (NKF Singapore) in 1997. Reasons for developing this include the rising rate of end-stage renal disease in the country, and the projected escalation because of the increase in chronic diseases that lead to end-stage renal disease (ESRD) such as diabetes mellitus and hypertension. Presented are progress and preliminary findings of this program, as well as that of the parallel initiative of Singapore's Ministry of Health. The NKF Singapore program incorporates primary, secondary and tertiary approaches to the prevention of chronic kidney disease. These include the population-based screening for early chronic kidney disease and chronic diseases that are associated with kidney disease and the implementation of disease management programs that aim to improve the multi-faceted care of patients with chronic diseases that lead to ESRD, including the development of community-based "Prevention Centers." The screening program identified risk factors for proteinuria, including the Malay race, increasing age, family history of kidney disease, and higher levels of systolic and diastolic BP even within the normal ranges. Longitudinal follow-up of both prevention programs are critical to provide evidence for the efficacy of such screening and intervention programs in improving chronic kidney disease outcomes, while reducing the cost of care.

Efficacy of urine screening at school: experience in Shanghai, China

To explore the prevalence of hematuria or proteinuria in school children in Shanghai and to evaluate the screening methods, we conducted urine screening in more than 40,000 school children between 2003 and 2005. Children were tested with dipsticks read manually (method A) or dipsticks read by machines (method B) combined with a sulfosalicylic acid test or microscopy. Some children were tested once, and others who had abnormal results in the first screening were tested again 2 weeks later. The prevalence of urine abnormalities in the first screening was more than 5.00% and of the second screening about 1.00%. Either method B or testing two urine samples for each child had higher specificity. As to the direct cost, that of screening twice with method A was lower than just screening once with method B. So using method A to screen twice for each child was not only convenient and economical, but also could reduce the false positive rate effectively. More than 10 months of follow-up diagnosed two cases of IgA nephropathy. Asymptomatic chronic renal diseases in school children could be detected through school urine screening. For Shanghai, China, screening twice using method A might be the best choice.

Familial Clustering of Chronic Kidney Disease

The incidence and prevalence rates of most forms of chronic kidney disease (CKD) had steadily been increasing for the past 30 years, although these rates now appear to have reached a plateau. It is clear that an individual's likelihood of developing progressive CKD results from complex interactions between multiple genetic and environmental factors. Familial clustering of CKD and end-stage renal disease (ESRD) is observed among all the common etiologies of nephropathy. This article reviews the epidemiology of the familial clustering of kidney disease, as well as potential environmental and genetic contributors. The related impact of familial clustering of cardiovascular disease (CVD) and the impact of CVD on the current epidemic of ESRD is also discussed. It is imperative that nephrologists and primary care physicians recognize that individuals who have relatives with advanced nephropathy are themselves at high risk for subsequent kidney disease, proteinuria, and atherosclerotic cardiovascular complications. Until kidney failure genes are identified, it is reasonable to use "family history" (FH) as a surrogate marker for risk of future nephropathy. The detection of kidney disease genes holds great promise for detecting novel pathways that initiate renal fibrosis and lead to progressive loss of renal function. These pathways are likely to offer new therapies that may slow or halt development of chronic kidney failure.

Stabilization of glomerular filtration rate in advanced chronic kidney disease: a two-year follow-up of a cohort of chronic kidney disease patients stages 4 and 5

This study examines whether stabilization of the glomerular filtration rate (GFR) is possible in patients with advanced chronic kidney disease (CKD), managed in a CKD clinic. A cohort of 82 patients with stages 4 and 5 CKD was followed for a period of 2 years after initiation of erythropoietin for anemia to determine the GFR and the frequency of primary outcomes (dialysis, transplantation, or death). GFR, calculated by the abbreviated Modification of Diet in Renal Disease formula, was determined every 3 months. After 24 months, 35 subjects (43%) developed a primary outcome. Controlled for other risk factors, the risk of having a primary outcome increased 19.7% for every unit that the GFR decreased (95% confidence interval [CI], 11.9%-26.8%, P < .001) and decreased 21.7% for every unit that the hemoglobin increased (95% CI, 0.5%-38.4%, P < .001). Blacks had a 3.1 times higher risk (95% CI, 1.4-6.9, P = .006) of developing a primary outcome than other ethnicities. In subjects who did not develop primary outcomes (n = 47 or 57%), GFR remained unchanged (19.5 +/- 9.1 at the end of the study v 20.8 +/- 5.3 mL/min/1.73 m(2) at baseline, P = .16). The standardized mortality rate was 4.75 and 9.77 per 100 person-year for stages 4 and 5, respectively. We conclude that stabilization of GFR over a 2-year period can be achieved in many patients with advanced CKD treated with erythropoietin in a CKD clinic. Although the precise reason for the stabilization of GFR cannot be elucidated from this study, our data are "proof of concept" that CKD outcomes can be improved in a CKD clinic setting.

Endothelial dysfunction contributes to renal function-associated cardiovascular mortality in a population with mild renal insufficiency: the Hoorn study

Mildly impaired renal function is associated with cardiovascular morbidity and mortality. There are indications that endothelial dysfunction and/or chronic inflammation, which play an important role in atherothrombosis, are present in early stages of renal insufficiency. This study investigated whether and to which extent endothelial dysfunction and inflammation were related to renal function and contributed to renal function-associated cardiovascular mortality in a population-based cohort (n = 613), aged 50 to 75 yr, that was followed with a median duration of 12.5 yr. During follow-up, 192 individuals died (67 of cardiovascular causes). At baseline, renal function was estimated with serum creatinine, the Cockcroft-Gault formula, and the Modification of Diet in Renal Disease equation of GFR (eGFR). Endothelial function was estimated by plasma von Willebrand factor, soluble vascular cell adhesion molecule-1, and the urinary albumin-creatinine ratio. Inflammatory activity was estimated by plasma C-reactive protein and soluble intercellular adhesion molecule-1. Renal function was mildly impaired (mean eGFR 68 +/- 12 ml/min per 1.73 m(2)) and independently associated with von Willebrand factor (standardized beta -0.09; 95% confidence interval [CI] -0.18 to -0.002; P < 0.05), soluble vascular cell adhesion molecule-1 (standardized beta -0.14; 95% CI -0.22 to -0.05; P < 0.01), and albumin-creatinine ratio (standardized beta -0.15; 95% CI -0.23 to -0.08; P < 0.001) but not with markers of inflammatory activity. Renal function was inversely associated with cardiovascular and all-cause mortality. The relative risk for cardiovascular mortality but not all-cause mortality associated with renal function decreased from 1.22 to 1.12 per 5 ml/min per 1.73 m(2) decrease of eGFR after adjustment for markers of endothelial dysfunction. In conclusion, endothelial dysfunction was related to renal function and contributed to the excess in cardiovascular mortality in this population-based cohort with mild renal insufficiency.

Genetic factors in end-stage renal disease

Despite more aggressive treatment of diabetes, hypertension, and hyperlipidemia, the incidence and prevalence rates of end-stage renal disease (ESRD) continue to increase worldwide. The likelihood of developing chronic kidney disease in an individual is determined by interactions between genes and the environment. Familial clustering of nephropathy has repeatedly been observed in all population groups studied and for multiple etiologies of kidney disease. A three- to nine-fold greater risk of ESRD is observed in individuals with a family history of ESRD. Marked racial variation in the familial aggregation of kidney disease exists, with high rates in African American, Native American, and Hispanic American families. Disparate etiologies of nephropathy aggregate within African American families, as well. These data have led several investigators to search for genes linked to diabetic and other forms of nephropathy. Evidence for linkage to kidney disease has been detected and replicated at several loci on chromosomes 3q (types 1 and 2 diabetic nephropathy), 10q (diabetic and nondiabetic kidney disease), and 18q (type 2 diabetic nephropathy). Multicenter consortia are currently recruiting large numbers of multiplex diabetic families with index cases having nephropathy for linkage and association analyses. In addition, large-scale screening studies are underway, with the goals of better defining the overall prevalence of chronic kidney disease, as well as educating the population about risk factors for nephropathy, including family history. Given the overwhelming burden of kidney disease worldwide, it is imperative that we develop a clearer understanding of the pathogenesis of nephropathy so that individuals at risk can be identified and treated at earlier, potentially reversible, stages of their illness.

The familial clustering of renal disease and related phenotypes

This article reviews the familial aggregation of chronic kidney diseases including end-stage renal disease and albuminuria, along with variation in glomerular filtration rate. In addition to environmental influences on the progression of nephropathy, epidemiologic evidence in support of the existence of renal failure susceptibility genes is presented.

Long-term protection of obese Zucker rat kidneys from fibrosis and renal failure with an angiotensin-converting enzyme inhibitor/diuretic combination

Some combinations of antihypertensive agents were shown to reduce proteinuria in patients with renal failure. However, preventive effects of such combinations on renal structure and function are presently unknown when treatment is administered before the onset of renal abnormalities. We thus investigated the long-term effects of an angiotensin-converting enzyme (ACE) inhibitor (perindopril)/diuretic (indapamide) combination (per/ind) in the Zucker rat, a classical model of chronic renal failure associated with obesity, hyperlipidemia, and insulin resistance. Two-month-old lean and obese Zucker rats, presenting normal renal structure and function at this young age, received per/ind (0.76 + 0.24 mg/kg of body weight/day) or the vehicle of this combination by daily gavage. After 8.5 consecutive months of treatment, those 10.5-month-old rats were used for determination of renal structural and functional parameters which were examined using standard renal clearance experiments and kidney tissue analysis. Per/ind prevented focal and segmental glomerular hyalinosis and tubulo-interstitial damage in obese rats. Treatment was also associated with a significant reduction in several staining markers of glomerular and interstitial fibrosis. The hypertrophy of superficial glomeruli and the mesangial expansion of deep glomeruli observed in control rats were reduced in per/ind-treated obese rats. The severe proteinuria observed in 10.5-month-old control obese rats was prevented by per/ind, while glomerular filtration and renal hemodynamic parameters reached similar values to those obtained in lean animals. These results show that long-term treatment with this ACE inhibitor/diuretic combination protects renal structure and function in the obese Zucker rat, emphasizing the potential efficiency of such therapy in renal failure prevention.

Kidney Early Evaluation Program (KEEP). Findings from a community screening program

PURPOSE

The Kidney Early Evaluation Program (KEEP), which was started in 1997, aims to identify persons at risk for chronic kidney disease (CKD) and encourage at-risk persons to seek evaluation and management from a healthcare provider.

METHODS

Community screening was conducted using a standardized questionnaire and test panel that was administered by local affiliates of the National Kidney Foundation (NKF) using volunteer lay and medical personnel. The screening was limited to persons at high risk for CKD, which was defined as those with a personal history of diabetes or hypertension, or a first-order relative with diabetes, hypertension, or kidney disease. The KEEP Data Coordinating Center was established to maintain a de-identified database of demographic information and test results on the screened persons.

RESULTS

Data on the first 11,246 participants were analyzed. As expected, the KEEP population was enriched with African Americans and was older than the general population. Diabetes was determined by self-report or abnormal blood glucose levels at screening and was present in 2690 of the persons screened. Chronic kidney disease was identified in 47.4% of this population.

CONCLUSIONS

Targeted community screening for kidney disease in a high-risk population can identify a significant number of persons with CKD, enhance awareness of the disease, and may improve health-seeking behavior.

The role of renin-angiotensin-aldosterone system inhibition in chronic kidney disease

Chronic kidney disease (CKD) is emerging as a new health pandemic. Underlying the global rise in CKD is an increase in diabetes, hypertension and other cardiovascular risk factors leading to progressive renal dysfunction. Emerging evidence strongly suggests that achieving target blood pressure goals via inhibition of the renin-angiotensin-aldosterone system confers significant renal and cardioprotection for patients with CKD. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) lower blood pressure, reduce proteinuria and reduce both the progression of CKD and adverse cardiovascular events. The role of aldosterone inhibition and combination therapy, such as ACEI/ARB, in CKD are under investigation. As our understanding of the basic mechanisms underlying CKD progression advances, novel therapies targeting post-translational endothelial and mesangial messengers downstream from angiotensin II and aldosterone may become available for clinical use.

Early detection of kidney disease in community settings: the Kidney Early Evaluation Program (KEEP)

BACKGROUND

Early identification of persons at risk for kidney disease provides an opportunity to prevent or delay its progression and decrease morbidity and mortality. Our hypothesis was that implementation of a targeted screening program in communities with high-risk populations would detect previously unidentified persons with or at high risk for chronic kidney disease (CKD) with a prevalence that exceeds that predicted for CKD in the general population.

METHODS

Persons with hypertension or diabetes or a first-order relative with hypertension, diabetes, or kidney disease were screened for kidney disease risk factors. Blood pressure, blood glucose level, serum creatinine level, hemoglobin level, microalbuminuria, hematuria, pyuria, body mass index, and estimated glomerular filtration rate (EGFR) were evaluated.

RESULTS

Six thousand seventy-one eligible persons were screened from August 2000 through December 2001: of these persons, 68% were women, 43% were African American, 36% were white, 10% were Hispanic, and 5% were Native American. Most reported high-school education or more (84%) and health insurance coverage (86%). Twenty-seven percent met the screening definitions for diabetes; 64%, for hypertension; 29%, for microalbuminuria; 8%, for anemia; 18%, for hematuria; 13%, for pyuria; 5%, for elevated serum creatinine level; 16%, for reduced EGFR; and 44%, for obesity. Among participants without a reported history of specified conditions, screening identified 82 participants (2%) with diabetes, 1,014 participants (35%) with hypertension, 277 participants (5%) with elevated serum creatinine levels, 839 participants (14%) with reduced EGFRs, and 1,712 participants (29%) with microalbuminuria. Thirty-five percent of participants with a history of diabetes had elevated serum glucose levels at screening (> or =180 mg/dL [10 mmol/L]), and 64% with a history of hypertension did not have blood pressure controlled to less than 140/90 mm Hg. Only 18% of participants with a history of diabetes and 31% with a reduced EGFR had blood pressure controlled to less than 130/80 mm Hg and less than 135/85 mm Hg, respectively.

CONCLUSION

Targeted screening is effective in identifying persons with previously unidentified or poorly controlled kidney disease risk factors, as well as persons with a moderately decreased EGFR.