The Contribution of Chronic Kidney Disease to the Global Burden of Major Noncommunicable Diseases

William G Couser; Giuseppe Remuzzi; Shanthi Mendis; Marcello Tonelli

Disclosures

Kidney Int. 2011;80(12):1258-1270. 

In This Article

The Rationale for Early Detection of CKD Through a Primary Health Care Approach

i. Measuring Albuminuria and GFR in Populations at Risk for NCDs Would Meaningfully Enhance Risk Prediction. Laboratory measurements of albuminuria and serum creatinine (to estimate GFR) are potentially useful additions to assessment of cardiovascular risk in primary-care settings. Measurement of urine albumin is already recommended for cardiovascular risk assessment in primary care even in resource-constrained settings.[6] Measurement of serum creatinine in selected patient groups is also recommended but is not feasible in primary-care settings at present in most low-income countries. The importance of considering proteinuria and reduced GFR separately is illustrated by the fact that in the United States only 25% of people with proteinuria have reduced GFR and only 25% of those with a low GFR have proteinuria[152]—and thus, focusing on either alone would miss a substantial proportion of people at risk. Albuminuria has been shown to predict the development of both hypertension[94,137] and diabetic nephropathy.[74] Finally, increases in albumin excretion can precede elevations in both blood sugar and blood pressure—thus identifying a population of patients that would not be detected by conventional screening methods for diabetes or hypertension.[137]

ii. Measuring Albuminuria in Populations at Risk for NCDs is Practical and Inexpensive. Readily available, inexpensive measurements of proteinuria using dipstick urinalysis alone are sufficient to identify high-risk patients.[9,125,138] Albumin dipsticks have a sensitivity of 88%, specificity of 80%, positive predictive value of 89%, and negative predictive value of 92% for detection of albuminuria—adequate for screening in most point-of-care settings.[138] More sophisticated measurements such as albumin/creatinine or protein/creatinine ratio are more sensitive for detection of less severe proteinuria but are more expensive and can be less easy to use at the point of care.[153]

CKD can be identified opportunistically during health-care encounters for management of other NCDs. For example, among nondiabetic subjects with normal serum creatinine levels undergoing percutaneous coronary interventions, about 78% had demonstrable CKD when screened more stringently for renal function (GFR, urine protein); 17% of those older than 65 years and 5% of those younger than 65 years had stage 3 or worse CKD.[154] The presence of CKD likely accelerated the development of coronary disease in these patients but also appears to increase their risk of periprocedural hemorrhage, contrast nephropathy, restenosis, and death.[155] CKD can also be identified in economically disadvantaged settings by mobile clinics and point-of-care laboratory testing. For example, a recent study from Mexico found that more than 30% of people with no history of cardiovascular disease who agreed to be screened for CKD and other cardiovascular risk factors had a projected risk of 30% for a cardiovascular event in the next 5 years.[127] A further 27% of these people had CKD that had not been previously recognized.

A recent high-quality economic analysis showed that using GFR to screen people from the general population with diabetes for CKD was highly cost-effective, independent of age.[129] Previous studies have reached similar conclusions about the benefits of screening using dipstick urinalysis or protein/creatinine ratio in people with diabetes, as well as the cost-effectiveness of treatments directed at reducing proteinuria in the subset of this population who are found to have CKD.[156] No direct evidence currently demonstrates the effectiveness and cost-effectiveness of screening for CKD in nondiabetic people without additional CKD risk factors.[157] However, because identification of CKD is expected to change management and improve outcomes (see below), screening for CKD in nondiabetic patients older than 55 years is currently recommended.[33,158]

iii. Identification of CKD Would Change Management of NCDs and Improve Outcomes. The rationale for including the prevention (or the slowing of the progression) of kidney disease in the public-health agenda for NCDs is usually provided by promises to reduce the enormous cost of renal replacement therapy. However, the substantial impact of CKD on cardiovascular disease and increases in costs associated with CKD itself provide a much more compelling rationale for including screening for CKD in government health programs, especially in high-risk populations. One example is the need to alter management of patients with CKD to minimize the increased risk of AKI mentioned above.

iv. Early Detection of CKD in Developed Countries. A recent expert panel has made recommendations to the US Centers for Disease Control and Prevention on how to accomplish this.[159] The implementation of mandatory calculation of GFR whenever serum creatinine is measured in countries such as the United States and the United Kingdom, accompanied by information to providers on how to interpret these values, has led to significant increases in both awareness and detection of CKD. A number of entities now collect and report data on CKD in the population, including surveillance systems such as the US Renal Data System,[160] the National Health and Nutrition Examination Survey (NHANES),[161] the regional ESRD Networks,[162] and the Quality Improvement Organization system.[159] Similar renal registries now exist in most developed countries. In the United States, the National Kidney Foundation's Kidney Early Evaluation Program (KEEP) carries out systematic screening and kidney disease education in high-risk groups.[163] Several awareness programs are sponsored by the National Institutes of Health through the National Kidney Disease Education Program.[164] The US Centers for Disease Control and Prevention through their Chronic Kidney Disease Initiative are undertaking CKD surveillance programs and an economic impact study designed to meet national Healthy People 2010 objectives and have developed new diagnostic codes for CKD.[165] The United Kingdom has recommended increased attention to early screening for CKD and added CKD screening as part of primary-care doctors' chronic-disease assessment incentive payments. In 2000, the National Kidney Foundation of Singapore initiated a comprehensive program that has screened more than 450,000 people and has already reduced the risk of progressive CKD and related NCDs among Singaporeans.[166] Effective programs aimed at preventing, identifying, and treating CKD have led to substantial reductions in the incidence of ESRD in Japan and promising improvements in the prevalence of CKD in Australia and Taiwan.[17,167]

v. Health Systems of Developing Countries are Already Scaling up eFforts to Identify and Treat CKD. In the developing world the challenges are considerably greater.[1,2,7] However, significant progress is being made. The Kidney Disease: Improving Global Outcomes (KDIGO) group continues to develop evidence-based approaches to providing care to kidney patients.[168,169] The International Society of Nephrology (ISN), through its Global Outreach Research and Prevention Committee, has focused on demonstrating that early detection and prevention programs can be carried out cost-effectively in very resource-poor settings using the Chronic Kidney Disease, Hypertension, Diabetes and Cardiovascular Disease (KHDC) template.[170,171] KHDC projects have now been supported and implemented at a research level in 22 settings in 15 countries, and data from over 60,000 screened people undergoing longitudinal follow-up are being collected and analyzed at the Kidney Disease Data Center at the Mario Negri Research Institute in Bergamo, Italy.[172] This ISN program has also assumed responsibility for collecting and analyzing data on renal and urologic diseases for the WHO Global Burden of Diseases, Injuries, and Risk Factors Study (the GBD 2005 Study), which is now ongoing.[171] A recent survey by the International Federation of Kidney Foundations evaluated CKD screening programs in 28 countries (most in the developing world) and showed significant improvement in program performance between 2005 and 2007, with continued growth expected.[173] National health systems in some developing countries, such as Uruguay, have already incorporated CKD into their NCD prevention and control programs. Mexico has recently launched the Strategic Network of Health Services against Chronic Kidney Disease. However, before such efforts are expanded on a national scale, it is necessary to obtain more information on sustainability, opportunity costs, and affordability of such programs to the public sector of low- and middle-income countries.

vi. Efforts to Raise Awareness About CKD. Important as all of these surveillance and data-gathering programs are, the resources to implement effective early detection and prevention programs for CKD (like all NCDs) must ultimately come from government health programs to improve the public health, to decrease the costs of managing CKD and cardiovascular disease, and to respond to public demand. World Kidney Day is a joint initiative of ISN and the International Federation of Kidney Foundations, which is organized to raise awareness regarding CKD. The sixth World Kidney Day (2011) focused on the kidney and cardiovascular disease and was celebrated with events in over 100 countries that included public activities such as free screenings for CKD and also meetings between leaders in the renal community and high-level government officials (including health ministers, prime ministers, and even presidents).[63] Over the next few years, continued growth of World Kidney Day is expected, allowing its associated activities to be progressively more effective for increasing awareness of CKD (and the other NCDs that often accompany CKD, such as diabetes, hypertension, and cardiovascular disease) among the general public as well as government decision makers.

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