in progress

Draft Research Plan

Chronic Kidney Disease: Screening

January 19, 2023

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The analytic framework depicts the relationship between the populations, interventions, outcomes, and harms for screening for chronic kidney disease. The far left of the framework describes the target population as asymptomatic adults without known CKD. To the right of the population is an arrow corresponding to key question 3, which represents the diagnostic accuracy of screening to identify adults with CKD stages 1 to 3. This arrow leads to either persons with CKD stages 1 to 3 or no CKD. From the CKD stages 1 to 3 area, an arrow leads to intermediate outcomes, including progression to stage 4 or 4/5 CKD, and a dotted line further leads to clinical outcomes of mortality, cardiovascular events, quality of life, and end-stage renal disease/composite renal outcomes. An overarching line corresponding to key question 1 from the population represents screening and the effects of screening on the outcomes. An arrow below corresponding to key question 2 represents potential harms of screening. In the center of the framework are areas for monitoring and treatment interventions corresponding to key questions 4, 6, and 7 and their effects on intermediate and clinical outcomes. An arrow below corresponding to key questions 5 and 8 represent potential harms from monitoring and treatment.

Abbreviation: CKD=chronic kidney disease.

  1. In asymptomatic adults without known chronic kidney disease (CKD),* what are the effects of screening for CKD vs. no screening on clinical outcomes?
  2. What are the harms of screening for CKD vs. no screening?
  3. What is the diagnostic accuracy of screening to identify adults with CKD stages 1–3?
    1. How does diagnostic accuracy vary in populations defined by race, ethnicity, age, and sex?
  4. Among adults with CKD stages 1–3,† what are the effects of monitoring for worsening kidney function, kidney damage, or both vs. no monitoring on clinical outcomes?
  5. Among adults with CKD stages 1–3,† what are the harms of monitoring for worsening kidney function, kidney damage, or both vs. no monitoring?
  6. Among adults with CKD stages 1–3,† what are the effects of treatment on likelihood of developing stage 4 or 5 CKD?
  7. Among adults with CKD stages 1–3,† what are the effects of treatment on clinical outcomes?
  8. Among adults with CKD stages 1–3,† what are the effects of treatment on harms?

*For screening, studies in which patients were selected on the basis of having conditions associated with CKD (e.g., hypertension, diabetes) are not eligible for inclusion. However, studies are not required to exclude patients with these conditions.
†For treatment, studies will not be restricted according to whether patients have screen- or non-screen-detected CKD, or whether patients are eligible for evaluated treatments for reasons other than CKD (e.g., presence of diabetes mellitus, hypertension, or dyslipidemia).

  1. What disparities are present in diagnosis of CKD and utilization of treatment, and what factors are associated with disparities?
  2. What is the effectiveness of interventions aimed at reducing disparities in persons with CKD?
  3. What are the harms of being labeled with a diagnosis of CKD stages 1–3?

To the extent possible, we plan to describe the participant characteristics and major intervention components of the included studies. Data on population characteristics will help us explore the degree to which the findings are broadly representative of the U.S. population, including individuals across age; sex and gender; racial, ethnic, and cultural identity; socioeconomic status; and geographic region. Evidence will be evaluated to determine if there are common components of efficacious interventions (e.g., diet approaches or medication dose), and to the extent possible, whether interventions tailored to specific groups tend to have larger effect sizes than those that are not tailored. As part of our effort to address health equity, we will search for and highlight interventions that demonstrate effectiveness in groups of individuals who historically have lower rates of screening and in traditionally stigmatized or underrepresented groups. Additionally, the proposed contextual questions are designed to address other important health equity considerations.

The Proposed Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the key questions.

Category Included Excluded
Populations Adults age 18 years or older

KQs 1–3: Asymptomatic patients without known CKD and not selected on the basis of presence of diabetes mellitus or hypertension, with or without recognized risk factors for CKD

KQs 4–8: Patients with screen-detected CKD or non-screen-detected CKD stages 1–3 (based on 2012 KDIGO or 2002 KDOQI definitions* or equivalent), including adults with diabetes mellitus or hypertension		 KQs 1–3:
  • Patients with known CKD or symptoms of CKD
  • Pregnant persons

KQs 4–8:

  • Patients with non-screen-detected CKD stages 4 to 5
  • Pregnant persons
Interventions KQs 1–5:
  • Estimation of GFR (KQ 3 restricted to 2021 CKD-EPI creatinine- or cystatin-based equations)
  • Albuminuria

KQs 6–8:

  • Angiotensin-converting enzyme inhibitors 
  • Angiotensin II receptor blockers
  • Calcium channel blockers
  • Mineralocorticoid receptor antagonist (finerenone)
  • Loop diuretics
  • Targeting thresholds of blood pressure control independent of specific antihypertensive agent(s)
  • Diet (Dietary Approach to Stop Hypertension [DASH] diet or similar)
  • Sodium-glucose cotransporter-2 inhibitors
  • Glucagon-like peptide-1 agonist
  • Statins
 Screening tests and treatments not described as included
Comparisons KQs 1, 2: Screening vs. no screening or usual care

KQs 3, 3a: Screening test vs. reference standard using an exogenous tool that measures kidney function directly

KQs 4, 5: Monitoring vs. no monitoring

KQs 6–8:

  • Active treatment vs. placebo, usual care, or no treatment
  • More intensive vs. less intensive treatment (management of blood pressure or dyslipidemia)
 Comparisons not described as included
Outcomes KQs 1, 4, 7:
  • All-cause mortality
  • Cardiovascular mortality
  • Myocardial infarction (any, fatal, or nonfatal)
  • Stroke (any, fatal, or nonfatal)
  • Congestive heart failure (hospitalization or death)
  • Composite cardiovascular outcomes
  • Quality of life
  • Physical function
  • Progression to stage 5 CKD (end-stage renal disease, including renal replacement)
  • Composite renal outcomes that include progression to stage 5 CKD and other renal outcomes (e.g., change in estimated GFR or creatinine or change in albuminuria)

KQs 1, 4, 6: Progression to stage 4 or stage 4/5 CKD

KQs 2, 5, 8:

  • Any adverse events
  • Serious adverse events
  • Specific adverse events
  • Renal adverse events

KQs 3, 3a:

  • Sensitivity
  • Specificity
  • Area under the receiver operating characteristic curve
 Outcomes not described as included
Setting No restrictions  
Study Design KQs 1, 2, 4–8: Trials and systematic reviews of trials

KQs 1, 2, 4, 5: Controlled observational studies

KQs 3, 3a: Studies reporting diagnostic accuracy		 Study designs not described as included
Study Quality Good-quality or fair-quality; poor-quality only if better quality studies are lacking KQs 6–8:
  • Sample size of <50 patients
  • Duration of followup <6 months

Abbreviations: CKD=chronic kidney disease; GFR=glomerular filtration rate; KDIGO=Kidney Disease Improving Global Outcomes; KDOQI=Kidney Disease Outcomes Quality Initiative.

*Definitions of CKD:

KDOQI, 2002: Kidney damage for ≥3 months, as defined by structural or functional abnormalities of the kidney, with or without decreased GFR, manifest by either: pathological abnormalities or markers of kidney damage, including abnormalities in the composition of the blood or urine, or abnormalities in imaging tests and/or GFR <60 mL/min/1.73 m2 for ≥3 months.1

KDIGO, 2012: Either of the following present for >3 months: markers of kidney damage (one or more), including albuminuria (albumin excretion rate ≥30 mg/24 hours; albumin to creatinine ratio ≥30 mg/g [≥3 mg/mmol]), urine sediment abnormalities, electrolyte and other abnormalities due to tubular disorders, abnormalities detected by histology, structural abnormalities detected by imaging, or history of kidney transplantation and/or decreased GFR (GFR <60 mL/min/1.73 m2; GFR categories G3a-G5).2 

1. National Kidney Foundation. K/DOQI Clinical practice guidelines for chronic kidney disease: evaluation, classification and stratification. Am J Kidney Dis. 2002;39(suppl 1):S1-S266.
2. KDIGO 2012 Clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2013;3(1):136-150.