CKD Awareness Among US Adults by Future Risk of Kidney Failure

Abstract

Rationale & objective: Persons with chronic kidney disease (CKD) are often unaware of their disease status. Efforts to improve CKD awareness may be most effective if focused on persons at highest risk for progression to kidney failure.

Study design: Serial cross-sectional surveys.

Setting & participants: Nonpregnant adults (aged≥20 years) with CKD glomerular filtration rate categories 3-4 (G3-G4) who participated in the National Health and Nutrition Examination Survey from 1999 to 2016 (n = 3,713).

Predictor: 5-year kidney failure risk, estimated using the Kidney Failure Risk Equation. Predicted risk was categorized as minimal (<2%), low (2%-<5%), intermediate (5%-<15%), or high (≥15%).

Outcome: CKD awareness, defined by answering "yes" to the question "Have you ever been told by a doctor or other health professional that you had weak or failing kidneys?"

Analytical approach: Prevalence of CKD awareness was estimated within each risk group using complex sample survey methods. Associations between Kidney Failure Risk Equation risk and CKD awareness were assessed using multivariable logistic regression. CKD awareness was compared with awareness of hypertension and diabetes during the same period.

Results: In 2011 to 2016, unadjusted CKD awareness was 9.6%, 22.6%, 44.7%, and 49.0% in the minimal-, low-, intermediate-, and high-risk groups, respectively. In adjusted analyses, these proportions did not change over time. Awareness of CKD, including among the highest risk group, remains consistently below that of hypertension and diabetes and awareness of these conditions increased over time.

Limitations: Imperfect sensitivity of the "weak or failing kidneys" question for ascertaining CKD awareness.

Conclusions: Among adults with CKD G3-G4 who have 5-year estimated risks for kidney failure of 5%-<15% and≥15%, approximately half were unaware of their kidney disease, a gap that has persisted nearly 2 decades.

Keywords: CKD awareness; Chronic kidney disease (CKD); albuminuria; disease management; estimated glomerular filtration rate (eGFR); health literacy; kidney failure prevention; nationally representative survey; patient empowerment; public health; renal function; renal insufficiency; self-care; urinary albumin-creatinine ratio (UACR).

Figure 1:. CKD awareness by 5-year Kidney Failure Risk, NHANES 1999–2016.

P values reported are for linear trends. ESKD risk is the estimated 5-year risk of dialysis or kidney transplant, calculated using the 4-variable Kidney Failure Risk Equation. In panel B, estimates are standardized to the 1999–2004 age distribution. In panel C, adjustment is for sex, race/ethnicity, presence of diabetes, and presence of hypertension. CKD = chronic kidney disease; NHANES = National Health and Nutrition Examination Survey; ESKD = end-stage kidney disease.

Figure 2:. CKD Awareness by Age and Kidney Failure Risk

ESKD risk is the estimated 5-year risk of dialysis or kidney transplant, calculated using the 4-variable Kidney Failure Risk Equation. In panel B, adjustment is for sex, race/ethnicity, presence of hypertension, and presence of diabetes. P values reported are for tests for interaction. CKD = chronic kidney disease.

Figure 3:. Comparative Awareness of CKD, Hypertension, and Diabetes, NHANES 1999–2016

P values reported are for linear trends. Diabetes awareness was defined as self-reported diabetes, insulin use, or diabetic pill use among persons with glycohemoglobin A1c ≥ 6.5% or documented diabetes medication use. Hypertension awareness was defined as self-reported hypertension or high blood pressure medication use among persons with systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or documented antihypertensive medication use. CKD awareness was defined as reporting having been told by a health provider one had “weak or failing kidneys”, among persons with estimated glomerular filtration rate 15 to <60 ml/min/1.73m² (defining CKD stages 3–4) or ≥15% 5-year risk of dialysis or kidney transplant, calculated using the 4-variable Kidney Failure Risk Equation (defining CKD with ≥15% ESKD risk) respectively. In panel B, adjustment is for age, sex, race/ethnicity, presence of diabetes, and presence of hypertension. CKD = chronic kidney disease, ESKD = end-stage kidney disease.