Glomerular filtration rate, albuminuria, and reported kidney disease in comparison: Results from the German National Cohort (NAKO)

BACKGROUND: Chronic kidney disease (CKD) can be asymptomatic for many years and is often diagnosed late. Given the availability of new treatments, the early identification of relevant findings from screening of the kidney markers estimated glomerular filtration rate (eGFR) and albuminuria in the general population is becoming increasingly important. METHODS: In the NAKO study, self-reported medical diagnoses of kidney disease in 195 182 participants were compared with relevant findings from screening biomarkers (eGFR < 60 mL/min/1.73 m² and albuminuria). For the purpose of comparison, various equations for assessing kidney function were evaluated as well. RESULTS: 2% of the participants reported having received a medical diagnosis of kidney disease, and 2% had an eGFR below 60 mL/min/1.73 m². There was, however, little overlap between these two groups: more than 80% of participants with an eGFR between 30 and 59 mL/min/1,73 m²) did not report any diagnosis of kidney disease. The additional inclusion of data on albuminuria did not materially affect this discrepancy: 6213 persons (17.5% of the cohort) with an abnormal eGFR or urinary albumin-to-creatinine ratio (UACR) did not report any diagnosis of kidney disease. Even among participants whose eGFR was in the range of 30-59 mL/min/1.73 m² and whose UACR was above 300 mg/g, less than half reported having a medically diagnosed kidney disease. CONCLUSION: These findings indicate a low level of awareness regarding the possible presence of CKD in the general population. Many people with abnormal screening findings needing further investigation due to their potential clinical relevance are unaware that they might be suffering from a kidney disease. As more effective treatments for kidney disease are now available, these findings indicate a need for structured screening and evaluation strategies to promote kidney health.