Quantifying Time to Diagnosis of CKD in the United States

Key Points. Many people with CKD are unaware of the condition. We estimated the time to CKD documentation after two eGFR measurements taken at least 90 days apart. Among many persons with early stage CKD, there are considerable delays in documenting the diagnosis in electronic health record-linked claims data. Background. An estimated 14% of US adults have CKD with over 90% unaware of their condition. Health care professionals diagnose CKD after two abnormal laboratory test results taken at least 3 months apart. Although there is evidence that delays from CKD onset to documentation are common, these delays remain unquantified. The objective of this study was to quantify the time from laboratory-based evidence of CKD to the documentation of CKD using International Classification of Diseases codes. Methods. A retrospective longitudinal cohort study was conducted using 2009–2020 Optum Market Clarity data. Adults aged 18 years and older were followed from the date of the second of two eGFRs <60 ml/min per 1.73 m2, 3–12 months apart until the first International Classification of Diseases Ninth or Tenth revision diagnosis of CKD, or censoring. Survival analysis was used to compare time to documentation among Kidney Disease Improving Global Outcomes (KDIGO) categories considering while analyzing deaths as competing risks. Results. A total of 1.39 million adults with laboratory evidence of CKD and a mean age of 71 years (SD, 10; 63% women; 87% White) were included. Over 94% were in KDIGO stage G3, 5% in stage G4, and 1% in stage G5. The median time to CKD documentation was 3.6 years (interquartile range, 1.0–8.4), ranging from 4.8 years for those in KDIGO G3a, 2 years in KDIGO G3b, and <1 year in KDIGO G4 and G5. Patient characteristics associated with longer time to CKD diagnosis included absence of diabetes or heart failure, less severe CKD, older age, and female sex. Conclusions. There was a substantial delay between laboratory evidence of CKD and the diagnosis being documented via coding. Reducing this delay offers a target for earlier recognition and management of CKD.