Patterns of follow-up testing of abnormal eGFR and UACR for the detection of chronic kidney disease in Australian primary care: analysis of a national general practice dataset

Objective To evaluate the patterns of abnormal estimated glomerular filtration rate (eGFR) and urine albumin–creatinine ratio (UACR) follow-up testing for the detection of chronic kidney disease (CKD) in Australian general practices.Design Retrospective, population-based observational study.Setting and participants 2 717 966 adults who visited a MedicineInsight participating general practice between 1 January 2012 and 31 December 2020, had ≥1 serum creatinine measurement (with or without a UACR measurement) and did not have CKD at baseline.Main outcome measure ‘Guideline-concordant follow-up’ was defined as having a record of a repeat eGFR or UACR testing (assessed separately) within 6 months following the abnormal (eGFR<60 mL/min/1.73 m 2; UACR≥2.5 mg/mmol in males, ≥3.5 mg/mmol in females) incident result. Multivariable logistic regression was used to identify patient factors associated with receiving appropriate follow-up testing.Results A total of 220 841 and 114 889 patients with an abnormal incident eGFR and UACR result, respectively, were identified. Nearly half (45.0%) of the patients with an abnormal eGFR result and over two-thirds (69.7%) of the patients with an abnormal UACR result did not have a follow-up test within 6 months. Patient factors associated with a higher likelihood of follow-up eGFR testing included indicators of poorer baseline health and greater CKD risk, such as comorbid diabetes (adjusted OR 1.36, 95% CI 1.32 to 1.40) or more severe incident eGFR (adjusted ORs for eGFR categories 30–44, 15–29 and <15 mL/min/1.73 m², respectively, vs eGFR 45–59 mL/min/1.73 m²: 1.51 (1.47 to 1.55), 1.85 (1.76 to 1.95) and 1.62 (1.47 to 1.78)). Higher incident UACR level was associated with greater follow-up UACR testing (adjusted OR for severely increased albuminuria vs moderately increased albuminuria (OR 1.42, 95% CI 1.37 to 1.48).Conclusions In this large, population-based study, we observed substantial gaps in the follow-up of abnormal eGFR and UACR for the detection of CKD in primary care settings. Effective strategies to optimise follow-up testing for CKD detection are needed.