Optimal Frequency of Urinary Albumin Screening in Type 1 Diabetes

Background. Kidney disease screening recommendations include annual urine testing for albuminuria after five years duration of type 1 diabetes. We aimed to determine a simple, risk factor-based screening schedule that optimizes early detection and testing frequency.

Methods. Urinary albumin excretion measurements from 1343 participants in the Diabetes Control and Complications Trial and its long-term follow-up were used to create piecewise-exponential incidence models assuming 6-month constant hazards. Likelihood of the onset of moderately or severely elevated albuminuria (confirmed albumin excretion rate AER ≥30 or ≥300 mg/24h, respectively) and its risk factors were used to identify individualized screening schedules. Time with undetected albuminuria and number of tests were compared to annual screening.

Results. The three-year cumulative incidence of elevated albuminuria following normoalbuminuria at any time during study was 3.2%, which was strongly associated with higher glycated hemoglobin (HbA1c) and AER. Personalized screening in 2 years for those with current AER ≤10 mg/24h and HbA1c ≤8% (“Low-Risk”, 0.6% 3-year cumulative incidence), in 6 months for those with AER 21-30 mg/24h or HbA1c ≥9% (“High-Risk”, 8.9% 3-year cumulative incidence), and 1 year for all others (“Average-Risk”, 2.4% 3-year cumulative incidence) was associated with 34.9% reduction in time with undetected albuminuria and 20.4% reduction testing frequency as compared to annual screening. Stratification by categories of HbA1c or AER alone were associated with reductions of lesser magnitude.

Conclusions. A personalized alternative to annual screening in type 1 diabetes can substantially reduce both the time with undetected kidney disease and the frequency of urine testing.