Early Trajectory of Estimated Glomerular Filtration Rate and Long-term Advanced Kidney and Cardiovascular Complications in Type 1 Diabetes
Methods: Annual percent change in eGFR (slope) was calculated during the Diabetes Control and Complications Trial (DCCT) for each of 1441 participants over a mean of 6.5 years and dichotomized by presence or absence of Early Rapid eGFR Loss (slope ≤-3% per year) as the exposure of interest. Outcomes were incident reduced eGFR (eGFR<60ml/min/1.73m2), composite cardiovascular events, or major adverse cardiovascular events (MACE) during the subsequent 24-years post-DCCT closeout follow-up.
Results: At DCCT closeout (the baseline for this analysis), diabetes duration was 12±4.8 years, most participants (85.9%) had normoalbuminuria, mean eGFR was 117.0±13.4 ml/min/1.73m2, and 149 (10.4%) had experienced Early Rapid eGFR Loss over the preceding trial phase. Over 24-year subsequent follow-up there were 187 reduced eGFR (6.3 per 1000 person-years) and 113 MACE (3.6 per 1000 person-years) events. Early Rapid eGFR Loss was associated with risk of reduced eGFR (HR 1.81;95% CI 1.18-2.79, p=0.0064), but not after adjustment for baseline eGFR level (HR 0.94;95% CI 0.53-1.66, p=0.84). There was no association with composite cardiovascular events or MACE.
Conclusions: In people with type 1 diabetes primarily with normal eGFR and normoalbuminuria, the preceding slope of eGFR confers no additional association with kidney or cardiovascular outcomes beyond knowledge of an individual’s current level.