Introduction: Baseline suPAR levels have been shown to be associated with an accelerated decline in eGFR (1). The aim of this study was to examine the relationship between longitudinal changes in suPAR levels and eGFR in patients with diabetes.

Methods:  From a clinic database, we identified patients with (n=16) and without (n=24) an early rapid decline in eGFR (rapid decline in eGFR defined as >3.5 ml/min/1.73m² per year). All patients had an initial eGFR > 60ml/min/1.73m² and those with a rapid decline in eGFR had a final value ≤ 60ml/min/1.73m². Patients were only included in the study if they had a minimum follow up of 4 years and at least 5 GFR estimations. A mixed effects regression model was used to examine the relationship between suPAR levels and eGFR over time.

Results: Median final eGFR values in patients with and without a rapid decline in eGFR were 41 (IQR 34-52) and 94 (IQR 80-102) ml/min/1.73m², respectively (p < 0.001). Median final suPAR values were higher in patients with (5.5 IQR 4.8-6.7 ng/mL) compared to those without (3.8 IQR 3.3-4.8 ng/mL) a rapid decline in eGFR (p < 0.001). In patients with a rapid decline in GFR, serial suPAR levels but not albuminuria was significantly associated with eGFR over time (p < 0.05). There was no relationship between suPAR levels and eGFR over time in patients without a rapid decline in eGFR.

Conclusions:  Circulating suPAR levels increase as eGFR declines. Serial measurements of suPAR levels may prove to be a useful method for identifying patients with diabetes that are at an exaggerated risk for an early decline in GFR.  However, whether this approach results in an incremental improvement on top of established risk markers for predicting eGFR decline remains to be fully defined.