Associations of Proteinuria Trajectories with Kidney Failure and Death in Individuals with CKD.

KEY POINTS: Clinicians may repeat proteinuria measurements multiple times but may overlook the significance of temporal patterns of proteinuria. Trajectory analyses identified four discrete proteinuria subgroups: low-slowly rising, high-slowly rising, regressing, and rapidly rising. Trajectories of proteinuria identify subgroups of patients with CKD who have increased risks of ESKD and death independent of known risk factors.

BACKGROUND

Despite repeating proteinuria measurements multiple times during the clinical course of a patient with CKD, clinicians may overlook the significance of temporal patterns of proteinuria. In addition, it is unclear whether proteinuria trajectories identify subpopulations with varying risks of adverse clinical outcomes.

METHODS

We used group-based trajectory modeling to identify proteinuria trajectories on the basis of annual urine protein–creatinine ratio (UPCR) measurements in 3209 participants of the Chronic Renal Insufficiency Cohort study who were alive and did not reach ESKD within 3 years of study entry. Multivariable-adjusted Cox proportional hazards models tested the associations of UPCR trajectories with ESKD and death in those who survived beyond the third annual visit.

RESULTS

Trajectory analyses identified four discrete groups on the basis of annual UPCR measurements: low-slowly rising (n=1528), high-slowly rising (n=1363), regressing (n=114), and rapidly rising (n=204). Compared with the low-slowly rising proteinuria trajectory group, participants in the other proteinuria trajectory groups had lower socioeconomic status, a greater prevalence of comorbid conditions, and lower eGFR. During a median follow-up of 8.6 years, 547 participants progressed to ESKD, and 836 participants died. Compared with the low-slowly rising group, all proteinuria trajectory groups were associated with higher risks of subsequent ESKD, but only the high-slowly rising group was associated with a higher risk of death.

CONCLUSIONS

Trajectories of repeated proteinuria measurements identify subgroups of patients with CKD who have increased risks of ESKD and death independent of known risk factors.