Time-centered approach to understanding risk factors for the progression of CKD

Abstract

Background and objectives Traditional approaches to modeling risk of CKD progression do not provide estimates of the time it takes for disease progression to occur, which could be useful in guiding therapeutic interactions between patients and providers. Our objective was to estimate median time spent in each of CKD stages 3a–5 and how the time differs according to risk factors associated with progression of disease. Design, setting, participants, & measurements We included 3682 participants of the Chronic Renal Insufficiency Cohort in mixed models to estimate person-specific trajectories of function, and used these trajectories to estimate time spent in each CKD stage. Results During 9.5 years of median follow-up, participants spent longer in earlier rather than later CKD stages, ranging from a median of 7.9 years (interquartile range, 2.3 to >12 years) in stage 3a to 0.8 years (interquartile range, 0.3–1.6) in stage 5. Known risk factors for CKD progression were also associated with larger differences in time until progression to the next CKD stage in earlier versus later stages of disease. For example, compared with systolic BP <140 mm Hg, systolic BP ≥140 mm Hg was associated with 6.1 years shorter time (95% confidence interval [95% CI], 4.5 to 7.5) spent in stage 3a, 3.3 years shorter time (95% CI, 2.7 to 4.0) in stage 3b, but only 2.4 months shorter time (95% CI, 0.8 to 3.6) in stage 5. Compared with those with proteinuria <1 g/g, proteinuria ≥1 g/g was associated with 8 years shorter time spent (95% CI, 6.8 to 9.6) in stage 3a, 5.6 years shorter time (95% CI, 5.0 to 6.4) in stage 3b, but only 6 months shorter time (95% CI, 3.8 to 8) in stage 5. Conclusions There are marked variations in the time spent in the different stages of CKD, according to risk factors and stage of disease.