Kidney Week

Abstract: TH-PO806

Time between Predicted versus Actual Time to RRT Initiation: Just How Early Are We Starting?

Session Information

• Dialysis: Epidemiology, Outcomes, Clinical Trials - Non-Cardiovascular - I
  November 02, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Dialysis

• 607 Dialysis: Epidemiology, Outcomes, Clinical Trials - Non-Cardiovascular

Authors

• Ku, Elaine, University of California San Francisco, San Francisco, California, United States

Elaine Ku,

• McCulloch, Charles E., University of California San Francisco, San Francisco, California, United States

Charles E. McCulloch,

• Johansen, Kirsten L., University of California San Francisco, San Francisco, California, United States

Kirsten L. Johansen,

Background

Prior studies have defined “early” vs. “late” renal replacement therapy (RRT) initiation based on eGFR at the time of RRT. Few studies have described timing of RRT based on time spent in CKD stage 5. Our goal was to compare time that could be spent in CKD stage 5 if RRT were initiated after a fall in eGFR to below 5mL/min/1.73 m² (a conservative threshold for RRT) vs. actual observed time spent in CKD stage 5.

Methods

We used mixed models to estimate the person-specific trajectory of renal function decline (using all eGFRs prior to RRT) among 736 Chronic Renal Insufficiency Cohort (CRIC) participants followed longitudinally for 9.6 years who eventually began RRT. We used these trajectories to estimate the expected amount of time in CKD stage 5 (between eGFR of 15 and 5 mL/min/1.73 m²), which we compared to the observed time spent in CKD stage 5 (until actual receipt of RRT). We then tested for differences between predicted and actual times in stage 5 according to known risk factors for CKD progression.

Results

Overall, the median difference between the predicted and actual time spent in CKD stage 5 was 9.6 months (i.e., patients started RRT 9.6 months before they were predicted to reach an eGFR of 5 mL/min/1.73 m²). Variations in the predicted time in CKD stage 5 were observed by race and ethnicity, co-morbidities, and laboratory parameters, but not by age or sex [figure]. In general, patients at lower risk of progression were started earlier than those at higher risk [Figure], with the time difference being largest among white patients (10.1 months), those with SBP <140 mmHg (9.7 months) and proteinuria <1 g/g (9.1 months).

Conclusion

We found marked differences in the actual vs. predicted amount of time spent in CKD stage 5 based on various risk factors of interest. RRT initiation occurred 10 months earlier than would be expected based on projected time to eGFR of <5 mL/min/1.73 m². Given the lack of mortality benefit to early RRT initiation, we have identified subgroups that may especially benefit from more a concerted effort to delay RRT.

Funding

• Other NIH Support