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Kidney Week

Abstract: SA-PO782

Trends in Mortality Among Medicare Beneficiaries with and Without CKD

Session Information

Category: CKD (Non-Dialysis)

  • 1901 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Shieu, Monica, University of Michigan, Ann Arbor, Michigan, United States
  • He, Kevin, Kidney Epidemiology and Cost Center, University of Michgian, Ann Arbor, Michigan, United States
  • Steffick, Diane, University of Michigan, Ann Arbor, Michigan, United States
  • Morgenstern, Hal, University of Michigan, Ann Arbor, Michigan, United States
  • Robinson, Bruce M., Arbor Research Collaborative for Health, Ann Arbor, Michigan, United States
  • Saran, Rajiv, University of Michigan, Ann Arbor, Michigan, United States
Background

Decreasing mortality rates have been observed for Medicare beneficiaries with claims-based diagnosis of CKD. It is unclear whether this is a true decline in CKD mortality or an artifact of increasing recognition of earlier stages of CKD. We sought to examine trends in mortality rate by stage of CKD.

Methods

Persons from 2008-16 Medicare 5% samples were required to be alive, aged >65 on Jan 1, without ESRD, and covered by Medicare Parts A and B but not C for all of the year. Years at risk were calculated from Jan 1 each year and censored at the start of ESRD, Dec 31, or disenrollment from Medicare. CKD claims-based diagnoses were searched from the year before, using ICD-9-CM and ICD-10-CM codes used to define CKD and its stages. The crude mortality rate each year was calculated as the number of deaths divided by the patient-years at risk. Cox regression, stratified by CKD stage, was used to estimate annual (hazard) rates standardized to the age-sex-race distribution of the Medicare 2011 population.

Results

Between 2008 and 2016, the percentage of people with diagnosed CKD stages 1-3 decreased. Persons without CKD had the lowest mortality rate each year, with unadjusted rate decreasing by 49.6 since 2008 to 41.9 in 2016. While the crude mortality rate decreased in CKD stages 1-2 and stage unknown by 17.6% and 27.5% respectively, the rates for stages 3-5 remained relatively unchanged. With standardization for age, sex, and race, we observed less change in mortality rates between 2008 and 2014, but sudden increases in 2015 and sudden decreases in 2016, especially in more advanced CKD stages. (See Figure)

Conclusion

The decline observed in the crude mortality rate among all CKD patients may be due to the changing distributions of age/sex/race/CKD stage, improved care of underlying risk factors, but not to greater recognition of early stage CKD. We acknowledge the limitations of claims-based diagnosis of CKD in this study. Furthermore, the sudden changes in standardized mortality rates between 2014 and 2016 remain unexplained and require further study.

Funding

  • NIDDK Support