Mortality outcomes for Māori requiring renal replacement therapy during critical illness: a single unit audit in Aotearoa New Zealand

Abstract

Background: Māori in New Zealand (NZ) are disproportionately affected by chronic kidney disease (CKD) and experience lower life expectancy on community dialysis compared with non-Māori. We previously identified a higher renal replacement therapy (RRT) requirement for Māori in our intensive care unit (ICU), the tertiary referral centre for NZ's Te Manawa Taki region.

Aim: To describe mortality outcomes by ethnicity in the population requiring RRT in our ICU.

Methods: Retrospective audit of the Australia and NZ Intensive Care Society database for adult admissions to our general ICU from Te Manawa Taki between 2014 and 2018. Patients were stratified by non-RRT requirement (non-RRT), RRT-requiring acute kidney injury (AKI-RRT) and RRT-requiring end-stage renal disease (ESRD).

Results: Relative to the population of Te Manawa Taki, Māori were over-represented across all strata, especially ESRD (61.8%), followed by AKI-RRT (35.0%) and non-RRT (32.4%) (P < 0.001). There was no excess mortality by ethnicity in any stratum. Crude in-ICU mortality was similar by ethnicity among AKI-RRT (30.8% among Māori, vs 31.5%; P = 1.000) and ESRD (16.4% among Māori, vs 20.6%; P = 0.826). This trend remained at 1 year. Adjusted for clinically selected variables, neither AKI-RRT nor ESRD mortality was predicted by Māori ethnicity, both in-ICU and at 1 year. Irrespective of ethnicity, AKI-RRT patients had highest in-ICU mortality (31.2%; P < 0.001), while ESRD had highest 1-year mortality (46.1%; P < 0.001).

Conclusion: Increased RRT requirement among Māori in our ICU is due to higher representation among ESRD. We did not demonstrate excess mortality by ethnicity in any stratum. AKI-RRT had higher in-ICU mortality than ESRD, but this reversed at 1 year.

Keywords: acute kidney injury; dialysis; ethnicity; intensive care unit; renal replacement therapy.