Impacts of preoperative kidney function and acute kidney injury on long-term kidney failure after cardiac surgery: a registry-based cohort study.

BACKGROUND: Acute kidney injury is a common complication of cardiac surgery and may lead to kidney failure. In a large sample sourced from national registries, we estimated the risk of kidney failure up to nine years following cardiac surgery and the associations with acute kidney injury, comorbidities and preoperative estimated glomerular filtration rate. METHODS: Data were linked probabilistically between population-based registries to identify adults with kidney failure (commencement of long-term kidney replacement therapy) following cardiac surgery. Risk of kidney failure accounting for the competing risk of death was estimated from 30 days following surgery using Fine-Gray models. Surgeries from 2010 to 2018 were included (n = 90 605) with follow-up until the end of 2018. RESULTS: A total of 465 adults (0.51%) developed kidney failure during follow-up and the cumulative incidence at five years was 0.65% (95% CI 0.59, 0.73). The risk of kidney failure increased with decreasing estimated glomerular filtration rate. The rate of any acute kidney injury was 26.2% and all stages were associated with kidney failure. For Stage 3 acute kidney injury compared with none, the adjusted subdistribution hazard ratio of kidney failure exceeded 4.4 at all intervals following surgery. CONCLUSION: Acute kidney injury presented an enduring risk of kidney failure following cardiac surgery, independent of baseline estimated glomerular filtration rate. People comorbid with diabetes also experienced a high adjusted risk of kidney failure. All patients could benefit from perioperative management optimized to prevent acute kidney injury and regular postoperative nephrology follow-up for more than a year to mitigate the burden of kidney disease on the health system. CLINICAL TRIAL NUMBER: Not applicable.