Survivors of critical illness should have their kidney health monitored in the early months after discharge from intensive care, finds a long term study led by Guy’s and St Thomas’.

During critical illness, acute kidney injury (AKI), also known as acute kidney failure, is common. In most cases, kidney function initially recovers when patients get better.

This long-term study shows that patients continue to have increased risk of poor health and death after they leave hospital which is thought to be caused by the progression of chronic disease and other risk factors.

The longitudinal study of around 3,000 patients over seven years showed substantial decline in kidney function, especially in the first six months after hospital discharge. At discharge from hospital, the kidney blood results were not always reliable whereas measurement of kidney function 2-3 months later appeared to be more informative for clinicians of kidney function decline.

The study recommends that follow-up after Acute Kidney Injury needs to incorporate regular monitoring of kidney function in the months after hospital discharge rather than relying on the blood results taken when the patient is discharged.

With no automatic follow-up clinic for patients who had AKI whilst in hospital, there is no agreed care pathway for this cohort of patients at present.

A lack of consensus on best practice after Acute Kidney Disease episodes reflects the limitations of the current epidemiological research. The study recommends a review at three months after intensive care unit (ICU) discharge is an appropriate stage for clinicians to assess long term kidney function, plan appropriate hospital or community follow-up, and control cardiovascular risk factors.

Dr Marlies Ostermann, consultant in nephrology and intensive care at Guy’s and St Thomas’, said:

“The long-term trajectory of kidney function recovery or decline for survivors of critical illness is not completely understood. Our long-term study corroborates the findings of international studies and provides clear evidence that survivors of critical illness and AKI should be viewed as high-risk patients.

“Appropriate clinical interventions for survivors of critical illness are crucial. Over half of the patients who are admitted to ICU experience an episode of Acute Kidney Disease and epidemiological research has shown a consistent association with chronic kidney disease, premature end stage kidney disease, and death.

“Despite the potential benefits, at present patients who experience the most severe form of Acute Kidney Disease requiring acute dialysis rarely receive specialist follow-up. This needs to change. It is likely that close follow-up and early intervention can avoid being reliant on long-term dialysis.

“A special thanks to Ryan Haines, Jonah Powell-Tuck, and Hugh Leonard for their invaluable contribution to this research project.”