Chronic kidney disease (CKD) is a life-threatening condition, but researchers have uncovered that preventing death from the disease in older Australians is not as straight-forward as previously thought.
In a new paper published by the Medical Journal of Australia, researchers from the University of Tasmania (UTAS) found that, in people aged over 65 with stage 4 CKD, death from kidney failure was less likely than death from other causes.
“People over 65 years of age with stage 4 CKD were more likely to die than to experience kidney failure, suggesting that more people die with CKD rather than directly because of CKD,” the researchers write.
The findings came from an analysis of linked data from the Tasmanian Chronic Kidney Disease study, for all Tasmanian adults diagnosed with incident stage 4 chronic kidney disease between January 1, 2004 and December 31, 2017.
The cohort of 6825 adults had a mean age of 79.3 years and 56 per cent were women.
Lead author of the study, Professor Matthew Jose, a professor of medicine at UTAS and consultant nephrologist at the Royal Hobart Hospital, says that three important conclusions can be drawn from the study.
“For people with stage 4 CKD, the five-year risk of kidney failure declines with age; the risk of death is greater than that of kidney failure for those over 65 years of age; and the risks of death and kidney failure for people over 65 are each greater for men than women.”
Jose tells Aged Care News that this difference between the genders is due to men’s higher likelihood of presenting with common comorbidities.
“Our data shows men are more likely than women to have risk factors for cardiovascular disease: more likely to have diabetes, high cholesterol and high blood pressure.
“The progression of kidney disease (loss of kidney function) is also greater in men than women.
“All of this together sets up a more “chronic inflammatory state” in the body of men, contributing to more CV events and death.”
And whilst the study shows that other conditions may be attributed to the ultimate cause of mortality, Jose explains that kidney disease and conditions such as heart disease are inextricably linked.
“Link between heart and kidneys is two-way, worse with lower kidney function (GFR),” he says.
‘GFR’ (glomerular filtration rate) is used by experts as a measure of the volume of blood that is filtered by your kidneys over a given period of time – providing a percentage indicator of kidney function (and decline).
As function declines, Jose says that many bodily symptoms are implicated.
“Essentially there are about 4000 molecules that are abnormal with low kidney function; these have varying effects on the body,” Jose says.
“There is also good evidence that people with kidney disease have more cancers (and worse survival), not just cardiovascular disease.”
“A high proportion of CKD patients self-report symptoms of depression and/or anxiety and decline in cognitive functioning,” the report reads.
“Our observations suggest that a decline in kidney function is associated with an increase in the inflammation marker neopterin and metabolism of tryptophan via the kynurenine pathway, without evident elimination of tryptophan metabolism via the 5-HT pathway.
“We also found along the continuum of CKD, significant associations between neopterin, indoxyl sulfate, kynurenine and its downstream metabolites, as well as several associations with cognitive function and subscales of depression and anxiety.”
From this body of research, the UTAS team concluded that, in light of this new, detailed evidence, standard clinical guidelines should be re-revaluated, which generally emphasises preparation for kidney failure or kidney replacement therapy.
“Clinical guidelines should recognise competing risks of death in older people with severe kidney disease, and consider holistic, supportive care, not just kidney replacement therapy.
“[…] mortality risks should be considered when discussing future kidney failure treatment options for patients over 65 years of age.”
How to prevent kidney disease
Kidney Health Australia notes that by maintaining overall health, your kidneys will remain happy and healthy. You can do this by:
- getting your blood pressure checked regularly and ensuring it stays below the levels recommended by your doctor,
- monitoring your blood glucose levels if you have diabetes and ensuring you stay within your targets,
- leading an active, healthy lifestyle and maintaining a healthy weight.
Those living with chronic kidney disease and their carers should also be aware of the condition-specific COVID-19 mitigations strategies and vaccination guidelines, found via this link.
To find out more about how your kidneys work and what you can do to ensure their optimal function, watch this video from Kidney Health Australia: