Kidney failure impacts life expectancy of women more than men

The impact of kidney failure on life expectancy is serious for everyone, but the University of Sydney led study shows the impact is much greater for women than men.

Researchers say the numbers show a significant disparity in premature death between men and women with kidney failure, the most serious stage of kidney disease.

Disparity in health outcomes between men and women is not uncommon and is an area of growing interest, however, researchers say the difference in health outcomes between women and men in kidney failure exceeds that seen in cardiovascular disease and even cancer.

“The fact we’ve got more women dying from kidney failure before their time than men - that’s what is really crucial.  We need to work out the reason for this difference, whether it relates to how people access healthcare, the treatment they get, or biological considerations,” said lead author and biostatistician Dr Nicole De La Mata.

“The life-years lost for women compared with men are far greater than I have seen for any other health condition, such as cardiovascular disease and cancer,” said senior author Professor Angela Webster from the University of Sydney’s NHMRC Clinical Trials Centre and Centre for Renal and Transplant Research at Westmead Hospital.

The study explored differences among people with kidney failure in Australia and New Zealand by examining health records for over 80,000 people, who identified as either male or female, spanning over 30 years. It drew on the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA).

This was then linked to the national death registers which record deaths and their causes in both countries.

Analysis found women with kidney failure had a higher probability of premature death compared to men with kidney failure – losing on average 3.6 years more life than men.

There were also more deaths in women, with 11 times the expected deaths compared to seven times in men.

The impact varied by the age a person experienced kidney failure. Younger women had the greatest loss in life expectancy and survival. A 15-year-old female with kidney failure will lose on average 33 years of life compared to what is expected in the general population, where a similar male with kidney failure would lose 27 years.

The findings are published today in The BMJ.

This was then linked to the national death registers which record deaths and their causes in both countries.

What sets the study apart from other, similar studies, is that the researchers compared survival to what would be expected in the general population, rather than just between people with kidney failure.

“It tells a more personal story for people with kidney disease; the analysis really illustrates how they are missing out on more years of life, compared to life expectancy in the general population,” said Dr De La Mata.

In the general population, females live longer than males for many reasons including biology. Other studies have shown chronic kidney disease is more prevalent in women, but men have a faster progression to kidney failure, and men represent most of the population with kidney failure.

However, the findings in The BMJ show this natural survival advantage is entirely lost for women with kidney failure.

“No one has ever really realised the extent of the disadvantage for women with kidney disease before,” said Professor Webster.  

The study adds to a growing pool of equity research and awareness examining disparities in health and healthcare.

“The reason for these sex differences needs further exploration – it could be due to biological reasons or differential health care access or treatment,” says Dr De La Mata.

Many chronic diseases have sex-specific mechanisms where women may not develop the same symptoms as men, which leads illnesses to go unrecognised – which also leads to systematic differences in care.

Professor Webster says other studies have shown women get worse access to healthcare compared to men. For instance, with treatment for cardiovascular diseases where women are treated at a later stage of disease and may have delayed access to better treatments.

“There is a need to identify differences in access to healthcare, and strategies to close any gap.”

Declaration: The data linkage was supported by a Kidney Health Australia project grant in 2015. Data analysis and conclusions were conducted independently.