Linking real-world data to understand the silent swell of kidney disease
Professor Austin Stack is analysing existing real-world data in Ireland in smart ways to uncover important trends about kidney disease, so we can protect people’s health and plan future healthcare, writes Dr Claire O’Connell.
7 min read - 30 Oct 2024
All day and night your kidneys work silently in the background. When they work well, they filter waste efficiently out of blood and keep blood pressure at healthy levels.
But if things start going wrong with your kidneys, you may not know about it until these hardworking organs are almost on their last legs.
How can we find out who is at risk of ‘silent’ kidney disease, and who already has it in Ireland?
Enter Professor Austin Stack, whose HRB-funded research takes a smart approach to gathering information about the state of the nation’s kidneys.
“My focus and the research focus of my team is to better understand kidney disease so we can improve the lives of patients who have the disease and of people who are who are at risk of it,” explains Professor Stack, who is Foundation Chair of Medicine at the University of Limerick School of Medicine and a consultant nephrologist at University Hospital Limerick.
“To do that well, we need quality information about who is at risk of kidney injury and disease, so we can mitigate or reduce that risk through effective preventive strategies, like controlling blood pressure and optimising treatment for diabetes. We also need comprehensive information about who already has kidney disease, so we can protect their kidney function slow progression, extend their survival and maintain a good quality of life well into older age.”
A silent swell of unwell
For most of us, kidney disease develops gradually, with no outward signs, which makes it more difficult to spot and intervene early, notes Professor Stack, who directs The Kidney Research Consortium at UL and the National Kidney Disease Surveillance System and Quality Assurance Programme (NKDSS).
“Chronic kidney disease is generally asymptomatic for most patients in that it typically has few if any symptoms in the early stages,” he explains. “In fact, there are often very few if any symptoms until one’s kidney function is down to about 10-15% of normal, when a lot of damage has already taken place.”
So if ailing kidneys aren’t declaring themselves from the rooftops, how can we know whose kidneys are at risk?
To find out, Professor Stack’s investigative team examines routinely collected data from within Irelands health systems that is collected on a day-to-day basis. These include the results of blood and urine tests which are used to identify kidney damage in people with conditions such as diabetes, heart disease and high blood pressure.
His team is able to track these patients over time by linking their test results with information on whether they needed to be hospitalised, needed dialysis, and even whether they died.
“A tremendous amount of knowledge can be gleaned from interrogating existing data and tell us about a particular disease, how well we are managing our patients, and how well we are doing as a health system,” says Professor Stack.
Looking at existing data is faster and cheaper than setting up new research studies from scratch to gather new information, he adds, but you need to do it smartly.
“The secondary data that can tell us so much about kidney disease is often hidden in silos around the country,” he says. “That means we had to develop new ways to link data sets and combine them, and we have done that successfully at the University of Limerick where we have linked large datasets in the Irish healthcare system in a way that has not been done before.”
When they analysed the linked datasets, the researchers discovered some stark findings about the extent and growth of kidney disease in Ireland.
“We found that the overall prevalence of chronic kidney disease in adults, age 18 and over, in Ireland is about 7%, or one in 15 people, and it is creeping up year by year,” says Professor Stack. “And when you look at kidney disease in people aged over 50, we see that the figure rises – to around one in 7 people have chronic kidney disease.”
The data don’t lie
When we compare our findings about kidney disease with those from the The Irish Longitudinal Study on Ageing (TILDA) renal report, a nationally representative cohort study which is restricted to over-50s findings, there is a remarkable concordance, and Professor Stack is encouraged by the parallels.
“The estimates we can get from the routinely collected data are in line with what TILDA found by following cohorts of people over time, which is an important validation of our findings from the secondary data,” he says. “It tells us that yes, by interrogating the clinical datasets that are already out there for the population in Ireland, we can identify with accuracy the burden of kidney disease.”
By interrogating routine clinical datasets in Ireland, Professor Stack and his team have also provided new information about the burden of anaemia (or a lack of iron or red blood cells in the body) in Ireland, identified groups that are most at risk, and has shown that the risk of anaemia, increases in lock-step with advancing kidney disease. Importantly, his team has shown that testing rates for common causes of anaemia is less than desired with very low testing rates for iron deficiency, B12 and folate deficiency.
“This study Prevalence of anaemia, iron, and vitamin deficiencies in the health system in the Republic of Ireland: a retrospective cohort study highlighted important gap in care delivery programs and the need for quality improvement initiatives,” he says.
Game-changing treatments
The current statistics paint a potentially worrying picture of kidney disease in Ireland. But on a more positive note, being able to identify people with early kidney disease or an elevated risk of it, means these patients can benefit from the raft of ‘game-changing’ new treatments that have become available, according to Professor Stack.
“When I started as a nephrologist more than 25 years ago, we had one or two specific treatments that we could use to protect kidney function and slow the rate of decline,” he recalls.
“Roll forward to the last five to seven years though, and we have an expanded menu of options, really effective treatments that have now become available thanks to the combined efforts of clinical research teams, pharmaceutical companies and in particular the patients who took part in clinical trials.”
These new treatments include sodium-glucose co-transporter-2 inhibitors (SGLT2), non-steroidal mineralocorticoid receptor antagonists (MRAs) and – probably the most famous new kid on the pharmaceutical block – the glucagon-like peptide-1 (GLP-1) agonists that not only encourage weight loss but protect the kidney too.
The race is on now to identify the patients who can benefit most from these and other treatments and lifestyle changes, according to Professor Stack.
“If we want to improve performance and patient outcomes, we need good quality data and we need to measure what we’re doing, so we can do it better and we can help people to slow kidney disease, meaning they don’t get to a point where they need dialysis,” he says.
“That doesn’t necessarily mean developing a brand-new system – we have shown that linking existing real-world data can provide answers to important questions. And having up-to-date, robust, timely, accurate information will help guide our treatments and our interventions to those who will benefit most. At a national level, harnessing the power of Irish health data will inform policy, support strategic planning and resource allocation. This can only be good for Irish patients and all of us who work in the health system. That’s it in a nutshell.”
7 min read - 30 Oct 2024