How have global clinical trials rewritten care for kidney patients?

The kidneys are a vital part of the body’s internal ‘plumbing’. As well as filtering waste products and excess fluid from the blood to produce urine, they play an essential role in regulating blood pressure and maintaining the correct balance of chemicals in the body. They also produce hormones essential for red blood cell production and bone health.  

Unfortunately, they can become damaged over time and struggle to perform these functions, leading to chronic kidney disease (CKD). This is usually the result of diseases such as diabetes and high blood pressure (hypertension) that put a strain on the tiny blood vessels and filters inside the kidneys.  

Globally, over 800 million people are estimated to have CKD, more than double the number in 1990. As populations grow and age, CKD is projected to become the fifth leading cause of death worldwide by 2040.  

With no cure for this complex disease, and prevalence on the rise, researchers working in Oxford Population Health’s Renal Studies Group are running some of the world’s largest clinical trials on kidney disease to understand its causes and identify new treatments. Their findings over the past 20 years have significantly improved outcomes for people living with CKD worldwide.  

What risk factors for CKD have they identified? 

Kidney disease can affect anyone at any age, but certain risk factors such as family history or being over the age of 60 put some people at higher risk than others. Being obese or overweight also significantly increases the risk of developing kidney disease, according to research carried out by Oxford Population Health. As well as directly increasing the risk of CKD, obesity is a risk factor for other conditions that can harm the kidneys, such as high blood pressure and diabetes.  

Cardiovascular disease and CKD also have strong links. Patients with CKD have an increased risk of developing cardiovascular disease. At the same time, cardiovascular disease can contribute to CKD by reducing blood flow to the kidneys and damaging the blood vessels critical for filtering waste.  

In addition to changes to diet, habits and lifestyle, large trials run by researchers at Oxford Population Health have demonstrated the significant benefits of cholesterol-lowering treatments for reducing the risk of heart attacks and strokes in CKD patients.  

The Study of Heart and Renal Protection, known as the SHARP trial, involved about 9,400 volunteers with CKD in 18 countries who were randomly allocated to take either placebo tablets or a combination of two cholesterol-lowering drugs – a low-dose statin plus a drug called ezetimibe, which blocks cholesterol absorption.  

The results, published in 2011, showed that patients who took the combination of cholesterol-lowering drugs had one-sixth fewer heart attacks, strokes and operations to unblock the arteries.  

The scale of the SHARP trial – the largest ever in kidney disease at the time – meant working with kidney specialists in 380 hospitals around the world. This global network provided the foundation for later trials carried out by the Renal Studies Group. 

How can we slow the progression of kidney disease? 

Besides treatments that can reduce cardiovascular risk in patients with CKD, there is an urgent need for interventions that can slow the progression of the disease to kidney failure and avoid the need for regular dialysis or a kidney transplant – options that are unavailable or unaffordable in many parts of the world. 

Progress in this area of research had stalled for nearly 20 years until trials on a class of drug called ‘gliflozins’, also known as sodium-glucose co-transporter-2 inhibitors (SGLT2) inhibitors, began reporting results in 2019. EMPA-KIDNEY was designed and conducted by the Renal Studies Group to test whether a medication called empagliflozin, originally developed to treat high blood sugar in people with diabetes, could help prevent kidney disease from worsening in people with CKD. The trial, involving 6,609 participants from the UK, Europe, North America, and East Asia (eight countries in total), also looked at whether the drug reduced deaths from heart disease or hospitalisation from heart failure. 

In March 2022, the trial was stopped early because evidence of the drug’s efficacy was so strong. Among participants who took a daily dose of empagliflozin, their risk of CKD progression or death from cardiovascular causes reduced by 28%. Crucially, the study found that the drug worked just as well for patients with kidney disease that was not linked to diabetes.  

‘It was a big shift to find a class of drugs that were so effective,’ says Professor Will Herrington, who co-leads the Renal Studies Group with Professor Richard Haynes. ‘It established that the treatment could be used for patients with a broad range of different kidney disease, and they all got the same benefit. That’s game changing.’ 

The findings triggered changes in clinical practice and gliflozins are now recommended for most adults with CKD worldwide.  

What next for kidney disease research? 

Empagliflozin can approximately halve the rate of long-term decline in kidney function, but it is not a cure for chronic kidney disease. 

‘We’ve made a big step forward, but there are still substantial numbers of patients progressing to kidney failure, and they’re still more likely to die from cardiovascular disease,’ says Herrington.  

He and his team are now recruiting 11,000 CKD patients to a new international trial – EASi-KIDNEYTM. The study will assess whether a drug called vicadrostat can further reduce the risk of kidney disease progression, hospitalisation from heart failure or death from cardiovascular disease when added to standard treatment, including empagliflozin.  

Recruiting such a large number of participants is ‘enormously challenging,’ reflects Herrington. ‘To enrol 6,609 volunteer participants into EMPA-KIDNEY between 2018 and 2020, we needed to invite many thousands of patients across 241 hospitals. It required patients’ willingness to help over three years, supported by 1,600 members of staff.  

‘We are exceedingly grateful for all the individual contributions which have made such important scientific progress possible for current and future patients with kidney disease.’  

Recruitment into EASi-KIDNEY TM began in 2025 and by June 2026, 6,500 people had been randomised (over half the number needed).  

‘Successfully running this trial relies on patients and collaborators from over 500 hospitals in 20 countries,’ says Co-Principal Investigator, Associate Professor Parminder Judge.  

‘We will have to wait until 2029 to learn whether the trial has delivered another breakthrough in treatment for kidney disease.’

Updated 16 June 2026.