How a study that started twenty-five years ago can make a difference in preventing chronic kidney problems

‘Large research in Groningen – Prevent cardiovascular and kidney diseases’ said the posters which were spread through the city years ago. This year, it is 25 years ago since the residents of Groningen were called upon to participate in a large medical scientific investigation. Researchers of the UMCG were looking for participants for the then newly founded PREVEND-cohort study. The purpose: to discover if protein loss in the urine could predict whether someone will develop chronic kidney problems.

‘Prevention of REnal and Vascular ENd stage Disease,’ in short PREVEND, started out as a prospective cohort study in 1997, focussing on cardiovascular and kidney diseases. This is the kind of research in which a large group of participants is examined for a prolonged time to investigate whether they would develop a certain disease. The researchers also try to discover what the risk factors are for developing the disease under examination. As these studies do not have a clear ending point, data is collected over the extended period and the researchers are therefore often able to answer multiple research questions.  The PREVEND study started however with one clear question: is protein loss in the urine a possible predictor for the development of renal function loss and cardiovascular diseases? 

Ron Gansevoort, professor Internal Medicine and nephrologist at the UMCG, had been involved in PREVEND from the beginning and is at present still daily involved in preventing and treating kidney diseases. Ron has recently been in the news as the leading researcher, for instance, because of the start of a large study on a new medicine that sometimes completely stops the deterioration of the kidney function and therefore prevents heart failure and deaths. Additionally, Ron is a member of the steering committee from the internationally known Chronic Kidney Disease Prognosis Consortium, which provides a scientific foundation for screening and prevention in the area of kidney diseases.  

Diminished quality of life

As you often cannot see that someone has a chronic kidney problem, the impact of the disease is sometimes forgotten. Kidney patients are generally very tired, have little exercise capacity and they are required to go to the hospital for dialysis weekly. Furthermore, there is an increased risk of mortality. To illustrate, a slightly reduced kidney function at the age of 50 is equivalent to a loss of ten years in life expectancy. Kidneys that do not function well cause a build-up off toxic waste products, which could eventually lead to cardiovascular diseases. To improve the quality of life for these people, the researchers want to prevent these problems. By screening these people, the risk factors can be mapped out. ‘But how do you give this shape?’, Gansevoort wondered.  

A data treasure thanks to the loyal residents of Groningen

To collect as much medical data as possible, PREVEND decided in 1997 to have a large publicity campaign to call upon the inhabitants of Groningen to participate in the study. Some 40.000 residents handed in their urine and completed a questionnaire. A cohort was created of this group of around 8.500 people, who had a heightened protein loss in the urine. These people had to undergo a screening every four years in one of the outpatient clinics at the UMCG.  

During such a visit, participants had to hand in blood and urine samples and the researchers carried out questionnaires and brain tests. After each screening, all participants were given a poster of a painting of the Groningen artists’ collective De Ploeg to reward their contribution to the research.  

Causes and consequences of protein loss

The collection process yielded a large amount of data that the PREVEND-team could use in their research. The long wait for results was rewarded after years of screenings, tests, and thanks to the cooperation of a very committed group of participants. The researchers found that a high amount of protein loss in the urine is indeed a predicting factor for chronic kidney and cardiovascular diseases in the future. An unhealthy lifestyle, hereditary predisposition, but also some diseases contribute to the development of such an increase amount of protein loss in the urine.  

The importance of prevention

Thanks to the findings of the PREVEND study, it is now possible to specifically screen on protein loss in the urine. Doctors can therefore recognise and treat chronic kidney problems earlier on. Moreover, the findings are internationally known and, among other things, have been cause for a new definition and classification of chronic kidney damage. Worldwide, doctors can now undertake targeted action to prevent and treat chronic kidney problems in their patients when they discover an increased loss of protein in the urine. Fortunately, there is sufficient medication available nowadays which can slow or stop the further development of kidney damage.  

Furthermore, there are good developments happening concerning the prevention of kidney problems, such as the Check@Home research. With the Check@Home home tests, it can be indicated in an early stage whether someone is at high risk of getting cardiovascular and kidney diseases, as well as diabetes. The home tests include a urine test, a heart rate test and a questionnaire. Last February, Ron has received a large subsidy of almost 9 million euros for this research. Ron’s eventual goal is  to do a national population study on chronic kidney problems, so people can be treated in time when needed.  

The relevance of PREVEND-data 

Although the PREVEND-cohort has been closed since 2001, the researchers are now, anno 2022, still using the collected data. In total, PREVEND has led to hundreds of publications and dozens of promotions. The success of PREVEND was also cause for starting the Lifelines investigation.