Kidney disease may be far more common in Africa than has been thought until now, with as many as one in eight people affected, says Wits nephrologist Dr June Fabian, co-lead author of a major new study.
Previously it was estimated one in 30 people are affected.
A widely used blood test to detect how well people’s kidneys function, imported from Europe and the US, appears to be less accurate among African populations, the paper published in The Lancet Global Health shows.
“If early kidney disease gets missed [in testing], we can’t implement measures to try to prevent the disease progressing to kidney failure,” says Fabian, head of clinical research at Wits Donald Gordon Medical Centre.
“If you are missed and progress, you will die without treatment, and in many African countries people do not have access to dialysis and transplantation. If kidney disease is picked up early, we can do something and hopefully prevent it getting to that point,” she says.
Given the higher prevalence of kidney disease revealed by this study and much cheaper cost of screening compared with treatment, the government now has more incentive to implement a screening programme, says Fabian.
“Screening is important because people do not feel sick or go to the doctor in the early stages. It is a silent disease and people only develop symptoms when they feel bad.”
The number one group at risk is people with high blood pressure, followed by those with HIV and diabetes, but diabetes is rising steadily.
If your kidney disease is missed and progresses, you will die without treatment.
— Dr June Fabian, Wits nephrologist
Access to life-saving kidney treatment is massively unequal in SA, depending on whether patients are being treated in the public or private health sector.
SA has 278 treatment centres, of which 249 are in private facilities and only 29 in the public sector, according to a study in the journal Kidney 360 in December 2020.
The new study — conducted among more than 2,500 people in SA, Uganda and Malawi by the African Research on Kidney Disease (ARK) consortium — was the biggest ever to analyse kidney disease testing and prevalence in Africa.
They analysed their results together with population data from Burkina Faso, Ghana, Kenya, Malawi, SA and Uganda to estimate overall levels of kidney disease.
“The equation used to test kidney function is wrong for 1.4-billion people — Africans,” stated Fabian on the study’s release.
The widely used creatinine and cystatin C-based tests to measure kidney function, developed in high-income countries, do not give accurate results for the people of Africa.
Senior author Dr Laurie Tomlinson, of the London School of Hygiene and Tropical Medicine, stated: “We have shown that for people living in Africa, differences in factors such as childhood health and current nutrition mean that if we’re using equations developed in the US and Europe, we may not be accurately estimating the kidney function of people globally.”
This study illustrates the value of large community-based studies in Africa to get a more accurate idea and early warning on kidney disease on the continent.
Fabian’s team conducted their research at the MRC/Wits-Agincourt Unit Rural Public Health and Health Transitions Research Unit in Mpumalanga. This allowed them to conduct in-depth research because the Wits unit works with population-based cohorts going back decades.
“You can’t just walk into a community and say ‘hi, I’m doing a study’ or go door-to-door. You have to know the population and be able to balance the men and women and ages (and other factors).”
As Fabian sums up: “If you are overestimating [test accuracy], you are underdiagnosing. If you are underdiagnosing, there is a risk for the individual and a public health impact.
“For government to start a screening programme for people at high risk is much better bang for their buck than waiting for kidney disease to progress and for individuals (to try avoid) a crisis in accessing treatment, a potentially catastrophic blow to family finances.”
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