Blog entry by Meguid El Nahas
Is There a Real Global Epidemic of Chronic Kidney Disease?
Numerous publications have asserted that the global prevalence of chronic kidney disease (CKD) in adults is generally between 10-13% (as determined from the KDOQI or KDIGO Classification schema, but using one-off, non-age calibrated determinations for identification of CKD ) and that the burden of this disease has reached “epidemic” proportions. In some developed countries (e.g. USA) the population-based prevalence rate of CKD has levelled off, at least in most adult age groups, and some countries have a much lower prevalence of CKD (e.g. Italy) than the global averages. A new and monumental study has put a fresh perspective to the issue of the global burden of CKD (Global Burden of Disease Study 2013 Collaborators, The Lancet, June 8, 2015 – on-line). This seminal study of the incidence, prevalence and years lived with disability (YLD) for 301 acute and chronic diseases (including CKD) and injuries in 188 countries during 1990 and 2013 sheds new light on the purported “epidemic” CKD. The data (35,620 distinct sources) were derived and analyzed in a fashion different from those publications using KDOQI or KDIGO criteria so they may not be strictly comparable. The inclusion of both adults and children may have also altered the prevalence data compared to KDOQI and KDIGO, which are confined to adults only.
Nevertheless the observations are quite informative. There were 324,666,000 cases of CKD in 1990 and 471,916,000 cases of CKD in 2013; after adjusted for aging and population growth the prevalence rate of CKD (per 100,000 population) actually declined overall by about 5% between 1990 and 2013. But the change in adjusted global prevalence rate between 1990- and 2013 was not uniform among the causes of CKD; to wit, the adjusted global prevalence rates of CKD due to glomerulonephritis and hypertension declined by 13.54% and 10.74% respectively whilst the adjusted global prevalence rates of CKD due to diabetes or other causes increased by 11.85% and 3.12% respectively. If the global population was 7.1 Billion in 2013 about 6.7% had some form of CKD; about 20% of which could be attributed to diabetes. The inclusion of children in both the denominator and numerator in this analysis may have diluted the overall prevalence rates of CKD, to some degee. But taken at face value, these figures indicate that generic CKD as a whole is not occurring in “epidemic” proportions globally, but that there are very worrisome trends over the last 2 decades in that CKD due to diabetes is a major and growing global problem. Correspondingly, the reported age and population standardized YLD rose by 10.6% and 6.9% for CKD due to Diabetes and other causes respectively between 1990 and 2013 whilst the age and population YLD fell 22.4% and 6.9% for CKD due to hypertension and glomerulonephritis respectively for a net decline in the YLD burden of CKD on a global basis.
Translating these intriguing findings into an action plan for control of the global disease burden linked to CKD is a difficult task and undoubtedly the answers will be different for developing compared to developed nations and depend greatly on the importance of CKD relative to other public health priorities (e.g. electrification, potable water, infectious disease, etc). What does seem abundantly clear, at least to me, is that the focus should not be on generic CKD, but rather on the problem of diabetes and its parent obesity. In my opinion, what the globe urgently needs is a coherent, culture-adapted approach to detection, prevention and management of obesity and diabetes (“diabesity”)—and not a population- based early detection program for generic CKD. Furthermore, more research leading to better understanding and treatments for the complex triad of obesity, diabetes and CKD are greatly needed. We should recognize that a global epidemic of generic CKD simply does not exist and relentlessly devote our energy to mitigating the world-wide problem of too many calories of the wrong kind and lack of energy consuming activities so as to avoid the CKD complications of “diabesity”.
Richard J. Glassock, MD
Geffen School of Medicine at UCLA
June 8, 2015