Is CKD a bubble?

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KDOQI guidelines emerged in 2002, classifying CKD in 5 stages based on the presence of kidney damage or GFR below 60ml/min, irrespective of cause. This classification increased the awareness of CKD in the general population and placed the kidney in the spotlight of many health policy discussions. However, one of the concerns of this classification is that it overestimates CKD, particularly in the elderly.
When this classification is applied to the general population, more than 25 million people are estimated to have CKD in the US, with more than 40% of CKD in those over 70 years old. The question than becomes: does the lower GFR in the elderly truly reflects disease or is just a consequence of aging? Does a lower GFR in the elderly without other comorbidities lead to an increased risk of other complications, like CV disease? Is there a way to better classify those patients, taking into account their prognosis? Finally, if we compare 2 patients with an eGFR of 45ml/min and different degrees of proteinuria (below 30mg/d or 700mg/day), do they carry the same risks?

The major changes will be two:

– subdivision of CKD stage III in A (45-59 ml/min) and B (30-44 ml/min).

– addition of albuminuric categories to every CKD stage : normal-30, 30-299, 300-1,999 and greater than 2,000 mg/day.

These changes are hoped to better risk stratify patients, help guide medical care and improve global outcome. By the way, the British have published a similar guideline in 2008.

In general, I liked the new classification, especially since I truly believe that proteinuria is a helpful marker for increased risk and I don’t believe most elderly should be classified as having progressive chronic kidney disease, with subsequent renal consultation. However, I am not sure how is going to affect my daily practice. I will continue to add my ACEI for those with proteinuria… And hope the readers of this blog will discover some new intervention in the near future that would improve my patients’ renal outcome… I have faith in you guys!


  1. Great point Francesco. The interpretation of results based on prior literature is of key importance. I do believe recommendations will change and perhaps therapies that were considered ineffective for stage III CKD in decreasing progression, might show some benefit in 3b patients with proteinuria for example? Will have to carefully test those hypothesis… In any case, this will open new venues in our nephrology field. Grazie!

  2. According to current classification criteria, 10-11% of Western people are CKD patients. Interestingly, nephrologysts largely disagree on timing for referral: stage 3 or 4?
    Stage 3 subdivision might be helpful to solve this controversy.
    However, distinguishing between stage 3a and 3b may lead to concerns about the interpretations of data from current published literature papers.
    In other words: if a therapeutic reccomendation has been established and largely accepted for stage 3 patients, after classification revision should the same treatment option be used for pts in stage 3a and 3b?

  3. Not published yet Carl. The KDOGI group are currently finalizing the classification. The source is from personal communication with a couple of active members of this group. Thx for your comments.

  4. Thanks for the interesting analysis. Has the new classification been published? I am wondering what source this came from. I have not see anything beside editorials.

  5. Completely agree Valeria! Thanks for the comments.

  6. I think it is a great change! And probably a new classification for the eldery should be made. It can`t be the same risk and especially the same prognosis a low GFR at the age of 30 than at the age of 70.

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