A few days ago, I was asked to present the new ACP guidelines for screening for CKD stages 1-3 to a group of non-nephrologists. These guidelines were published online last October in Annals of Internal Medicine and provoked a furious response from some nephrology groups including the ASN. The ASN's statement in particular took issue with the first recommendation and suggested that population screening of adults for CKD was justified. I'm going to present the 4 recommendations, briefly review the evidence and give a score for each recommendation based on what I believe. I know I'm sticking my neck out but I welcome any comments.
1. The ACP recommends against screening for CKD in asymptomatic adults without risk factors for CKD. (Grade: weak recommendation, low quality evidence).
In the response to this the ASN said "If detected early in its progression, kidney disease can be slowed and the transition to dialysis delayed. This evidence based fact is why regular screening and early intervention by a nephrologist is so important to stemming the epidemic of kidney disease in the US and why the ASN strongly recommends it". The problem with this response is that there is no evidence from trials that it is true. Remember that it is stages 1-3 CKD that we are talking about and that about 50% of individuals identified through screening will have stages 1-2. The risk of progression to ESRD in this population is very small. Note that the recommendation only refers to adults without risk factors. There is no suggestion that individuals with risk factors (diabetes, hypertension etc.) should not be screened.
The PREVEND study screened 41,000 adults in the Netherlands for albuminuria. After 9 years follow-up, 45 individuals required RRT. Screening only those who had risk factors (a history of hypertension, diabetes or CVD) identified 87% of those who eventually required dialysis. Of the 26,000 individuals without risk factors who were screened, only 5% had albuminuria and just 6 eventually required dialysis. Of those 6, only 2 had albuminuria at the time of screening. More recently, a cost-effectiveness study sponsored by the CDC found that the cost per QALY of screening was $155,000 for adults without risk factors compared with $21,000 for those with diabetes and $55,000 for those with hypertension when using CKD progression/ESRD as the outcome. It should be said that a subgroup analysis of the PREVEND study did find that there was marginal benefit to screening for microalbuminuria to prevent CVD with ACEi treatment. The benefit was substantially higher if only those with risk factors or individuals over the age of 60 were included. Another recent study examined the cost-effectiveness of albuminuria screening in African Americans and found that the cost-effectiveness was far higher in this population. However, they made a number of assumptions including that ACE therapy would be as effective in non-diabetics and non-hypertensives as in patients with these conditions and that ACE therapy would have the same effect on CKD progression as it does in non-African Americans.
It should be noted that the ACP is not the only group that recommends against population screening for CKD. The US Preventative Services Task Force also recommend against screening while the most recent KDIGO guidelines recommend screening for albuminuria and decreased GFR only in individuals with risk factors. Even KDIGO has an issue with the frequency of screening and recommendations range from yearly to every 3 years depending on the presence of co-morbid conditions.
Overall, after reviewing the (extremely poor) evidence, I would tend to agree with the ACP on this one. However, given the high prevalence of CKD in older populations, I would perhaps include individuals over the age of 65 in the group of those who should be screened along with patients with diabetes, hypertension and a family history of CKD. Score one for the ACP.
After writing this, I realize that I can't deal with all of the recommendations in one post so I'm going to split it up and post on the remaining recommendations over the weekend.
1. The ACP recommends against screening for CKD in asymptomatic adults without risk factors for CKD. (Grade: weak recommendation, low quality evidence).
In the response to this the ASN said "If detected early in its progression, kidney disease can be slowed and the transition to dialysis delayed. This evidence based fact is why regular screening and early intervention by a nephrologist is so important to stemming the epidemic of kidney disease in the US and why the ASN strongly recommends it". The problem with this response is that there is no evidence from trials that it is true. Remember that it is stages 1-3 CKD that we are talking about and that about 50% of individuals identified through screening will have stages 1-2. The risk of progression to ESRD in this population is very small. Note that the recommendation only refers to adults without risk factors. There is no suggestion that individuals with risk factors (diabetes, hypertension etc.) should not be screened.
The PREVEND study screened 41,000 adults in the Netherlands for albuminuria. After 9 years follow-up, 45 individuals required RRT. Screening only those who had risk factors (a history of hypertension, diabetes or CVD) identified 87% of those who eventually required dialysis. Of the 26,000 individuals without risk factors who were screened, only 5% had albuminuria and just 6 eventually required dialysis. Of those 6, only 2 had albuminuria at the time of screening. More recently, a cost-effectiveness study sponsored by the CDC found that the cost per QALY of screening was $155,000 for adults without risk factors compared with $21,000 for those with diabetes and $55,000 for those with hypertension when using CKD progression/ESRD as the outcome. It should be said that a subgroup analysis of the PREVEND study did find that there was marginal benefit to screening for microalbuminuria to prevent CVD with ACEi treatment. The benefit was substantially higher if only those with risk factors or individuals over the age of 60 were included. Another recent study examined the cost-effectiveness of albuminuria screening in African Americans and found that the cost-effectiveness was far higher in this population. However, they made a number of assumptions including that ACE therapy would be as effective in non-diabetics and non-hypertensives as in patients with these conditions and that ACE therapy would have the same effect on CKD progression as it does in non-African Americans.
It should be noted that the ACP is not the only group that recommends against population screening for CKD. The US Preventative Services Task Force also recommend against screening while the most recent KDIGO guidelines recommend screening for albuminuria and decreased GFR only in individuals with risk factors. Even KDIGO has an issue with the frequency of screening and recommendations range from yearly to every 3 years depending on the presence of co-morbid conditions.
Overall, after reviewing the (extremely poor) evidence, I would tend to agree with the ACP on this one. However, given the high prevalence of CKD in older populations, I would perhaps include individuals over the age of 65 in the group of those who should be screened along with patients with diabetes, hypertension and a family history of CKD. Score one for the ACP.
After writing this, I realize that I can't deal with all of the recommendations in one post so I'm going to split it up and post on the remaining recommendations over the weekend.
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