LETTER TO THE EDITOR
Year : 2011 | Volume
: 22 | Issue : 1 | Page : 156--158
The elderly with advanced chronic kidney disease
King Fahad Specialist Hospital, P O Box 15215, Dammam, Saudi Arabia
King Fahad Specialist Hospital, P O Box 15215, Dammam
|How to cite this article:|
Abutaleb N. The elderly with advanced chronic kidney disease.Saudi J Kidney Dis Transpl 2011;22:156-158
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Abutaleb N. The elderly with advanced chronic kidney disease. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2020 Jul 15 ];22:156-158
Available from: http://www.sjkdt.org/text.asp?2011/22/1/156/74375
To the Editor,
The conclusions made by Dr. Aimun et al in their recent article entitled "Chronic kidney disease in older people; disease or dilemma?" need to be further expanded. I might, however, start by forwarding a few comments. The choice of 59 mL/min/1.73 m2 eGFR as a cut-off value that differentiates out age-related from pathological GFR decline may be questioned. The bulk of the patients in the CKD3 stage are elderly patients with, otherwise, no evidence of CKD process. The above assumption about age-related GFR decline has allowed inflating stage 3 and probably 4 by a majority of these individuals. The assumption has ignored the gender-related GFR differences and the effect of advancing age. Based on NHANES 19992004,  the US CKD3 population number is 15.5 million (only 0.7 in stage 4), only 24.4% of whom have microalbuminuria. The comparable figure for CKD3 was only 20.4% in a Taiwan study.  While the mean ages of the CKD stage 1 and 2 patients in the above Taiwan study were 35.3 (SD 12.3) and 45.3 (SD 14.4) years, respectively, the mean age of CKD3 patients in the same study was 61.9 (SD 11.4) years. The median age of the CKD3 patients in a Norway study  was 75.0 years.
Age-Related GFR Decline is Not a CVD Risk Factor
Dr. Aimun et al have stressed the strong association between cardiovascular disease (CVD) and GFR decline, but they have overlooked the repeated finding of losing this association among CKD3 patients in the absence of microalbuminuria. This has occurred despite the well-established finding of increasing the prevalence of CVD risk factors with GFR decline. The PREVEND study  found that the prognosis of individuals (mostly aged) was not affected by having an eGFR in the range of 30-59 mL/min, regardless of the presence or absence of albuminuria. The prognosis was, however, worse among those with albuminuria. Similar data were also reported by O'Hare et al  and Wen et al  The study by Go et al  also reported an HR of 1.0 for death and hospitalization among subjects with eGFR <60 mL/ min/1.73 m2 compared with those with a higher GFR in the sub-group that had regular follow-up. The HR was found to be 1.2 for CVD events. It is worthy to note that some of these reported HRs were not dissected according to the presence of albuminuria or patient's age; the aged are less likely to be affected by the CKD process. 
Patients in CKD3b constituted only 11.7% and 12.3% of the CKD3 patients in the studies reported by Wen et al  and by White et al,  respectively. The percentage of CKD3b among the 187,701 total CKD3 patients that was reported by Go et al can be calculated as 18.3%.  As CKD3a contains about 80% of the total CKD3 population, ,, and as the CKD population number drops even more sharply thereafter, i.e. by stage 4, we can easily conclude that the bulk of the mortality among CKD patients is occurring at stage 3a, which suggests that such CKD mortality can not be attributed to CKD-related uremic processes. The mean age for CKD patients is highest among those in stage 3; the low proportion of patients with kidney damage within CKD3 supports the above notion that this stage was inflated by a majority of the aged individuals with mainly age-related GFR decline. Their high actual mortality within CKD3 is like the rest of the population in their age; it has nothing to do with their renal dysfunction itself.
Also, Minimal Need for RRT in the Elderly, especially in those with no Kidney Damage even within CKD5
The actual risk of needing RRT among CKD3 patients (median 44 months) in a Norway study  was only 0.1% (not 1% as quoted by Aimun et al); i.e., only four out of 3047 patients needed RRT. The risk was even lower among the aged and among females (less likely to be true CKD3!). It is worthy to note that the overall rate of the GFR loss in the CKD3 subgroup with no albuminuria was significantly lower in both the Norway and the PREVEND data. In fact, an overall eGFR improvement over a 7.5-years follow-up was noted in the last study. As quoted by Dr. Aimun et al, the aged are less likely to need RRT even when they reach CKD 4-5.
The Approach for RRT Preparation Needs to be Modified for the Elderly
In response to the above data suggesting a distinct CKD etiological, prognostic and natural history profile among the elderly CKD patients, I suggest that it is time to adopt a different RRT preparation approach for the elderly CKD patients, especially for those with no kidney damage or obvious underlying active etiology.
In my practice, I needed, repeatedly, to admit to several such elderly patients with eGFR significantly below 10 mL/min who had refused such preparations (as AVF construction) but then had maintained the same degree of renal function with a reasonable quality of life for many years afterwards that my approach was not the best! I have no doubt that colleague nephrologists would recognize a majority of such individuals in their practices who did well for many years despite reaching eGFR levels that indicate the need for initiating RRT. These patients are receiving all the usual CKD care except for holding RRT in the absence of a clinical indication regardless of their eGFR values. The current guidelines did not account for an age effect on timing the preparation and initiation of RRT. One may wonder that many of such elderly patients who are doing well for many years with very low but stable eGFR would have been unnecessarily exposed to dialysis-related morbidities had they started on dialysis electively. This could provide one major explanation for the repeatedly reported finding ,,, of worsened or absent survival or clinical benefit from early introducing dialysis. The occasional differentiation between early peritoneal and hemodialysis therapy  might reflect the rapid loss of residual renal function on hemodialysis as one among many other morbidity factors on early RRT. We need to remember that studies of the value of early vs. late dialysis did not concentrate on the elderly patients who are less likely to need RRT and did not address the elderly subgroup with no kidney damage that I am stressing here.
In summary, I have questioned, here, the specificity of our current CKD diagnostic criteria and pointed to the frequent inappropriate diagnosis of CKD among the elderly (especially the females). Such understanding, when coupled with the present knowledge of very low rate of both GFR decline and need for RRT and the proven value of conservative approach, should result in adopting appropriate adjustments in our approach toward introdu-cing RRT for the elderly patients.
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