1 Department of Nephrology, School of Medicine, Democritus University, Alexandroupolis, Greece 2 Department of Medicine, Division of Nephrology, The Toronto Hospital and University of Toronto, Canada
Sir,
After studying a mixed group of 84 type 2 diabetics consisting of 9 with acute renal failure (ARF), 25 with acutely aggravated chronic renal failure (AACRF) and 50 with chronic renal failure (CRF), Chantrel et al. [1] were impressed with the high mortality in this group (28/84) after a follow-up of 211 days. They commented on the abysmal prognosis of these patients. We believe that the results of this retrospective study will not help the authors and the readers in their efforts to improve their results, unless these dramatically different groups are studied separately.
Regarding those with ARF or acute exacerbation of their chronic renal failure (AERF), it is obvious that the main reasons for the extremely high mortality were mismanagement of the patients before their referral (as stated by the authors) and late referral. Thus, almost 90% of those with ARF and AERF were treated under emergency conditions because of hyperkalaemia, acute left-ventricular dysfunction, severe acidosis, pericarditis secondary to radiocontrast use, nephrotoxicity, urinary-tract obstruction and cardiac surgery. Many patients were overhydrated and only limited use was made of ACE inhibitors, beta-blockers and statins.
The patients with CRF had results that may not have been so abysmal but their care can certainly be improved. The authors state that 12 of these CRF patients recovered their kidney function, which suggests that these patients should not have been labelled as suffering from CRF. Unfortunately they do not describe how they handled these patients when calculating the actuarial survival of this group. Looking at their Figure 1, although the number of patients who have been on dialysis for more than 6 months is small, one can extrapolate a survival of 75% over the first year which is similar to that reported by other workers.
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Another important factor influencing overall mortality of ESRD patients is the outcome during the first 90 days after initiation of dialysis. A number of registries, like the USRDS, exclude deaths occurring during the first 90 days, mainly because such deaths are not related to dialysis per se but to the comorbid conditions. We might have a more accurate view of the role of dialysis in Chantrel's unit if they reanalysed their results after removing the patients who died during the first 90 days.
In conclusion we believe that these abysmal results in those with ARF and those with AACRF could be improved if we, as nephrologists, concentrate on the education of the referring physician, with emphasis on early referral to renal centres for dialysis and associated treatment. Furthermore, we do not believe that the results of dialysis in type 2 diabetics with CRF are abysmal and, with greater attention to detail we believe that results can improve as our experience over the last 10 years has shown [1].
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Department of Nephrology, Hôpitaux Universitaires de, Strasbourg 1, Strasbourg, France
Sir,
We would like to thank Passadakis et al. for their interest and comment on our study [1] in a cohort of diabetic patients entering dialysis in a single centre for 2 years.
The first point of this study was to show that the classification acute (ARF) vs chronic renal failure (CRF) may be too dichotomic and can be difficult in some cases. Our pragmatical approach was to include all consecutive patients starting dialysis whatever their mode of presentation. Our data clearly show the occurrence of ARF or acutely aggravated CRF with irreversible end-stage renal failure (ESRF). An interesting point was to find a high proportion of patients with aggravating factors, mostly of iatrogenic nature and thus potentially amenable to prevention.
The strong message we wished to deliver was that we need to increase awareness and eviction of these precipitating factors in the whole medical community dealing with diabetic patients, i.e. the cardiologist, surgeon, radiologist, internist, intensivist, diabetologist and others. The second point was to illustrate the role of comorbidity and late referral on mortality in these patients. We would like to point out a special feature of our department of nephrology: we are dealing with patients with ARF, including patients that in another place would have been referred primarily to ICU or intensivists. These patients with a high risk of mortality in the short term may be overlooked in some centres according to local referral policy.
As pointed out by Passadakis et al. another source of confusion is related to the exclusion of death within the first 90 days of dialysis in most of the studies and registers including the USRDS. Updating our initial publication, we reanalysed the survival curves of our cohort in the patients (n=69) without recovery of ESRF, both including and excluding the deadline of day 90 after the start of dialysis. As depicted on Figure 1, the 47 patients surviving to the first 3 months of dialysis exhibit a survival rate of 76, 62 and 30% at 1, 2 and 5 years follow-up respectively.
In these surviving patients, prognosis is not, indeed, abysmal. For the good conscience of nephrologists, exclusion of the death rate within the first 3 months is certainly beneficial. For primary care physicians, however, it could be valuable to increase awareness of the high mortality rate of these patients soon after starting dialysis, especially where iatrogenic factors are concerned. This may be one of the ways to improve care in this diabetic population.
In his editorial, Friedman [2] was amazed by the extraordinary epidemiology in France with a large disparity in the prevalence of diabetics ESRD from 15.7% in whole France upto 40% in Strasbourg area. Meanwhile the results of the UREMIDIAB 2 study [3] have been published and shed light on this issue. Prevalence of type 2 diabetic ESRD in France is actually heterogeneous, ranging from 6.45% in western France to 25% in north-eastern France (Alsace). Of note, the prevalence of diabetic ESRD parallels the smooth gradient of the increasing prevalence of type 2 diabetes from south-west France to north-east border (Alsace) where the prevalence of diabetes and diabetic ESRD is close to that observed in Germany, at the vicinity of the French border [4]. For example, according to the Monica registry the prevalence of diabetes ranges from 3.9% (WHO criteria) (5.8% A.D.A. 97 criteria) in Toulouse (south-west of France) [5] up to 6.7% (WHO criteria) (8.1% A.D.A. 97 criteria) in Strasbourg [6]. This south-west to north-east gradient has been shown throughout Europe for both diabetes and diabetic nephropathy [4].
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