Necker Hospital, Paris, France
Correspondence and offprint requests to: P. Jungers, Hôpital Necker, 161 rue de Sèvres, F-75730 Paris Cedex 15, France.
Increasing incidence of progressive renal insufficiency is a major public health problem
The relentlessly rising incidence of end-stage renal failure (IRF) is a major problem for all public health systems in Western countries. For more than 10 years, the number of new patients accepted on renal replacement therapy (RRT) has been increasing by about 9% per year in the USA [1], and the increment in most European countries is at least about 4% per year. In consequence, the prevalence of patients on dialysis is continuously growing, inasmuch as it is not compensated for by a corresponding annual number of kidney transplantations, and constitutes a heavy burden for national health budgets.
The growing annual incidence of ESRD patients requiring RRT is chiefly due to the increasing number of patients with diabetic nephropathy and hypertensive vascular disease, because better treatment of diabetes and hypertension means that a greater proportion of affected patients live longer, and develop renal complications. Therefore, the increasing incidence of ESRD appears inexorable, unless early, adequate management of patients is able to prevent the development of renal disease, or at least slow progression of renal insufficiency. However, a number of patients with renal disease do not benefit from the therapeutic options available today, chiefly because they are not referred to the nephrologist early enough.
Nephrological management improves the course of renal disease
The deleterious effects of late nephrological referral in terms of higher morbidity and short-term mortality, poorer nutritional condition, need for longer hospitalization, and higher costs have been repeatedly stressed [13]. Therefore, early referral of renal patients and, more importantly, effective nephrological management during the predialysis phase is crucial to improve the care of renal patients and reduce or retard the need for RRT, and preserve the nutritional and cardiovascular condition of patients [4].
Obviously, intervention by the nephrologist can take place only if the patient is referred to him. However, late referral is very frequent. As many as 2550% of chronic renal failure (CRF) patients are referred only at a very advanced stage of renal failure, within less than 2 months of reaching ESRD, frequently requiring emergency dialysis within 1 or 2 days of hospitalization. Even if referral some months prior to ESRD is sufficient to psychologically and medically prepare the patient for dialysis and create a functional vascular access (if haemodialysis is the chosen option), the patient will still have been exposed for a long time to the deleterious consequences of uraemia. These include uncontrolled hypertension, left ventricular hypertrophy, accelerated atherosclerosis and malnutrition, all of which result in increased morbidity and mortality both in the predialysis period and while on RRT [4,5]. Only early management of CRF patients guided by a nephrological team in close cooperation with the family doctor can give the patient the best chance to avoid such complications and slow the progression of renal failure. Thus, the true aim is not only early nephrological referral, but early effective nephrological care of renal patients.
Nephrological management has three major goals:
All of these measures are well-known to nephrologists but they have to be shared with non-nephrological colleagues to improve detection of renal disease and management of patients.
Benefits of screening for renal disease in high-risk populations
Obviously, most of the measures aimed at preventing or slowing renal insufficiency could and should be implemented primarily `upstream' of the nephrologist, i.e. by general practitioners, internists, diabetologists, cardiologists, urologists, geriatrists and more generally by all health care providers. Early therapeutic intervention is especially desirable in high risk groups, namely diabetic and hypertensive patients, certain ethnic minorities or patients with systemic disease.
One may expect that targeted intervention in well-defined populations particularly at risk of developing renal disease and progressive renal insufficiency, such as diabetic and/or hypertensive patients, will result in significant savings in terms of health for patients and costs for the community. Evidence has been provided that search for microalbuminuria allows the detection of the initial step of renal involvement. At this stage therapeutic intervention by means of stringent blood pressure control, electively using angiotensin II neutralizing agents, stops or retards evolution to macroalbuminuria and progressive renal failure. Even in patients with established renal insufficiency, treatment with ACEIs has been shown to significantly slow progression in diabetics with overt nephropathy [6] and the same is true for patients with essential hypertension. Guidelines for prevention and optimal treatment of diabetic and/or hypertensive nephropathy already exist and could easily be implemented by every informed physician.
Unfortunately, this is frequently not the case. In an interesting epidemiological study in the London area that appears in the present issue of NDT, Kissmeyer et al. observed that only half of patients identified as diabetics or hypertensives had their plasma creatinine checked at least once during the previous 2 years. Of these, 11% were found to have plasma creatinine in excess of 125 µmol/l, but only a quarter of the latter had already been referred to a nephrologist [7].
The only way to effectively improve the care of diabetic patients should be to improve the cooperation between general practitioners, diabetologists and nephrologists. Clear guidelines, especially the need for regular urine screening together with blood pressure and serum creatinine monitoring, and optimal antihypertensive therapy should be provided through professional organizations and/or public health authorities to all physicians. General practitioners should implement adequate clinical and laboratory surveillance and medical treatment, including use of ACEIs themselves. They should coordinate their action with the nephrologist as soon as renal insufficiency, defined by serum creatinine in excess of 125150 µmol/l, is present.
Benefits and feasability of generalized preventive intervention in renal patients
Diabetes and essential hypertension, although presently the most prevalent causes of progressive renal failure in most northern populations, are not the unique cause of ESRD. Ideally, all patients in whom renal disease is detected or suspected should be best referred immediately to a nephrologist.
Detection of renal disease relies on very simple clinical or laboratory signs. The most frequent are presence of proteinuria and/or haematuria on dipsticks, hypertension, oedema, anaemia, elevated serum creatinine or abnormal kidney morphology on a fortuitous abdominal echography. Opportunities for such findings are multiple: military service in males, contraceptive pill prescription or pregnancy follow-up in females, and in both genders pre-employment medical visit, annual worker health surveillance, insurance subscription, preanesthetic clinic, serum creatinine control prior to use of iodine contrast media or prescription of NSAIDs or ACEIs (especially in older and/or atherosclerotic patients), etc. Deliberate screening should be performed in patients with a family history of renal disease, such as polycystic kidney, diabetes mellitus and/or hypertension. Whatever the revealing sign or symptom of nephropathy, every patient should be referred to a nephrologist for aetiological evaluation and optimal management of renal disease, especially if renal insufficiency is already present. Effectiveness of optimal blood pressure control in non-diabetic nephropathies is now well established especially when heavy proteinuria is present. However, again this is often not the case. A number of studies both in Europe and in the USA indicate that at best half of patients identified with patent renal insufficiency (serum creatinine in excess of 300 µmol/l or higher) are not referred to the nephrologist, especially older patients and patients with major comorbidity [2]. Often, such patients are ultimately hospitalized under emergency conditions that require immediate dialysis without any preparation. This situation precludes any possibility for an informed choice of dialysis modality. Moreover, one can hypothesize that many patients with only mild proteinuria, microscopic haematuria, anaemia or apparently essential hypertension do not receive adequate attention and investigation for uropathy or nephropathy. This is most unfortunate, since active blood pressure control, especially in patients with heavy proteinuria, has been shown to significantly delay progression [8,9].
Cost-effectiveness of a generalized, systematic screening for renal disease in the community has been questioned. Given the relative rarity of renal insufficiency in the general population such generalized screening may not be productive. However, whenever a biologist identifies a serum creatinine in excess of the normal range, the physician in charge (or, if appropriate the patient) should be alerted. Perhaps the most cost effective way is to properly investigate and manage in a targeted fashion every patient in whom urinary pathology or abnormal serum creatinine concentrations have been found.
How to improve early nephrological management of renal patients?
If 2550% of CRF patients are referred late to the nephrologist, this means that reciprocally 5075%, i.e. the majority of patients, are referred in time. The question here is: why are the other patients not referred? The possible reasons have been analysed by several authors [14]. Schematically, reasons are either material (lack of health insurance and free access to the medical system) or psychological (insufficient awareness of the goals and results of nephrological care), according to the health systems and cultural habits in the various countries.
Therefore, the best way to encourage earlier and closer cooperation between nephrologists and family doctors is to provide better information to non-nephrologists to make them aware of the benefits of specialized management of renal patients. Clear and simple guidelines should be provided to all physicians through professional associations and/or public health administrations [10]. Renal patient associations should become involved in spreading information concerning the benefits of referral to the nephrologist. Optimally, medical networks should be implemented, based on formal cooperation between nephrologists, general practitioners, diabetologists, biochemistry laboratories and other health care providers.
There is definite evidence that optimal pre-ESRD management favourably influences morbidity and short-term mortality of patients, and reduces costs of dialysis. Probably the most motivating argument is the evidence that early predialysis nephrological care has an impact upon long-term survival and quality of life of patients on RRT. This may be expected, as optimal management of all identified cardiovascular risk factors, as recently recommended by the National Kidney Foundation in the USA [11] should reduce cardiovascular morbidity and mortality both in the predialysis phase and after start of RRT.
The principles of preventive therapy are now well established, and evidence that appropriate drug intervention is effective in halting or at least slowing renal insufficiency has been provided [12]. We have to find ways adapted to the individual situations in different countries to improve early diagnosis of renal diseases, primary care of renal patients, and better cooperation between non-nephrologists and nephrologists. It is ethically important that all renal patients may benefit from recent advances, as only shared progress is effective progress: Le progrès ne vaut que s'il est partagé.
Notes
Please see also Original Article by Kissmeyer et al. (pp. 21502155 in this issue)
References