1 Taleghani University Hospital, Shahid Beheshti Medical Sciences University, Tehran, Iran, 2 Rasoul Akram University Hospital, University of Medical Sciences of Iran, Tehran, Iran, 3 Azienda Ospedale di Lecco, A. Manzoni Hospital, Lecco, Italy and 4 Department of Nephrology, University of Heidelberg, Heidelberg, Germany
Abstract
Introduction. The epidemiology of end-stage renal disease (ESRD) and renal replacement therapy (RRT) is under continuous evolution all over the world. We report here the epidemiological analysis of ESRD and RRT in Iran and discuss it against the background of the international situation.
Methods. This epidemiological report is based on data from centre questionnaires which were collected in Iran from 1997 onwards, with a response rate of 100%.
Results. The prevalence/incidence of RRT patients were 238/49.9 p.m.p. in the year 2000. Haemodialysis and kidney transplantation were the most common RRT modalities, accounting for 53.7% and 45.5% of prevalent RRT patients, respectively. The proportion treated by peritoneal dialysis was very low (<1%). Home haemodialysis was not performed. The majority of haemodialysis centres used synthetic membranes (70%) and 100% of the sessions were performed using acetate as a buffer; 42.5% of haemodialysis patients were treated with a twice-weekly regimen, whilst 49.6% were on the standard thrice-weekly regimen. The majority of RRT patients in Iran were young to middle aged. The great majority of renal allografts came from living donors (mainly unrelated to recipients). The main renal diseases leading to ESRD were diabetes and hypertension. The third most common category was cause unknown.
Conclusion. The epidemiology of RRT in Iran is characterized by: (i) young patient age (younger than the international average); (ii) high proportion of patients receiving renal allograft; (iii) use of living-unrelated donors as the major source of renal allografts.
Introduction
The epidemiology of end-stage renal disease (ESRD) and renal replacement therapy (RRT) is under continuous evolution all over the world.
In the Western countries, an increase in the prevalence of patients on RRT (dialysis plus transplantation) has been observed during the recent past [1]. This results from a decreased mortality rate on the one hand and an increase in the incidence rate on the other. The latter is mainly accounted for by the increased acceptance of diabetic, older and sicker patients.
A similar epidemiological trend begins to be observed in other nations as well [2]. As the wealth of a nation increases and the population's living standards improve, the demand for healthcare services increases including those which involve complex and expensive therapies, such as RRT: hence the need to collect epidemiological data on RRT, in order to properly organize and set-up the necessary services in such nations. Moreover, there is the necessity to exchange the respective experiences with experts from all over the world.
The European Renal Association-European Dialysis and Transplantation Association (ERA-EDTA) and the Iranian Society of Nephrology perceived this demand, and, in collaboration with the Iranian Center of Dialysis and Organ Transplantation and the Iranian Red Crescent Society, organized the Dialysis and Transplantation Symposium Joint Meeting in Tehran, 2830 April 2001, aimed at focusing on the present state of art and discussing key topics in clinical nephrology, dialysis and kidney transplantation. The meeting focused particularly on the epidemiology of ESRD in Iran, against the background of international data. The present report provides a summary of the epidemiological presentations and discussions at this conference.
Subjects and methods
This epidemiological report is based on data from centre questionnaires, which started to be collected in 1997 under the responsibility of trained physicians in each centre. The data were sent to the Dialysis and Organ Transplantation Center of Ministry of Health and Education. The data were checked for contradictions or incongruity. Regular periodic visits of the centres were organized. The response rate was 100%. Patients were included in the data base if they were treated by RRT for more than 1 month.
Results
The principal epidemiological data are summarized in Table 1.
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There was an increasing incidence of ESRD patients (from 38.5 p.m.p. in 1998 to 49.9 p.m.p. in 2000). The great majority of patients were admitted to dialysis, indicating that pre-emptive transplantation played a marginal role.
The increase in the number of patients admitted to RRT was mirrored by an increase in the number of haemodialysis units from 180 in 1998 (2.83 p.m.p.) to 227 in 2000 (3.57 p.m.p.), and by an increase in the number of haemodialysis machines from 1256 in 1998 (19.84 p.m.p.) to 1776 in 2000 (27.92 p.m.p.). The number of transplantation centres, i.e. 23 centres (0.36 p.m.p.), remained stable in the past 3 years, whilst the number of kidney allograft transplantations increased slightly from 1192 operations in 1998 (19.3 p.m.p.) to 1387 operations in 2000 (21.8 p.m.p.). Both the number of transplantation centres and of transplantations had markedly increased over the past 15 years, however (number of transplantation centres: 2 in 1986, 14 in 1990, 18 in 1993, 21 in 1997; number of transplantations: 95 in 1986, 517 in 1990, 700 in 1993, 951 in 1997).
Of the 8300 prevalent haemodialysis patients in the year 2000, 145 (1.7%) were 014 years old, 624 (7.5%) were 1524, 2231 (26.88%) were 2544, 3311 (39.9%) were 4564, 1464 (17.6%) were 6574, 370 (4.45%) were >75 (the age of 155 patients [1.88%] was unknown). In the year 2000, the age distribution was similar for incident patients (Table 2). The majority of both prevalent and incident patients was middle-aged.
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Of the 227 haemodialysis units, 202 (89%) were public and 25 (11%) were private. Two hundred and one dialysis centres were located in hospitals, 23 were located in dialysis and transplantation centres and three were free-standing centres.
Interestingly, 100% of the haemodialysis sessions was performed using acetate as a buffer. Synthetic membranes were used in the majority of cases. Polysulfone membranes were employed in 70% of patients, whilst cuprophane membranes were used in 30% of patients. Haemodiafiltration and haemofiltration were not performed.
A roughly similar proportion of dialysis patients were treated with a twice-weekly regimen (42.5%) and a thrice-weekly regimen (49.6%), whilst 6.9% of the patients were dialysed on a once-weekly regimen. The average duration of each session was 34 h in 97% of the sessions and >4 h in 3% of the sessions.
Of the prevalent patients alive with a functioning kidney graft as RRT modality, 3.8% were aged 115 years, 27.9% were 1630, 29.4% were 3145, 13.4% were 4660 and 1% were >60 years (in 24.5% of the patients age was missing); 63.4% were males and 36.6% were females.
The characteristics of the allograft donors are given in Table 3: it is very interesting to note that the proportion of cadaveric donors was negligible (<1%), whilst the majority of donors were unrelated living-donors. The majority of kidney donors were males (4293 donors, 64.7%).
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Discussion
The demand for resources and social assistance imposed by RRT patients becomes a challenge to the healthcare systems of all nations. The implementation of dialysis and renal transplantation programmes depends both on the state of the art in medical knowledge and the socio-economic conditions of a given nation. Accordingly, the widely varying prevalence rates of RRT patients world-wide are strongly influenced by the level of the gross domestic product. Obviously, economic considerations may limit the number of patients starting RRT [3]. This explains why the inclusion criteria for patients entering RRT are context-dependent and vary from country to country.
Renal registries are important tools for the collection of data on patients undergoing RRT. They are important sources of data on epidemiology, which are relevant for resource allocation, and on clinical patterns associated with different patient outcomes. International, national and regional renal registries have been established in Western countries for many years: notable examples are the ERA-EDTA Registry [4], the United States Renal Data System (USRDS) [5], the Lombardy Registry of Dialysis and Transplantation [6]. A remarkable example of how much the analysis of registry data can lead to improved management of RRT patients was provided by the comparison of registry data from the USA (USRDS) with Lombardy and Japan. The reports documenting higher mortality in USA dialysis patients, mainly associated with a shorter dialysis time [79], led to prolongation of the duration of dialysis sessions in the USA.
The importance of collecting RRT patients' data has also been perceived by nephrologists in Iran, and led to a systematic collection of epidemiological data since 1997 in order to better plan the health services on the basis of objective quantitative data. The prevalence of patients undergoing RRT in Iran is similar to that of some Eastern European countries, such as Poland, and higher than that of most countries of the former Soviet bloc (Figure 1), but it is still far below the high-prevalence rates recorded in the USA, Japan and other Western countries. The incidence of patients requiring RRT in Iran has been increasing since 1998, yet it is still low compared with other nations (Figure 2
), reflecting the fact that inclusion criteria into the RRT programme are still somewhat restricted. This conclusion is also supported by the observation that the majority of RRT patients in Iran are middle-aged, whilst in the Western countries the majority of the dialysis population and, to a lesser extent, also of the transplant population are elderly [10].
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One of the most remarkable observations emerging from the analysis of the RRT modalities in Iran is the high percentage of RRT patients with a functioning renal graft (Figure 3). The proportion is far higher than the average percentage of 22% in the 14 countries of Eastern Europe, as reported by Rutkowski [11]. It is also higher than the proportion reported from Western nations such as the USA and Italy. If we compare the relative importance of renal transplantation in the Baltic countries with that of other Western European countries [12] (Figure 4
), we can see that renal transplantation in Iran accounts for a similarly high proportion of RRT patients as in the United Kingdom, Holland and Spain and a higher proportion than reported from Italy, Germany, France, where haemodialysis is prominent. A remarkably high proportion of transplanted patients among RRT ones is also observed in Lithuania and Estonia [2], a point of interest because this probably reflects that, when dialysis equipment is not easily available, the development of an active transplantation programme is the only option to provide RRT and to save lives. Of note, 42.5% of the Iranian prevalent haemodialysis patients received a twice-weekly regimen, not far from the 49.6% who were on a thrice-weekly one, possibly indicating that haemodialysis facilities are not completely sufficient to cope with the demand.
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Admittedly, these issues are hot, not only because there are many religious, ethical and social concerns with which each nation has to deal, but also because of economic pressure. As a matter of fact, kidney transplantation is less expensive and provides better survival and rehabilitation than dialysis [1416].
Haemodialysis is mainly performed in hospital centres in Iran. Home haemodialysis is not performed and peritoneal dialysis is very scarcely represented. Therefore, possible solutions for the increasing demand of RRT treatments could be provided by limited care haemodialysis, that is haemodialysis performed in the presence of nursing staff under the medical supervision of a nephrologist (who is not necessarily on site but can always be reached at a referring hospital whenever needed). This has proved successful in some countries, such as Italy, where about 15% of patients are dialysed in such units [17]. Another solution to develop the RRT programme may be provided by peritoneal dialysis.
Among the causes leading to ESRD in incident patients in Iran, diabetes mellitus was the most frequent one, and has increased by nearly 5% from 1998 to 1999. This is relevant, as diabetes mellitus, particularly type 2, is an important and increasing cause of ESRD all over the world: therefore, in a recent review, it has been defined as a medical catastrophe of world-wide dimensions' [18]. Nonetheless, the proportion of patients with diabetes as a cause of ESRD varies among different countries. The proportion in Iran is similar to that registered in the South European countries, such as Italy, and is much lower than the 4045% reported in the USA. The frequency of type 2 diabetes and of diabetic nephropathy is determined, to a variable extent in the different countries, by factors such as diet, life expectancy, genetic background and others. Hypertension/vascular disease represented another frequently reported cause of ESRD. The proportion reported in Iran is not far from that reported in the USA (26%) [5] and Italy (22%) [19].
Finally, in the Iranian data base the relatively high percentage of ESRD of unknown cause (23.5% in 1999) is remarkable and points to the necessity of improved pre-ESRD work-up. Others (18.3% in 1999) probably includes pyelonephritis/interstitial nephritis and urological abnormalities. The problem of different criteria for referral of patients to nephrologists and for performing renal biopsies and the problem of different nosographic criteria, impacting on the diagnosis of renal diseases, may flaw comparisons between countries.
In conclusion, the epidemiological panorama of RRT in Iran, interpreted in an international perspective, is characterized by a relatively young dialysis population and a high proportion of RRT patients alive with a functioning renal allograft. It is safe to predict that the demand for RRT will increase in the future.
Acknowledgments
We would like to thank Dr Mohsen Nafar, Mrs Azita Nowroozi and all nephrologists from Iran for their collaboration in collecting the epidemiological data. Part of the data incorporated in Figures 1, 2
and 3
have been supplied by the United States Renal Data System (USRDS) (references [1] and [5]). The interpretation and reporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the US Government. Part of the data incorporated in Figures 1
, 2
, 3
and 4
were taken from references [11,12,18]. Part of the data presented in Table 3
were taken from reference [13].
Notes
* Data of the Dialysis and Transplantation Symposium Joint Meeting, Tehran, 2830 April 2001.
Correspondence and offprint requests to: Prof. Dr Francesco Locatelli, Department of Nephrology and Dialysis, Ospedale A. Manzoni, Via Dell'Eremo 9/11, I-23900 Lecco, Italy. Email: nefrologia{at}ospedale.lecco.it
References