A survey of waiting lists for kidney transplantation in northeastern Iran

1Health Information Technology Research Center, Isfahan University of Medical Sciences, Isfahan, Iran 2Department of Medical Informatics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 3Kidney transplantation complication research center, Department of Internal Medicine, Ghaem Hospital, Faculty of Medicine, Mashhad University of Medical Science, Mashhad, Iran 4Organ Procurement Center, Montaserie Hospital, Mashhad University of Medical Sciences, Mashhad, Iran


Introduction
End-stage renal disease (ESRD) is the last stage (stage five) of chronic kidney disease (CKD), which is diagnosed when glomerular filtration rate (GFR) falls below 15 mL/min (1). In ESRD, the kidneys no longer function well enough to meet the needs of daily life. As a result, in ESRD patients, renal replacement therapy is necessary. ESRD continues to be a public health challenge. In the United States, there were 120 688 new cases of ESRD reported in 2014 (1.1% increase compared to 2013) (2) and approximately 600 000 individuals were diagnosed with ESRD until 2015 (3). Kidney transplantation is an effective therapeutic procedure for ESRD patients (4,5). Patients, on the advice of a qualified nephrologist, are registered on a waiting list, and then referred to the transplantation center. On waiting list, patients are transplanted according to their waiting time (according to the first date of dialysis), by blood group.

Objectives
In this study, we report the status of the

Key point
In the present study, the status of waiting list in northeastern Iran can help nephrologists to make appropriate decisions about the organ seeking candidates. On the other hand, it is concluded that the status of waiting list is very useful to know the growing and stratifying candidates to decision about them.
waiting list in northeastern Iran until September 2017.

Study patients
This study was conducted at Montaserie hospital in Mashhad, Iran. This hospital is a specialty transplantation center, and provides renal services to the entire northeastern (Razavi, north, and south Khorasan province) Iran region. All patients with symptomatic CKD and ESRD in northeastern Iran are admitted either by the nephrologists, private hospitals or Montaserie hospital directly. Details of every individual admitted with ESRD were collected with a unique identifier number on a unified waiting list, thus preventing any duplication of records or redundancy of referrals. We reviewed the clinical records of all ESRD patients referred to this hospital until September 2017, retrospectively.

Ethical issues
The research followed the tenets of the Declaration of Helsinki. The Ethics Committee of Mashhad University of Medical Sciences approved this study. The institutional ethical committee at Mashhad University of Medical Sciences approved all study protocols(IR.SBMU.MSP. REC.1396.900). Accordingly, written informed consent was taken from all participants before any intervention. This study was extracted from thesis of PhD at this university (Thesis #950393).

Statistical analysis
Data was compiled and cleaned in Excel 2013. Then it was completed using a data linkage method and analyzed using SPSS version 23.

Results
A total of 1956 patients (1198 male, 758 females, 1.58:1 ratio) were studied from the waiting list. The most frequent blood group was O (33.3%), the least frequent was AB (7.2%) (Figure 1), and the mean population age was 44.7 ± 14.4 years (3-80 years). With regard to age distribution ( Table 1), 43% of patients were in the 26-45 years range, which represents the dominant age group.
The main causes of ESRD were reported as unknown (44.1%), diabetes (18.4%) and hypertension (10.9%) (Table 2, Figure 2). The distribution of reported ESRD causes in the past 5 years is illustrated in chart 2. 41% of diabetic patients suffered from type 1 diabetes and 59% from type 2. Only two reported causes ("preeclampsia" and "lupus nephritis disease") were more prevalent in women than in men. The main causes of ESRD in patients aged fewer than 18 were unknown sources (31.8%), reflux nephropathy (15.3%), and finally FSGS (focal segmental glomerulosclerosis) (13.1%). Main causes of ESRD in other age groups are shown in Table 3.
In men, the main causes of ESRD were unknown (44.9%), diabetes (19.7%), and hypertension (9.6%) while  for women it was reported as unknown (42.2%), diabetes (16%), and hypertension (12.9%). Hemodialysis was the dominant preferred renal replacement therapeutic procedure for 91.1% of patients on the waiting list, while 5.5% underwent peritoneal dialysis (3.4% preemptive). The maximum registered waiting time for an individual patient was 295 months, the minimum was one month, and the mean waiting time was 63 months. Table 4 shows the distribution of waiting time, categorized by the length of waiting time in months. The category with the largest number of patients was the 37-72 months waiting period (34%). The number of registered patients on the waiting list has grown by 22.4% over the past 5 years. The proportion of patients waiting for the first, second and third kidney transplantation was 86%, 13.2% and 0.7%, respectively.

Discussion
Results of our analysis demonstrate a steady increase in the number of registered patients on the waiting list. Over the past 5 years, 1020 patients were added to the waiting list and 581 patients have undergone transplantation. The number of patients on our studied waiting list increased 8% over the last year alone. Comparatively, in the United States, a 3% increase in the number of registered patients on the waiting list has been reported over the last year (2016) (2). Usually, the demand for kidney transplantation overwhelmingly exceeds actual performed transplantation procedures, which leads to an increase in the number of patients on the waiting lists (6). In this study, the waiting time category with the largest number of patients was 37-72 months (34% of patients fell into this category). The US statistics report that nearly 30% of patients were on the waiting list for 72 months or more in 2013 (7) and approximately 33% of European patients were on waiting lists for more than 60 months in 2017 (8). This figure varies across different European countries. For example, the figure falls at 29% in Austria, 27% in Belgium, and 57% in Germany (9).
The mean age of ESRD patients in our studied waiting list was 44.7 ± 14.4 years. The number of cases was most frequent among the 26-45year group (42.6%) in our study. Considering the trend, it can be inferred that the age of ESRD patients has decreased over the last 15 years and number of males was more than females obviously (1.58:1). Therefore, in the United States number of males was higher than females (1.2:1) (10).  In most of the studies conducted in Iran, unknown etiology is reported as of the most dominant causes of ESRD. More effort to study the ESRD etiology and identify the causes of the disease is deemed essential. A possible reason for the high reported rate of unknown causes may be due to delays in referral problems.
Diabetes and hypertension were found to be two of the most common causes of ESRD (29.3%). It seems that if patients with diabetes and hypertension are provided with a better healthcare, it will have an influential reductive effect on diagnosed cases of ESRD. Moreover, the percentage of diabetes and nephrotic syndrome (causes of ESRD) in comparison with similar rates in the last year has been increased and unknown and FSGS have been reduced.
Polycystic kidney disease (4.4%) was another cause of ESRD. The number of patients who get ESRD due to polycystic kidney disease and other causes is less.
In this study, 91.1% of the patients received hemodialysis for renal replacement therapy, 5.5% underwent peritoneal dialysis and 3.4% underwent preemptive kidney transplantation.

Conclusion
Unfortunately, the number of patients on the waiting list is rising. Additionally, unknown is the high percentage of ESRD causes. Hence, the specialists should effort to define the ESRD causes is needed and refer patients as soon as possible.

Limitation of the study
A lack of the registry in ESRD patients and the limited sources of funding only allowed a regional study spanning northeastern Iran. A more comprehensive study can have a broader coverage, investigating all reported ESRD cases in Iran.