Oman’s treated chronic kidney failure population in years 1980 to 2015: an epidemiology research

Background and aim: Epidemiological studies on incidence, prevalence, and other epidemiological variables of Oman’s treated kidney failure population have been limited, and questionable as to their use of rigorous research methods. The main aim of this study was to identify the epidemiological variables of treated patients with advanced kidney disease in Oman, the status of publishing on the studied population, and describing the dialysis sub-population characteristics in the northern region of Oman. Methods: First, a secondary data analysis was performed using data from the Oman's renal replacement therapy (RRT) register (1980-2015). The studied epidemiological variables included: incidence, prevalence, death figures, causes of death and treatment costs of the Oman’s treated kidney failure population, especially dialysis sub-population. The publications on chronic kidney failure population of Oman were explored at this stage. Secondly, a multi-centre, cross-sectional study (i.e. survey research) was conducted covering the dialysis sub-population of the northern region of Oman. The basic aim of the survey was to assist in developing the first description of the main characteristics (e.g. demography, primary diagnoses, and co-morbidities) of dialysis-treated patients with advanced kidney disease living the northern region of Oman. A convenience sample (n = 341) of participants were recruited from four renal dialysis centres (RDCs). Those who met the pre-specified study inclusion criteria were surveyed using a researcher-administered survey during October and November 2014. SomeFrom December 2014 to December 2015, there were some additional data was gathered (e.g. death figures) from December 2014 to December 2015. Results: The first RRT care that started in Oman was peritoneal dialysis (PD) in April 1980, while the well-structured PD programme started in 1992 and was boosted in 2007. In 1983, the first dialysis center was opened with seven machines for haemodialysis, serving 35 patients. By the end of 2015, the Ministry of Health (MOH) had 18 RDCs serving 1,439 patients on dialysis per annum for Oman’s population. The analysis of the RRT register's data showed that the mean prevalence for all years (1983-2015) was 724.9 dialysis patients per year. The mean incidence for the same years was 203.7 kidney failure patients per year. The mean death rate calculated for all years (1983-2015) was 58 deaths per year. The recorded causes of death were cardiovascular diseases, and infection. Over the years, it was described that death due to infections and cardiovascular diseases were increasing among the RRT population and particularly within dialysis cohort. The cost of the dialysis sessions increased dramatically from 2,246,627 OMR (~ 4.5 million GBP) in 1998 to 9,543,572 OMR (~20 million GBP) in 2015, which is a 325% increase. Among the databases searched, there were 44 articles, which either focused on, or mentioned Oman’s chronic kidney failure population. Most of these articles focused on kidney transplantation and were of limited and questionable methodologies. In the multi-centre cross-sectional study, the northern region of Oman was divided into two subdivisions. The average age of this population was 51.7 ± 15.8 (mean ± SD) with no statistical evidence of difference between the subdivisions of the northern region of Oman (P = 0.177). There were more males (n = 187 = 54.8%) than females (n = 154 = 45.2%), with no significant difference between subdivisions (P = 0.598). It was described that the divorce frequency was low in this population (n = 22 = 6.4%), with no significant difference between subdivisions (P = 0.49), but unemployment was high (n = 292 = 85.9%), showing no significant difference between subdivisions (P = 0.537). Nearly half of this population were illiterate (n = 164 = 48.1%), with more illiterate females (n = 103= 66.9%) compared to males (n = 61= 32.6%), and no significant difference between subdivisions (P = 0.174). Nearly half of the participants had been on dialysis for five years at the time of data collection (n = 165 = 48.4%). The most common co-morbidities reported by these participants were hypertension and diabetes combined (n = 156 = 32.4%). The main reported causes of death shown by the data gathered were cardiovascular diseases (n = 41 = 41.5%) and infection (n = 10 = 10.2%). More than half of the participants were hoping to have kidney transplantations as soon as possible (n = 173 = 50.7%). Conclusion: This study is a comprehensive description of the Oman’s RRT epidemiology. The data showed a significant increase in the incidence and prevalence of treated chronic kidney failure in Oman. It showed the increase in the cost of dialysis in Oman for the past 17 years (1998-2015), which is in line with the recent publications from Oman (Al-Alawi et al., 2017; Al-Ismaili et al., 2016) and is in line with global findings. This research’s results have contributed to providing a deeper understanding of the Oman’s treated chronic kidney failure population. It appears that there is a heavy burden borne by the country, the health sector and the patients on dialysis because of the complex nature of life-long treatment. Oman’s publications on this health problem were limited. Therefore, it is necessary to conduct additional research with rigorous methods to obtain a complete picture of this health problem in Oman.