Decreasing incidence of CKD/CKDu in North Central Province of Sri Lanka: is it related to provision of drinking water reverse osmosis plants?

doi:10.21203/rs.3.rs-3128119/v1

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Decreasing incidence of CKD/CKDu in North Central Province of Sri Lanka: is it related to provision of drinking water reverse osmosis plants?

https://doi.org/10.21203/rs.3.rs-3128119/v1

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published 11 Mar, 2024

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Background

We assess the impact of provision of reverse osmosis (RO) water on the incidence of CKD/CKDu in North Central Province (NCP) of Sri Lanka.

Methods

A cross sectional survey was conducted on data from 2010–2020 on the incidence of CKD/CKDu, CKD/CKDu screening and provision of drinking water reverse osmosis (RO) plants in NCP. Analysis was conducted using descriptive statistics, ANOVA and chi-square test.

Results

The incidence of CKD/CKDu (per 100 000 population) in 2010–2013, 2014–2016 and 2017–2020 periods in Anuradhapura district were 129.07, 331.06 and 185.57 (p = 0.002) while in Polonnaruwa district these were 149.29, 326.12 and 296.73 (p = 0.04) respectively. In NCP provision of Reverse Osmosis (RO) plants commenced after 2011 and the decline in the incidence of CKD/CKDu occurred in 25 of the 29 Divisional Secretary Divisions when more than 20% of the families received access to drinking RO water projects. In both districts mean time taken to reduce the incidence rate of CKD/CKDu after reaching 20% of family coverage is 0.8 years.

Conclusions

CKD/CKDu incidence increased in NCP from 2010 to 2016 and continuously decreased thereafter. Continuous declining of CKD/CKDu incidence was observed after more than 20% of the families received access to drinking water RO plants.

Chronic Kidney Disease of uncertain origin (CKDu)

decreasing incidence of CKD/CKDu

provision of safe drinking water

The incidence of CKD/CKDu in CKDu affected North Central Province of Sri Lanka is decreasing probably due to provision of safe drinking water

Chronic kidney disease of uncertain origin (CKDu) was first identified in Sri Lanka in early 1990s from Madawachchiya Divisional Secretariat (DS) Division in the Anuradhapura district (1). Two decades later it was endemic in the North Central Province (NCP) and had spread to bordering districts as well (2). Despite many studies the cause of CKDu still remains elusive (3–10). Nevertheless, most of these CKDu causation hypotheses linked drinking water as the source of entry of the injurious agent to the human body (11). The water in NCP is hard and unpalatable (12, 13) resulting in residents drinking inadequately to quench their thirst (14). Based on this hypothesis the government commenced provision of Reverse Osmosis (RO) water (15, 16). This was supplemented by health education programmes to promote adequate drinking of safe water (17). A recent publication described a decrease in the incidence of CKDu in NCP possibly due to provision of safe drinking water (2). In this study we analyzed the impact of provision of RO water on the incidence of CKDu in North Central Province of Sri Lanka.

The methodology of this study assessing the incidence of chronic kidney disease (CKD)/CKDu in NCP was previously described in detail (2). To calculate the CKDu incidence, all newly diagnosed patients were prospectively collected from 11 hospitals on a monthly basis. The hospitals included Teaching Hospitals, District General Hospitals, Base Hospitals and Divisional Hospitals of the Anuradhapura and Polonnaruwa districts. The diagnosis of CKD (which includes CKD and CKDu) and staging of the disease had been made by a Nephrologist or Consultant Physician according to the Kidney Disease: Improving Global Outcomes paper (18). The GFR estimations were derived using the CKD-EPI creatinine Eq. (19). As the definitive guidelines for distinguishing CKD from CKDu (in Sri Lanka) according to World Health Organization criteria became available only after 2016 (20), attempts were not made to distinguish between CKD and CKDu.

The CKD/CKDu screening information from 2010–2020 was obtained from the Regional Director of Health Services of Anuradhapura and Polonnaruwa districts.

The information with regard to RO plants were gathered routinely by the National Renal Disease Prevention and Research Unit (NRDPRU) of the Ministry of Health, Sri Lanka. NRDPRU conducts surveys in DS Divisions of NCP to map the drinking water RO plants as provision and management of drinking water RO plants is part of their responsibility. To date more than 1,000 drinking water RO plants have been provided to North Central Province. Before visiting the DS Division for the drinking water RO plant survey, a map of the CKD/CDKu patients in the area along with main roads was created using ArcGIS. ArcGIS is a Geographic Information System (GIS), which is used to display geographic data and create maps. Information on drinking water RO plant locations were gathered on each Gramaniladhari (GN) division of DS Divisions separately from the existing database of NRDPRU. A GN Division is the smallest administrative division in the country and each DS Division in NCP is made up of more than 25 GN Divisions. During the survey, drinking water RO plants provided and managed through other organizations were searched by interviewing key informant field officers (eg. Gramasewaka, Samurdhi Officer, and Agriculture Officers) and private drinking water suppliers of the GN Division. The operator of the RO plant was also interviewed separately to obtain the required information.

The data gathered was statistically analyzed using STATA 13 student version. Counts and percentages were used to express discrete variables while mean and standard deviation were used to express continuous variables. For analysis purposes we divided the study population into two groups; from years 2010 to 2016 and 2017 to 2020, as the declining of CKD/CKDu incidence has commenced from 2017 according to a previous study conducted by us (2). To calculate the incidence, population data was obtained from the 2011 Census [21] and expressed as per 100,000 population. The annual CKD/CKDu incidence increase rate was calculated by subtracting the incidence of the current year from the previous year.

During 2010 to 2020 period 362,293 and 205,767 were screened for CKD/CKDu, in Anuradhapura and Polonnaruwa districts respectively. In Anuradhapura district the highest number of population was screened in 2016 (89,184) and in Polonnaruwa in 2017 (44,681). Average proportion of population annually screened for CKD/CKDu in both districts was 6.7% (3.1 SD) and 8.5% (2.2 SD) respectively. From 2015 to 2020, In Anuradhapura district, among the six highest incidence DS divisions of CKD/CKDu (annual incidence of > 500 per 100,000 population from 2014 to 2016) three had screened more than 50% of the population while among the six lowest incidence DS divisions (annual incidence of < 185 per 100,000 population from 2014 to 2016) 4 had screened less than 23% of the population. In both districts a higher proportion was screened from 2014 to 2016 period.

There were a total of 30,596 new CKD/CKDu patients reported from North Central Province during the period of 2010 to 2020 (19,378 and 11,218 from Anuradhapura and Polonnaruwa districts respectively). The incidence of CKD/CKDu increased from 2013 to 2016 and continuously declined thereafter in both districts. Table 01 compares the selected characteristics of the incidence of CKD/CKDu, CKD/CKDu screening details and provision of drinking water RO plants in Anuradhapura and Polonnaruwa districts from 2010–2013, 2014–2016 and 2017–2020 period.

Table 01: Selected characteristics of the incidence of chronic kidney disease / chronic kidney disease of uncertain origin, screening details for chronic kidney disease / chronic kidney disease of uncertain origin and provision of drinking water reverse osmosis plants in Anuradhapura and Polonnaruwa districts from 2010–2016 period and 2017–2020 period.

The rate of increase of CKD/CKDu incidence was highest for Anuradhapura district (158.7) in 2014 while for Polonnaruwa district (143.6) this was observed in 2016. The rate of decrease of CKD/CKDu incidence was highest for Anuradhapura district in 2017 (105.4) while for Polonnaruwa district this was observed in 2020 (136.4).

Figure 01 shows the incidence of CKD/CKDu, CKD/CKDu screening proportion and the percentage of families receiving RO plant water from 2010 to 2020 in Anuradhapura and Polonnaruwa districts and Fig. 2 demonstrates these at each DS divisions of NCP.

Figure 01: The incidence of chronic kidney disease/chronic kidney disease of uncertain origin, screened proportion for chronic kidney disease/chronic kidney disease of uncertain origin and the percentage of families receiving reverse osmosis plant water from 2010 to 2020 in Anuradhapura and Polonnaruwa districts

Figure 02: The incidence of chronic kidney disease/chronic kidney disease of uncertain origin, screened proportion for chronic kidney disease/chronic kidney disease of uncertain origin and the percentage of families receiving reverse osmosis plant water from 2010 to 2020 in each DS division of North Central Province

Figure 3 illustrates the distribution of incidence of CKD/CKDu in NCP for the years a) 2010, b) 2016 & c) 2019 and the availability of RO water in d) 2016 and e) 2018.

Figure 3: The distribution of incidence of chronic kidney disease/chronic kidney disease of uncertain origin in North Central Province for the years a) 2010, b) 2016 & c) 2019 and the availability of RO water in in North Central Province for the years d) 2016 and e) 2018.

In Anuradhapura district after initiation of drinking water RO systems mean time taken to reduce the incidence rate of CKD/CKDu is 3.2 years while the mean time taken after reaching 20% of family coverage is 0.8 years. The corresponding figures for Polonnaruwa district is 3.5 years and 0.8 years respectively.

The occurrence of CKD/CKDu has previously shown a clustering pattern (Fig. 3) with highly endemic areas being clustered closely together (2). Areas with a high incidence of CKD/CKDu are located mainly within the NCP together with DS divisions of adjacent districts (2, 22). The incidence of CKD/CKDu decreases gradually from the epicenter of high incidence areas (2). This may be because environmental factor/factors contributing to CKDu reduce gradually when moving away from the epicenter of high CKD/CKDu incidence areas.

The incidence of CKD/CKDu in Anuradhapura and Polonnaruwa districts increases from 2010 to 2016 and thereafter decreases (Fig. 1). The incidence of CKD/CKDu in all DS divisions of Anuradhapura and Polonnaruwa districts demonstrate a more or less similar trend (Fig. 2).

Most hypotheses for the causation of CKDu identified water as the medium of toxin entry into the human body (11). This knowledge and poor accessibility to safe drinking water in the affected areas, led to acceleration of provision of safe drinking water to NCP by the government (15, 16). The provision of community based drinking water RO plants commenced after 2011 in NCP (15, 16). From 2010–2013 period 11 DS Divisions has commenced drinking water RO plant projects and in all of these the decline in the incidence of CKD/CKDu occurred after more than 20% of the families received access to drinking RO water projects. The rest of 18 DS Divisions has commenced drinking water RO plant projects during 2014–2016 period and in 14 of these the decline in the incidence of CLD/CKDu occurred after more than 20% of the families received access to drinking RO water projects. In four DS divisions of Anuradhapura district decline begins well before reaching “20% family target” probably because these communities have started to access safe drinking water in different formats. Further these were CKD/CKDu low incidence areas (all four areas reporting the highest CKD/CKDu incidence rate of less than 215 per 100,000 population) and the residents were socio economically higher compared to other DS divisions. They may have started purchasing safe drinking water before commencement of drinking water RO plants. The initiation of community-based drinking water RO plants were late in these areas and also the number of coverage of drinking water RO plants are less in these areas probably indicating less requirement for community based water projects due to their accessibility to safe drinking water.

The coverage of families accessing drinking water RO plants exceeds 100% in some of the DS Divisions as some families were accessing more than one drinking water RO plant.

In 2014 formal systematics CKD/CKDu screening commenced in NCP. The increase in CKD/CKDu incidence may be attributed to initiation of proper CKD/CKDu screening programmes, however the increase in the incidence continues even after the annual proportion being screened drops in most of the DS divisions. When comparing the annual screening rates from 2014–2016 period with 2017–2020 period there was no significant difference (p = 0.36 in Anuradhapura district and p = 0.54 in Polonnaruwa district) further indicating the trend in CKD/CKDu incidence not related to the CKD/CKDu annual screening rates. This concludes that there had been a general increase in the incidence of CKD/CKDu from 2013–2016 period and thereafter a rapid continuous decline. Thus, the screening rate and incidence of CKD/CKDu does not seems to have a relationship.

There may be several reasons for the declining trend in CKD/CKDu incidence in NCP. Water may have been contaminated or there may have been some inherent factor which was causing the CKDu but aggravated by contaminated water. Thus, provision of safe drinking water may remove the risk of CKDu. Another hypothesis would be the provision of safe drinking water is palatable compared to hard water in the area thus an increase consumption of water due to palatability may have reduced the CKD/CKDu incidence.

The reduction of the CKD/CKDu incidence does not necessarily mean that the water is the transporter of the cause. The provision of safe drinking water probably resulted in a behavioral change in residents of CKDu affected areas to consume more water (15–17) which may have also reduced the risk for the disease. CKDu has also been reported in Central America (23), Andhra Pradesh in India (24), Tierra Blanca in Mexico (25), El-Minia Governorate in Egypt (26) and in Tunisia (27). The arguments for the causation of CKDu in these areas are more or less similar compared to the Sri Lankan situation with high emphasis on contaminated water and occupational driven heat stress (28–31). It would be noteworthy to assess the impact of provision of safe drinking water on incidence of CKDu in these areas.

In Anuradhapura and Polonnaruwa districts of NCP an increase in the incidence of CKD/CKDu was observed from 2010 to 2016 followed by a decreasing trend since 2017. Similar trend in the incidence of CKD/CKDu was seen in all DS divisions of Anuradhapura and Polonnaruwa districts as well. Provision of drinking water RO plants commenced in 2011 in NCP targeting CKD/CKDu high incidence areas. Continuous declining of CKD/CKDu incidence was observed after more than 20% of the families received access to drinking water RO plants in Anuradhapura and Polonnaruwa districts. This declining trend may be associated with provision of drinking water RO plants.

Ethics approval: Not applicable

The data used for this study are anonymised aggregated (routinely gathered) secondary data (personally identifiable data were not used). We have obtained this secondary data and conducted the analysis. During our study we have not come in contact with any patients for data gathering as anonymised secondary data were used, therefore consent was not sought since it was impossible to identify the individual persons. Therefore, ethical approval was not sought. All methods were carried out in accordance with relevant guidelines and regulations. Most of this data is also available in the Sri Lanka Renal Registry. The aggregate data is accessible to any persons. The approval for the study was obtained from the Ministry of Health, Sri Lanka.

Consent for publication: Not applicable

Availability of data and materials: We have provided the raw aggregate data we used for analysis in Table 02, which is also available at the renal registry https://nicst.com/iframe-renal-dev/. The incidence information is also published in the Sri Lanka Annual Health Bulletin 2021. However, if anyone requires the same raw aggregate data they can be obtained from the National Renal Disease Prevention and Research Unit, Ministry of Health, Sri Lanka.

Competing interests: The authors declare that they have no competing interests

Funding: None

Author contributions: AVR, APDS and CDC came up with the original idea. AVR, LCS, GWGP, RHK, APDS, JMCNG, SKCRK, MSFS, and CDS all helped to design the study and prepare the methodology. JMCNG, SKCRK and MSFS extracted the data from the secondary data sources. GWGP, RHK, APDS.JMCNG, SKCRK and MSFS did the analysis. AVR, LCS, GWGP, RHK, APDS, KGDS, JMCNG, SKCRK, MSFS, JSC and CDS all helped to interpret the data and write the manuscript. They all approved the final version and agreed to be accountable for all aspects of the work.

Acknowledgments: We thank the hospital and field staff of North Central Province. We acknowledge BMC Nephrology for waiving off 50% of the article processing fee. We are also grateful for Lucenxia Healthcare (Pvt.) Ltd for contributing for the remaining 50% of the article processing fee. Lucenxia Healthcare (Pvt.) Ltd provide automated peritoneal dialysis services in Sri Lanka.

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Table 1 and 2 are available in the Supplementary Files section.

No competing interests reported.

Table01.docx
Table 01: Selected characteristics of the incidence of chronic kidney disease / chronic kidney disease of uncertain origin, screening details for chronic kidney disease / chronic kidney disease of uncertain origin and provision of drinking water reverse osmosis plants in Anuradhapura and Polonnaruwa districts from 2010-2016 period and 2017-2020 period.
Table02.docx
Table 02: Incidence of chronic kidney disease/chronic kidney disease of uncertain origin, number screened for chronic kidney disease/chronic kidney disease of uncertain origin and the percentage of families provided with reverse osmosis water from 2010 to 2020in Anuradhapura and Polonnaruwa districts

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Decreasing incidence of CKD/CKDu in North Central Province of Sri Lanka: is it related to provision of drinking water reverse osmosis plants?

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