How reliable are data on CKDu?


Since chronic kidney disease with unknown aetiology (CKDu) was identified in 1990s, there has been a spate of research publications consisting of about 46 articles in peer-reviewed journals and about 50 in newspapers. Looking at these publications, especially those focusing on the incidence of the disease, it is quite obvious that there is no consistency of data, and hence the validity and reliability of the data are questionable.

Chandrajith et al (2011) calculated the prevalence of CKDu in the selected districts as about 2–3% of the population aged over 18. Applying this rate of incidence suggests that the number of people affected by CKDu in Anuradhapura District comes to about 21,000, which is similar to the figures published for 2010 by the Ministry of Health (MOH), namely 20,336.

In 2012, based on a sample study of 2,200 households with 4,941 people from twenty Grama Niladhari Divisions (GN Divisions or village headman divisions) randomly selected from six District Secretariat Divisions in three Districts in the North Central Region (Anuradhapura, Polonnaruwa and Badulla), the WHO calculated the overall incidence of CKDu as 15.3% with a higher prevalence in females (16.8%) than males (13.3%) (WHO 2013; Jayatilake et al 2013). This would suggest that, taking Anuradhapura alone with a total population of 856,232 (Census and Statistics 2011), the CKDu positive population has increased from around 21,000 in 2011 (based on data provided by Chandrajith 2011) to over 130,000 in 2012, a more than sixfold increase over one year. The incidence of the disease so determined not only points to an astonishing increase in the CKDu patient population in the affected districts, but also suggests an unfolding disaster; particularly so when the scientists convincingly show that the disease is spreading into other districts as well.

The WHO data indicate that the prevalence of the disease is slightly higher among females, but this is not corroborated by any other research carried out so far. Demographic information collected by Jayasekara et al (2013) from Northern Region clinics, covering 11,323 patients, shows that the male: female ratio among those suffering from the disease was 2.4:1. Other published research also shows that males form the majority of the affected population.

The study published by the Indian Centre for Science and Environment (Johnson et al 2012) reports that, within the first two years after diagnosis, about 80% of patients die from kidney failure. According to Rathnasooriya (2009), the death toll due to the disease surpasses that in the recent secessionist war. A research team from Kelaniya University has found that at least two persons die every day due to kidney failure, while over 200,000 patients who suffer from Chronic Kidney Disease (CKDu) have been identified, and many thousands more are at risk (Sunday Leader Feb 17, 2013). Given uncertainties and discrepancies in the underlying data, the question is how credible these figures are.

The data available with the Ministry of Health (MOH) show that there have been 20,336 patients treated in hospitals in the affected districts in 2010. The website of the Department of Health Services of the North Central Province (DOH) gives a completely different picture. According to the website of the DOH, in 2010, Anuradhapura and Polonnaruwa had 1,451 and 277 patients respectively. This compares with figures of 8,044 and 2,332 according to the corresponding MOH data.

One can understand that there could be a difference between the number of patients reported in hospitals and the number of people actually suffering from the disease. However, it is quite amazing that there should be such a vast difference between the MOH and DOH figures for the number of patents seeking treatment in hospitals.

Problems with data can affect the validity of research based upon it. So the magnitude of the affected population as discussed in various publications becomes questionable. For example, how do we square the figure of 130,000 people affected in Anuradhapura alone, as implied by the WHO study, with the much lower numbers reported for hospital attendance? Are we really to believe that, in a country such as Sri Lanka where seeking medical treatment is a well-established practice, so many people affected by the disease refrain from going to hospital? In this respect, a number of questions arise:

1. Are the calculations of incidence rates, the male female ratios, and death rates as set out in various publications correct?

2. Does the reported number of patients in MOH and DOH websites indicate the actual number of patients in the districts?

3. How reliable are the scientific publications that are based on this problematic data?

The hospitals, the main repositories of CKDu data, are protective of their blood test results and patient data, and so access to such information is restricted. So far the data has not been analyzed by reference to the socioeconomic characteristics of the patients, and this may be because the data is not readily accessible to social scientists. It is high time that the authorities concerned take measures to clear up these issues and publish valid and reliable data, as such clarity and validity is essential for research and planning in public health.

Amarasiri de Silva,

PhD (formerly Professor, Department of Sociology, University of Peradeniya)

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