Screening for chronic diseases in South Africa
Screening for disease is one of the cornerstones of medicine and public health, used to help make a diagnosis in individuals presenting with suggestive clinical signs and symptoms, and to find early signs of disease in high-risk groups such as tuberculosis in miners and pre-eclampsia in pregnant women. In addition, community-based screening for chronic diseases is becoming a regular part of healthcare systems in middle- and high-income countries. This has been defined as ‘the systematic application of a test or enquiry to identify individuals at sufficient risk of a specific disorder to benefit from further investigation or direct preventive action, among people who have not sought medical attention because of symptoms of that disorder’.1 The concepts and principles of screening have been well documented in the past, with criteria established for deciding on whether a population-wide screening service should be developed and some of the challenges related to this.2 In particular, the disease must be well defined, of known prevalence, and amenable to treatment or prevention. The test to be used should be simple and safe, and the distribution of test values in affected and unaffected individuals known. The screening service should be cost-effective and available to those who should be covered. The procedures following a positive result should be agreed on and acceptable to both those providing the service and those to be screened. There should be equity of access to the service, and it should form part of a comprehensive set of services aimed at preventing, treating and caring for those who have the disorder being screened for. Most of these services need to be embedded in primary healthcare settings.3
A recent review of screening for chronic diseases in South Africa in an insured population, published in this issue of SAMJ, shows the magnitude of the challenge of developing an effective set of services for the country.4 Even in this relatively wealthy, well-served group uptake of services was low, and the outcome of the service as a whole is not known or available for review. Given this low uptake, and the likelihood that those least likely to benefit from the service are those most likely to use it, the impact of current services is probably small. In the majority of the population, who do not have private insurance but who probably have the biggest burden of diseases, coverage in most situations will probably be worse. As the country moves towards universal coverage of services under National Health Insurance, there are major questions to be resolved about the role that community-based screening for chronic diseases will play, and the priorities for services to be developed across the country.
South Africa will need to decide on what screening services are required and for who, based on its own pattern of disease burden, as has already started with routine HIV counselling and testing (HCT). However, there is value in looking at the experiences of other countries, both in terms of policies and the evidence behind them. For example, the US Preventive Services Task Force is an independent group that reviews the evidence on screening and other preventive services and makes regular recommendations to government.5 These recommendations are then used to provide extensive guidance to care providers through groups such as the American Academy of Family Physicians.6 For example, this group recommends screening for alcohol misuse in adults in primary care settings, breast cancer in women over 50, cervical cancer in women aged 21 - 65, colorectal cancer in adults aged 50 - 75, hypertension in those 18 and above and adult obesity, but advises against screening for type 2 diabetes in asymptomatic adults with normal blood pressure, and for prostatic cancer using prostate-specific antigen (PSA). Similar agencies provide reviews and recommendations in the UK7 and Australia.8
As in other parts of the world, chronic and
non-communicable diseases are increasing in South Africa.9
The government is already building on the progress it has made
with tobacco by further reducing the future burden through
regulation of salt and trans-fatty acid content in food, and
banning advertising of alcohol to children. These efforts to
promote health and prevent ill health could in future be
complemented by more systematic community-based screening. The
successes in the HCT campaign provide a good starting point,
and the inclusion of tests for some non-communicable diseases
provides useful lessons for future national screening
policies. As South Africa introduces National Health
Insurance, guidance and recommendations will be required to
guide national policy and the further development of screening
services. There are a large number of options that could be
developed, and an increasing number of commercially available
screening tests. As in other countries, independent experts
will be required to advise on priorities, screening tests,
evaluations of screening coverage and outcomes, and to provide
up-to-date guidance for service providers.
Senior
Adviser, seconded to the South African National Department of
Health from the UK Department for International Development
1. Wald NJ. Guidance on terminology. J Med Screen 2001;8(1):56. [http://dx.doi.org/10.1136/jms.8.1.56]
2. Strong K, Wald N, Miller A, Alwan A, on behalf of the WHO Consultation Group. Current concepts in screening for noncommunicable disease: World Health Organization Consultation Group Report on methodology of non-communicable disease screening. J Med Screen 2005;12(1):12-19. [http://dx.doi.org/10.1258/0969141053279086]
3. Comino EJ, Davies GP, Krastev Y, et al. A systematic review of interventions to enhance access to best practice primary health care for chronic disease management, prevention and episodic care. BMC Health Serv Res 2012;12(1):415. [http://dx.doi.org/10.1186/1472-6963-12-415]
4. Adonis L, An R, Luiz J, et al. Provincial screening rates for chronic diseases of lifestyle, cancers and HIV in a health-insured population. S Afr Med J 2013;103(5):309-312. [http://dx.doi.org/10.7196/SAMJ.6686]
5. US Preventive Services Task Force. http://www.uspreventiveservicestaskforce.org/about.htm (accessed 3 April 2012).
6. Summary of Recommendations for Clinical Preventive Services. American Academy of Family Physicians. October 2012. http://www.aafp.org/online/etc/medialib/aafp_org/documents/clinical/CPS/rcps08-2005.Par.0001.File.tmp/October2012SCPS.pdf (accessed 3 April 2013).
7. Public Health England. UK Screening Portal. http://www.screening.nhs.uk/ (accessed 3 April 2012).
8. Australian Government Department of Health and Ageing. http://www.cancerscreening.gov.au/ (accessed 3 April 2012).
9. Global Burden of Disease Study 2010. Lancet 2012;380(9859):2053-2260.
S Afr Med J 2013;103(5):289. DOI:10.7196/SAMJ.6934
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