9.3 Screening programmes

Screening programmes are public health initiatives intended to identify a given disease or condition in the population. They generally involve a large-scale programme in which specific medical tests are carried out on the general population across a country or region, often in an ongoing cycle. The intention of screening programmes is to identify occurrences of disease as early as possible to promote rapid intervention and reduce morbidity and mortality. This object explores a number of potential roles that GIS can play in the management of screening programmes.

It is rarely appropriate to implement a screening programme with ‘blanket coverage’, i.e. one that aims to target an entire population. More often, it is medically appropriate and financially and logistically necessary to identify a specific sub-group of population for screening services. This targeting may be based on risk: the genetic or behavioural predisposition of certain sub-groups to the condition in question. There are many examples of the use of GIS and associated spatial analysis techniques to assess spatial variations in risk or prevalence of diseases that are routinely screened for such as cancer (Bell et al., 2006) and sexually transmitted diseases (Law et al., 2004). Whilst knowledge of the spatial pattern of risk is useful for decision makers in planning a screening programme, it is by no means the only factor. The level of under-diagnosis of the disease is likely to vary spatially, as are levels of access to and uptake of existing services. GIS has enormous potential to inform the geographical targeting and organization of screening services so as to maximise accessibility and compliance.

The use of mobile facilities, sometimes deployed at non-health locations like supermarkets or retail centres, has been proposed as one means of overcoming inequalities in service access in relation to screening. Thus, mobile services may make screening services more widely accessible by bringing such services closer to groups who would traditionally struggle to use them, such as the very deprived, elderly, disabled, and those lacking public transport access. However, it is uncertain how effective such a strategy is. Evidence from the UK on the use of mobile breast cancer services is ambiguous: those from deprived areas were less likely to access both mobile and fixed facilities.

The Slough Primary Care Trust (PCT) is the body responsible for delivering public health care to the Slough region in the UK. As with elsewhere across the developed world, a substantial proportion of the population in Slough are likely to have diabetes without knowing it. To address this public health problem, Slough PCT required a GIS programme to identify those areas likely to have the highest risk which could be targeted in their ‘Action Diabetes’ screening and awareness campaign. This programme was implemented by the medical consultancy Dr Foster Intelligence who used their social marketing approaches to produce risk maps based on detailed socio-economic neighbourhood profiles coupled with data on diabetes morbidity. The programme resulted in a 164% increase in early detection of diabetes in the region.
 

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