Select Committee on Science and Technology Sixth Report

CHAPTER 3: Data Collection


3.1.Allergy is a complex immunological mechanism which can manifest itself in several different organs of an individual at once. So for example, hayfever involves itching in the eyes and runny nose, and sometimes this is also associated with wheeze. Increasingly, allergic individuals suffer from several atopic allergic conditions at the same time so, for example, a patient could have rhinitis caused by housedust mites and eczema triggered by a food allergy.

3.2.Allergy, and the allergic disorders that result from it, are therefore extremely complicated to research, monitor and treat. This chapter outlines the problems involved in collecting data on allergy prevalence, and aims to explain the current gaps in establishing the allergy burden. To understand fully the problems involved with collecting data, it is necessary to look briefly at the way in which allergy patients are treated in the United Kingdom, although the provision of allergy services is discussed in detail in Chapter 9.

Data collection problems


3.3.Allergy UK, a charity which supports allergy patients across the United Kingdom, reported that "for the patient the major problem is the lack of knowledge at primary care level. GPs do not recognise allergic symptoms when presented with them due to a lack of training in allergy" (p 292). Dr Glenis Scadding, a consultant allergist at the Royal National, Throat, Nose and Ear Hospital agreed, saying "GPs are not adequately trained to deal with allergic diseases. In medical schools the amount of allergy training is absolutely minute, if it exists at all" (Q 788). This lack of GP training in allergy means that in many patients the allergic basis of their symptoms is often not recognised, and referrals may be made to several organ-based specialists, who might not necessarily have an adequate training in allergy either. Problems with the clinical services therefore makes it difficult to accurately assess the prevalence of allergy, as Professor Tak Lee, Director of the MRC-Asthma UK Centre in Allergic Mechanisms of Asthma noted "we also have to take into account the other patients in dermatology clinics, respiratory clinics and so on," and not just the few who find their way to an allergy centre (Q 240).

3.4.The EAACI also pointed out that "much of the current provision of alternative and complementary services for allergy is driven by failure of provision within the state-funded healthcare sector" (p 70). Thus, disillusion with the provision of services within the National Health Service (NHS) causes many patients to self-care or seek treatment through private practitioners, so NHS statistics will significantly underestimate the true number of people suffering from allergic disease.


3.5.As "allergy" is not a single disease there is no definitive database which records the incidence of all allergic disorders within the United Kingdom. Different organisations collect data in different ways, making it difficult to obtain an accurate overview of allergy in total. Charities tend to carry out patient-based surveys which often rely on subjective statements and opinions, and usually focus on the particular sub-section of allergic disease relevant to their organisation, such as food allergies or asthma. In contrast, the Department of Health (DH) relies heavily on the clinical records produced from primary and secondary care consultations, based on the clinical manifestation or the clinical service needed to treat the patient. Academic epidemiological studies are more likely to categorise the disorders according to the pathological processes involved.

3.6.The range in severity of allergic disorders also poses a problem. For example, the symptoms of food allergy range from a mild rash to severe anaphylaxis but there is no standardisation of a diagnostic threshold and so Dr Richard Pumphrey, Consultant Immunologist, St Mary's Hospital, Manchester claimed that "a small change in your criteria could produce a 30-fold change in the numbers of people you are counting" (Q 439). In addition, the diagnostic classification systems on NHS patient records do not enable allergy to be consistently recorded. For example, Dr Mark Levy, representing the Royal College of General Practitioners, noted that a patient with allergic rhinitis referred to an Ear, Nose and Throat (ENT) specialist, might be coded as "ENT consultation" not "allergy consultation" (Q 353).

3.7.In 2002 the DH introduced allergy as a disease code, but the department admits that this code is underused. Professor Martin Marshall, Deputy Chief Medical Officer and Director General of the Healthcare Quality Directorate, said the DH hoped that the introduction of a new Systemized Nomenclature of Medicine (SNOMED-CT, a semi-automated classification system) would "classify the allergy in a much more specific way" (Q 8). However Dr Shuaib Nasser, an allergy consultant at Addenbrooke's hospital, pointed out that this system was at an "embryonic stage" (Q614) and Professor Aziz Sheikh, Professor of Primary Care Research and Development at the University of Edinburgh, commented that "consistent training" across all the different NHS sectors would be needed to ensure accurate data entry. But Professor Sheikh added that approximately 40 countries already used SNOMED-CT so "in terms of international comparisons through routine data sets the potential is phenomenal" (Q 106).

3.8.We recommend that the Department of Health should ensure the Systemized Nomenclature of Medicine (SNOMED) system is supported by appropriate training, to ensure its efficacy as a simple consistent classification system to record allergic disease, monitor its prevalence and inform the commissioning of allergy services.


3.9.Obtaining accurate data on the prevalence of work-related allergic disorders is particularly difficult because occupational illnesses can have many causes, not just allergy. Allergy to flour causes Bakers' Lung in bakery workers, but Professor Anthony Newman Taylor, Chairman, Industrial Injuries Advisory Council pointed out that other occupational asthma, such as that caused by "an irritant chemical, such as chlorine or sulphur dioxide" is not allergy-related (p 92).

3.10.The Health and Safety Executive (HSE) collects data on occupational diseases through a range of sources. Their lead source is usually the survey of self-reported work-related illness, but this fails to give "reliable estimates" of the prevalence of occupational lung and skin disease (Q 58). The HSE also co-ordinates the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 (RIDDOR) which requires employers and self-employed people to report cases of occupational illness. Professor Raymond Agius, Director of The Health and Occupation Reporting (THOR) network, claimed that RIDDOR suffered from "substantial under-reporting" (p 93) because, as the British Occupational Health Research Foundation (BOHRF) commented, "patient consent" was required to report a case of occupational illness (p 340). Mr Rob Miguel, Health and Safety Officer at Amicus the Union, added that employment law in the United Kingdom deterred people from reporting disease because "if a worker is deemed not to be able to do his job then he can be laid off" (Q 264).

3.11.For occupational asthma and contact dermatitis, the HSE therefore relies "quite heavily" on data produced from THOR network, run by the Centre for Occupational and Environmental Health at the University of Manchester (Q 58). The THOR network includes a number of occupational health surveillance schemes which collect information from occupational specialists who voluntarily report cases of work-related illness. Of relevance to allergic disorders are the EPIDERM project, which monitors occupational skin disorders, and the Surveillance of Work-related and Occupational Respiratory Disease (SWORD) scheme, which collects information about respiratory disorders.

3.12.However, some witnesses criticised the accuracy of the THOR data. Professor David Gawkrodger, Honorary Treasurer, British Association of Dermatologists, told us that there was "a core group of reporters who report every single case of occupational skin disease that they see" but another sampling group only reported for one month every year. He added that "you only have to have suspicion" that an allergen is involved to report it, and pointed out that verification by occupational allergen testing was not required. Furthermore, general practitioners (GPs) were "not educated sufficiently" to recognise occupational skin disease, so the numbers produced by the THOR schemes were "an estimate not a firm figure" (Q 635) because, as Professor Newman Taylor pointed out, "only about 12 per cent of the workforce" can access an occupational physician (Q 265). The BOHRF felt that their "voluntary" nature also accounted for the under-reporting of these schemes (p 340).

3.13.Mr Patrick McDonald, Chief Scientist and Director of the Corporate Science and Analytical Services Directorate at the HSE, described an extension to the THOR scheme, THOR GP, which is "based on GPs who have had occupational health training" (Q 58). But Dr David Orton, Consultant Dermatologist, Amersham Hospital, Buckinghamshire pointed out that allergens causing dermatitis were "not only found at work" but also in "people's domestic environments" so diagnosis required expert interpretation of the results of skin tests. Similarly, Professor Newman Taylor pointed out that investigations into occupational asthma also had to be carried out "in specialist centres" (Q 304). In an attempt to improve data capture, the HSE is contributing to two European Union (EU) working groups, the European Statistics of Accidents at Work project and the European Occupational Disease Statistics group, which are trying "to standardise the position for work-related illness and injury" (Q 66).

3.14.Professor Agius told us how the THOR schemes compensate for factors that lead to underreporting (Q 298), but described their funding as currently under threat. Although the GP reporting scheme had been granted HSE funding until November 2008, the specialist schemes were relying on reserve funds and charitable support. He noted that "the HSE provided us with a commitment in principle 10 months ago to fund specialist schemes for a further five years, but they tell us that they are under severe financial constraints and so far that commitment has not been made good into a contract, which we seriously need because we have good staff leaving" (Q 302).

3.15.Mr Ivan Lewis, Parliamentary Under Secretary of State for Care Services, told us that there were "ongoing contractual negotiations" (Q 836) to "guarantee funding of data collection within the THOR GP scheme until 31 December 2010 and the THOR Specialist scheme until 31 December 2011" (p 320). However, Professor Agius told us that the HSE's latest offer would only fund around a quarter of the full economic costing. The University of Manchester had suggested another option to the HSE where "with their agreement, we could save money on extant work that we are doing for them and thus reduce our costs for the extension of the THOR schemes even further" but this would still leave a "substantial gap" (p 111).

3.16.We welcome the involvement of the Health and Safety Executive in EU working groups to standardise the collection of data on occupational illness. The use of common standards in the diagnosis of occupational allergic conditions would allow international comparisons of disease incidence, and enable the evaluation of disease reduction strategies. We recommend that the Health and Safety Executive should fund The Health and Occupation Reporting network with the full economic cost of its surveillance programmes, and we urge the Government to ensure support for this work in the future.

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