I. INTRODUCTION

The lack of recognition of occupational diseases is an important public health problem1,2,3 that will receive increasing attention by managed care organizations as they focus more resources on clinical preventive services. 4, 5, 6 Occupational diseases can be prevented by removing the worker from exposure or by making changes in the workplace. 7, 8 When occupational diseases are not recognized in the clinic, then the opportunity for prevention is lost.

The clinical recognition of occupational diseases is dependent upon an exposure history that can be efficiently and effectively performed. Such an exposure history can be viewed as a screening test.9 One of the requirements of a suitable screening test is that it can be quickly and easily administered.10

When screening for relatively rare diseases, the predictive value of a positive test will be low even if the test has fairly high sensitivity and specificity.11 A low positive predictive value means that the costs of investigating false positive results may exceed the benefits of the screening program. If this cost occurs in the form of time spent asking questions about false positive results on an occupational history questionnaire, then practitioners will realize that the activity is a waste of time, i.e., the costs exceed the benefits.

In order to improve the recognition of occupational diseases, an alternative method for screening is needed. This method should be quick and easy to administer and have high positive predictive value. There are two strategies for increasing the positive predictive value of a screening test.11 One is to target individuals in high risk groups. The other is to increase the specificity of the test. Both strategies reduce the number of false positives.

These strategies could be achieved by targeting patients belonging to certain occupations. For patients with asthma, only those belonging to occupations known to have higher risks for work-related asthma would be screened with specific questions for that occupation. The effect would be to break down the occupational history into two steps. The first step would determine if the patient's occupation was a known risk factor for the disease affecting the patient. The second step would determine whether or not the patient was exposed at a level sufficient to cause occupational disease on a more probable than not basis. Figure 1 illustrates this concept. Such a system of screening would take too much time to be implemented in a clinic with paper-based medical records. However, as computer-based patient record systems become more widely established during the next few years,12, 13, 14 and as clinical services become increasingly "evidence-based" and "population-based," the implementation of this kind of screening for occupational diseases will become feasible.

A number of studies have shown the capacity of computerized reminder systems and critiquing programs to improve clinical practice.16, 17, 18, 19, 20 In one recent study,21 a software program was used to critique the hypertension management of primary care physicians. After linking to the computer-based patients records (CPR), the program was able to review the coded data regarding blood pressure measurements, symptoms, laboratory results and medication usage to generate recommendations concerning drug information, diagnostic workup requirements and criteria for judging the efficacy of treatment. These recommendations compared favorably with the recommendations of physicians who independently audited the same medical records.

There are a number of reasons why occupational asthma was chosen as an occupational disease that could provide a useful model for the purposes of this study:

1) It appears that occupational asthma is now the most common occupational respiratory disease, at least in the materially developed parts of the world.22 Because of successful federal regulations and advances in industrial hygiene to reduce exposures by means of product substitution, improved engineering controls, and more effective use of personal protective equipment and medical surveillance, new cases of many of the "traditional" occupational diseases are rarely seen. However, the prevalence of occupational allergic disorders has not decreased, and there is evidence that the incidence of occupational asthma is increasing.23

2) The diagnosis of occupational asthma is very information intensive. There are over 200 known causal agents that have been associated with several hundred specific jobs.24, 25 Information about relative risks for different occupations is available from studies in the United States, Finland and the United Kingdom, e.g., incidence rates of 8 per million clerks and 1833 per million spray painters.26. 27, 28, 29

3) Unrecognized occupational asthma can result in significant patient morbidity. The natural history of immunologic occupational asthma (OA) can be diagrammed as:

onset of exposure > sensitization > OA > removal from exposure > persistence of asthma30

Each step is an opportunity to practice primary or secondary prevention (before asthma is diagnosed), or tertiary prevention (after asthma is diagnosed, but before work-relatedness is recognized).

4) Occupational asthma may be difficult to distinguish from non-occupational asthma, especially when the symptoms are not clearly related to work. Patients may present with recurrent attacks of cough and rhinitis. Patients with OA caused by low molecular weight compounds may experience isolated late reactions so that symptoms occur only at night.31 Symptoms may be exacerbated by nonspecific triggers such as cold air or exercise.32 Occupational asthma due to high molecular weight compounds is more likely to occur in atopic patients. These patients may have a history of pre-existent asthma caused by agents that are not work-related.33

In order to explore the opportunities for using CPR systems in primary care to improve the recognition of occupational diseases, a chart review of asthma patients was done at Group Health Cooperative of Puget Sound, Seattle, Washington. The objective of the study was to test the following hypothesis:

The currently used paper-based patient record system does not support effective screening for occupational asthma because it provides no means to target patients in high risk occupations nor to assist the physician in taking exposure histories relevant to those occupations.

Given the assumption that the CPR system has the features necessary to overcome the deficiencies of the paper-based system,34 then the corollary follows:

A computer-based patient record system could support effective screening of occupational asthma by helping physicians to focus on the patients that belong to high risk occupations and to take an exposure histories relevant to those occupations.

 

Notes to Chapter I

  1. Levy BS, Wegman DH, eds. Occupational Health: Recognizing and Preventing Work-Related Disease. 3rd ed. Boston, Mass: Little Brown and Company; 1995:5-12.
  2. Rosenstock L, Cullen MR, eds. Textbook of Clinical Occupational and Environmental Medicine. Philadelphia, Penn: WB Saunders; 1994:22-24.
  3. U.S. Department of Health and Human Services. Healthy People 2000: National Health Promotion and Disease Prevention Objectives. Boston, Mass: Jones and Bartlett; 1992:308.
  4. Bokor A, Halbert RJ, Joslyn K, Neumann A. The Preventive Medicine Manager: A New Role for Preventive Medicine Specialists in Managed Care. Am J Prev Med. 1996;12:143.
  5. Greenlick MR. Education Physicians for Population-Based Clinical Practice. JAMA. 1992;267:1645-1646.
  6. Voelker R. Population-Based Medicine Merges Clinical Care, Epidemiologic Techniques. JAMA. 1994;271:1301.
  7. Meredith SK, McDonald JC. Work-Related Respiratory disease in the United Kingdom, 1989-1992: Report on the SWORD Project. Occup Med Oxf.1994;44:183-188.
  8. Mullan RJ, Murthy LI. Occupational Sentinel Health Events: An Up-Dated List for Physician Recognition and Public Health Surveillance. Am J Ind Med. 1991;19:775-799.
  9. Rosenstock L, Cullen MR, eds. Textbook of Clinical Occupational and Environmental Medicine. Phiadelphia, Penn: WB Saunders; 1994:4.
  10. Hennekens CH, Buring JE; Mayrent SL, ed. Epidemiology in Medicine. Boston, Mass: Little Brown & Company; 1987:331.
  11. Ibid.:339.
  12. Dick RS, Steen EB, eds. The Computer-Based Patient Record: An Essential Technology for Health Care. Washington, DC: National Academy Press; 1991:137.
  13. Geiger, G., Merrilees, K., Walo, R., Gordon, D. Kunov, H. An Analysis of the Paper-Based Health Record: Information Content and Its Implications for Electronic Patient Records. MEDINFO. 1995;295.
  14. Rind DM, Safran C. Real and Imagined Barriers to an Electronic Medical Record. Proc Ann Symp Comput Appl Med Care. 1993; 74-78.
  15. Greenlick MR. Education Physicians for Population-Based Clinical Practice. JAMA. 1992;267:1647.
  16. Elson RB, Connelly DP. Computerized Patient Records in Primary Care: Their Role in Mediating Guideline-Driven Physician Behavior Change. Arch Fam Med. 1995;4:700-701.
  17. Ornstein SM, Garr DR, Jenkins RG, Musham C, Hamadeh G, Lancaster C. Implementation and Evaluation of a Computer-based Preventive Services System. Fam Med. 1995;27:260-265.
  18. McDonald CJ. Protocol-Based Computer Reminders, The Quality Of Care And The Non-Perfectability Of Man. N Engl J Med. 1976;295:1351-1355.
  19. Borst F, Griesser V, Rossier P, Bourdilloud R, Scherrer JR. Fifteen Years of Medical Encoding in the Diogene HIS. MEDINFO. 1995;43-46.
  20. Kahn CE Jr. Validation, Clinical Trial, and Evaluation of a Radiology Expert System. Methods Inf Med. 1991;30:268-274.
  21. van der Lei J, Musen MA, van der Does E, Man In ‘T Veld AJ, van Bemmel JH. Comparison of Computer-Aided and Human Review of General Practitioners’ Management of Hypertension. Lancet. 1991;338:1504-08.
  22. Nordman H. Occupational Asthma—Time for Prevention. Scand J Work Environ Health. 1994;20(special issue):108.
  23. Reijula K, Patterson R. Occupational Allergies in Finland in 1981-91. Allergy Proc. 1994;15:163.
  24. Chan-Yeung M, Malo J. Aetiological Agents in Occupational Asthma. Eur Respir J. 1994;7:346-371.
  25. Malo JL, Chan-Yeung M. Chapter 91. 1996; (in press)
  26. Reilly MJ, Rosenman KD, Watt FC, et al. Surveillance for Occupational Asthma—Michigan and New Jersey. 1988-1992. MMWR. 1994;43:9-17.
  27. Reijula K, Patterson R. Occupational Allergies in Finland in 1981-91. Allergy Proc. 1994;15:163-168
  28. Meredith SK, McDonald JC. Work-Related Respiratory disease in the United Kingdom, 1989-1992: Report on the SWORD Project. Occup Med Oxf.1994;44:183-188.
  29. Gannon P, Burge P. The SHEILD Scheme in the West Midlands Region, United Kingdom. Br J Ind Med. 1993;50:791-796.
  30. Malo JL, Ghezzo H, D’Aquino C, L’Archeveque J, Cartier A, Chan-Yeung M. Natural History of Occupational Asthma: Relevance of Type of Agent and Other Factors in the Rate of Development of Symptoms in Affected Subjects. J Allergy Clin Immunol. 1992;90:942.
  31. Chan-Yeung M, Lam S. Occupational Asthma. Am Rev Respir Dis. 1986;133:692-693.
  32. Rosenstock L, Cullen MR, eds. Textbook of Clinical Occupational and Environmental Medicine. Philadelphia, Penn: WB Saunders; 1994:199.
  33. Levy BS Wegman DH, eds. Occupational Health: Recognizing and Preventing Work-Related Disease. 3rd ed. Boston, Mass: Little Brown and Company; 1995:441.
  34. Dick RS, Steen EB, eds. The Computer-Based Patient Record: An Essential Technology for Health Care. Washington, DC: National Academy Press; 1991.

Home Page

| Abstract | Slides | Introduction | Discussion |