Health and employment after a diagnosis of occupational asthma: a descriptive study

Work-related asthma consequences on socioeconomic, asthma control, quality of life, and psychological status compared with non-work-related asthma: A cross-sectional study in an upper-middle-income country

BACKGROUND

Work-related asthma (WRA) is the most prevalent occupational respiratory disease, and it has negative effects on socioeconomic standing, asthma control, quality of life, and mental health status. Most of the studies on WRA consequences are from high-income countries; there is a lack of information on these effects in Latin America and in middle-income countries.

METHODS

This study compared socioeconomic, asthma control, quality of life, and psychological outcomes among individuals diagnosed with WRA and non-work-related asthma (NWRA) in a middle-income country. Patients with asthma, related and not related to work, were interviewed using a structured questionnaire to assess their occupational history and socioeconomic conditions, and with questionnaires to assess asthma control (Asthma Control Test and Asthma Control Questionnaire-6), quality of life (Juniper's Asthma Quality of Life Questionnaire), and presence of anxiety and depression symptoms (Hospital Anxiety and Depression Scale). Each patient's medical record was reviewed for exams and use of medication, and comparisons were made between individuals with WRA and NWRA.

RESULTS

The study included 132 patients with WRA and 130 with NWRA. Individuals with WRA had worse socioeconomic outcomes, worse asthma control, more quality-of-life impairment, and a higher prevalence of anxiety and depression than individuals with NWRA. Among individuals with WRA, those who had been removed from occupational exposure had a worse socioeconomic impact.

CONCLUSIONS

Consequences on socioeconomic, asthma control, quality of life, and psychological status are worse for WRA individuals when compared with NWRA.

Socioeconomic impact of work-related asthma

Work-related asthma (WRA) accounts for 10-15% of adult asthma. This review will summarize the available information related to the socioeconomic outcomes inherent to WRA. A substantial proportion of subjects suffering from WRA experience prolonged work disruption and subsequent loss of income. Moreover, recent studies have established that WRA is associated with a higher use of healthcare resources and a lower quality of life than asthma unrelated to work. The negative socioeconomic consequences are mostly influenced by professional and demographic factors, including reduced possibilities for relocation to an unexposed job within the same company, lack of effective retraining programs and low level of education. These socioeconomic considerations should be regarded as a central component in the implementation of rational management and prevention policies.

Grading quality of evidence and strength of recommendations in clinical practice guidelines: Part 2 of 3. The GRADE approach to grading quality of evidence about diagnostic tests and strategies

The GRADE approach to grading the quality of evidence and strength of recommendations provides a comprehensive and transparent approach for developing clinical recommendations about using diagnostic tests or diagnostic strategies. Although grading the quality of evidence and strength of recommendations about using tests shares the logic of grading recommendations for treatment, it presents unique challenges. Guideline panels and clinicians should be alert to these special challenges when using the evidence about the accuracy of tests as the basis for clinical decisions. In the GRADE system, valid diagnostic accuracy studies can provide high quality evidence of test accuracy. However, such studies often provide only low quality evidence for the development of recommendations about diagnostic testing, as test accuracy is a surrogate for patient-important outcomes at best. Inferring from data on accuracy that using a test improves outcomes that are important to patients requires availability of an effective treatment, improved patients' wellbeing through prognostic information, or - by excluding an ominous diagnosis - reduction of anxiety and the opportunity for earlier search for an alternative diagnosis for which beneficial treatment can be available. Assessing the directness of evidence supporting the use of a diagnostic test requires judgments about the relationship between test results and patient-important consequences. Well-designed and conducted studies of allergy tests in parallel with efforts to evaluate allergy treatments critically will encourage improved guideline development for allergic diseases.

Predictors of delayed return to work or job loss with respiratory ill-health: a systematic review

INTRODUCTION

Every year approximately 17,000 people in the UK are off work through sickness for six or more weeks. Only fifty percent of those off for six months return to work.

METHODS

A systematic review was conducted to identify potential risk factors for non-return to work within six to 26 weeks or job loss in adult workers with respiratory ill-health. Twelve databases, citation and author lists and cited references were searched. All abstracts and papers were double read and quality assessed. Main outcome measures were return to work and employment status.

RESULTS

Five studies of variable methodological quality were identified, all focussing on asthma, occupationally induced or not, with two single studies also covering chronic obstructive pulmonary disease or rhinitis. In the single study of a general working population, blue collar workers having either asthma or chronic obstructive pulmonary disease, were from two to six times less likely to return to work quickly compared with office workers. Overall, unemployment was high with becoming unemployed three times higher in those with all forms of asthma compared with rhinitis. Also, in those with occupational asthma, job loss was more likely if working in smaller companies and being less well educated.

CONCLUSIONS

Evidence on predictors for non-return to work or job loss with respiratory ill-health in a general working population is limited. Yet without an understanding of these, interventions to reduce the further step to long term disability cannot be designed and implemented.

Outcome of occupational asthma after cessation of exposure: a systematic review

BACKGROUND

Patients with occupational asthma, and their medical advisers, need valid information about the prognosis of their disease.

METHODS

A systematic review of the published literature on the symptomatic and functional outcomes of occupational asthma was carried out after avoidance of exposure to the causative agent. Through a full search of electronic and bibliographic sources, original studies documenting complete recovery from asthma (n = 39,1681 patients) or improvement in non-specific bronchial hyper-responsiveness (NSBHR; n = 28,695 patients) were identified. The median duration of follow-up was 31 (range 6-240) months for studies of symptomatic recovery and 37 (6-240) months for studies of NSBHR. Most studies were of patients recruited from special clinics.

RESULTS

Reported rates of symptomatic recovery varied from 0% to 100%, with a pooled estimate of 32% (95% CI 26% to 38%). These rates were lower with increasing age (p = 0.019) and among clinic based populations (p = 0.053). Patients with the shortest durations of exposure (< or =76 months) had the highest rate of recovery (36%; 95% CI 25% to 50%), but the effect was not linear. The pooled prevalence of persistent NSBHR at follow-up was 73% (95% CI 66% to 79%). This figure was higher among patients whose disease was due to high-molecular-weight agents (p = 0.006) and, less clearly, those from clinic-based populations (p = 0.561). In between-study comparisons, no clear patterns of improvement relating to total duration of exposure or follow-up were found. From within-study comparisons there was some evidence that a shorter duration of symptoms was associated with a higher rate of symptomatic recovery.

CONCLUSION

The available data on the prognosis of occupational asthma are insufficiently consistent to allow confident advice to be given to patients with the disease. Clinicians and epidemiologists with an interest in this disease should consider a collaborative and carefully standardised study of the prognosis of occupational asthma.

The prognosis of occupational asthma due to detergent enzymes: clinical, immunological and employment outcomes

BACKGROUND

Little is known about the prognosis of occupational asthma induced by high molecular weight proteins.

OBJECTIVE

Our objective was to measure the clinical, immunological and employment outcomes of individuals with occupational asthma induced by detergent enzymes.

METHODS

We undertook a workforce-based follow-up study in 35 (78%) of the 45 ex-employees from a single factory with occupational asthma. In each case the diagnosis was supported by evidence of specific sensitization and characteristic changes in peak flow or a positive response to specific bronchial provocation testing.

RESULTS

This group had left the factory on average 37 months before study. On review 25 (71%) reported chest symptoms during the last month. Compared with when working at the factory, most (86%) reported that their symptoms had improved. Twenty continued to attend their general practitioner for respiratory symptoms and 19 still used asthma medications. Since leaving the factory 16 (46%) and four (11%) had found full-time or part-time employment, respectively; of these 16 found they were paid less than when they worked at the factory. The remaining 15 subjects had not had any paid employment. All but two had positive skin prick tests to one or more three detergent enzymes. The estimated half-life of serum-specific IgE antibodies was 20 months for protease, and 21 months for cellulase and amylase.

CONCLUSIONS

Population-based follow-up studies of the prognosis of occupational asthma are rare but probably avoid the bias in clinic-derived surveys. This study demonstrates that 3 years after the avoidance of exposure with detergent enzymes most patients continue to be troubled by, albeit improved, symptoms and experience difficulty in re-employment.

Gender and snow crab occupational asthma in Newfoundland and Labrador, Canada

Fish and shellfish processing employs many thousands of people globally, with shellfish processing becoming more important in recent years. Shellfish processing is associated with multiple occupational health and safety (OHS) risks. Snow crab occupational asthma (OA) is work-related asthma associated with processing snow crab. We present a gender analysis of findings from a 3-year multifaceted study of snow crab OA in Newfoundland and Labrador, Canada. The study was carried out in four snow crab processing communities between 2001 and 2004. An anonymous survey questionnaire on knowledge, beliefs, and concerns related to processing snow crab administered to 158 workers attending community meetings at the start of the research found that women were significantly more likely than men to associate certain health problems, especially chest tightness, difficulty breathing, and cough, with crab processing (P<0.001). Worker health assessments carried out with 215 processing workers (187 current/28 former; 120 female/95 male) found that female participants were more likely to be diagnosed as almost certain/highly probable snow crab OA and allergy (P=0.001) and to be sensitized to snow crab (P=0.01) than male participants. Work histories from the health assessments were used to classify processing jobs as male or female. Allergen sampling (211 allergen samples: 115 area, 96 personal breathing zone) indicated that the plant areas where these male jobs were concentrated were associated with lower levels of aerosolized crab allergens (the agents responsible for OA to snow crab) than areas associated with female jobs. This difference was statistically significant in the two plants with poor ventilation (p<0.001 and P=0.017 for these plants). A gender analysis of work history data showed that female health assessment participants were likely to have worked longer processing snow crab than males (5 years versus 3.5 years, respectively). Cross-referencing of work history results with allergen sampling data for male and female job areas showed a gender difference in median cumulative exposures (duration of exposure x level of exposures) for health assessment participants. Health assessment participants with estimated higher median cumulative exposures were more likely to receive a diagnosis of almost certain/highly probable OA and allergy. Semistructured interviews with 27 health assessment participants (24 female/ 3 male) with a diagnosis of almost certain/highly probable or possible snow crab OA indicated that these workers can experience substantial quality of life impacts while working and that they seek to reduce the economic impact of their illness by remaining at their jobs as long as possible. Indications of selection bias and other study limitations point to the need for more research exploring the relationship between the gender division of labor and knowledge, beliefs, and concerns about snow crab processing, as well as gender differences in prevalence, quality of life, and socioeconomic impact.

Surveillance for isocyanate asthma: a model based cost effectiveness analysis

AIMS

Because logistical and financial obstacles impede using large prospective cohort studies, surveillance decisions in occupational settings must often be made without evidence of relative benefits and costs. Using the example of isocyanate induced asthma, the most commonly reported immune mediated occupational asthma, the authors developed a model based approach to evaluate the costs and benefits of surveillance from both an employer and a societal perspective.

METHODS

The authors used a mathematical simulation model of isocyanate asthma to compare annual surveillance to passive case finding. Outcome measures included symptom free days (SFD), quality adjusted life years (QALY), direct costs, productivity losses, and incremental cost effectiveness ratio (CER), measured from the employer and the societal perspectives. Input data were obtained from a variety of published sources.

RESULTS

For 100,000 exposed workers, surveillance resulted in 683 fewer cases of disability over 10 years. Surveillance conferred benefits at an incremental cost of 24,000 dollars/QALY (employer perspective; 13.33 dollars/SFD) and was cost saving from the societal perspective. Results were sensitive to assumptions about sensitisation rate, removal rates, and time to diagnosis, but not to assumptions about therapy costs and disability rates.

CONCLUSIONS

Baseline results placed the CER for surveillance for isocyanate asthma within the acceptable range. Costs from the societal and employer perspective differed substantially with a more attractive CER from the societal perspective, suggesting opportunities for employer/societal cost sharing. The analysis demonstrates the value of a model based approach to evaluate the cost effectiveness of surveillance programmes for isocyanate asthma, and to inform shared decision making among clinicians, patients, employers, and society. Such a modeling approach may be applicable to surveillance programmes for other work related conditions.

Clinical practice guidelines: medical follow-up of patients with asthma--adults and adolescents

The follow-up of patients with asthma should focus on asthma control (disease course over a number of weeks).

Work, unemployment and life satisfaction among patients with diisocyanate induced asthma--a prospective study

Occupational asthma has been found to be associated with lowered socio-economic outcomes, an increased unemployment rate and a decreased quality of life. The compensation of occupational diseases is comparatively favourable in Finland. Our aim was to follow-up the working status and life satisfaction of patients with diisocyanate-induced asthma in 245 cases diagnosed during 1976-1992. A questionnaire was sent out on average 10 (3-19) yr after the diagnosis to the surviving 235 patients. The questionnaire was validated by re-examining 91 of them clinically, and with spirometry, histamine challenge test and peak flow surveillance. Of the 213 responding patients, 14% were unemployed, and for 50% of them unemployment was caused by asthma. Unemployment was associated with nocturnal asthma symptoms (OR 10.93; CI 2.69-44.452), increased PEF variability (OR 8.46; CI 1.52-46.97) and with the use of short-acting beta-sympathomimetic medication (p=0.045). Satisfaction with life was associated with present working (OR 3.50; CI 1.73-7.06) and with good condition of asthma as assessed by the use of asthma medication (OR 0.49; CI 0.27-0.89) and objective measurements of the asthma condition, e.g. PEF variability (OR 0.21; CI 0.08-0.59). As a conclusion, unemployment was remarkably low as compared with earlier reports and related to the period of simultaneous economic recession. Unemployment, as well as dissatisfaction with life were associated with poor conditions of asthma. Unemployment was associated with improper asthma care favouring the use of short-acting beta-sympathomimetic medication. Proper follow-up of asthma is essential for minimizing the social complaints of occupational asthma, as well as for enhancing life satisfaction.

Evidence based guidelines for the prevention, identification, and management of occupational asthma

BACKGROUND

Occupational asthma is the most frequently reported work related respiratory disease in many countries. This work was commissioned by the British Occupational Health Research Foundation to assist the Health and Safety Executive in achieving its target of reducing the incidence of occupational asthma in Great Britain by 30% by 2010.

AIM

The guidelines aim to improve the prevention, identification, and management of occupational asthma by providing evidence based recommendations on which future practice can be based.

METHODS

The literature was searched systematically using Medline and Embase for articles published in all languages up to the end of June 2004. Evidence based statements and recommendations were graded according to the Royal College of General Practitioner's star system and the revised Scottish Intercollegiate Guidelines Network grading system.

RESULTS

A total of 474 original studies were selected for appraisal from over 2500 abstracts. The systematic review produced 52 graded evidence statements and 22 recommendations based on 223 studies.

DISCUSSION

Evidence based guidelines have become benchmarks for practice in healthcare and the process used to prepare them is well established. This evidence review and its recommendations focus on interventions and outcomes to provide a robust approach to the prevention, identification, and management of occupational asthma, based on and using the best available medical evidence. The most important action to prevent cases of occupational asthma is to reduce exposure at source. Thereafter surveillance should be performed for the early identification of symptoms, including occupational rhinitis, with additional functional and immunological tests where appropriate. Effective management of workers suspected to have occupational asthma involves the identification and investigation of symptoms suggestive of asthma immediately they occur. Those workers who are confirmed to have occupational asthma should be advised to avoid further exposure completely and early in the course of their disease to offer the best chance of recovery.

Costs of occupational asthma and of occupational chronic obstructive pulmonary disease

PURPOSE OF REVIEW

The purpose of this review is to summarize the most recent findings on the costs of occupational asthma and chronic obstructive pulmonary disease, illustrating the different approaches for estimates, the results and the social and financial implications.

RECENT FINDINGS

Many published data in the literature show that occupational asthma and chronic obstructive pulmonary disease represent a relevant proportion of the total prevalence of these diseases. Previous findings demonstrated that occupational asthma has adverse economic and employment consequences for the worker, and a significant cost related to the claims. Recent studies using a standard method have specifically estimated the cost of the proportion of cases of asthma and chronic obstructive pulmonary disease attributable to occupational exposure out of the total costs of these diseases, and demonstrated that it is significant. Some recent data indicate a beneficial outcome of occupational asthma and a reduction in the number of the claims from primary and secondary preventive intervention at the workplace.

SUMMARY

In conclusion, occupational asthma and chronic obstructive pulmonary disease are likely to pay a substantial contribution to the total costs of the two disorders. These costs are expected to rise with the increasing prevalence of the diseases. Intervention strategies for effective control and prevention at the workplace should lessen the burden of long-term illness and impact on public health costs.

Persistence of airway responsiveness to occupational agents: what does it matter?

In the majority of workers with occupational asthma, the disease remains active even several years after removal from exposure or diminution of the levels of exposure to the causal agent. Only 25% or so normalize their lung function and their bronchial responsiveness to nonspecific agents. The aim of this review is to present recent findings illustrating the persistence of specific bronchial responsiveness and the associated factors in workers who apparently have recovered from occupational asthma. This subject is also examined from a socioeconomic perspective.

Reported incidence of occupational asthma in the United Kingdom, 1989-97

OBJECTIVES

To examine trends in estimated population based incidence of occupational asthma by age, sex, occupation, geographical region, and causal agents based on 9 years of the Surveillance of Work Related and Occupational Respiratory Disease (SWORD) data.

METHODS

In January 1989 the SWORD scheme for the surveillance of occupational respiratory disease was established in the United Kingdom to make good the lack of epidemiological information on the incidence of these diseases in the United Kingdom. Between 80% and 90% of chest and occupational physicians report voluntarily all new cases they see, on a monthly or random sampling basis. During the 9 years 1989-97, an estimated 25 674 new cases of occupational respiratory disease, including 7387 of occupational asthma, were reported. Suspected causal agents were classified into 44 categories and estimated annual incidences of asthma were calculated with denominators from the labour force survey.

RESULTS

Overall, a third of the suspected causes of asthma were organic, a third chemical, 6% metallic, and the rest miscellaneous, or in 8%, unknown. There was evidence of an increase since 1989 in cases due to latex, and possibly glutaraldehyde, and an apparent drop since 1991 in the proportion of cases attributed to isocyanates. Incidences were higher in men than women and the disparity was especially marked in the population aged 45 years or more in which rates for men were at least twice those for women. Average annual rates per million workers for 1992-7 ranged from 7 (95% confidence interval (95% CI) 5 to 9) for the lowest risk group of professional, clerical, and service workers to 1464 (95% CI 968 to 2173) for coach and other spray painters. Except for laboratory technicians, all other occupations with rates over 100 were concerned with manufacturing and processing that used chemicals, metals, and organic materials. Incidences were two to three times higher in the north and midlands than in East Anglia and the south. The introduction of a sampling scheme in 1992 doubled estimates of reported incidence of occupational asthma, but there was little evidence of other temporal changes.

CONCLUSIONS

The SWORD scheme has produced consistent estimates of the causes and incidence of occupational asthma as seen by chest and occupational physicians. It has allowed the epidemiology of occupational asthma in the population to be studied and high risk occupations to be identified. There is certainly more occupational asthma in the population than that which reaches specialists in occupational and chest medicine; therefore the incidence rates presented here are underestimates, but by how much remains unknown.