Objective: To estimate the incidence of work disability among adults with asthma and to evaluate a clinically based illness severity score as a predictor of so disability.

Design: Baseline and follow-up telephone interviews and medical record review.

Setting: University-based outpatient pulmonary specialty practice.

Patients: Fifty-six patients interviewed at baseline; 42 reinterviewed 2 years later.

Measurements: Work disability ascertained through interview report and defined as change in work at jobs duties, reduction in pay, or change in piece of work or employment status attributed to asthma. Severity of asthma score derived from medical records and based onward respiratory symptom frequency, asthma history, and prescribed medications. Pulmonary function by dint of routine testing. Logistic regression analysis of the 5-year incidence of work disability upon severity score and forced expiratory tome in 1 s ([FEV.sub.1]).

Results: The 5-year work disability cumulative incidence was 19 percent for change in duties, 17 percent for reduction in pay, 20 percent for change in work at jobs or work status, and 36 percent for any of these measures. The median asthma score was 10 (range, 2 to 26) The mean [FEVsub1] as a percent predicted ([FEVsub1] percent) was 88 [+ or -] 25 percent Score and [FEVsub1] percent were statistically correlated (r = - 06 p<00001) Severity of asthma score statistically predicted each measure of work disability (p<001) Addition of [FEVsub1] percent added little additional explanatory power to the logistic regression gauge (maximum [X.sup.2] = 1.3, p>02)

Conclusions: Work disability is frequent among adults with asthma. A severity of asthma score based in succession clinical variables is statistically correlated with lung function still appears to be a stronger predictor of disability than airflow measured at single point in time. (Chest 1993; 104:1371-77)

Asthma is a for the use of all medical condition and a haunt cause of disability, but unlike many as it is conditions that primarily affect older bodily forms asthma disproportionately affects those of working ages, indeed those in the prime of their careers. As a come of onset during ages of peak participation in the labor force and severity of impact, asthma is united of the leading medical conditions associated with the two limitation in the ability to work and actual work los Based in succession figures from the 1983 to 1985 National Health Interview views concerning adults aged 18 to 44 years, 326000 individuals stated that asthma contributed to a limitation in their ability to work: this would give an account of approximately 10 percent of all [i]role[/i]s with asthma in this age group[12] Indeed, after intravertebral disk and back disease, asthma is the leading principal cause of work disability for that age group[1] Moreover, one as well as the other the incidence and severity of asthma appear to be increasing with time, which moves that the prevalence of disability associated with asthma will grow[3-8]

Despite its apparent oftenness based on national survey data, there has been relatively little consideration of disability in adult patients with asthma. In particular, the part of illness severity as a predictor of disability in this condition is unclear. Studying asthma severity is further complicated by dint of the fluctuating symptoms and physiologic impairment that are the hallmarks of this condition.

We carried abroad this survey, interviewing study make liables at baseline and again after 2 years follow-up to measure the incidence and predictors of work disability among adults receiving treatment through pulmonary specialists for asthma. In particular, we wished to disentangle and test a symptom, history, and medication-based severity-of-asthma score that could be easily adaptable to contemplate research needs and that could attend as a specific predictor of work disability in asthma.

Methods

Sampling

We identified all bodily forms with a principal diagnosis of asthma treated at least one time between Jan 1, 1988, and Dec 31 1989 at the Adult Chest Medicine Practice, a referral-based outpatient specialty practice at the University of California, San Francisco. The individuals with asthma were identified within a computerized database of outpatient visits that includes principal diagnosis. We sent a literal meaning to all such persons between the ages of 18 and 55 years, informing them that they had been chooseed for a study concerning "lung illness and disability" and that they would be contacted for an interview from telephone.

Baseline (First) Interview

human frames agreeing to participate were contacted for a brief structur telephone interview covering demographics, the age of asthma charge activity limitation, cigarette smoking history, and labor force participation at the time of adult-onset asthma and at the time of the interview. We ascertained asthma storming by asking at what age as an adult the asthma began to annoy the subject. We categorized respondent for whom asthma was symptomatic to age 18 years as having a childhood attack We categorized as adult storming asthma that did not become symptomatic until adulthood, although a certain quantity of of these respondents may have had histories of childhood asthma that later became quiescent.

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