Chest
Volume 108, Issue 1, July 1995, Pages 10-15
Journal home page for Chest

Clinical Investigations
Asthma
Mortality and Markers of Risk of Asthma Death Among 1,075 Outpatients With Asthma

https://doi.org/10.1378/chest.108.1.10Get rights and content

Background: According to national health statistics, mortality rates for asthma have been increasing steadily over the past decades. Mortality and markers of risk of death from asthma were studied among asthmatics attending a chest clinic in Copenhagen between 1974 and 1990.

Methods: The study group consisted of 1,075 asthmatics in whom the diagnosis of asthma had been verified by objective/paraclinical criteria; they were compared with a sex- and age-matched group of nonasthmatic patients. Both groups of subjects comprised 425 men (mean age, 37.3 years [SD 15.2]) and 650 women (mean age, 38.5 years [SD 16.0]), and the mean follow-up period was 8.6 years (SD 4.2) in both asthmatics and controls.

Results: Mortality from all causes was significantly increased in the asthmatic subjects (93 deaths) compared with the control group (41 deaths); relative risk [RR], 2.4; 95% confidence interval [CI], 1.6 to 3.4). The predominant cause of excess mortality was obstructive pulmonary disease, that is, status asthmaticus (14 vs 0 deaths, RR 8.2) and COPD not classified as status asthmaticus (19 vs 0 deaths, RR 8.3). Overall, 91% of the asthmatic cohort survived the mean follow-up period of almost 9 years compared with 96% of the controls. Mortality analysis employing the multiple regression model of Cox revealed that age, pack-years of smoking, eosinophilia, level of FEV1 percent predicted, and degree of reversibility in FEV1 were significant predictors of death from asthma, whereas no association was found between previous hospital admissions for asthma and subsequent death from asthma. In subjects with eosinophilia (>0.45 mia [109/L]), the risk of dying from asthma was 7.4 (CI 2.8 to 19.7) greater than in those without eosinophilia. Compared with subjects with 15 to 24% reversibility in FEV1, the subjects with 25 to 49% and >50% reversibility had a 2.7 and 7.0 higher risk of death from asthma, respectively.

Conclusion: Mortality was significantly increased in asthmatics compared with matched controls, primarily because of death from acute and chronic asthma. Furthermore, the present findings suggest that eosinophilia and pronounced increase in FEV1 after bronchodilator are strong markers of subsequent risk of death from asthma.

Section snippets

Patients With Asthma (Cases)

The study population consisted of subjects (>15 years of age) referred to the Allergy and Chest Clinic at Frederiksberg Hospital, Copenhagen, by general practitioners because of known or suspected asthma (ICD-8 code 493.0) during the years 1974 to 1990. Patients were included in the analysis only if they met at least two, unless stated otherwise, of the following criteria for asthma: (1) typical history, that is, attacks of breathlessness, wheezing or both, chest tightness and dry cough either

Results

Information concerning current status (dead or alive) at the end of follow-up (1993) was obtained for all the asthmatics (cases, n=1,075) and the controls (n=1,075). Each of the two groups of subjects studied (cases and controls) comprised 425 men and 650 women. The mean follow-up period was 8.6 years (SD 4.2 years) in cases and controls. The age distribution by sex of the asthmatics is given in Table 1.

Mortality from all causes was significantly increased among the asthmatic subjects compared

Discussion

The present study revealed an excess mortality in asthmatics compared with matched controls primarily caused by death from acute and chronic asthma; and, furthermore, eosinophilia and high degree of reversibility following bronchodilator, together with age, level of pulmonary function, and smoking habits are predictors for an increased risk of death from asthma. These findings are of relevance both to epidemiologists who wish to investigate asthma mortality and to clinicians who wish to

References (33)

  • ShefferAL et al.

    Proceedings of the Asthma Mortality Task Force

    J Allergy Clin Immunol

    (1987)
  • MarkoweHLJ et al.

    Prognosis in adult asthma: a national study

    BMJ

    (1987)
  • AlmindM et al.

    A 7-year follow-up study of 343 adults with bronchial asthma

    Dan Med Bull

    (1992)
  • UlrikCS et al.

    Mortality and decline in lung function in 213 adults with bronchial asthma: a 10-year follow-up

    J Asthma

    (1992)
  • BeasleyR et al.

    Use of near fatal asthma for investigating asthma deaths [editorial]

    Thorax

    (1993)
  • RiesAK

    Response to bronchodilators

    In: Clausen JL, ed. Pulmonary function testing: guidelines and controversies. New York: Academic Press

    (1982)
  • Cited by (0)

    Manuscript revision accepted January 23.

    View full text