Impact of asthma severity as risk factor to future exacerbations in patients admitted for asthma exacerbation


Background: To investigate the impact of disease severity on exacerbation patterns and identify its potential as a risk factor for future exacerbations in patients admitted for asthma exacerbations.
Methods: We analyzed frequency and time to next exacerbation over a period of three years in 532 patients admitted for exacerbation. Disease severity was selected as a potential risk factor for the events. Kaplan-Meier analysis was used to identify the probability of future exacerbations. A Cox-proportional hazards model was used to assess independent relative risks.
Results: Of 532 patients analyzed, the frequency of exacerbations rose as the severity of the asthma increased. The exacerbation rates in the following year were 1.66 per person for patients with mild asthma and 3.98 for patients with severe asthma. The median time to the next exacerbation in patients with mild asthma was 61.4 weeks (95% CI, 40.1-82.6) compared to 15.0 weeks (95% CI, 11.3-18.6) in patients with severe asthma (p<0.001). Multivariate analysis showed that asthma severity (severe vs mild asthma, HR=1.42, 95% CI, 1.07-1.89), a history of 1-2 exacerbations (HR=1.95, 95% CI, 1.45-2.63) or > 2 exacerbations (HR=2.32, 95% CI, 1.56-3.44) in the previous 12 months, and a high number of comorbidities (≥5 vs none, HR=2.5, 95% CI, 1.41-4.45) were independent predictors of the probability of future exacerbations.
Conclusion: Asthma severity is a strong independent risk factor for future exacerbations, and exacerbation rates also become more frequent as the severity of the asthma increases. These findings help in better understanding of the natural course of exacerbations across the spectrum of asthma disease severity



PlumX Metrics


Download data is not yet available.


GBD 2016 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet 2017;390:1211–59. DOI:

Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention, Updated 2020. Accessed: November 1, 2020. Available from:

British Thoracic Society. BTS/SIGN British Guideline on the Management of Asthma updated 2019. Accessed: December 1, 2019. Available from:

Schatz M, Meckley LM, Kim M , Stockwell BT, Castro M. Asthma exacerbation rates in adults are unchanged over a 5-year period despite high-intensity therapy. Allergy Clin Immunol Pract 2014;2:570-4. DOI:

McCoy K, Shade DM, Irvin CG, Mastronarde JG, Hanania NA, Castro M, et al. Predicting episodes of poor asthma control in treated patients with asthma. J Allergy Clin Immunol 2006;118:1226-33. DOI:

Turner MO, Noertjojo K, Vedal S, Bai T, Crump S, FitzGerald JM. Risk factors for near-fatal asthma. A case-control study in hospitalized patients with asthma. Am J Respir Crit Care Med 1998;157:1804-9.

Miller MK, Lee JH, Miller DP, Wenzel SE. Recent asthma exacerbations: a key predictor of future exacerbations. Respir Med 2007;101:481-9. DOI:

Boulet LP. Influence of comorbid condition on asthma. Eur Respir J 2009;33:897-906. DOI:

Osborne ML, Pedula KL, O'Hollaren M, Ettinger KM, Stibolt T, Buist AS, et al. Assessing future need for acute care in adult asthmatics: the Profile of Asthma Risk Study: a prospective health maintenance organization-based study. Chest 2007;132:1151-61. DOI:

Bloom CI, Palmer T, Feary J, Quint JK, Cullinan P. Exacerbation patterns in adults with asthma in England. A population-based study. Am J Respire Crit Care Med 2019;199:446-453. DOI:

Peters SP, Antonisen N, Castro M, et al. Randomized comparison of strategies for reducing treatment in mild persistent asthma. N Engl J Med 2007;356:2027-39. DOI:

Bateman ED, Reddel HK, O'Byrne PM, Barnes PJ, Zhong N, Keen C, et al. As-needed budesonide-formoterol versus maintenance budesonide in mild asthma. N Engl J Med 2018;378:1877-87. DOI:

O'Byrne PM, FitzGerald JM, Bateman ED, Barnes PJ, Zhong N, Keen C, et al. Inhaled combined budesonide-formoterol as needed in mild asthma. N Engl J Med 2018;378:1865-76. DOI:

Ding B, Small M. Disease burden of mild asthma: finding from a cross-sectional real-world survey. Adv Ther 2017;34:1109-27. DOI:

Bleecker ER, FitzGerald JM, Chanez P, Papi A, Weinstein SF, Barker P, et al. Efficacy and safety of benralizumab for patients with severe asthma uncontrolled with high-dosage inhaled corticosteroids and long-acting β 2-agonists (SIROCCO): a randomised, multicentre, placebo-controlled phase 3 trial. Lancet 2016;388:2115-27. DOI:

FitzGerald JM, Bleecker ER, Nair P, Korn S, Ohta K, Lommatzsch M, et al. Benralizumab, an anti-interleukin-5 receptor α monoclonal antibody, as add-on treatment for patients with severe, uncontrolled, eosinophilic asthma (CALIMA): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet 2016;388:2128-41. DOI:

Mcdonald VM, Hiles SA, Godbout K, Harvey ES, Marks GB, Hew M, et al. Treatable traits can be identified in a severe asthma registry and predict future exacerbations. Respirology 2019;24:27-47. DOI:

Taylor DR, Bateman ED, Boulet LP, Boushey HA, Busse WW, Casale TB, et al. A new perspective on concepts of asthma severity and control. Eur Respir J 2008;32:545-54. DOI:

Price DB, Rigazio A, Campbell JD, Bleecker ER, Corrigan CJ, Thomas M, et al. Blood eosinophil count and prospective annual asthma disease burden: a UK cohort study. Lancet Respir Med 2015;3:849-58. DOI:

Bel EH. Clinical phenotypes of asthma. Curr Opin Pulm Med 2004;10:44-50. DOI:

Bloom CI, Nissen F, Douglas IJ, Smeeth L, Cullinan P, Quint JK. Exacerbation risk and characterization of the UK’s asthma population from infants to old age. Thorax 2018;73;313-20. DOI:

FitzGerald JM, Barnes PJ, Chipps BE, Jenkins CR, O'Byrne PM, Pavord ID, et al. The burden of exacerbations in mild asthma: a systematic review. ERJ Open Res 2020;6:00359-2019. DOI:

Chipps BE, Haselkorn T, Paknis B, Ortiz B, Bleecker ER, Kianifard F, et al. More than a decade follow-up in patients with severe or difficult-to-treat asthma: The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) II. J Allergy Clin Immunol 2018;141:1590-7. DOI:

Chung KF, Wenzel SE, Brozek JL, Bush A, Castro M, Sterk PJ, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J 2014:43:343-73.

Dales RE, Schweitzer I, Kerr P, Gougeon L, Rivington R, Draper J. Risk factors for recurrent emergency department visits for asthma. Thorax 1995;50:520-4. DOI:

Turner MO, Noertjojo K, Vedal S, Bai T, Crump S, Fitzgerald JM. Risk factors for near-fatal asthma. A case-control study in hospitalized patients with asthma. Am J Respir Crit Care Med 1998;157:1804-9. DOI:

Adams RJ, Smith BJ, Ruffin RE. Factors associated with hospital admissions and repeat emergency department visits for adults with asthma. Thorax 2000;55:566-73. DOI:

Image by <a href=";utm_medium=referral&amp;utm_campaign=image&amp;utm_content=6273079">Anup Sharma</a> from <a href=";utm_medium=referral&amp;utm_campaign=image&amp;utm_content=6273079">Pixabay</a>
Original Research Articles
asthma severity, asthmatic exacerbation, hospitalization
  • Abstract views: 1319

  • PDF: 55
  • HTML: 0
How to Cite
Nakwan, N. (2021). Impact of asthma severity as risk factor to future exacerbations in patients admitted for asthma exacerbation. Multidisciplinary Respiratory Medicine, 16.