The impact of comorbidities on productivity loss in asthma

Rationale Health-related productivity loss and the impact of comorbidities on the economic burden of asthma are important, yet overlooked, components. I aimed at revising recent estimates of the costs of asthma worldwide. The empirical research involved evaluating the effect of comorbidities on productivity loss among adult asthma patients. Methods A literature review was conducted on studies regarding the costs of asthma (January 2008 to January 2015) and subsequently on the effects of comorbidities on productivity. In parallel data from a prospectively evaluated random sample of employed adults with asthma was used and the prevalence of comorbidities measured using a validated self-administered comorbidity questionnaire (SCQ), range 0 – 39, (the higher the score, the higher the level of comorbidity). Productivity loss, including absenteeism and presenteeism, were also measured using validated instruments in 2010 Canadian dollars ($). I used a two-part regression model to estimate the adjusted difference of productivity loss across levels of comorbidity, controlling for potential confounding variables. Results The review demonstrated that asthma imposes a major economic burden, however there are large discrepancies in the reported estimates. There is also uncertainty about the indirect costs of asthma and the effects of comorbidities on these costs. A random sample of 284 adults with the mean age of 47.8 (SD 11.8) was included (68% women). The mean SCQ score was 2.47 (SD 2.97, range 0-15) and the average productivity loss was $317.5 per week (SD $858.8). Comorbidity was significantly associated with productivity loss. One-unit increase in the SCQ score was associated with a 14% (OR=1.14, 95% CI 1.02-1.28) increase in the odds of reporting productivity loss, and 9.0% (OR=1.09, 95% CI 1.01-1.18) increase in productivity loss among those who reported any loss of productivity. A person with a SCQ score of 15 had $1,685 per week more productivity loss than a patient with a SCQ of zero. Conclusion This study demonstrates that comorbidities substantially decrease productivity in working asthma patients. Asthma management strategies must be cognizant of the role of comorbidities and should properly incorporate the effect of comorbidity and productivity loss in estimating the benefit of disease management strategies.Medicine, Faculty ofGraduat