Investigating the Burden of Comorbidities in Patients With Asthma

A recent meta-analysis found that comorbidities and chronic respiratory diseases were associated with asthma and severe asthma, suggesting that the assessment of these comorbidities and associations is important in gaining an understanding of asthma control and patient-centered asthma management.

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In the meta-analysis, which was published in the journal European Respiratory Review, researchers aimed to quantify the strength of association between comorbidities and asthma, in relation to the prevalence of the comorbidity in patients without asthma.

“Correct diagnosis of these comorbidities is pivotal to optimize asthma management by a multidimensional approach and to assess whether poor symptom control is related to uncontrolled asthma or to uncontrolled underlying comorbidities,” wrote the authors.

Using a comprehensive literature search with no time limit up to October 6, 2021, the researchers gathered studies reporting data on comorbidities among patients with asthma and without asthma. The search criteria performed was for observational studies written in English that reported on comorbidities in asthma and non-asthma populations. A total of 2019 databases were identified.

After screening, 294 reports were assessed for retrieval and eligibility, and 33 studies were included: 15 cross-sectional, 14 cohort, and 4 case control studies. From these studies, the researchers obtained results from 5,493,776 individuals. Of these individuals, 4,615,552 did not have asthma, 878,224 had asthma, and 1791 of patients with asthma had severe asthma.

Furthermore, the researchers measured the rates of comorbidities in non-asthma populations using the Cohen’s d method, with cut-off values for small (d = 0.2), medium (d = 0.5), and large (d = 0.8) effect sizes, respectively.

The analysis revealed allergic rhinitis (odds ratio [OR], 4.24; 95% CI, 3.82-4.71), allergic conjunctivitis (OR, 2.63: 95% CI, 2.22-3.11), bronchiectasis (OR, 4.89; 95% CI, 4.48-5.34), hypertensive cardiomyopathy (OR, 4.24; 95% CI, 2.06-8.90), and nasal congestion (OR, 3.30; 95% CI, 2.96-3.67) were strongly associated with asthma (Cohen’s d > 0.5 and £ 0.8), with COPD (OR, 6.23; 95% CI, 2.43-8.77) and other chronic respiratory diseases (OR, 12.85; 95% CI, 10.14-16.29) being very strongly associated (Cohen’s d > 0.8).

Furthermore, stronger associations were identified between comorbidities and severe asthma.

However, the researchers acknowledged some limitations to the study. The observational studies included may be susceptible to heterogeneity due to differences in populations or outcomes, survey recruitment, measurement tools, timing of outcome measurements, and data reporting. Furthermore, the researchers observed that the assessment of comorbid disorders varied across the studies depending on the population, diagnostic criteria, and measurement tools.

Despite these limitations, the researchers believe the study highlights key comorbidities with strong associations to asthma and severe asthma.

“Indeed, this quantitative synthesis is a first step to help clinicians to better place each asthmatic patient in the context of their own comorbidities according to disease severity,” wrote the researchers. “This is of interest because we have demonstrated that even non-severe patients may have a galaxy of concomitant disorders to be managed along with asthma.”

Reference

Rogliani P, Laitano R, Ora J, Beasley R, Calzetta L. Strength of association between comorbidities and asthma: a meta-analysis [published correction appears in Eur Respir Rev. 2023 Jun 7;32(168):]. Eur Respir Rev. 2023;32(167):220202. Published 2023 Mar 8. doi:10.1183/16000617.0202-2022