Asthma and psoriasis are immune-mediated diseases that have common inflammation-related, cytokine-mediated mechanisms, and based on the role of the interleukin-17 family in the pathophysiology of psoriasis, there are possibilities that asthma and psoriasis may be related. The risk of asthma in patients with psoriasis was previously assessed, but a bidirectional association between the 2 has not been fully explored. Authors of a study published in BMC Pulmonary Medicine conducted a meta-analysis to assess existing evidence for a bidirectional connection between asthma and psoriasis.
For this systematic review and meta-analysis, the investigators searched PubMed, Embase, and the Cochrane Library to find relevant observational studies published from the databases’ launch to October 2023 to evaluate a potential bidirectional association between asthma and psoriasis. The review and meta-analysis adhered to guidelines of the Preferred Reporting Items for Systemic Reviews and Meta-Analyses.
Inclusion criteria consisted of the following: any cohort, case-control, or cross-sectional studies describing the prevalence or risk factors patients with psoriasis and asthma may have; case or exposure groups that include patients with asthma and a control group with patients who do not have asthma (and the same structure for patients with psoriasis); and studies of human subjects. Duplicate publications, conference abstracts, comments, letters, or studies with irrelevant results were excluded.
According to the investigators, 16 studies conducted between 2011 and 2023 with a total of 16,657,369 participants were considered relevant and included in the analysis. Two of the studies were cohort studies and 10 cross-sectional that looked at the prevalence of asthma in patients with psoriasis, whereas the prevalence of psoriasis in asthma patients was assessed in 4 cohort studies.
In the 2 cohort studies and 10 cross-sectional studies that assessed the risk of asthma in patients with psoriasis, the meta-analysis shows that asthma as associated with an increased incidence of psoriasis (OR = 1.480, 95% CI: 1.282–1.678, I2 = 95.8%, P < .001). Similarly, the 4 cohort studies that explored the risk of psoriasis in patients with asthma found that there was an association of psoriasis with an increased incidence of asthma (OR = 1.331, 95% CI: 1.231–1.440, I2 = 90.6%, P < .01); however, the authors note that 1 article included may lead to a high heterogeneity because of its sensitivity analysis, resulting in this study’s exclusion from the final results.
Key Takeaways
- Bidirectional Link Between Asthma and Psoriasis: The meta-analysis revealed a significant bidirectional association between asthma and psoriasis, with asthma patients showing an increased incidence of psoriasis and vice versa. This finding underscores the interconnected nature of these immune-mediated diseases.
- Influence of Age, Study Type, and Psoriasis Severity: The study found that the risk of asthma in patients with psoriasis varies based on study type, age, and psoriasis severity. Adults, those with moderate to severe psoriasis, and patients who were enrolled in cross-sectional studies exhibited higher risks of developing asthma.
- Limitations and Need for Further Research: Despite demonstrating a bidirectional association, the study faced limitations such as high heterogeneity and incomplete subgroup analyses. The authors call for more research to confirm and expand upon these findings.
Additionally, the investigators noted that they grouped 12 studies based on their type and age, and grouped 10 studies on the severity of psoriasis, specifically focusing on the risk of asthma in patients who had psoriasis. The risk of psoriasis among patients with asthma could not be analyzed by subgroup because of the small number of included articles.
The investigators observed that the type of study, age, and severity of psoriasis was affected by asthma. Additionally, the risk of asthma in patients who had psoriasis was higher in the cross-sectional studies (OR = 1.489, 95% CI [1.224, 1.81]) than in the cohort studies (OR = 1.322, 95% CI [1.235, 1.415]), the risk of asthma was higher in adults (OR = 1.490 95% CI [1.234, 1.799]) than in adolescents (OR = 1.344, 95% CI [1.112, 1.624]), and the risk of asthma was higher in those with moderate to severe psoriasis (OR = 1.390, 95% CI [1.243, 1.55]) compared with those who had mild psoriasis (OR = 1.235, 95% CI [1.072, 1.424]). According to the investigators, these findings demonstrate that there are significant differences between the study type, age, and psoriasis severity groups (p = .000).
Limitations of the study include the unknown source of heterogeneity following the sensitivity analysis, the lack of completed subgroup analysis, and the potential of a recall bias. Despite the limitations, the authors note that this is the first study to conclusively claim a bidirectional link between asthma and psoriasis using a systemic review and meta-analysis. Additionally, they recommend that more evidence should be conducted to further support the findings.
Reference
Wu, D., Zhou, X., Wu, F. et al. Association between psoriasis and asthma: a systematic review and bidirectional meta-analysis. BMC Pulm Med 24, 293 (2024). doi:10.1186/s12890-024-03078-7
