Pulmonary function impaired in psoriasis

Dermatologists play a significant role in screening for psoriasis comorbidities and asking about shortness of breath as a routine part of medical history-taking, shows a study published in BMJ.

Psoriasis is associated with a small reduction of pulmonary function and those with psoriasis are more likely than people without the disease to report shortness of breath, according to a population-based study published in the British Journal of Dermatology.

“Dermatologists are generally well aware that psoriasis is a systemic inflammatory disease with a range of comorbidities, including cardiovascular disease and diabetes. Our results add to evidence that pulmonary disease is part of the deal, and although the magnitude of reduced pulmonary function in patients with psoriasis found in our study was small, it can contribute to shortness of breath in individual patients,” says study author Peter Riis Hansen, M.D., D.M.Sc., Ph.D., of Herlev and Gentofte Hospital, Hellerup, Denmark.

Dermatologists, Dr. Hansen says, play a significant role in screening for psoriasis comorbidities and asking about shortness of breath as a routine part of medical history-taking.

“Our results put pulmonary symptoms a bit more on the clinical radar in patients with psoriasis and they emphasize that smoking cessation remains a fundamental part of psoriasis treatment,” he says.

Until now, there had been only a small study on pulmonary function in psoriasis subjects, which found reduced pulmonary function in psoriasis patients. Other research suggests that smoking is a risk factor for psoriasis. And epidemiological studies have linked psoriasis to increased risk of pulmonary infections, chronic obstructive pulmonary disease (COPD) and asthma.

Dr. Hansen and colleagues studied 20,422 adults older than 20 years of age in the Danish General Suburban Population Study, which included 1,173 people with psoriasis. Participants had pulmonary function tests with hand-held spirometers, as well as answered questions about whether they had psoriasis, shortness of breath and pneumonia during the past decade.

At the study’s start, psoriasis patients were more likely than controls to smoke, report shortness of breath or prior pneumonia. They also had a higher mean body mass index than those without psoriasis. The increased risks of shortness of breath and pneumonia remained significantly higher in the psoriasis group even after adjusting for smoking.

The researchers found forced expiratory volume in the first second in percent of expected values was reduced, at an average 93.2 in the psoriasis group, versus 94.9 in controls. The forced expiratory volume in the first second- forced vital capacity ratio was also lower among psoriasis patients at an average 0.76 versus 0.77. However, force vital capacity was similar in both groups. And after adjusting for smoking, only the average reduction in forced expiratory volume in the first second remained significant in the psoriasis group.

The finding that forced vital capacity was similar in both groups suggests that psoriasis’s predominate pulmonary effect is on airway obstruction. And the finding related to the forced expiratory volume in the first second- forced vital capacity ratio in the psoriasis group is compatible with COPD or asthma and in line with observational studies that have found an increased risk of CODP in psoriasis patients, the authors note.

The authors write they’re tempted to speculate that psoriasis-related inflammatory airway injury and remodeling plays a role in psoriasis’s potential associations with respiratory infections and more.

“Indeed, psoriasis is considered to be an interleukin 23/T helper cell 17-driven disease and similar inflammatory mechanisms have been implicated in the pathogenesis of airway inflammation,” they write.

Dr. Hansen says these findings are an extension of what is known about smoking’s link to psoriasis, as well as psoriasis patients’ increased risks for pulmonary infections, chronic obstructive pulmonary disease and asthma.

“[Our study demonstrates] a small reduction of pulmonary function in psoriasis. Preliminary studies have suggested that subjects with severe psoriasis have increased subclinical airway inflammation and inflammatory pathways may coincide between psoriasis and obstructive lung disease,” he says. “More research is needed to define these mechanisms and their clinical consequences.”

These results indicate that pulmonary disease should be counted among psoriasis comorbidities, and they underscore that psoriasis is a systemic inflammatory disease and not just a skin disorder, Dr. Hansen says.

References:

Hansen, P. R., Isaksen, J. L., Jemec, G. B., Kanters, J. K. and Ellervik, C. (2018), Pulmonary function in subjects with psoriasis: A cross‐sectional population study. Br J Dermatol. Accepted Author Manuscript. . doi:10.1111/bjd.16539