A new study has found that 40 percent of adults with severe asthma screened positive for possible cognitive impairment. The research, published in BMC Pulmonary Medicine, evaluated 145 patients who were all receiving biologic therapy. It concluded that cognitive dysfunction is an under-explored issue in managing severe asthma. The findings show the impairment was linked more to age, metabolic conditions and genetics than to conventional measures of asthma severity.
Overall, 58 of the 145 patients met the study's criteria for possible cognitive dysfunction. The researchers used two screening tools, the Mini-Mental State Examination and the Montreal Cognitive Assessment. They defined possible cognitive dysfunction as any impairment identified on either test. Normal cognitive status required a normal score on both instruments.
The Montreal Cognitive Assessment identified cognitive abnormalities in a larger proportion of patients than the Mini-Mental State Examination. "The Montreal Cognitive Assessment detected cognitive abnormalities more frequently than the Mini-Mental State Examination, particularly milder abnormalities that were not identified by the Mini-Mental State Examination," the researchers noted. It captured deficits in individuals whose scores on the other test were normal. Patients who screened positive for possible cognitive dysfunction were significantly older and had higher rates of adult-onset asthma, diabetes and high blood pressure. In contrast, measures like lung function, asthma control scores, annual exacerbation frequency, systemic corticosteroid exposure and specific type 2 inflammatory biomarkers showed no significant differences between the two groups.
Genetic testing involved genotyping selected cytokine gene polymorphisms, specifically interleukin-4, interleukin-6, interleukin-13 and tumor necrosis factor-alpha. The interleukin-6 polymorphism showed a significant association with cognitive screening status. In a multivariable logistic regression analysis, diabetes mellitus emerged as an independent predictor associated with increased odds of possible cognitive dysfunction. Childhood-onset asthma was independently associated with reduced odds.
The study involved an initial cross-sectional evaluation of the patients, followed by a longitudinal assessment focused on clinical remission. Cognitive testing was done only at the start and was not repeated. The longitudinal monitoring found that neither the achievement of clinical remission nor its individual clinical components differed significantly according to baseline cognitive status. Based on the results, the authors recommend targeted cognitive screening alongside confirmatory neuropsychological testing for high-risk patients with severe asthma. "Cognitive screening status was associated more closely with age, metabolic comorbidity, and selected inflammatory genetic factors than with routine asthma metrics, type 2 inflammation, or clinical remission," the authors concluded. The research highlights that severe asthma is a complex systemic condition often accompanied by multiple comorbid disorders.