New study reveals patients with COPD almost have a two times higher prevalence
Dr. Balwinder Singh, MD, Research Physician and Master’s Scholar, Department of Neurology, Mayo Clinic, Rochester and colleagues examined the association of chronic obstructive pulmonary disease (COPD) with mild cognitive impairment (MCI) and MCI subtype: amnestic MCI and non-amnestic MCI, in a population-based study of elderly patients.
This new study included 1,927 participants aged 70 to 89 years, and enrolled in the population-based Mayo Clinic Study of Aging, which examined the prevalence, incidence and risk factors for mild cognitive impairment (MCI) and dementia.
Participants were evaluated by using a nurse assessment, neurological evaluation, and neuropsychological testing, and the diagnosis of MCI was made by a consensus panel according to the standardized criteria. Chronic obstructive pulmonary disease was identified by the review of medical records.
The study was conducted from October 1, 2004, through July 31, 2007. The associations of COPD and disease duration with MCI and its subtypes were evaluated by using logistic regression models adjusted for potential covariates.
Among the participants 288 had COPD, 18% men and 12% women.
The results showed that participants with COPD had a higher prevalence of mild cognitive impairment at 27% compared to those without COPD at 15%.After adjustment for a range of confounders; the odds for any MCI in patients with COPD were 87% greater than for participants without.
The odds ratio for mild cognitive impairment was almost two times higher (1.87%) for those with COPD compared to participants without COPD, 1.34%, with the effects being similar between men and women.
The researchers also reported a dose relationship for the odds ratio of mild cognitive impairment and found that those with COPD had an increased risk for mild cognitive impairment by 1.60 for a duration of five years or less to 2.10 in patients with a COPD duration of more than 5 years.
In their conclusion the team writes “This population-based study suggests that COPD is associated with increased odds of having MCI and its subtypes. There was a dose-response relationship with the duration of COPD after controlling for the potential covariates.”
Dr. Singh explained that this study is one of the few studies to examined mild cognitive impairment in patient with COPD. Several past studies have demonstrated an increased risk for clinical cognitive dysfunction among those with COPD.
The researchers suggest that these findings may be related to hypoxia, (a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply) that could result in an increased risk for neuronal injury, as well as chronic inflammatory processes in COPD. The team also notes that while cardiovascular comorbidities (either the presence of one or more disorders (or diseases) in addition to a primary disease or disorder) could also lead to cognitive impairments, the results of this study is independent of this therefore, it is suggested the observed association was not due to confounding risk factors such as stroke or vascular disease.
This study appears in the Mayo Clinic Proceedings.
In 2011, 12.7 million U.S. adults (aged 18 and over) were estimated to have COPD. However, close to 24 million U.S. adults have evidence of impaired lung function, indicating an under diagnosis of COPD.
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