A recent study found that patients with chronic obstructive pulmonary disease (COPD) had an increased risk of mild cognitive impairment and dementia.
A systematic review and meta-analysis published in Global Journal of Clinical Cases found an elevated risk of dementia and mild cognitive impairment (MCI) in patients with chronic obstructive pulmonary disease (COPD).
The investigators searched the online databases PubMed, Embase, Google Scholar and Cochrane Library for studies published before March 31, 2021.
Studies were included if they investigated the association between COPD and the risk of MCI or dementia; passed a definitive result of cognitive impairment or dementia; the raw reported values needed to calculate the odds ratio (OR) or HR; contained control cases, were prospective or retrospective, or had a cross-sectional design; and compared the association between patients with and without COPD. Studies were excluded if they did not report relevant results or if the full text was not accessible.
The review included 27 studies published between 1996 and 2020. Ten were case-control studies, 10 were cross-sectional, 4 were prospective cohort studies and 3 were retrospective cohort studies. The quality score, assessed by the Newcastle-Ottawa scale, was high in 12 studies, medium in 7 and low in 6.
The 10 studies that investigated the association between COPD and MCI had 71,174 patients with COPD and 22,082 controls. The meta-analysis found a strong association between COPD and MCI (OR, 2.11; 95% CI, 1.32-3.38). There was significant heterogeneity and patients with COPD were 1.26 times more likely to have MCI than non-COPD controls.
There was a significant association between COPD and MCI (HR, 1.22; 95% CI, -1.18 to -1.27) when adjusted HRs were pooled from 4 studies.
The 7 studies that investigated the association of COPD and dementia included 108,606 patients with COPD and 347,939 controls. The meta-analysis found an increased risk of dementia in patients with COPD (OR, 1.16; 95% CI, 0.98-1.37) compared to non-COPD controls.
There was also a relationship between COPD and dementia when adjusted RRs were pooled from 6 studies (RR, 1.32; 95% CI, -1.22 to -1.43).
There were 17 studies that reported mean mini-mental state examination (MMSE) scores for patients with and without COPD; these included 1392 patients with COPD and 5097 controls. There was a significantly lower MMSE score, indicating deterioration in cognition, in patients with COPD compared to controls ( MD , -1.68; 95% CI, -2.66 to -0.71).
There were some limitations to this review. The studies included in this review had different designs, which may be a cause of heterogeneity. There were only 7 studies assessing the relationship between COPD and dementia, which limits the results of this review. Heterogeneity may be due to different geographic populations, variation in COPD diagnostic criteria, and diversity of factors for multivariate analysis of included studies.
The studies lacked long-term follow-up data that would help researchers perform subgroup analysis based on age, comorbidities, and gender. The included studies also used different methods to assess and diagnose COPD and cognitive impairment.
The researchers concluded that there was an elevated risk of MCI and dementia in patients with COPD.
“Appropriate clinical management and attention are needed to prevent or ameliorate the incidence of MCI and dementia in patients with COPD,” the authors wrote.
Zhao LY, Zhou XL. Association of chronic obstructive pulmonary disease with mild cognitive impairment and dementia risk: a systematic review and meta-analysis. World J Clin Case. 2022;10(11):3449-3460. doi:10.12998/wjcc.v10.i11.3449