Prevalencia de deterioro cognitivo leve en pacientes ambulatorios con enfermedad pulmonar obstructiva crónica: estudio transversal en Bogotá, Colombia

Prevalence of mild cognitive impairment among outpatients with chronic obstructive pulmonary disease: A cross-sectional study in Bogotá, Colombia

Introducción. Ya que es una enfermedad sistémica, los pacientes con enfermedad pulmonar obstructiva crónica (EPOC) pueden presentar deterioro cognitivo. En Colombia no hay estudios sobre la prevalencia de deterioro cognitivo, incluido el deterioro cognitivo leve (DCL), en esta población.

Objetivo. Determinar la prevalencia de DCL en pacientes con EPOC grave o muy grave atendidos en un centro de atención primaria de Bogotá (Colombia).

Materiales y métodos. Estudio transversal realizado en 139 pacientes con EPOC grave o muy grave atendidos en un centro de atención primaria de Bogotá entre mayo de 2019 y marzo de 2020. Se administró un cuestionario ad hoc (variables sociodemográficas) y la herramienta Montreal Cognitive Assessment (MoCA). También se obtuvo información sobre VEF₁, relación VEF₁/CVF, PaO₂ y grado de hipoxemia (historias clínicas). Se consideraron dos puntos de corte para DLC: <26 y <21, este último se usó porque ha sido recomendado para población adulta mayor colombiana. Se exploró la asociación entre la presencia de DCL según cada punto de corte y el sexo y el nivel educativo (prueba de chi cuadrado de independencia con cálculo de Odds Ratio crudos).

Resultados. La edad promedio de los pacientes fue 72.07 años, 51.80% eran mujeres, 51.79% tenía un nivel socioeconómico bajo, 79.14% tenían escolaridad básica primaria y 54.68% tenía hipoxemia severa. Respecto a la puntuación en el MoCA, 49.64% obtuvieron <26 puntos y 17.27 % <21. Los dominios cognitivos más comprometidos fueron Recuerdo diferido y Capacidad visuoespacial/ejecutiva (54.68% y 38.13% de los participantes obtuvieron ≤2 puntos, respectivamente). Tener solo educación primaria se asoció significativamente con mayor riesgo de DCL, especialmente en el punto de corte <21 (OR: 7.33; IC95%: 1.08-315.22; p=0.02).

Conclusión. Casi la mitad de los pacientes con EPOC evaluados presentó DCL usando el punto de corte recomendado por el instrumento MoCA (i.e., <26). Estos hallazgos respaldan la necesidad de incluir la evaluación cognitiva sistemática en el abordaje integral de esta población con instrumentos sensibles como el MoCA. Finalmente, tener un bajo nivel educativo (solo educación primaria) aumentó la probabilidad de DCL.

Introduction: Since chronic obstructive pulmonary disease (COPD) is a systemic disease, patients with this condition may present cognitive impairment. In Colombia, there are no studies on the prevalence of cognitive impairment, including mild cognitive impairment (MCI), in this population.

Objectives: To determine the prevalence of MCI in patients with severe or very severe COPD treated at a primary care center in Bogotá, Colombia.

Materials and Methods: Cross-sectional study conducted on 139 patients with severe or very severe COPD treated at a primary care center in Bogotá between May 2019 and March 2020. The Montreal Cognitive Assessment (MoCA) was administered, along with an ad hoc questionnaire covering sociodemographic variables. Information on FEV₁, FEV₁/FVC ratio, PaO₂, and the degree of hypoxemia was also obtained from medical records. Two cutoff points for MCI were considered: <26 and <21. The latter cutoff was utilized because it has been specifically recommended for the Colombian older adult population. The association between MCI according to each cutoff point, sex, and educational level was explored using the chi-square test of independence with calculation of crude Odds Ratios.

Results: The mean age of the patients was 72.07 years, 51.80% were women, 51.79% had a low socioeconomic level, 79.14% had basic primary education, and 54.68% had severe hypoxemia. Regarding the MoCA score, 49.64% of participants scored <26 and 17.27% scored <21. The most compromised cognitive domains were delayed recall and visuospatial/executive ability, as 54.68% and 38.13% of participants obtained ≤2 points, respectively. Having only primary education was significantly associated with a higher risk of MCI, especially at the <21 cutoff point (OR: 7.33, 95%CI: 1.08-315.22, p=0.02).

Conclusion: Nearly half of the evaluated patients with COPD presented MCI when using the cutoff point recommended by the MoCA instrument (<26). These findings support the need to include systematic cognitive evaluation in the comprehensive management of this population, using sensitive instruments such as the MoCA. Finally, having a low educational level (primary education only) increased the probability of MCI.

Original research

Alejandra Villadiego-Cortina1 Nidia Pinto-Martínez1 Nelci Becerra-Martínez1

1 Javesalud IPS - Centro Médico Javeriana - Comprehensive Care Program for Patients with COPD - Bogotá D.C. - Colombia.

Open access

Received: 22/05/2025

Accepted: 11/03/2026

Corresponding author: Nelci Becerra-Martínez. Centro Médico Javeriana, Javesalud IPS. Bogotá D.C. Colombia. E-mail: nbecerra@javesalud.com.co.

Keywords: Chronic Obstructive Pulmonary Disease; Prevalence; Cognitive Dysfunction; Dementia; Outpatients (MeSH).

Palabras clave: Enfermedad Pulmonar Obstructiva Crónica; Prevalencia; Disfunción Cognitiva; Demencia; Pacientes Ambulatorios (DeCS).

How to cite: Villadiego-Cortina A, Pinto-Martínez N, Becerra-Martínez N. Prevalence of mild cognitive impairment among outpatients with chronic obstructive pulmonary disease: A cross-sectional study in Bogotá, Colombia. Rev. Fac. Med. 2026;74:e120532. English. doi: https://doi.org/10.15446/revfacmed.v74.120532.

Cómo citar: Villadiego-Cortina A, Pinto-Martínez N, Becerra-Martínez N. [Prevalencia de deterioro cognitivo leve en pacientes ambulatorios con enfermedad pulmonar obstructiva crónica: estudio transversal en Bogotá, Colombia]. Rev. Fac. Med. 2026;74:e120532. English. doi: https://doi.org/10.15446/revfacmed.v74.120532.

Copyright: ©2026 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, as long as the original author and source are credited.

Abstract

Resumen

Introduction

Chronic obstructive pulmonary disease (COPD) is defined as a group of diseases, including emphysema and chronic bronchitis, that block airflow to the lungs and cause respiratory problems due to damage to the airways or other parts of the lung.1,2 The most common symptoms are dyspnea, wheezing, fatigue, and cough (sometimes with sputum) and its diagnosis is established through spirometry.1,3 COPD is caused by the interaction of genetic and environmental factors that can damage the lungs or alter their normal aging process. The main environmental factors include tobacco smoking, occupational exposure to particles, toxic gases, and chemical substances, and exposure to outdoor and indoor air pollution.1,2

According to data from the Global Burden of Disease, there were 213.39 million prevalent cases of COPD worldwide in 2021, with a standardized prevalence of 2 512.86 cases per 100 000 inhabitants. Likewise, in that same year, this disease was the fourth leading cause of death globally, causing between 3.5 and 3.72 million deaths.2,4 In Latin America and the Caribbean, according to a recent systematic review and meta-analysis, the prevalence of COPD in the population over 35 years of age is 8.9%.5

There is no recent information on the epidemiology of COPD in Colombia. For instance, the PREPOCOL study, conducted in five cities across the country between 2003 and 2004, reported an 8.9% prevalence of COPD among individuals aged 40 and older.6 Similarly, Gil-Rojas et al.,7 using data reported between 2010 and 2015 in the Registro Individual de Prestaciones de Servicios de Salud (Individual Registry of Health Services Provision - RIPS by its Spanish acronym), estimated that the prevalence of COPD adjusted for age, under-registration, underdiagnosis, and misdiagnosis was 5.13%.

Although COPD has been traditionally considered a lung disease, it is now recognized as a systemic condition that can affect various organs and systems, including the central nervous system.8,9 In this regard, patients with COPD may present cognitive impairment, which can be global or affect specific cognitive domains such as information processing, attention and concentration, memory, executive functioning, and self-control.9 This damage may be due to hypoxemia and hypercapnia resulting from chronic airway obstruction, as well as disease exacerbations and decreased physical activity.8,9 Furthermore, according to López-Torres et al.,10 the cognitive status of these patients varies across clinical stages, and certain cognitive domains may be more severely affected.

Several studies have documented an association between COPD and cognitive impairment. For example, Singh et al.11 reported that COPD significantly increases the risk of non-amnestic mild cognitive impairment (MCI) by 83% (HR=1.83; 95%CI: 1.04-3.23), while Wang et al.12 found that having COPD was associated with a higher risk of cognitive impairment (RR=1.30, 95%CI: 1.13-1.49, I2=50.1%, z=3.72, p<0.001).

According to recent systematic reviews, the pooled prevalences of cognitive impairment and MCI in COPD range between 20% and 32%, and 24% and 25%, respectively.13,14 In Colombia, although there are no data on the prevalence of cognitive impairment or MCI in patients with COPD, some studies have determined its prevalence in older adults (≥60 years), the population group most susceptible to developing COPD.15 For instance, Sarmiento-Buitrago et al.16 reported a prevalence of 19.7%, while Molina-Estrada17 reported figures between 11.36% and 36.99% depending on the age group.

Based on the above, the objective of the present study was to determine the prevalence of MCI in patients with severe or very severe COPD treated at a primary care center in Bogotá (Colombia).

Materials and methods

Study type

Cross-sectional descriptive study.

Study population and sample

The study population consisted of 507 outpatients with a diagnosis of severe and very severe COPD treated at a primary care center in Bogotá between May 2019 and March 2020 as part of a comprehensive care program for patients with this disease. Based on this population size, the sample size was calculated with a 95% confidence level, an expected proportion of 14.5%, and a 5% margin of error, resulting in a sample size of 139 participants. The expected proportion of 14.5% was defined based on the evidence available for the Colombian population, particularly the study by Molina-Estrada,17 which included 315 non-institutionalized older adults in Cali, reporting an overall prevalence of cognitive impairment of 33.94% (95%CI: 26.41-42.38), with age group estimates ranging between 12.9% and 24.8%. Complementarily, the most recent situational analysis on cognitive impairment in Colombia was taken into account, which reported prevalences of 8.9% for cognitive impairment without dementia and 10.8% for dementia.18 Considering the variability of these estimates, an expected proportion of 14.5% was selected to calculate the sample size as a conservative estimate within the range reported for comparable populations.

Patients under 79 years of age with a confirmed diagnosis of COPD made through spirometry who agreed to participate in the study were included. Patients with conditions that hindered or prevented the administration of the Montreal Cognitive Assessment (MoCA), such as visual or hearing impairments, were excluded, as well as patients with a history or presence of neuropsychiatric diseases (diagnosis of major depression or schizophrenia according to ICD-10 classification) according to their medical records.

Upon entry into the comprehensive care program, patients are evaluated by a multidisciplinary team that includes clinical and psychological assessments, though no standardized screening instrument for depression was systematically applied. Participants were recruited through convenience sampling until the sample size was reached.

Procedures and variables

Patients were invited to participate in the study during one of their routine consultations. Upon agreement, they were asked to stay for a few additional minutes after the visit for the administration of the two instruments described below.

First, participants were asked to complete an ad hoc questionnaire to collect information on the following variables: age, sex, educational level, socioeconomic status, residential location within the city, last occupation, and current occupation. Subsequently, the MoCA was administered, as described in the following subsection. In addition, medical records were reviewed to obtain data on COPD classification according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (severe and very severe), forced expiratory volume in one second (FEV1), the FEV1/FVC ratio (based on the most recent spirometry), and partial pressure of oxygen (PaO2) (based on the most recent arterial blood gas test). The degree of hypoxemia (moderate or severe) was determined according to the PaO2.

Data were collected between May 2019 and March 2020 by medical professionals from the program who were trained in MoCA administration and scoring. To ensure consistency in testing and data recording, the collection process followed standardized protocols and there were no changes in the staff responsible for this process. Moreover, periodic reviews of the forms and the database were conducted to ensure the quality of the collected information.

It should be noted that socioeconomic status in Colombia is divided into six strata based on place of residence and access to basic services. Strata 1 (low-low) and 2 (low) represent the lowest levels, strata 3 (low-middle) and 4 (middle) represent the middle levels, and strata 5 (upper-middle) and 6 (high) represent the highest levels.19

Montreal Cognitive Assessment Instrument

Cognitive evaluation was performed using the Spanish version 8.1 of the MoCA, available on the MoCA Cognition website (https://mocacognition.com/paper#paper_form_full).

The original version of this instrument demonstrated high levels of reliability and validity, with 87% sensitivity and 90% specificity for MCI detection using a cutoff point <26. In patients with Alzheimer’s, it showed 87% sensitivity and 100% specificity with a cutoff point <18.20 This version was also validated in the Colombian population.21

The MoCA evaluates multiple cognitive areas across the following domains: visuospatial/executive ability (5 points), naming (3 points), memory (no points), attention (5 points), language (3 points), abstraction (2 points), delayed recall (5 points), and orientation (6 points). Detailed information regarding point allocation for each domain is available in the administration and scoring instructions for the instrument.22 The total score is obtained by adding the scores of each domain. The maximum score is 30 points and a score ≥26 is considered normal. If the patient has 12 years of education or less, one point must be added to the total. In addition to using the <26 cutoff point for MCI, this study also employed the <21 cutoff point proposed by Pedraza et al.21 for the Colombian older adult population.

Statistical analysis

Data were entered into and organized in a Microsoft Excel spreadsheet and subsequently exported to the R statistical software (version 4.1.2) for analysis. Qualitative variables are described using absolute and relative frequencies, while quantitative variables are presented as means and standard deviations, as they followed a normal distribution according to the Shapiro-Wilk test.

Bivariate analyses (chi-square test of independence) were performed by calculating odds ratios (OR) to explore the association between the presence of MCI, based on both cutoff points (<26 and <21 points), and sex and educational level (primary education only vs. secondary or higher education). A statistical significance level of p<0.05 was considered. It should be noted that sex and educational level were the only variables included in the bivariate analyses because literature identifies them as the sociodemographic variables with the strongest and most consistent evidence of a direct association with MCI risk.16,23 Although data were collected for other sociodemographic variables (age, socioeconomic status, occupation), they did not present sufficient variability or a distribution that allowed to perform a sound epidemiological categorization for the bivariate analysis.

Ethical considerations

The study followed the ethical principles for medical research involving human subjects established in the Declaration of Helsinki24 and the scientific, technical, and administrative standards for health research in accordance with Resolution 8430 of 1993 issued by the Colombian Ministry of Health.25 The research was also approved by the Javesalud Research Ethics Committee under approval record PII_2019_002A on May 7, 2019.

Results

The mean age of the patients was 72.07 years (±5.75), 51.80% were women, 51.79% had a low socioeconomic status (strata 1-2 in Colombia), and only 20.86% had an education level higher than primary school. Regarding occupation, 20.14% reported previous employment in cement plants, brickyards, or factories, while 48.20% reported that their current occupation was related to household chores. The sociodemographic characteristics of the sample are presented in Table 1.

Table 1. Sociodemographic characteristics of participants (n=139).

Variables		n (%)
Age (years) Mean (SD)		72.07 (5.75)
Sex
	Female	72 (51.80)
	Male	67 (48.20)
Educational level
	Primary school	110 (79.14)
	High school	14 (10.07)
	Technical	9 (6.47)
	Undergraduate	4 (2.88)
	Postgraduate	2 (1.44)
Locality of residence in Bogotá D.C.
	Usaquén	11 (7.91)
	Chapinero	2 (1.44)
	Santa Fe	1 (0.72)
	San Cristóbal	16 (11.51)
	Usme	6 (4.32)
	Tunjuelito	2 (1.44)
	Bosa	5 (3.60)
	Kennedy	28 (20.14)
	Fontibón	8 (5.75)
	Engativá	18 (12.95)
	Suba	16 (11.51)
	Teusaquillo	2 (1.44)
	Los Mártires	1 (0.72)
	Antonio Nariño	2 (1.44)
	Rafael Uribe Uribe	12 (8.63)
	Ciudad Bolívar	4 (2.88)
	No data	5 (3.60)
Socioeconomic status
	Low-low (stratum 1)	10 (7.20)
	Low (stratum 2)	62 (44.60)
	Low-middle (stratum 3)	52 (37.41)
	Middle (stratum 4)	11 (7.91)
	Upper-middle (stratum 5)	4 (2.88)
Previous occupation
	Household chores	30 (21.59)
	Employment in cement plants, brickyards, and factory workers	28 (20.14)
	Office work	13 (9.35)
	Agriculture	11 (7.91)
	Commerce	10 (7.19)
	Driver	8 (5.76)
	General trades	6 (4.32)
	None	2 (1.44)
	Other	31 (22.30)
Current occupation
	Unemployed	37 (26.61)
	Household chores	67 (48.20)
	Retired	26 (18.71)
	General trades	9 (6.48)

Source: Own elaboration.

Concerning clinical characteristics, 71.94% of participants had severe COPD. The mean FEV1 (percentage of predicted value) was 40.72%, the mean FEV1/FVC ratio was 53.76%, and the mean PaO2 was 45.95 mmHg. All participants exhibited some level of hypoxemia, with severe hypoxemia being the most frequent (54.68%).

Table 2. Clinical characteristics of participants (n=139).

Variable		n (%)
COPD classification
	Severe (GOLD 3)	100 (71.94)
	Very severe (GOLD 4)	39 (28.06)
FEV1 (% predicted), mean (SD)		40.72 (11.00)
FEV1/FVC (%), mean (SD)		53.76 (10.65)
Presence of hypoxemia
	Moderate hypoxemia	63 (45.32)
	Severe hypoxemia	76 (54.68)
PaO2 (mmHg), mean (SD)		45.95 (7.80)

COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in one second; FVC: forced vital capacity; PaO2: partial pressure of oxygen.

Source: Own elaboration.

The prevalence of MCI was 49.64% using the <26 cutoff point and 17.27% with the <21 cutoff point. Greater cognitive impairment was observed in the visuospatial/executive and delayed recall domains; according to the operative criteria defined in this study (score ≤2 points in each domain), 38.1% and 54.6% of participants, respectively, obtained low scores (Table 3).

Table 3. Cognitive assessment results (n=139).

Cognitive domains	n (%)
Visuospatial/executive
0	18 (12.95)
1	13 (9.35)
2	22 (15.83)
3	27 (19.42)
4	29 (20.86)
5	30 (21.58)
Naming
0	0 (0.00)
1	1 (0.72)
2	11 (7.91)
3	127 (91.37)
Attention
0	1 (0.72)
1	1 (0.72)
2	5 (3.60)
3	13 (9.35)
4	30 (21.58)
5	28 (20.14)
6	61 (43.88)
Language
0	2 (1.44)
1	9 (6.47)
2	31 (22.30)
3	97 (69.78)
Abstraction
0	0 (0.00)
1	10 (7.19)
2	129 (92.81)
Delayed recall
0	7 (5.04)
1	23 (16.55)
2	46 (33.09)
3	24 (17.27)
4	22 (15.83)
5	17 (12.23)
Orientation
0	1 (0.72)
1	0 (0.00)
2	2 (1.44)
3	0 (0.00)
4	2 (1.44)
5	12 (8.63)
6	122 (87.77)
MoCA <26 cutoff
≥26	70 (50.36)
<26	69 (49.64)
MoCA <21 cutoff
≥21	115 (82.73)
<21	24 (17.27)

Source: Own elaboration.

Finally, the bivariate analysis showed that educational level was significantly associated with the presence of MCI. The probability of having MCI according to the established cutoff points (<26 and <21 points) was between 4 and 7.3 times higher in participants who had only completed primary education (OR=4.01, p=0.002 and OR=7.33, p=0.02, respectively). A trend toward a higher probability of MCI in men was also observed for both cutoff points, although the association was not statistically significant (Table 4).

Table 4. Association between sex and educational level and the presence of mild cognitive impairment according to the two cutoff points considered.

Variables	Presence of MCI
	MoCA<21 OR (95%CI)	p-valueª	MoCA<26 OR (95%CI)	p-valueª
Sex
Female	1	0.11	1	0.27
Male	2.09 (0.77-6.12)		1.45 (0.70-3.001)
Educational level
Secondary education or higher	1	0.02	1	0.002
Primary education only	7.33 (1.08-315.22)		4.01 (1.50-12.10)

ª Chi-square test of independence.

Source: Own elaboration.

Discussion

In the present study, the prevalence of MCI in patients with COPD treated at a primary care center in Bogotá was 49.64% (n=69) using a MoCA cutoff point of <26. This figure is considerably higher than the 24% (95%CI: 17–32%) reported by Zhang et al.13 in a recent (2025) systematic review and meta-analysis that included data from 138 030 patients with COPD (41 studies). Nevertheless, it should be noted that the instruments used to assess MCI varied among the studies included in the review by Zhang et al.;13 in fact, only 9 used the MoCA. Regarding studies specifically using the MoCA, Villeneuve et al.,26 reported a lower MCI prevalence (36%) in a study of 45 patients with moderate to severe COPD at a hospital in Montreal (Canada). Conversely, Yohannes et al.,27 found a higher MCI frequency (54%) in a multicenter study involving 220 individuals with COPD in the United States.

No population-based studies estimating the prevalence of cognitive impairment specifically in people with COPD were found in Colombia. Therefore, the situational analysis based on the SABE Colombia 2015 survey, the most robust national study available, was used as a reference.18

The prevalence of MCI found in our cohort is higher than that reported in the SABE Colombia 2015 survey (8.9% for cognitive impairment without dementia and 10.8% for dementia type cognitive impairment). This holds true regardless of the cutoff point used, as the one proposed by Pedraza et al.21 for the Colombian older adult population (<21) was also considered, resulting in an MCI prevalence of 17.27% (n=24). However, this comparison should be interpreted with caution, as the SABE Colombia 2015 assessed global cognitive impairment in older adults from the general population using the Mini-Mental State Examination, while our study focused on assessing MCI in patients with COPD, a population with distinct characteristics and risks.

The high proportion of patients with MCI observed in our study may be attributed to several factors, namely, the high sensitivity of the MoCA instrument, which may have facilitated the detection of mild cases; the clinical characteristics of the sample (patients with severe and very severe COPD); and the presence of hypoxemia in all participants. In this regard, several studies have identified hypoxemia as a risk factor for cognitive impairment in patients with COPD,8,28,29 making it essential to evaluate and optimize hypoxic status in this population.29

When analyzing the results by MoCA domains, the greatest cognitive impairment was observed in the delayed recall domain, as 54.68% of participants scored ≤2 points and only 12.23% reached the maximum score (5/5). This impairment of short-term memory is consistent with reports in the literature about cognitive decline associated with chronic hypoxemia, which is common in patients with advanced COPD.8,9,14,30-32 Likewise, the second most affected domain was visuospatial/executive ability, where 38.13% of participants scored ≤2 points and only 21.58% reached a maximum score, suggesting early executive dysfunction. This finding is consistent with available evidence indicating that patients with COPD often present alterations in executive and visuospatial functions, potentially linked to chronic hypoxemia, systemic inflammation, and cerebral microvascular changes.8,11,33-35

In contrast, cognitive status in the naming, abstraction, and orientation domains was not affected in the majority of patients, with 87.77% to 91.37% reaching the maximum score in these domains. This pattern is consistent with the description by López-Torres et al.,10 who observed that these MoCA subdomains show less impairment and tend to improve across different clinical stages of COPD. Concerning the attention and language domains, between 5.04% and 30.22% scored ≤2 points in these functions. Overall, the findings suggest a pattern of non-amnestic, multi-domain cognitive impairment, characteristic of patients with severe COPD, especially those with chronic hypoxemia.13,35,36

As to the participants’ sociodemographic variables, the mean age was 72.07 years (±5.75) and 51.80% were women. These findings are similar to those obtained by Rojas-Laverde et al.37 in a study of 248 patients with COPD treated in Boyacá (Colombia), where the mean age was 74.78 years (±9.4) and 47.2% were women.

Primary education, equivalent to a maximum of five years of schooling, was the most frequent educational level in our study (79.14%). This finding is consistent with local studies that have reported an average of 4.7 years of formal education.18,38 Nevertheless, the proportion observed in this study is lower than that reported by Rojas-Laverde et al.,37 who found that 56.5% of patients had primary education only and 36.3% had no formal education at all. The high proportion of patients with low educational levels in our study could be related to the predominance of lower socioeconomic statuses, as 89.21% belonged to the low-low, low, and medium-low levels (strata 1, 2, and 3, respectively).

The findings from the bivariate analysis demonstrated a significant association between low educational level and cognitive impairment, using both the conventional MoCA cutoff (<26) and the more specific one (<21). Particularly, subjects with only primary education presented a significantly higher risk of cognitive impairment (OR=7.33; 95%CI: 1.08–315.22 for MoCA <21, and OR=4.01; 95%CI: 1.50–12.10 for MoCA <26). These results align with the cognitive reserve theory, which posits that lower educational attainment is associated with greater vulnerability to neurodegenerative effects and the cognitive consequences of chronic diseases such as COPD.13,39

Furthermore, although a higher probability of cognitive impairment was observed in men, this association did not reach statistical significance at either of the evaluated cutoff points; this could be due to the sample size or uncontrolled differences between the groups. These results reinforce the importance of considering educational level when assessing cognitive risk in patients with COPD and support the use of the MoCA as a sensitive tool for the early detection of cognitive impairment in this population.20

The literature reports that although COPD is a leading cause of death worldwide, up to two-thirds of these patients die from non-pulmonary causes; therefore, the early detection of comorbidities associated with impaired quality of life and mortality in this population is a must,40 but cognitive assessment is still not a routine practice in the management of these patients.40 This is highly relevant, as the failure to timely detect cognitive impairment can negatively affect clinical management by hindering autonomy, self-care, treatment adherence, and the quality of life of this population.12,41-43 These points, as well as the results of the present study, underscore the need to systematically incorporate cognitive assessments into the comprehensive approach for COPD patients to promote early detection and allow for personalized interventions that improve clinical outcomes. This cognitive screening should be performed using sensitive tools, such as the MoCA, which allow for the early identification of frequently underdiagnosed cognitive dysfunctions.

The present study has certain methodological limitations that should be considered when interpreting its findings. First, its cross-sectional design does not allow for the establishment of causal relationships between COPD and the observed MCI, limiting the conclusions to specific associations. Second, although the MoCA is a sensitive tool for MCI detection, it does not replace a full neuropsychological evaluation; therefore, some cognitive domains may have been over- or underestimated. Furthermore, while individuals with neuropsychiatric comorbidities (ICD-10 diagnosis of major depression or schizophrenia) were excluded, and all patients underwent psychological evaluation upon entering the comprehensive care program, the absence of a standardized screening instrument might limit the identification of subclinical depressive symptoms. This is particularly relevant given that depression is highly prevalent in patients with COPD44 and may be associated with attentional deficits that may mimic MCI (depressive pseudodementia).

A further limitation involves the lack of a systematic exclusion of other potential causes of cognitive decline, such as sleep disorders, medication side effects, or metabolic alterations, which could have influenced the results. This is compounded by the educational and sociocultural level of the participants, since, although considered when adjusting the cutoff point, these factors might still affect cognitive test performance. Specifically, the high proportion of patients with low educational attainment may have influenced their MoCA scores, implying that the instrument alone might not fully discriminate between educational bias and pathological cognitive impairment. Consequently, these results should be interpreted as a screening-based approximation rather than a definitive neuropsychological diagnosis. Finally, the sample was drawn from a single institution in Bogotá, which limits the generalizability of the findings to other regions of the country or rural settings.

Despite these limitations, the present study provides valuable evidence regarding the high frequency of cognitive alterations in patients with COPD within the Colombian context. These findings underscore the need to incorporate systematic, validated, and culturally adapted cognitive screening protocols as an essential component of the comprehensive care for this population. Moreover, they stress the importance of further characterizing cognitive function in COPD patients, particularly in low- and middle-income countries, where the burden of disease is higher.

Conclusions

In this study, a high frequency of MCI was observed among patients with COPD treated at a primary care center in Bogotá (Colombia). This prevalence is higher than that reported in most of the international literature, although it should be noted that assessment instruments vary across studies. The cognitive domains showing the greatest impairment were delayed recall and visuospatial/executive ability. Furthermore, having a low educational level (primary education only) significantly increased the probability of MCI, demonstrating the importance of considering social characteristics in the functional assessment of these patients.

These results support the need to implement systematic, validated, and culturally sensitive cognitive screening strategies as part of the comprehensive management of COPD.

Conflicts of interest

None stated by the authors.

Funding

None stated by the authors.

Acknowledgments

None stated by the authors.

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