Chronic Obstructive Pulmonary Disease (COPD) represents a major global health challenge and is currently the third leading cause of death worldwide. Characterized by persistent respiratory symptoms and progressive airflow limitation, COPD arises from a complex interplay of environmental exposures, most notably tobacco smoke, and individual host factors such as genetic predisposition and comorbidities [1]. In recent years, the focus of COPD management has expanded beyond pulmonary impairment to include the impact of systemic inflammation and comorbid conditions that significantly influence disease trajectory and patient outcomes [2].

Among the most prevalent and clinically significant comorbidities in COPD are obesity and type 2 diabetes mellitus (T2DM). Traditionally, COPD has been associated with undernutrition and cachexia; however, this paradigm has shifted with an increasing number of patients presenting with overweight or obesity, particularly in high-income and urbanized settings [3]. Obesity may alter chest wall mechanics, reduce diaphragmatic efficiency, and increase the work of breathing, all of which may contribute to worsening dyspnea and exercise intolerance in COPD patients [4]. Moreover, adipose tissue acts as an endocrine organ that releases pro-inflammatory cytokines, thereby exacerbating the chronic systemic inflammation already present in COPD [5].

T2DM, on the other hand, may contribute to COPD pathogenesis and progression through multiple mechanisms. Insulin resistance and hyperglycemia have been linked to impaired pulmonary function, increased oxidative stress, and a heightened risk of infections, all of which may potentiate acute exacerbations of COPD (AECOPD) [6]. Furthermore, diabetes may negatively affect the immune response, making COPD patients more susceptible to respiratory pathogens and resulting in more frequent or severe exacerbations [7]. The coexistence of COPD and diabetes is estimated to occur in 15–25% of patients, and evidence suggests this combination is associated with increased hospitalizations, prolonged recovery, and higher mortality [8].

The relationship between these metabolic disorders and the risk of AECOPD is of particular interest, as exacerbations are the primary driver of health care costs, decline in lung function, and deterioration in quality of life in COPD patients [9]. Recent studies indicate that patients with comorbid obesity and/or diabetes may experience a greater number of exacerbations annually and have higher rates of emergency visits and hospital admissions [10]. The exact mechanisms are multifactorial, involving systemic inflammation, impaired mucociliary clearance, microbiome alterations, and neurohormonal dysregulation.

Despite the known associations, the combined impact of obesity and diabetes on COPD exacerbation frequency has not been adequately addressed in routine clinical evaluations. Most management guidelines still approach COPD from a predominantly pulmonary perspective, without fully integrating metabolic risk assessments. Therefore, understanding the prevalence of these comorbidities and their potential to predict exacerbation risk may help stratify patients more accurately and guide comprehensive therapeutic interventions.

This study aims to evaluate the prevalence of obesity and diabetes in patients with COPD and to explore their correlation with the frequency and severity of exacerbations. By identifying these associations, clinicians may improve risk stratification and design more effective, multidisciplinary approaches to COPD care.

Study Design and Setting

This was a hospital-based, cross-sectional observational study conducted over a period of six months in the Pulmonology outpatient and inpatient departments of a tertiary care center.

Study Population

A total of 200 adult patients diagnosed with Chronic Obstructive Pulmonary Disease (COPD) as per the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were included. All patients had stable COPD at the time of recruitment. Patients with acute respiratory infections, bronchial asthma, interstitial lung disease, or those on long-term systemic steroids for other conditions were excluded.

Data Collection

After obtaining informed consent, detailed history and clinical examination were conducted. Demographic variables, smoking status, and comorbidities were recorded. Body Mass Index (BMI) was calculated using standard formula (weight in kg / height in m²) and categorized as per WHO guidelines. Diabetes mellitus was identified either through patient history, use of anti-diabetic medication, or HbA1c ≥6.5%. Number of exacerbations in the previous 12 months was recorded, including those requiring hospitalization or emergency department visits.

Pulmonary Function Testing

Spirometry was performed for all patients using a calibrated spirometer to determine FEV1, FVC, and FEV1/FVC ratio, post-bronchodilator.

Statistical Analysis

Data were analyzed using SPSS version 25.0. Continuous variables were expressed as mean ± SD, and categorical variables as frequencies and percentages. Correlation between obesity, diabetes, and exacerbation frequency was assessed using Pearson’s or Spearman’s correlation coefficients. A p-value <0.05 was considered statistically significant. Multivariate logistic regression was performed to identify independent predictors of frequent exacerbations.

Table 1: Baseline Characteristics of Study Population

Findings:
The study enrolled 200 COPD patients, with a mean age of 61.8 ± 9.4 years. Males constituted 68.5% of the sample, while 31.5% were females. A history of smoking was present in 72% of patients. Regarding BMI distribution, 26% were obese (BMI ≥30), 42% overweight (BMI 25–29.9), 28% normal weight, and 4% underweight. The prevalence of type 2 diabetes mellitus was found to be 38%, while hypertension coexisted in 41% of cases. The majority of patients belonged to GOLD Stage II (44%), followed by Stage III (31%).

Table 1: Baseline Characteristics of COPD Patients (n=200)

Table 2: Frequency of Exacerbations by BMI Category

Findings:
Patients categorized as obese had significantly more exacerbations in the past year compared to those with normal weight. Obese individuals experienced a mean of 2.7 ± 1.1 exacerbations per year, compared to 1.6 ± 0.9 among normal-weight patients. The correlation between BMI and exacerbation frequency was positive and statistically significant (p < 0.01).

Table 2: Number of Exacerbations by BMI Category

                                               *Statistically significant compared to normal weight group

Table 3: Exacerbation Frequency in Diabetic vs. Non-Diabetic Patients

Findings:
Patients with diabetes had a significantly higher mean number of exacerbations per year (2.5 ± 1.0) than non-diabetic patients (1.7 ± 0.8), with a p-value of <0.001. This suggests that diabetes may be a risk factor for more frequent COPD exacerbations.

Table 3: Exacerbations in Diabetic vs. Non-Diabetic COPD Patients

                                          *Statistically significant

Table 4: Multivariate Logistic Regression for Predictors of Frequent Exacerbations (≥2/year)

Findings:
In the multivariate logistic regression model, both obesity (OR: 2.14; 95% CI: 1.21–3.78) and diabetes (OR: 1.88; 95% CI: 1.09–3.26) were identified as significant independent predictors of frequent exacerbations. Smoking history and GOLD stage also showed significant associations.

Table 4: Predictors of Frequent Exacerbations (Logistic Regression)

                                             *Statistically significant

The findings of this study highlight a significant prevalence of both obesity and type 2 diabetes mellitus (T2DM) among patients with Chronic Obstructive Pulmonary Disease (COPD), underscoring the importance of recognizing metabolic comorbidities in respiratory care. With 26% of patients classified as obese and 38% identified as diabetic, the burden of these comorbidities appears to be substantial, especially considering their strong correlation with increased exacerbation risk.

Previous studies have shown that T2DM is more prevalent among COPD patients with severe and very severe disease, supporting the data observed in the current population [1]. The interaction between hyperglycemia and chronic inflammation contributes to impaired pulmonary defense mechanisms, enhancing susceptibility to infections and thus increasing the frequency of acute exacerbations [4,11]. Moreover, COPD patients with diabetes often present with higher levels of inflammatory biomarkers like high-mobility group box-1 (HMGB1), which are linked to systemic inflammation and poor respiratory outcomes [4].

Obesity has similarly been implicated in adverse outcomes in COPD. Although an “obesity paradox” has been proposed in literature—wherein mild obesity may offer protective survival benefits—this paradox does not extend to exacerbation frequency. On the contrary, obesity was significantly associated with higher exacerbation rates in this study, consistent with findings from earlier reports [3,12]. Increased abdominal fat compromises diaphragmatic mobility, exacerbates ventilation-perfusion mismatch, and promotes a systemic pro-inflammatory state, all of which contribute to worsening respiratory symptoms [13].

The co-occurrence of metabolic syndrome in COPD has also been recognized as a predictor of poor outcomes. Studies from both rural and urban Indian populations demonstrate high rates of metabolic syndrome among female COPD patients, with significant associations between increased BMI, waist circumference, and systemic inflammation [6]. These findings align with our results, wherein overweight and obese patients had significantly more frequent exacerbations than those of normal weight.

Importantly, diabetes and obesity were both found to be independent predictors of frequent exacerbations (≥2/year), even after adjusting for age, smoking history, and GOLD stage in multivariate analysis. This supports the hypothesis that metabolic dysregulation contributes to COPD morbidity beyond pulmonary mechanics alone [2,14].

Other contributing factors may include altered lipid metabolism and oxidative stress, which have also been associated with poorer clinical profiles in COPD patients with metabolic comorbidities [7,15]. Obesity and diabetes may also influence medication responses and complicate pharmacologic management, especially with the use of corticosteroids, which can worsen glycemic control and lead to fluid retention.

Considering these interactions, integrated care models that address both pulmonary and metabolic health are crucial. Early identification of obesity and diabetes in COPD patients, along with tailored interventions such as lifestyle modification, dietary guidance, and glycemic control, may reduce exacerbation rates and improve overall quality of life.

This study establishes that obesity and diabetes are prevalent comorbidities in COPD and significantly correlate with higher exacerbation frequency. Both conditions independently predict acute exacerbations, highlighting the need for routine metabolic screening in COPD management. Integrative, multidisciplinary approaches addressing both respiratory and metabolic components may improve long-term outcomes, reduce hospitalization, and enhance quality of life in this patient population.

1. Stojkovikj J, Zafirova-Ivanovska B, Kaeva B, Anastasova S, Angelovska I, Jovanovski S, et al. The Prevalence of Diabetes Mellitus in COPD Patients with Severe and Very Severe Stage of the Disease. Open Access Maced J Med Sci. 2016;4(2):253–8.
2. Lenártová P, Gažarová M, Mrázová J, Kopčeková J, Habánová M, Chlebo P, et al. Obesity, smoking status and their relationships in selected population groups. Rocz Panstw Zakl Hig. 2021;72(3):291–9.
3. Huang J, Zeng T, Tian Y, Wu Y, Yu J, Pei Z, et al. Clinical significance of high-mobility group box-1 (HMGB1) in subjects with type 2 diabetes mellitus (T2DM) combined with chronic obstructive pulmonary disease (COPD). J Clin Lab Anal. 2019;33(6):e22910.
4. Roy R, Gautam AK, Singh NP, Kumar A. Metabolic Syndrome and Its Correlates Among Female Chronic Obstructive Pulmonary Disease Patients at a Rural Tertiary Health Care Center in Northern India. Cureus. 2022;14(8):e28611.
5. Markelić I, Hlapčić I, Rogić D, Rako I, Samaržija M, Popović-Grle S, et al. Lipid profile and atherogenic indices in patients with stable chronic obstructive pulmonary disease. Nutr Metab Cardiovasc Dis. 2021;31(1):153–61.
6. Dudka I, Khukhlina O, Dudka T, Voyevidka O, Roshchuk O. Peculiarities of formation of carbohydrate metabolism disorders with comorbid chronic pancreatitis and chronic obstructive pulmonary disease. Wiad Lek. 2023;76(7):1586–93.
7. Meteran H, Backer V, Kyvik KO, Skytthe A, Thomsen SF. Comorbidity between chronic obstructive pulmonary disease and type 2 diabetes: A nation-wide cohort twin study. Respir Med. 2015;109(8):1026–30.
8. Figueira Gonçalves JM, García Bello MÁ, Golpe R, Alonso Jerez JL, García-Talavera I. Impact of diabetes mellitus on the risk of severe exacerbation in patients with chronic obstructive pulmonary disease. Clin Respir J. 2020;14(12):1208–11.
9. Lin L, Shi J, Kang J, Wang Q. Analysis of prevalence and prognosis of type 2 diabetes mellitus in patients with acute exacerbation of COPD. BMC Pulm Med. 2021;21(1):7.
10. Chen G, Lin Q, Zhuo D, Cui J. Elevated blood glucose is associated with severe exacerbation of chronic obstructive pulmonary disease. Int J Chron Obstruct Pulmon Dis. 2022;17:2453–9.
11. Zafirova-Ivanovska B, Stojkovikj J, Dokikj D, Anastasova S, Debresliovska A, Zejnel S, et al. The Level of Cholesterol in COPD Patients with Severe and Very Severe Stage of the Disease. Open Access Maced J Med Sci. 2016;4(2):277–82.
12. Mahishale V, Angadi N, Metgudmath V, Eti A, Lolly M, Khan S. Prevalence and impact of diabetes, hypertension, and cardiovascular diseases in chronic obstructive pulmonary diseases: A hospital-based cross-section study. J Transl Int Med. 2015;3(4):155–60.
13. Acharyya A, Shahjahan MD, Mesbah FB, Dey SK, Ali L. Association of metabolic syndrome with chronic obstructive pulmonary disease in an Indian population. Lung India. 2016;33(4):385–90.
14. Castañ-Abad MT, Montserrat-Capdevila J, Godoy P, Marsal JR, Ortega M, Alsedà M, et al. Diabetes as a risk factor for severe exacerbation and death in patients with COPD: a prospective cohort study. Eur J Public Health. 2020;30(4):822–7.
15. Selim S, Alam MS, Talukder SK, Kabir ML, Gaffar AJ, Kabir MA, et al. Status of lipid control in Bangladeshi subjects with type 2 diabetes mellitus on lipid-lowering drugs: a multicenter, facility-based, cross-sectional study. BMC Endocr Disord. 2023;23(1):268.