Insulin resistance as a systemic complication of chronic obstructive pulmonary disease

Abstract

The aim of this study is to examine the mechanisms of insulin resistance (IR) as a systemic complication in patients with chronic obstructive pulmonary disease (COPD) and to evaluate its prevalence in relation to disease severity, clinical characteristics, and standard therapy, specifically the use of inhaled corticosteroids (ICS).

Materials and methods. We examined 151 patients with COPD (mean age 55.2 ± 8.8 years; 85.4 % men) and 40 control subjects without respiratory pathology. Fasting glucose, insulin, and glycated hemoglobin (HbA1c) levels were determined, and the HOMA-IR was calculated. All patients underwent spirometry; clinical data including smoking history, body mass index (BMI), disease duration, and ICS use were documented. Statistical analysis was performed using correlation and comparative methods.

Results. Patients with COPD demonstrated significantly higher levels of insulin (9.4 ± 1.8 mU/L vs. 8.3 ± 0.3 mU/L, p < 0.05), HbA1c (6.1 ± 0.3 % vs. 5.0 ± 0.4 %, p < 0.05), and HOMA-IR (2.2 ± 1.1 vs. 1.4 ± 0.1, p < 0.05) compared to the control group. IR (defined as HOMA-IR ≥ 2.5) was identified in 31.8 % of patients. HOMA-IR statistically significantly correlated with BMI (R = 0.4, p < 0.05) and showed a significant, albeit weak, association with COPD duration (R = 0.1, p < 0.01) and smoking history (R = 0.3, p < 0.05). Elevated HOMA-IR was accompanied by a significant increase in C-reactive protein levels (18.4 ± 3.9 mg/L vs. 7.6 ± 0.1 mg/L, p < 0.01), indicating the role of systemic inflammation in metabolic disturbances. Furthermore, a strong dose-dependent correlation was found between HOMA-IR and both the duration and dosage of ICS therapy (R = 0.7, p < 0.05), suggesting that long-term or high-dose ICS use may contribute to metabolic dysfunction.

Conclusions. Patients with COPD, even in the absence of concomitant diabetes mellitus, exhibit signs of dysglycemia and insulin resistance. Key risk factors include obesity, smoking, disease duration, and treatment with inhaled corticosteroids. Regular monitoring of HOMA-IR and HbA1c is recommended for the early detection of metabolic risks and timely adjustment of therapy.