Effect Of Type 2 Diabetes Mellitus on the Pulmonary Functions of the Patient and Their Association with Glycemic Control at Tertiary Care Institute of Northern India

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a systemic metabolic disorder associated with chronic hyperglycemia that affects multiple organ systems. The lungs, though not classically recognized as a target organ, may exhibit functional impairments due to microvascular damage and non-enzymatic glycation of connective tissue. This study aimed to evaluate the correlation between glycemic control and pulmonary function tests (PFTs) in T2DM patients.

Objectives: To assess pulmonary function parameters in patients with T2DM and to correlate these findings with glycemic control as measured by glycated hemoglobin (HbA1c).

Materials and Methods: A cross-sectional study was conducted involving 100 T2DM patients attending the outpatient department of a tertiary care hospital. Pulmonary function was assessed using spirometry, recording Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 second (FEV₁), FEV₁/FVC ratio, Peak Expiratory Flow Rate (PEFR), and Forced Expiratory Flow 25–75% (FEF₂₅–₇₅%). Glycemic control was evaluated through HbA1c levels. Patients were categorized into good (HbA1c ≤7%) and poor (HbA1c >7%) glycemic control groups.

Results: A statistically significant reduction in FVC, FEV₁, PEFR, and FEF₂₅–₇₅% was observed in patients with poor glycemic control compared to those with good control (p < 0.05). The most common pattern observed was a restrictive ventilatory defect. A negative correlation was found between HbA1c levels and pulmonary function parameters, indicating worsening lung function with increasing glycemic levels.

Conclusion: Pulmonary function is significantly impaired in T2DM patients, especially among those with poor glycemic control. Routine pulmonary function testing may be beneficial in the early detection of subclinical lung involvement in diabetic patients.