Association between handgrip strength and small airway disease in patients with stable chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) is associated with airflow limitation resulting from a combination of small airway disease (SAD) and parenchymal destruction. Although various diagnostic methods for SAD exist, access to these tools can be limited.Objectives: This study aimed to explore the correlation between handgrip strength (HGS) and SAD in COPD patients.Design: Cross-sectional prospective study.Methods: HGS was measured using a hand dynamometer. SAD was evaluated using impulse oscillometry, with results reported as the difference between respiratory resistance at 5 and 20 Hz (R5-R20). SAD was defined as R5-R20 >= 0.07 kPa/L/s. The receiver operator characteristic (ROC) curves, sensitivity, and specificity values were calculated to determine the optimal cutoff value of HGS for predicting SAD.Results: Sixty-four patients (90.6% male) were included. The average age was 72.1 +/- 8.3 years, and body mass index was 23.4 +/- 4.2 kg/m2. FEV1 was 71.6 +/- 21.3%, and HGS was 30.2 +/- 8.1 kg. R5-R20 was 0.11 +/- 0.08 kPa/L/s. SAD was found in 64.1% of patients. A negative correlation between HGS and R5-R20 was observed (r = -0.332, p = 0.007). The best cutoff value for HGS in detecting SAD was determined to be 28.25 kg, with a sensitivity of 73.9%, specificity of 65.9%, and an area under ROC curve of 0.685 (95% CI 0.550-0.819, p = 0.015).Conclusion: SAD is common in COPD patients, and HGS is significantly negatively correlated with SAD. This tool might serve as an alternative or adjunctive assessment for small airway dysfunction in COPD patients.Registration: This study was registered with ClinicalTrials.gov with number NCT06223139. Association of handgrip strength with small airway disease in COPDIn chronic obstructive pulmonary disease (COPD), the condition of small airways (those less than 2 mm wide) is closely linked to disease severity. Small airway disease (SAD) leads to reduced lung function, increased retention of excess gas in the lung, and poorer health in COPD patients. While various diagnostic methods exist for SAD, they may not always be accessible. This study investigated handgrip strength as a potential alternative way to assess SAD. Our findings show a significant negative correlation between handgrip strength and SAD in COPD patients. This suggests that handgrip strength could be used alongside existing methods to evaluate small airway dysfunction in these patients.