The Significance of Assessing Quadriceps Contractile Index in COPD Patients

The respiratory system is not the only organ system affected by chronic obstructive pulmonary disease (COPD); muscle mass is also impacted. As skeletal and respiratory muscles deteriorate, ventilation, the severity of the illness, and clinical symptoms are all negatively impacted. According to recent studies, ultrasonography is a dependable and user-friendly method for determining the quadriceps contractile index (Qci) in patients with COPD. Objective: Evaluate the Qci by ultrasound in patients with COPD and correlate with different clinical, 6-minute walk test (TM6), and ventilatory variables. Methods: We conducted a prospective, observational study from 2021 to 2024. A total of sixty-one consecutive patients with spirometry-confirmed stable COPD were included after obtaining informed written consent. Demographic and clinical data, spirometric values, the modified Medical Research Council (mMRC) dyspnea score, TM6, COPD assessment test (CAT), Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification 2023, and measurement of Qci were collected for analysis. This is a prospective study conducted at Constantine Regional Military University Hospital. Results: The mean total quadriceps muscle thickness (Qthick) in our patients with COPD is 1.95 ± 0.85 cm. The mean Qci in our patients with COPD is 68 ± 9%. A negative correlation has been reported between Qci and the dyspnea mMRC, P = 0,010. Patients in group E according to GOLD 2023 constitute more than half of our cohort, representing 54.1% of cases. A negative correlation has been reported between Qci and the stage of GOLD 2023 classification, P = 0,010. In our study, a correlation between the Qci and spirometric data (FVC, FEV1) was objectified with P < 0,001 and FEV1/FVC P = 0,008. The average distance travelled in the TM6 test was 470 129.37 m. Our study has shown that the more EXdi increases, the distance patients travel increases (P = 0,001). Conclusion: In patients with COPD, the Qci appears to be associated with airway obstruction, TM6, CAT score, as well as perception of dyspnea.