CRP and chronic obstructive pulmonary disease: Baseline IL-6 showed a trend toward higher levels in the ≥3-session group (305.5 pg/mL, IQR 53.2–1306.3) than in the 1-session (143.1 pg/mL) or 2-session (37.0 pg/mL) groups (p = 0.056), while baseline CRP and comorbidities such as diabetes, hypertension, obesity, and COPD were similarly distributed (all p > 0.28).