D) Diffuse involvement. The distribution of disease severity was mild in 40.9% (n 221), severe in 53.7% (n 290), and critical in 5.4% (n 29) of patients (Table 3). The median patient age was significantly lower among patients with mild disease than among patients with severe or critical disease (p 0.001 for both comparisons). In this study, there were more male patients (55.9%) than female patients (44.1%). However, no significant sex-related difference was observed in terms of disease severity (p 0.178). Smoking frequency (ie, median packs/year) was significantly lower in patients with mild disease than in patients with severe or critical disease (p 0.001 and p 0.016, respectively). Table 3 Comparisons of Age, Sex, Smoking, Vital Signs and Risk Score in Patient Groups Classified According to the Disease Severity (Mild, Moderate, and Severe)