Similarly, SpO2 was significantly lower in patients with clubbing in the CTD-ILD group (93 ± 2.5 (N = 6) versus 96.6 ± 0.3 (N = 38); p=0.004), serum KL-6 was significantly higher (2262 ± 547.4 U/mL (N = 6) versus 969.7 ± 108.2 U/mL (N = 43); p=0.0006), and pulmonary function test results were significantly lower in those with clubbing (%DLCO: 45.3 ± 4.1 (N = 6) versus 73.5 ± 4.2 (N = 33); p=0.008). Here, MUC1 is linked to interstitial lung disease.