As shown in Table 1, no significant correlation (p = 0.209) was observed between higher surfactant protein D (SP-D) levels of 4.96 ng/mL (IQR 3.26–7.96) in COPD patients as compared to 3.64 ng/mL with an IQR of 2.60–8.59 in controls. Here, SFTPD is linked to chronic obstructive pulmonary disease.