To analyze the correlation between systemic immune-inflammation index (SII) and severity of moderate-severe patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

A total of 174 patients with AECOPD hospitalized in respiratory wards of Shanghai Yangsi Hospital and Shanghai Pudong New District Punan Hospital from March, 2023 to March, 2024 were selected as study participants. According to severity of AECOPD, all the participants were divided into control group (n=90), and observation group (n=84). Routine blood test, serum C-reactive protein (CRP), serum procalcitonin (PCT), arterial blood gas analysis, dyspnea scores, and SII, were recorded for two groups, at admission and 10 days after admission. The abovementioned parameters were compared between two groups, before and after treatment. Correlation between the SII and other parameters was analyzed.

At the admission, control group SII (1 354.5±324.5)×10⁹/L, CRP(60.2±16.4)mg/L, PCT(3.26±0.58)ng/ml, pH(7.18±2.11), PaO₂(55.9±13.8)mmHg, PaCO₂(56.6±16.8)mmHg, oxygenation index(266.4±60.2)mmHg、dyspnea score (2.54±0.51). observation group(1 892.3±511.2)×10⁹/L, (78.3±20.1)mg/L, (7.32±2.21)ng/ml, (7.09±2.16), (46.5±11.4)mmHg, (76.5±23.4)mmHg, (222.1±45.5)mmHg, (3.44±0.66); 10 days after the admission, control group SII (667.1±156.1)×10⁹/L, CRP(25.4±5.4)mg/L, PCT(1.49±0.39)ng/ml, pH(7.34±2.32), PaO₂(76.2±18.8)mmHg, PaCO₂(45.7±14.2)mmHg, oxygenation index(362.8±88.7)mmHg, dyspnea score(1.08±0.36), observation group(987.2±261.3)×10⁹/L, (33.2±10.9)mg/L, (2.11±0.90)ng/ml, (7.32±2.21), (66.2±15.3)mmHg, (55.3±17.8)mmHg, (318.3±73.5)mmHg, (2.15±0.59). There were statistical differences between pairwise comparison among the control group and observation group, in the SII, serum CRP, serum PCT, pH, PaO₂, PaCO₂, oxygenation index and dyspnea score, at the admission and 10 days after the admission, respectively (P<0.05). The abovementioned parameters at the admission were statistically different from those 10 days after the admission, in each group (P<0.05). The SII was positively correlated with the serum CRP, PCT, PaCO₂ and dyspnea score, whereas negatively correlated with the pH, PaO₂ and oxygenation index, at the admission and 10 days after the admission, for the two groups. In the observation group, 74 cases survived(88.10%), 10 cases death (11.90%). In the control group, 88 cases survived(97.78%), 2 cases death (2.22%), the mortality rate of the observation group was statistically higher than control group (P<0.05).

There is a definite positive correlation between SII and severity of moderate-severe patients with AECOPD. The severer the AECOPD, the higher the SII.