Abstract:Objective To study the relationship of serum Ang-2 and PGRN with prognosis of elderly patients with severe pneumonia complicated with respiratory failure treated with nasal high-flow nasal canal humidification oxygen therapy.Methods Totally 302 elderly patients with pneumonia complicated with respiratory failure treated in our hospital from April 2017 to February 2020 were selected as the observation subjects. According to the 28-day prognosis of the patients, they were divided into survival group (n =224) and death group (n =78). The baseline data between the two groups were analyzed by univariate analysis, and logistic regression analysis was used to analyze the statistically significant differences between the two groups. The prognostic value of serum Ang-2 and PGRN was evaluated by the receiver working characteristic curve.Results The expression of serum Ang-2 and PGRN were decreased follow the time after treatment (P < 0.05). Ang-2 and PGRN were lower in the survival group compared with the death group at different time points (P < 0.05), and the gradual decline trend was also different (P < 0.05). There were significant differences in white blood cell count, lymphocyte count, neutrophil count, interleukin-10, interleukin-6, C-reactive protein, procalcitonin, and APACHE II score between the two groups (P <0.05); Logistic regression analysis showed that APACHE II score [O^R = 1.379 (95% CI: 1.094, 1.737)], serum Ang-2 before treatment [O^R = 2.255 (95% CI: 1.810, 2.808)], and serum PGRN before treatment [O^R = 1.493 (95% CI: 1.206, 1.849)] were independent risk factors for poor prognosis (P < 0.05); according to the ROC curve, the critical value of serum Ang-2 diagnosis was 4.10 ng/ml, the corresponding sensitivity was 69.64%, the specificity was 61.54%, and the AUC was 0.790 (95% CI: 0.735, 0.846); the critical value of serum PGRN diagnosis was 133.27 mg/L, the corresponding sensitivity was 70.54%, and the specificity was 62.82%, and the AUC was 0.764 (95% CI: 0.710, 0.818). At the critical tangent point, the sensitivity of parallel joint detection was 84.82%, the specificity was 58.97%, and the AUC was 0.872 (95% CI: 0.834, 0.911), all of them had predictive value.Conclusion The level of serum Ang-2 and PGRN were related to the prognosis, thus monitoring their level had important clinical significance for the diagnosis, treatment, and prognosis of patients with severe pneumonia complicated with respiratory failure.