From severity prediction to respiratory-support resource planning in mNGS-confirmed chlamydia psittaci pneumonia: a cohort study

Objective To develop a preliminary framework for anticipatory respiratory-support resource planning in mNGS-confirmed Chlamydia psittaci pneumonia (CPP), integrating conventional severity indicators, RALE score, and exploratory Wei-Factor. Secondary aim: describe clinical, laboratory, imaging, and treatment-related resource occupancy. Methods In this retrospective study, 51 CPP patients admitted to Jiangmen People's Hospital (January 2019–April 2026) were divided into advanced respiratory support (NIV/IMV due to oxygenation index <300 or clinical respiratory failure) and no advanced support (conventional oxygen or HFNC alone). We analyzed risk factors, treatment response, and resource indicators. Results Among 51 patients, 76.47% had avian exposure, 78.43% were ≥50 years, and no deaths occurred. Advanced support was required in 33.3% (17/51). Associated factors included older age (67.35 ± 13.28 years), smoking (58.82%), chronic respiratory disease (29.41%), elevated D-dimer, and higher RALE score ( P < 0.05). Imaging mainly showed patchy high-density shadows (92.16%), often bilateral or consolidative. RALE score correlated with PCT. Wei-Factor correlated with RALE but not with PCT.Wei-Factor was positive in all patients but did not differ between groups ( P = 0.899). Fever resolution time differed significantly among regimens (overall P = 0.044), with the azithromycin group showing the shortest numerical time (1.20 ± 1.10 days) and the moxifloxacin plus doxycycline group showing 1.36 ± 0.51 days. Hospital stay did not differ ( P = 0.389). Due to non-randomized design and confounding by indication, no regimen superiority can be concluded. Conclusion CPP has atypical presentation but predictable severe trajectory. For hospital administrators, age, smoking history, chronic respiratory disease, D-dimer, and RALE score should guide early identification of high-risk patients and proactive allocation of high-flow oxygen, NIV/IMV, and ICU beds. RALE may serve as an adjunct monitoring tool. Wei-Factor remains preliminary and should not be used for resource planning; larger prospective validation is needed.