A Retrospective Study on Clinical Characteristics and Outcomes of Patients With Pneumonia

Retrospective Analysis of Clinical Characteristics and Prognostic Factors in Hospitalized Pneumonia Patients from April 2023 to April 2026. Background: Pneumonia remains the leading cause of death from infectious diseases in adults worldwide, with an increasingly severe disease burden exacerbated by population aging and the frequent emergence of drug-resistant bacteria; in China, severe pneumonia accounts for a striking 13.58% to 20.05% of hospitalized cases. In recent years, shifts in the pathogen spectrum (e.g., COVID-19, influenza A) and patient demographic characteristics have posed new challenges for clinical management. However, existing studies mostly focus on single pathogens or specific populations (e.g., ICU patients), lacking systematic analyses of the full-disease course characteristics of general hospitalized pneumonia patients. Furthermore, in the post-pandemic era, the clinical phenotypes, treatment responses, and prognostic factors of pneumonia may have evolved, necessitating evidence-based support from real-world data. This study aims to conduct a retrospective analysis to clarify the epidemiological characteristics, etiological distribution, and prognostic factors influencing current hospitalized pneumonia patients, thereby providing a basis for optimizing diagnosis and treatment strategies.

Study Overview

• Status: Not yet recruiting
• Conditions: Pneumonia

• Study Type: Observational
• Enrollment (Estimated): 500

Contacts and Locations

• Study Contact: Name: Liang Peng, Doctor; Phone Number: 86-020-85959142; Email: pl_206@126.com

Study Locations

• China
  • Guangzhou, China
    • Fifth Affiliated Hospital of Guangzhou Medical University
    • Contact: Liang Peng, Doctor; Phone Number: 86-020-85959142; Email: pl_206@126.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

From April 2023 to April 2026, all adult patients who were hospitalized due to pneumonia and met the diagnostic criteria

Description

Inclusion Criteria:

1. Age ≥ 18 years old;
2. Meet the diagnostic criteria for pneumonia (acute onset + new infiltrates on imaging);
3. Have a positive result from pathogen testing;
4. Time from onset to admission ≤ 72 hours (to ensure being in the acute phase of the disease);

5. Sign a written informed consent form.

   Inclusion criteria for the severe group:

   A diagnosis of "severe pneumonia" can be made if one of the main criteria or ≥ 3 of the secondary criteria are met.

   Main criteria:

   ① Tracheal intubation requiring mechanical ventilation

   ② Need for vasoactive drugs after active fluid resuscitation for septic shock

   Secondary criteria:

   • Respiratory rate ≥ 30 breaths/min

     • PaO₂/FiO₂ ≤ 250 mm Hg

       • Multiple lobe infiltrates

         • Confusion and/or disorientation ⑤ Blood urea nitrogen ≥ 20 mg/dL

           ⑥ Leukopenia (WBC < 4×10⁹/L)

           • Thrombocytopenia (PLT < 100×10⁹/L)

             • Decreased body temperature (central body temperature < 36 ℃) ⑨ Hypotension requiring fluid resuscitation

   Exclusion Criteria:

   • 1) Patients with severely lacking medical records;

2) Those whose main manifestations are other non-infectious diseases (such as pulmonary edema, lung cancer, pulmonary embolism, etc.); 3) Those whose main diagnosis is active pulmonary tuberculosis, non-infectious interstitial lung disease, etc.; 4) Patients considered not applicable by the researchers.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
pneumonia

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
28-day all-cause mortality rate	28 days after admission

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Demographic characteristics	Demographic data (age, sex, etc.)	28 days after admission
Comorbidities	Comorbidities, such as chronic obstructive pulmonary disease (COPD), diabetes mellitus, and cardiovascular diseases.	28 days after admission
Symptomatic manifestations	Symptomatic manifestations (e.g., fever, cough, dyspnea)	28 days after admission
Laboratory tests	Laboratory tests (including blood routine, liver and kidney function, etc.)	28 days after admission
Imaging Examination	Imaging Examination: Radiological manifestations and image data from chest X-ray or CT scans	28 days after admission
ICU Length of Stay		28 days after admission
Duration of Mechanical Ventilation		28 days after admission
Length of Hospital Stay		28 days after admission

Other Outcome Measures

Outcome Measure	Time Frame
Utilization of Antimicrobial Agents	28 days after admission
Clinical Outcomes (cured, improved, deceased)	28 days after admission

Collaborators and Investigators

• Sponsor: Zhonghao Fang
• Collaborators: Fifth Affiliated Hospital of Guangzhou Medical University
• Investigators: Study Director: Zifeng Yang, The First Affiliated Hospital of Guangzhou Medical University

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: April 28, 2026
• First Submitted That Met QC Criteria: May 5, 2026
• First Posted (Actual): May 8, 2026

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: pneumonia
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Respiratory Tract Diseases; Lung Diseases; Pneumonia
• Other Study ID Numbers: P-2026-003

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Due to concerns over patient privacy and confidentiality issues, the individual patient data (IPD) cannot be shared.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No