Curriculum hierarchies as conversion factors: career guidance, capability, and inequality in South African schools: a conceptual review.

Chronic Obstructive Pulmonary Disease (COPD) is a common respiratory disease characterized by persistent airflow limitation, with acute exacerbation being a critical event in its disease course (). Acute exacerbations not only accelerate lung function decline but also significantly increase the risk of rehospitalization and mortality (). Previous studies have primarily focused on triggers and treatment strategies for acute exacerbations, while understanding of the dynamic patterns of symptom changes during recovery remains insufficient (). Clinical practice has revealed substantial individual variation in recovery trajectories following acute exacerbation, with some patients experiencing prolonged or recurrent symptoms (). AECOPD is frequently precipitated by respiratory infections that can drive systemic inflammatory responses; in a subset of patients, this dysregulated host response fulfills Sepsis-3 criteria—defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, identified by an acute SOFA score increase of ≥2 points (). Sepsis-related systemic inflammatory activation, reflected by biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT), may compromise airway repair mechanisms and impede symptom resolution. However, as complete SOFA data (including hepatic, renal, cardiovascular, and neurological sub-scores) were not systematically collected in this study, formal Sepsis-3 classification was not feasible; CRP and PCT are used herein as surrogate biomarkers of systemic inflammatory burden alongside the available respiratory SOFA sub-score. Identifying different symptom recovery patterns and their prognostic significance is of great value for developing individualized follow-up protocols (). This study employed Group-Based Trajectory Modeling (GBTM) to investigate symptom trajectory types during Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD) recovery and their association with prognosis, with particular attention to the role of systemic inflammatory burden in shaping recovery heterogeneity. This study enrolled AECOPD patients hospitalized in the Department of Respiratory Medicine at our hospital between January 2023 and December 2024. The study protocol was approved by the hospital ethics committee. Inclusion criteria: (1) Meeting the 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) diagnostic criteria, i.e., post-bronchodilator Forced Expiratory Volume in 1 s (FEV1)/Forced Vital Capacity (FVC) < 0.70; (2) Meeting AECOPD diagnostic criteria, i.e., acute worsening of respiratory symptoms (dyspnea, cough, and/or sputum production) beyond normal day-to-day variations requiring medication change; (3) Age ≥40 years; (4) Hospital stay ≥48 h to ensure adequate acute treatment and sufficient time for baseline symptom assessment; (5) Completion of at least 12 months of follow-up after discharge.