Introduction
Chronic obstructive pulmonary disease (COPD) is a worldwide public health problem and one of the leading causes of mortality and morbidity [1,2]. Acute exacerbation of COPD (AECOPD), a severe status of COPD, is characterized by worsening of respiratory manifestations and was associated with increased mortality [3,4]. It was reported that AECOPD accounted for about 13% of all admitted patients [5]. Mounting evidence showed that length of hospital stay (LHS) was independently associated with the severity of AECOPD [6]. Although the risk factors for hospitalization in AECOPD were well explored [7-10], the predictors for prolonged LHS in AECOPD patients were still not very clear.
In developing countries, AECOPD causes a heavy burden on the health care system [11,12]. The direct and indirect costs of AECOPD at least include health care resources devoted to the diagnosis, illness management, workability loss, premature mortality, and family caregiver costs [13,14]. Dalal AA, et al. found that the average cost was $9,745 for standard admission, and $33,440 for an ICU stay in hospitalized AECOPD patients [2]. Chen YH, et al. showed that length of ICU stay, non-invasive or invasive ventilation intervention, and use of antibiotics and systemic steroids were the major predictors of hospitalization costs in AECOPD [15]. Therefore, LHS was noticeably associated with the medical costs of hospitalized AECOPD patients.
LHS was essential for the prediction of AECOPD severity [8,16-18]. However, the threshold of prolonged LHS in AECOPD was still in controversy [8,17,18]. In a cohort study, Mushlin AI et al. showed that the mean LHS was 6 to 7 days in AECOPD patients [19]. They also found that longer LHS was associated with increased PCO2levels, symptoms of more than 1 day, and antibiotic treatment at the time of admission. In another prospective study, Crisafulli E et al. divided the AECOPD patients into normal (≤7 days) and prolonged LHS (>7 days) groups [20]. Their results showed that prolonged LHS were independently associated with mMRC (modified Medical Research Council) dyspnea score ≥2 and the presence of acute respiratory acidosis. In a retrospective study, 8 days were obtained to define the prolonged LHS in hospitalized AECOPD [17]. Meanwhile, in a prospective cohort study, 9 days was used as the threshold of prolonged LHS in AECOPD [18]. They revealed that baseline dyspnea, physical activity level, and hospital variability were the independent predictors of prolonged LHS in hospitalized AECOPD patients. Simultaneously, Wang Y, found that LHS above the 75th percentile was 11 days in AECOPD patients. And, they also identified that admission between Thursday and Saturday, heart failure, diabetes, stroke, high arterial PCO2, and low serum albumin level were independently associated with prolonged LHS in AECOPD patients.
Collectively, in our study, 7 days and 11 days were used as the thresholds of mild prolonged LHS and severe prolonged LHS in AECOPD patients, respectively. The purpose of this cross-sectional study was to identify the independent risk factors for prolonged LHS in hospitalized AECOPD patients.