Prolonged stay predictors in patients admitted with chronic obstructive pulmonary disease acute exacerbation

316 © 2018 Indian Chest Society | Published by Wolters Kluwer - Medknow COPD management across hospitals[4] and countries.[5] Such variability partly depends on the characteristics of both patients and admitting hospitals. Identifying the factors influencing mean stay could improve resource use and efficiency. The aim of this study is to identify the factors related to prolonged stay in those patients admitted with AECOPD to our hospital. INTRODUCTION With high prevalence, chronic obstructive pulmonary disease (COPD) is a major health care issue globally.[1] Acute exacerbations of COPD (AECOPD) are frequent in the course of the disease, they are associated with high morbidity and mortality,[1,2] and they account – especially those acute exacerbation episodes requiring hospitalization – for a large share of treatment costs.[1] Admission costs partly depend on the length of stay.[3] Previous studies have shown great variability in Original Article Objectives: The study aimed to identify the factors related to prolonged stay in those patients admitted with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) to our hospital. Methods: We conducted a retrospective study by reviewing the medical records of all patients admitted with AECOPD to the University Hospital Complex of Santiago de Compostela in 2007 and 2008. To identify variables independently associated with length of stay, we conducted a logistic regression including those variables which proved to be significant in the univariate analysis. Results: Six hundred and sixty‑one patients were assessed; 76.6% were male and the mean age was 74.5 years (standard deviation [SD]: 11.48). The mean stay was 11.9 days (SD: 8) and 24% of all patients required prolonged stay. Factors associated with prolonged mean stay in multivariate analysis were admission to the Intensive Care Unit (odds ratio [OR], 14.7), hospitalization by internal medicine (OR, 2.1), and use of noninvasive mechanical ventilation (OR, 1.75). Conclusions: Prolonged stay in AECOPD is primarily related to the unit patients are admitted to, and to the need for more intensive care. KEY WORDS: Chronic obstructive pulmonary disease exacerbation, hospital admission, predictors, prolonged stay Prolonged stay predictors in patients admitted with chronic obstructive pulmonary disease acute exacerbation María‑Teresa García‑Sanz, Francisco‑Javier González‑Barcala1,2,3,4, Juan‑Carlos Cánive‑Gómez5, Nuria García‑Couceiro6, Sara Alonso‑Acuña6, José‑Martín Carreira7 Department of Emergency, Salnés County Hospital, Vilagarcía de Arousa, 1Department of Medicine, University of Santiago de Compostela, 2Spanish Biomedical Research Networking Centre‑CIBERES, Barcelona, 3Department of Respiratory Medicine, University Hospital Complex of Santiago de Compostela, 4Health Research Institute of Santiago de Compostela, 5Family and Community Medicine, Pontevedra, 6Nursing Staff, University Hospital Complex of Santiago de Compostela, 7Department of Radiology, University Hospital Complex of Santiago de Compostela, Spain ABSTRACT Address for correspondence: Dr. Francisco‑Javier González‑Barcala, Department of Respiratory Medicine, University Hospital Complex of Santiago de Compostela, Travesía da Choupana sn 15706 Santiago de Compostela, Spain. Email: [email protected] How to cite this article: García-Sanz MT, González-Barcala FJ, Cánive-Gómez JC, García-Couceiro N, Alonso-Acuña S, Carreira JM. Prolonged stay predictors in patients admitted with chronic obstructive pulmonary disease acute exacerbation. Lung India 2018;35:316-20. This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. For reprints contact: [email protected] Access this article online Quick Response Code: Website: www.lungindia.com DOI: 10.4103/lungindia.lungindia_469_17 García‑Sanz, et al.: Pronlonged stay predictors in COPD exacerbation Lung India • Volume 35 • Issue 4 • July-August 2018 317 METHODS Ethical approval All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. As it is a retrospective study, formal consent is not required. We conducted a retrospective study by reviewing the medical records of all patients admitted with AECOPD to the University Hospital Complex of Santiago de Compostela in 2007 and 2008. Data were retrieved from the hospital database and included all patients admitted to the internal medicine unit (IMU) and pneumology unit. For each patient, we reviewed the first admission with AECOPD in the study period, and we excluded all those patients with different reasons for admission, such as pneumonia or acute pulmonary edema, as well as those deceased during admission. The study sample includes 661 patients, whose baseline characteristics, comorbidities, AECOPD characteristics, and analyses conducted both at the emergency department (ED) and during the stay were recorded. COPD diagnosis and baseline severity were defined following GOLD criteria.[6] In those cases with no spirometry available, COPD diagnosis was accepted by consensus of the research team for patients with a smoking history and clinical and radiological characteristics consistent with such diagnostic hypothesis.[1,7] Patients who had quitted smoking at least a year before the moment of admission were considered former smokers.[8] Alcohol users were sorted into four different categories: those consuming over 1 g alcohol/day (regular drinkers),[9] those consuming <1 g alcohol/day (occasional drinkers), those who quitted at least a year before (former drinkers),[10] and never drinkers. Comorbidity was assessed with the Charlson index[11] and categorized into three groups: patients scoring “0,” “1 or 2,” and “over 2” points, respectively. COPD baseline therapy was noted: short‑acting and long‑acting beta2‑agonist inhalers, oral or inhaled corticosteroids, anticholinergics, theophylline, oxygen therapy, and noninvasive mechanical ventilation (NIV) at home. The use of at least 5 mg prednisone/day for at least 3 months in a row was considered chronic steroid therapy.[12] Weekends were defined as the period between Friday midnight and Sunday midnight.[13] Patients with prolonged stay were identified as those staying over the 75th percentile of length of stay in our sample, in our case 14 days.[14] Vital signs and arterial blood gas values were obtained upon patient arrival to the ED. In those cases where no blood gas was determined, a record of O2 saturation by pulse oximetry was obtained. Data from the CBC and serum biochemistry tests conducted on the first sample obtained upon arrival to the hospital were recorded. Statistical analysis Data obtained were expressed as mean values ± standard deviation (SD) for continuous variables and as frequencies and percentages for categorical variables. Continuous variables were compared with either Student’s t‑test or with Wilcoxon’s test; as for categorical variables, they were compared with the Chi‑squared and Fisher’s exact tests. To identify variables independently associated with length of stay, we conducted a logistic regression including those variables with P ≤0.05intheunivariate analysis. We considered statistically significant those variables associated with P < 0.05. Data were analyzed with SPSS 15. RESULTS A number of 661 patients were assessed; 76.6% were male and the mean age was 74.5 years (SD: 11.48). The mean stay was 11.9 days (SD: 8), and 24% of all patients required prolonged stay (14 days). Patients’ baseline characteristics are shown in Table 1. Acute exacerbation characteristics and complementary test results are shown in Table 2. The following factors were significantly associated with prolonged stay: older age (P = 0.02), chronic kidney disease (P = 0.008), hospitalization by the IMU (P < 0.0001), lower hemoglobin count (P = 0.001), need for admission to the Intensive Care Unit (ICU) (P < 0.0001), and the need for NIV (P = 0.04). Factors associated with prolonged mean stay in multivariate analysis were admission to the ICU, hospitalization by the IMU, and the need for NIV [Table 3]. DISCUSSION Prolonged stay may identify more fragile patients who may need more careful attention.[15] The parameters better identifying prolonged stay in our study are primarily related to the unit patients are admitted to, and to the need for more intensive care. By patients with AECOPD, severe dyspnea unresponsive to treatment, altered state of consciousness, PO2 worsening, acidosis, the need for mechanical ventilation, and hemodynamic instability are considered indicators of admission to the ICU.[1] This is, admission to the ICU seems related to AECOPD severity, to the occurrence of AECOPD‑related complications, or to the decompensation of preexisting comorbidities.[16,17] 2.6% of all our patients required admission to the ICU. As baseline characteristics in these patients did not differ from those admitted to the conventional hospitalization ward, it seems reasonable to attribute ICU admission to AECOPD severity or to the García‑Sanz, et al.: Pronlonged stay predictors in COPD exacerbation 318 Lung India • Volume 35 • Issue 4 • July-August 2018 occurrence of complications. Previous studies related prolonged stay to mechanical ventilation and to the occurrence of complications during stay.[18,19] With ICU admission figures similar to ours, Quintana et al. found an association between length of stay due to AECOPD and the stay in the ICU in their study.[14] This is, AECOPD severity – and not COPD baseline severity – seems to affect the mean length of stay. In our study, patients with AECOPD admitted to the IMU stayed longer compared to those admitted to the pneumology unit. Several factors could at least partially explain these differences: on the one hand, patients admitted to the ICU were older and scored more frequently higher in the Charlson Index, and older age and number of comorbidities had both been associated with longer stays in previous studies.[20] The percentage of patients with atrial fibrillation and ischemic heart disease was higher among those admitted to the IMU; both conditions are subject to decompensation with beta2‑agonist and anticholinergics used to treat AECOPD, and subsequent complications could affect the length of stay.[21‑23] However, the contribution by these factors does not seem relevant in our patients, since none of them was independently related to longer stays, as shown in the multivariate analysis. On the other hand, AECOPD management by pneumologists follows guidelines closer than that by internists, and this may lead to better management of hospitalized patients and to shorter mean stays.[24,25] Indications for NIV include respiratory acidosis and severe dyspnea with clinical signs of muscle fatigue or increased Table 1: Patient baseline characteristics Hospital stay P ≤14days(n=502), n(%) >14days(n=159), n(%) Age (mean±SD) 73.9 (11.7) 76.3 (10.4) 0.02 Gender (males) 384 (76.5) 122 (76.7) 0.9 Tobacco use Never smokers 119 (74.8) 40 (25.2) 0.3 Active smokers 94 (76.4) 29 (23.6) Former smokers 162 (72.6) 61 (27.4) OH use Regular drinkers 142 (76.8) 37 (23.2) 0.1 Occasional drinkers 16 (76.2) 5 (23.8) Never drinkers 40 (66.7) 20 (33.3) Former drinkers 151 (80.7) 36 (19.3) GOLD I 59 (17.7) 12 (11.5) 0.1 II 137 (41.1) 42 (40.4) III 7 (2.1) 2 (1.9) IV 130 (39) 48 (46.2) Comorbidities AF/atrial flutter 125 (25.1) 41 (25.9) 0.8 Hypertension 249 (49.6) 79 (49.7) 0.9 Diabetes 122 (24.4) 37 (23.4) 0.8 Ischemic heart disease 100 (20) 28 (17.6) 0.5 Cancer 62 (12.4) 23 (14.5) 0.4 Cerebrovascular accident 48 (9.6) 22 (13.8) 0.1 Dementia 23 (4.6) 5 (3.1) 0.4 Chronic kidney disease 35 (7) 22 (13.8) 0.008 Liver disease 35 (7) 8 (5) 0.3 Charlson 0 3 (100) 0 (0) 0.2 1 188 (78.7) 51 (21.3) >2 308 (74.2) 107 (25.8) Baseline therapy Inhaled anticholinergics 274 (60) 93 (66.4) 0.1 SABA 165 (36.1) 48 (34.5) 0.7 LABA 269 (58.9) 73 (52.5) 0.1 Inhaled corticosteroids 274 (60) 81 (58.3) 0.7 Theophylline 22 (4.8) 7 (5) 0.9 Oral corticosteroids 23 (5) 10 (7.2) 0.3 Oxygen therapy at home 126 (25.1) 47 (29.6) 0.2 NIV at home 34 (6.8) 15 (10.1) 0.1 Admissions due to AECOPD‑previous year 137 (27.6) 47 (29.9) 0.5 Emergency due to AECOPD‑previous year 199 (40.2) 55 (35.3) 0.2 AF: Atrial fibrillation, SABA: Short‑acting beta2 agonists, LABA: Long‑acting beta2 agonists, NIV: Noninvasive ventilation, AECOPD: Acute exacerbation of chronic obstructive pulmonary disease, SD: Standard deviation, GOLD: Global initiative for chronic obstructive lung disease Table 2: Characteristics of acute exacerbation (univariate analysis) Hospital stay P ≤14days (n=502), n(%) >14days (n=159),n(%) HR 89.9 (19.4) 89.6 (19.3) 0.8 SBP 131 (23.2) 131 (27.2) 0.8 DBP 74 (13.6) 73 (13.2) 0.3 BT ≥38°C 152 (30.3) 48 (30.2) 0.9 Tachypnea 190 (55.4) 61 (63.5) 0.1 Weekend admission 110 (21.9) 32 (20.1) 0.6 Admission unit Pneumology 379 (80.8) 90 (19.2) <0.0001 IMU 123 (64.1) 69 (35.9) Laboratory data, n (SD) Hemoglobin 13.7 (2.05) 13 (2.4) 0.001 Platelets 247,321 (99193) 255,589 (112,969) 0.3 Leukocytes 11,600 (5640) 11,500 (4665) 0.8 Glucose admission 144 (70) 142 (59) 0.7 Urea admission 66 (35) 67 (40) 0.8 Creatinine admission 1.1 (0.6) 1.1 (0.5) 0.7 Total protein count 6.3 (0.6) 6.4 (0.7) 0.6 Albumin 3.9 (3.6) 3.6 (0.4) 0.3 Fibrinogen 456 (150) 427 (143) 0.1 Initial blood gas, n (SD) pH 7.4 (0.08) 7.4 (0.07) 0.4 PCO247.4 (15.5) 47.4 (17.5) 0.9 PO258.4 (20.4) 57.5 (16.6) 0.5 Bicarbonate 28.4 (5.3) 29 (6.6) 0.2 SatO289 (43) 87 (0.6) 0.6 O2/FiO2241 (64) 242 (55) 0.8 Chest radiograph Pleural effusion 71 (14.2) 17 (10.7) 0.2 Cardiomegaly 150 (29.9) 38 (23.9) 0.1 Atelectasis 25 (5) 8 (5) 0.9 Bronchiectasis 20 (4) 8 (5) 0.5 ICU 3 (0.6) 14 (8.8) <0.0001 NIV 66 (13.1) 31 (19.5) 0.04 Antibiotic therapy 435 (86.7) 143 (89.9) 0.2 HR: Heart ratio, SBP: Systolic blood pressure, DBP: Diastolic blood pressure, BT: Body temperature, IMU: INTERNAL Medicine Unit, ICU: Intensive Care Unit, NIV: Noninvasive ventilation, SD: Standard deviation García‑Sanz, et al.: Pronlonged stay predictors in COPD exacerbation Lung India • Volume 35 • Issue 4 • July-August 2018 319 respiratory effort. Early NIV use is recommended in patients admitted with moderate and severe AECOPD.[1] In our sample, 14.7% of all patients were treated with NIV, and this was associated with longer stays, as in the study by Zacho Priess Leere and Møller Weinreich.[26] According to other authors, patients treated with NIV stay shorter than those treated with mechanical ventilation; however, patients treated with NIV stay longer and with worse outcomes in the event of NIV failure.[27] Our results should be interpreted with caution due to the limitations inherent to retrospective studies, including selection bias and the assumption that the information in the files reflects clinical practice. Furthermore, as our data come from a single hospital, they might not be generalized to other populations. CONCLUSIONS Prolonged stay likelihood by AECOPD hospitalizations is higher in those patients assisted by the IMU, in those admitted to the ICU, and in those requiring NIV. Acknowledgment We would like to acknowledge S. García Sanz for the translation of the manuscript. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest. REFERENCES 1. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. Updated; 2015. Available from: http://www.goldcopd.org/uploads/users/files/GOLD_Report_2015.pdf. [Last accessed on 2016 Feb 11]. 2. Lima FV, Yen TY, Patel JK. Trends in in‑hospital outcomes among adults hospitalized with exacerbation of chronic obstructive pulmonary disease. COPD 2015;12:636‑42. 3. Sullivan SD, Ramsey SD, Lee TA. The economic burden of COPD. Chest 2000;117:5S‑9S. 4. Rivas‑Ruiz F, Redondo M, González N, Vidal S, García S, Lafuente I, et al. Appropriateness of diagnostic effort in hospital emergency room attention for episodes of COPD exacerbation. J Eval Clin Pract 2015;21:848‑54. 5. 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ICU: Intensive Care Unit, IMU: Internal Medicine Unit, NIV: Noninvasive ventilation, OR: Odds ratio, CI: Confidence interval García‑Sanz, et al.: Pronlonged stay predictors in COPD exacerbation 320 Lung India • Volume 35 • Issue 4 • July-August 2018 25. Wijayaratne K, Wilson J, Sivakumaran P, Sriram KB. Differences in care between general medicine and respiratory specialists in the management of patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease. Ann Thorac Med 2013;8:197‑203. 26. Zacho Priess Leere M, Møller Weinreich U. Mortality and readmissions in patients with acute exacerbation of chronic obstructive pulmonary disease treated at a specialised pulmonary ward and general wards. Dan Med J 2014;61:A4938. 27. Stefan MS, Nathanson BH, Higgins TL, Steingrub JS, Lagu T, Rothberg MB, et al. Comparative effectiveness of noninvasive and invasive ventilation in critically ill patients with acute exacerbation of chronic obstructive pulmonary disease. 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