Logo
Arch Neurosci

Image Credit:Arch Neurosci

Incidence and Risk Factors of Delirium in COPD Patient in Intensive Care Unit

Author(s):
Alireza KashefizadehAlireza KashefizadehAlireza Kashefizadeh ORCID1, Aminollah VasighAminollah VasighAminollah Vasigh ORCID2, Seyed Hossein AghamiriSeyed Hossein AghamiriSeyed Hossein Aghamiri ORCID3,*
1Department of Internal Medicine, Shahid Labbafinezhad Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
2Department of Anesthesiology, School of Allied Medical Sciences, Ilam University of Medical Sciences, Ilam, Iran
3Department of Neurology, Imam Hossein Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran


Archives of Neuroscience:Vol. 12, issue 2; e161269
Published online:Apr 29, 2025
Article type:Research Article
Received:Mar 15, 2025
Accepted:Apr 14, 2025
How to Cite:Alireza KashefizadehAminollah VasighSeyed Hossein AghamiriIncidence and Risk Factors of Delirium in COPD Patient in Intensive Care Unit.Arch Neurosci.2025;12(2):e161269.https://doi.org/10.5812/ans-161269.

Abstract

Background:

Delirium is an abnormal mental state that, in some patients, is associated with disturbances in sleep cycles, orientation, and perception.

Objectives:

The aim of this study was to determine the incidence and risk factors of delirium in patients with chronic obstructive pulmonary disease (COPD) in the intensive care unit (ICU).

Methods:

In this registry study conducted in Iran, data from 74 COPD patients aged over 18 years, without dementia, and hospitalized in the internal ICU for more than 2 days were analyzed. The registry checklist included information on gender, infection, fever, serum creatinine ≥ 1.2 mg/dL, hypertension, diabetes mellitus, smoking, chronic renal failure, discharge destination, age, number of days in the hospital, Glasgow Coma Scale (GCS) score, and partial pressure of oxygen (PaO2). Data analysis was performed using SPSS version 18 software.

Results:

Of the 74 patients examined, 19 (25.7%) experienced delirium, while 55 (74.3%) showed no symptoms of delirium. The incidence of delirium was higher in patients with a history of infection and fever. Delirium was significantly associated with older age, lower GCS scores, and lower PaO2 levels (P < 0.05). In the delirium group, the mean age was 73.21 ± 7.64 years, the length of stay (LOS) in the hospital was 27.42 ± 11.57 days, the GCS score was 6.10 ± 0.87, and the PaO2 was 75.26 ± 3.42 mmHg. In contrast, in the non-delirium group, the mean age was 66.25 ± 11.12 years, the LOS was 23.87 ± 8.16 days, the GCS score was 10.65 ± 2.61, and the PaO2 was 82.12 ± 4.93 mmHg.

Conclusions:

The incidence of delirium in COPD patients in the ICU was high. Identifying effective and aggravating factors is crucial, and necessary measures should be implemented to reduce the occurrence of delirium.

1. Background

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation and is the third leading cause of death globally. This condition not only imposes a significant economic and social burden worldwide but also places a substantial caregiving burden on the patient's caregivers (1, 2). The COPD is a multidimensional disease requiring patients to adapt to various situations and interactions. It involves airway obstruction, leading to reduced life expectancy and disability. Clinical symptoms of COPD include dyspnea, cough, increased sputum production, and fatigue (3-5).

Dyspnea in COPD patients interacts with physical, psychological, social, and environmental factors, often described in relation to activities likely to cause shortness of breath (6). As COPD progresses, exertional dyspnea increases, leading to shortness of breath and an inability to perform daily activities, causing fatigue even with simple tasks (7, 8). Due to airway obstruction, COPD patients often develop ineffective breathing habits, which can be mitigated through pulmonary rehabilitation (9).

Beyond the gradual decline in lung function, COPD affects other systems, including the nervous system, potentially causing cognitive disorders. Many COPD patients experience memory impairment, prolonged reaction times, lack of attention, and reduced information processing speed (2, 10). Respiratory failure is a common reason for intensive care unit (ICU) admission, and patients undergoing mechanical ventilation may develop delirium due to psychological reactions (11, 12). Delirium is an abnormal mental state associated with disturbances in sleep cycles, orientation, and perception (13, 14). Factors influencing delirium development include metabolic disorders, psychiatric history, blood transfusion, renal failure, and age (15, 16). Delirium is linked to prolonged hospitalization, increased mortality, physiological disorders, and higher medical costs (17-19).

2. Objectives

The aim of this study was to determine the incidence and risk factors of delirium in COPD patients in the ICU.

3. Methods

This study is part of the Iran ICU Registry (IICUR), a Persian ICU-based registry launched in 2018 in collaboration with the Australian and New Zealand Intensive Care Society (ANZICS). The IICUR was approved with ethics number IR.SUMS.REC.1397.559 and is recognized by the Iran Ministry of Health as the first and only registry of adult ICUs in Iran. In this study, registry data from 74 COPD patients aged over 18 years, with no history of surgery within the last 3 months and without dementia, who were hospitalized in the internal ICU for more than 2 days, were analyzed.

The registry checklist included information on gender, infection, fever, serum creatinine ≥ 1.2 mg/dL, hypertension, diabetes mellitus, smoking, chronic renal failure, discharge destination, age, number of days in the hospital, Glasgow Coma Scale (GCS) score, and partial pressure of oxygen (PaO2). The diagnosis of delirium was based on clinical examination and the opinion of a specialist physician, with the completion of the instruments performed by one of the researchers. All patient information was kept completely confidential. Data analysis was conducted using SPSS version 18 software.

4. Results

According to the findings, of the 74 patients examined in this study, 19 (25.7%) experienced delirium, while 55 (74.3%) showed no symptoms of delirium. Among the patients, 50% were male, 82.4% had no infection, and 48.6% had hypertension (Table 1). The incidence of delirium was higher in patients with a history of infection and fever compared to other patients. Additionally, delirium was significantly associated with older age, lower GCS scores, and lower PaO2 levels (P < 0.05) (Table 2).

Table 1.Comparing the Relationship Between Delirium and Qualitative Variables in Patients with Chronic Obstructive Pulmonary Disease a
VariablesDeliriumNo DeliriumOverallP-ValueF
Gender0.0644.67
Male13 (68.4)24 (43.6)37 (50)
Female6 (31.6)31 (56.4)37 (50)
Infection0.00133.43
Yes8 (42.1)5 (9.1)13 (17.6)
No11 (57.9)50 (90.9)61 (82.4)
Fever0.020.36
Yes12 (63.2)18 (32.7)30 (40.5)
No7 (36.8)37 (67.3)44 (59.5)
Serum creatinine ≥ 1.20.293.88
Yes12 (63.2)27 (49.1)39 (52.7)
No7 (36.8)28 (50.9)35 (47.3)
Hypertension0.233.21
Yes7 (36.8)29 (52.7)36 (48.6)
No12 (63.2)26 (47.3)38 (51.4)
Diabetes mellitus0.522.14
Yes13 (68.4)33 (60)46 (62.2)
No6 (31.6)22 (40)28 (37.8)
Smoking0.354.65
Yes5 (26.3)21 (38.2)26 (35.1)
No14 (73.7)34 (61.8)48 (64.9)
Chronic renal failure0.176.92
Yes4 (21.2)5 (9.1)9 (12.2)
No15 (78.9)50 (90.9)65 (87.8)
Discharge destination 0.0730.72
Died6 (31.6)10 (18.2)16 (21.6)
Ward13 (68.3)38 (69.1)51 (68.9)
Other 0 (0)7 (12.7)7 (9.5)

Comparing the Relationship Between Delirium and Qualitative Variables in Patients with Chronic Obstructive Pulmonary Disease a

Table 2.Comparing the Relationship Between Delirium and Quantitative Variables in Patients with Chronic Obstructive Pulmonary Disease a
VariablesDeliriumNo DeliriumFtSignificant (2-Tailed)95% CI of the Difference
LowerUpper
Age73.21 ± 7.6466.25 ± 11.126.4682.5230.0141.4588712.45309
Hospital days27.42 ± 11.5723.87 ± 8.168.3071.4590.149-1.300188.39683
GCS Score6.10 ± 0.8710.65 ± 2.6126.749-7.4000.000-5.77473-3.32384
PaO275.26 ± 3.4282.12 ± 4.930.547-5.6030.000-9.30613-4.42210

Comparing the Relationship Between Delirium and Quantitative Variables in Patients with Chronic Obstructive Pulmonary Disease a

According to the findings, of the 74 patients examined in this study, 19 (25.7%) experienced delirium, while 55 (74.3%) showed no symptoms of delirium. Among the patients, 50% were male, 82.4% had no infection, and 48.6% had hypertension (Table 1). The incidence of delirium was higher in patients with a history of infection and fever compared to other patients. Additionally, delirium was significantly associated with older age, lower GCS scores, and lower PaO2 levels (P < 0.05) (Table 2).

5. Discussion

The results showed that delirium was significantly higher in patients with older age, lower GCS scores, and lower PaO2. In a study by Robinson et al. involving surgical patients, a relationship was found between older age, hypoalbuminemia, pre-existing comorbidities, and delirium status (20). Pendlebury et al. reported that the risk of delirium increased with age, prior dementia, severe illness, infection, and dehydration (21). Pham et al. found a relationship between delirium and the number of sedative, haloperidol, and opioid days in patients with respiratory failure, but no association with gender, ethnicity, BMI, or creatinine levels (22). Generally, the rate of delirium was higher in mechanically ventilated patients and was directly related to ICU hospitalization indicators (23).

In this study, of the 74 patients examined, 19 (25.7%) had delirium, while 55 (74.3%) did not. Fu et al. found that in 237 COPD patients admitted to the ICU, the incidence of delirium was 21.94%. Factors such as age over 75 years, BMI ≤ 19 kg/m2, CPOT ≥ 5, APACHE II score ≥ 15, hypertension, PaO2 ≤ 75 mmHg, and sedation were associated with delirium. In the delirium group, the mean age was 78.11 years, 31 were male, the BMI was 18.12 ± 4.67 kg/m2, 76.92% had hypertension, 48.08% had diabetes mellitus, and 38.46% had hyperlipidemia (24). Szylinska et al. reported that in 283 postoperative COPD patients, 65 (22.97%) experienced delirium, with correlations found between delirium, intubation time, CRP levels, pneumonia, and lower survival rates (16).

Delirium is a common disorder in COPD patients, particularly in the ICU, where its rate is high. Xia et al. found a delirium incidence of 16% in patients receiving statins, compared to 19.1% in the non-statins group and 13.4% in the statins group (P < 0.001) (19). Xu et al. reported a 37.46% incidence of delirium in 2621 COPD patients, with a relationship between delirium, hospitalization, and the need for post-discharge care (25). Zhang et al. found that among 1083 intubated patients, 18.1% had delirium, with associations between delirium, hospital mortality, ICU stay, older age, ICU mortality, APACHE II score, lower GCS, and lower pH, but no association with PaCO2, gender, heart rate, underlying disease, or PaO2/FiO2 (26). Erfani et al. (2025) reported a delirium rate of 22% (CI: 16.8 - 28.3%) (27).

5.1. Conclusions

The rate of delirium in COPD patients in the ICU was high. Identifying effective and aggravating factors is crucial, and necessary measures should be implemented to reduce the occurrence of delirium.

Footnotes

References

  • 1.
    World Health Organization. The top 10 causes of death. Geneva, Switzerland: World Health Organization; 2020. Available from: http://who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death.
  • 2.
    Dobric A, De Luca SN, Spencer SJ, Bozinovski S, Saling MM, McDonald CF, et al. Novel pharmacological strategies to treat cognitive dysfunction in chronic obstructive pulmonary disease. Pharmacol Ther. 2022;233:108017. [PubMed ID: 34626675]. https://doi.org/10.1016/j.pharmthera.2021.108017.
  • 3.
    Vestbo J, Hurd SS, Agusti AG, Jones PW, Vogelmeier C, Anzueto A, et al. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease: GOLD executive summary. Am J Respir Crit Care Med. 2013;187(4):347-65. [PubMed ID: 22878278]. https://doi.org/10.1164/rccm.201204-0596PP.
  • 4.
    Zou W, Ou J, Wu F, Xiao S, Deng Z, Li H, et al. Risk of All-Cause Mortality in Mild Chronic Obstructive Pulmonary Disease: Evidence From the NHANES III and 2007-2012. Int J Chron Obstruct Pulmon Dis. 2025;20:217-29. [PubMed ID: 39901929]. [PubMed Central ID: PMC11789505]. https://doi.org/10.2147/COPD.S497634.
  • 5.
    Wang X, Zhao X, Cen T, Yu Y, Xu Z, Shen L, et al. Treatment patterns for chronic obstructive pulmonary disease under the tiered medical system. Sci Rep. 2025;15(1):844. [PubMed ID: 39755745]. [PubMed Central ID: PMC11700116]. https://doi.org/10.1038/s41598-024-85010-x.
  • 6.
    Mahler DA. Mechanisms and measurement of dyspnea in chronic obstructive pulmonary disease. Proc Am Thorac Soc. 2006;3(3):234-8. [PubMed ID: 16636091]. https://doi.org/10.1513/pats.200509-103SF.
  • 7.
    Ebadi Z, Goertz YMJ, Van Herck M, Janssen DJA, Spruit MA, Burtin C, et al. The prevalence and related factors of fatigue in patients with COPD: a systematic review. Eur Respir Rev. 2021;30(160). [PubMed ID: 33853886]. [PubMed Central ID: PMC9489028]. https://doi.org/10.1183/16000617.0298-2020.
  • 8.
    Ghanbari A, Shirmohamadi N, Paryad E, Kazemnejad Leili E. [Predictors of fatigue in patients with chronic obstructive pulmonary disease]. J Knowledge Health; Shahroud Univ Med Sci. 2016;11(3). FA.
  • 9.
    Amini M, Gholami M, Aabed Natanzi H, Shakeri N, Haddad H. [Effect of Diaphragmatic Respiratory Training on Some Pulmonary Indexes in Older People With Chronic Obstructive Pulmonary Disease]. Salmand: Iran J Ageing. 2019;14(3):332-41. FA. https://doi.org/10.32598/sija.13.10.330.
  • 10.
    Moradi F, Askarizadeh G, Bagheri M. [Information Processing Speed, Visuospatial Working Memory and Cognitive Failures in Middle-aged and Older Adults With Chronic Obstructive Pulmonary Disease]. Salmand: Iran J Ageing. 2024;19(1):84-99. FA. https://doi.org/10.32598/sija.2023.3711.1.
  • 11.
    Oli R, Mishra JK, Srivastava GN, Mishra S. Association of Low body Mass Index with Respiratory Failure in Chronic Obstructive Pulmunary Disease. J Nepal Health Res Counc. 2021;19(1):135-9. [PubMed ID: 33934148]. https://doi.org/10.33314/jnhrc.v19i1.3372.
  • 12.
    Ellingsen I, Fondenes O, Overland B, Holmedahl NH. The severity of sleep hypoventilation in stable chronic obstructive pulmonary disease. Sleep Breath. 2021;25(1):243-9. [PubMed ID: 32405994]. https://doi.org/10.1007/s11325-020-02097-y.
  • 13.
    Staveski SL, Pickler RH, Khoury PR, Ollberding NJ, Donnellan AL, Mauney JA, et al. Prevalence of ICU Delirium in Postoperative Pediatric Cardiac Surgery Patients. Pediatr Crit Care Med. 2021;22(1):68-78. [PubMed ID: 33065733]. https://doi.org/10.1097/PCC.0000000000002591.
  • 14.
    Shivji S, Stabler SN, Boyce K, Haljan GJ, McGloin R. Management of delirium in a medical and surgical intensive care unit. J Clin Pharm Ther. 2021;46(3):669-76. [PubMed ID: 33277703]. https://doi.org/10.1111/jcpt.13319.
  • 15.
    Kotfis K, Szylinska A, Listewnik M, Brykczynski M, Ely EW, Rotter I. Diabetes and elevated preoperative HbA1c level as risk factors for postoperative delirium after cardiac surgery: an observational cohort study. Neuropsychiatr Dis Treat. 2019;15:511-21. [PubMed ID: 30863073]. [PubMed Central ID: PMC6388975]. https://doi.org/10.2147/NDT.S196973.
  • 16.
    Szylinska A, Rotter I, Listewnik M, Lechowicz K, Brykczynski M, Dzidek S, et al. Postoperative Delirium in Patients with Chronic Obstructive Pulmonary Disease after Coronary Artery Bypass Grafting. Medicina (Kaunas). 2020;56(7). [PubMed ID: 32660083]. [PubMed Central ID: PMC7404780]. https://doi.org/10.3390/medicina56070342.
  • 17.
    Mather JF, Corradi JP, Waszynski C, Noyes A, Duan Y, Grady J, et al. Statin and Its Association With Delirium in the Medical ICU. Crit Care Med. 2017;45(9):1515-22. [PubMed ID: 28622167]. https://doi.org/10.1097/CCM.0000000000002530.
  • 18.
    Lee DS, Lee MY, Park CM, Kim DI, Kim YW, Park YJ. Preoperative statins are associated with a reduced risk of postoperative delirium following vascular surgery. PLoS One. 2018;13(3). e0192841. [PubMed ID: 29570715]. [PubMed Central ID: PMC5865715]. https://doi.org/10.1371/journal.pone.0192841.
  • 19.
    Xia J, Hu C, Wang L, Zhang Y. Association between statin use on delirium and 30-day mortality in patients with chronic obstructive pulmonary disease in the intensive care unit. Eur J Med Res. 2023;28(1):572. [PubMed ID: 38062497]. [PubMed Central ID: PMC10704755]. https://doi.org/10.1186/s40001-023-01551-3.
  • 20.
    Robinson TN, Raeburn CD, Tran ZV, Angles EM, Brenner LA, Moss M. Postoperative delirium in the elderly: risk factors and outcomes. Ann Surg. 2009;249(1):173-8. [PubMed ID: 19106695]. https://doi.org/10.1097/SLA.0b013e31818e4776.
  • 21.
    Pendlebury ST, Lovett NG, Smith SC, Dutta N, Bendon C, Lloyd-Lavery A, et al. Observational, longitudinal study of delirium in consecutive unselected acute medical admissions: age-specific rates and associated factors, mortality and re-admission. BMJ Open. 2015;5(11). e007808. [PubMed ID: 26576806]. [PubMed Central ID: PMC4654280]. https://doi.org/10.1136/bmjopen-2015-007808.
  • 22.
    Pham AT, Peterson RA, Slaughter S, Martin M, Hippensteel JA, Burnham EL. Association of central nervous system-related biomarkers with hospital delirium in ICU patients with respiratory failure. CHEST Critical Care. 2025;In press(In press). https://doi.org/10.1016/j.chstcc.2025.100143.
  • 23.
    Oh TK, Park HY, Song IA. Factors associated with delirium among survivors of acute respiratory distress syndrome: a nationwide cohort study. BMC Pulm Med. 2021;21(1):341. [PubMed ID: 34724913]. [PubMed Central ID: PMC8559136]. https://doi.org/10.1186/s12890-021-01714-0.
  • 24.
    Fu X, Wang L, Wang G, Liu X, Wang X, Ma S, et al. Delirium in elderly patients with COPD combined with respiratory failure undergoing mechanical ventilation: a prospective cohort study. BMC Pulm Med. 2022;22(1):266. [PubMed ID: 35810306]. [PubMed Central ID: PMC9271245]. https://doi.org/10.1186/s12890-022-02052-5.
  • 25.
    Xu HB, Xue F, Ye Y, Zhang HG. Association of Delirium with Long-Term Mortality in Critically Ill Patients with COPD Who Survived to Discharge: A Retrospective Cohort Study. Lung. 2024;202(5):533-41. [PubMed ID: 38914868]. https://doi.org/10.1007/s00408-024-00725-y.
  • 26.
    Zhang R, Bai L, Han X, Huang S, Zhou L, Duan J. Incidence, characteristics, and outcomes of delirium in patients with noninvasive ventilation: a prospective observational study. BMC Pulm Med. 2021;21(1):157. [PubMed ID: 33975566]. [PubMed Central ID: PMC8111378]. https://doi.org/10.1186/s12890-021-01517-3.
  • 27.
    Erfani A, Shabeeb HH, Jamshidi YA, Amin NG, Vasigh A. Updated Systematic Review and Meta-Analysis Delirium Prevalence in Iranian Hospitals Patients. Arch Anesthesiol Critical Care. 2024;In press(In press).
comments

Leave a comment here


Crossmark
Crossmark
Checking
Share on
Cited by
Metrics

Purchasing Reprints

  • Copyright Clearance Center (CCC) handles bulk orders for article reprints for Brieflands. To place an order for reprints, please click here (   https://www.copyright.com/landing/reprintsinquiryform/ ). Clicking this link will bring you to a CCC request form where you can provide the details of your order. Once complete, please click the ‘Submit Request’ button and CCC’s Reprints Services team will generate a quote for your review.
Search Relations

Author(s):

Related Articles