Abstract
Introduction: Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable progressive condition characterized by persistent airflow limitation. Objective: To identify prognostic factors for mortality in patients with chronic obstructive pulmonary disease in the intensive care unit. Method: A descriptive, longitudinal, prospective study was conducted from January 2023 to December 2024 at the “Abel Santamaría Cuadrado” General Teaching Hospital. The study population consisted of 43 patients admitted to the intensive care unit with a diagnosis of chronic obstructive pulmonary disease. Results: In terms of incidence, among those over 69 years of age, women, Caucasians, and smokers, 46.10% had more than two previous hospitalizations and needed ventilatory support (76.74%). The overall mortality was 53.48%, with a high number of comorbidities and a low incidence of respiratory infection. High-risk stratification was observed in 74.41% of patients, and acute episodes were assessed as severe or very severe in 53.48% of patients. Conclusions: Multidimensional assessment of chronic obstructive pulmonary disease, including previous hospitalization, age, comorbidities, need for ventilatory support, risk stratification, and severity assessment of acute episodes, is an indicator of the need for specialized care and mortality.
Keywords
Chronic obstructive pulmonary disease, Risk factors, Intensive care
INTRODUCTION
Chronic obstructive pulmonary disease (COPD) is a complex, multicomponent, and underdiagnosed disease associated with high morbidity and mortality and represents a major public health problem. (1)
Scientific advances in recent years have necessitated a continuous update of knowledge and scientific evidence regarding what we now call COPD because of its heterogeneous clinical presentation. This has led to new proposals regarding its definition and syndromic approach, severity classification, and the identification of various phenotypes with clinical, prognostic, and therapeutic implications, all of which are linked to increasingly personalized medicine. (1,2)
The current recognition that exacerbation is a syndrome resulting from various etiopathogenic mechanisms, all with similar clinical manifestations, and the ongoing need to advance knowledge toward increasingly personalized medicine. (2,3)
COPD is the respiratory condition with the highest prevalence and socioeconomic impact worldwide, despite being a preventable disease. Owing to its high prevalence, progressive clinical course, and healthcare requirements, it is among the leading causes of mortality globally and results in high consumption of healthcare resources. (4)
The health burden of this disease is significant, not only in terms of fatalities but also in terms of the disability it causes, its impact on the quality of life of patients and their families, and the costs to individuals and the healthcare system. (5)
Estimates by the World Health Organization (WHO) indicate that by 2030, COPD will be the fourth leading cause of death worldwide and the seventh leading cause of years of life lost or lived with disability. (6)
In Cuba, COPD was the seventh leading cause of death, with a total of 3,558 deaths and a crude rate of 31.8 per 100,000 inhabitants in 2020; this figure rose to 5,207 deaths in 2021, with a crude rate of 46.5. A similar trend was observed in the province of Pinar del Río, where rates of 41.3 per 100,000 inhabitants were recorded at the end of 2021. This resulted in an average of 1.5 and 2.6 years of potential life lost per 1,000 inhabitants in 2020 and 2021, respectively. (7)
The accuracy of the records could also be affected by the large number of underdiagnoses as well as diagnostic errors. The main reason for this is that a COPD diagnosis must be confirmed by spirometry, an objective method that demonstrates airflow obstruction and is still rarely available in many countries. (5) Approximately half of individuals with a previous diagnosis of COPD, chronic bronchitis, or emphysema had never undergone spirometry. (6)
Certainly, there are many aspects of this condition that require updating for healthcare personnel, a factor that sparks interest in understanding some fundamental generalities about the behavior of COPD and evaluating the prognostic factors that most influence the fatal course of the disease, as a starting point for timely strategic decisions to improve efficiency and decision-making in the comprehensive management of the disease in intensive care.
Therefore, the objective of this study was to identify the prognostic factors for mortality in patients with COPD in intensive care.
METHOD
An observational, descriptive, longitudinal, and prospective study was conducted on patients who were diagnosed with COPD and hospitalized in the intensive care unit of the “Abel Santamaría Cuadrado” General Teaching Hospital in the province of Pinar del Río from January 2023 to May 2024.
Data collection was established for the specified period; sequential sampling was performed, and all patients admitted to the intensive care units with a diagnosis of COPD were included. The study population consisted of 43 patients, all of whom were studied.
The variables studied were age, sex, comorbidities, risk factors (smoking, biomass combustion products), body mass index (BMI), degree of dyspnea (mMRC scale), exacerbations, infections, length of hospital stay, usual treatment, oxygen therapy, and ventilatory support.
The collected data were entered into a database created for this purpose. Descriptive statistics were used for data analysis.
Ethical standards for conducting health research were adhered to, ensuring respect, autonomy, beneficence, and justice in the research.
RESULTS
The mean age of the 43 patients was 70.7 years; 65.11% were female, and 86.04% were white (Table 1).
General characteristics | |||
|---|---|---|---|
No. of patients | 43 | [empty cell] | [empty cell] |
Age | X= 70.7 | SD = 29.69 | 95% CI |
Gender | [empty cell] | [empty cell] | [empty cell] |
Female | 28 | 65.11% | [empty cell] |
Male. | 15 | 34.88% | [empty cell] |
Skin color | [empty cell] | [empty cell] | [empty cell] |
White | 37 | 86.04% | [empty cell] |
Black | 6 | 13.95% | [empty cell] |
Source: Medical records.
The data in Table 2 show that the age group between 70 and 79 years is predominant, accounting for 39.53% of the total, with 53.48% of deaths occurring in this group.
Age group | Alive | Alive | Deceased | Deceased | Total | Total |
|---|---|---|---|---|---|---|
[empty cell] | No | % | No | % | No | % |
40–59 years | 3 | 6.97 | 1 | 2.32 | 4 | 9:30 |
60–69 years old | 8 | 18.60 | 8 | 18.60 | 16 | 37.20 |
70–79 years | 7 | 16.27 | 10 | 23.25 | 17 | 39.53 |
80 years or older | 2 | 4.65 | 4 | 9.30 | 6 | 16.27 |
Total | 20 | 46.51 | 23 | 53.48 | 43 | 100 |
Source: Medical records.
As shown in Table 3, in the study group, 72.09% of the participants reported smoking as a factor in the onset and progression of the disease, with a low percentage of those who had quit smoking.
Variables | No | % | Deceased | % |
|---|---|---|---|---|
Smoker | [empty cell] | [empty cell] | [empty cell] | [empty cell] |
YES | 31 | 72.09 | 18 | 41.86 |
NO | 12 | 27.90 | 5 | 11.62 |
Previous Income | [empty cell] | [empty cell] | [empty cell] | [empty cell] |
0 - 1 | 16 | 37.20 | 7 | 16.27 |
≥ 2 | 27 | 46.10 | 16 | 37.20 |
Length of stay | [empty cell] | [empty cell] | [empty cell] | [empty cell] |
< 5 days | 9 | 20.93 | 4 | 9.30 |
5 to 10 days | 18 | 41.86 | 9 | 20.93 |
>10 days | 16 | 37.20 | 10 | 23.25 |
Ventilatory support | [empty cell] | [empty cell] | [empty cell] | [empty cell] |
YES | 33 | 76.74 | 18 | 41.86 |
No | 10 | 23.25 | 5 | 11.62 |
Source: Medical records.
As shown in Table 4, among the associated comorbidities, the most frequent was hypertension, with 27 cases representing 62.79%, accounting for 46.51% of deaths.
Comorbidities Associated | Total | Total | Deaths | Deaths |
|---|---|---|---|---|
Comorbidities Associated | No | % | No | % |
High blood pressure | 27 | 62.79 | 20 | 46.51 |
Ischemic heart disease | 11 | 25.58 | 9 | 20.93 |
Heart failure | 9 | 38.70 | 7 | 16.27 |
Cardiac arrhythmias | 5 | 11.62 | 4 | 9.30 |
Chronic cor pulmonale | 4 | 9.30 | 3 | 6.97 |
Diabetes Mellitus | 17 | 39.53 | 13 | 30.23 |
Malnutrition | 21 | 48.83 | 17 | 39.53 |
CRF | 7 | 16.27 | 5 | 11.62 |
Cancer | 3 | 6.97 | 2 | 4.65 |
Source: Medical records.
The data in Table 5 show that among the causes related to admission and mortality, lower respiratory tract infection was predominant, accounting for 53.48% of the study sample and being associated with 34.88% of deaths.
Causes | Total | % | Deaths | % |
|---|---|---|---|---|
Exacerbation | 11 | 25.58 | 3 | 6.97 |
Lower respiratory tract infection | 23 | 53.48 | 15 | 34.88 |
Cardiovascular | 7 | 16.27 | 5 | 11.62 |
Other | 2 | 4.65 | 0 | 0 |
Source: Medical records.
With respect to risk stratification and mortality, 32 patients were in the high-risk group, accounting for the majority of deaths (18 patients) (Figure 1).
Source: Medical records.
As shown in Table 6, 53.48% of the patients presented with a severe or very severe acute episode, all with a high baseline risk, reflecting the advanced stage of the disease, and of the 11 patients (25.58%) assessed as low risk, 5 were admitted with a moderate acute episode.
Assessment of the acute episode | Assessment of the acute episode | Assessment of the acute episode | Assessment of the acute episode | |
|---|---|---|---|---|
[empty cell] | Dyspnea | Consciousness | Respiratory rate | Gases |
Mild 11 | < 2 | Absent | [empty cell] | SaO2 ≥95% |
Mild 11 | 6 | 6 | [empty cell] | 6 |
Moderate 9 | [empty cell] | [empty cell] | 24–30 | Sao2 90–94% |
Moderate 9 | 5/9 | 5/9 | 9 | 9 |
Severe 12 | ≥3 | Drowsiness | >30 | PaO2 < 60% SaO2 < 60% |
Severe 12 | 12 | 10 | 12 | 12 |
Very severe 11 | ≥3 | Stupor, coma | >30 | pH < 7.30 PCO₂ > 60 |
Very severe 11 | 11 | 11 | 11 | 11 |
Source: Medical records
Among the 43 patients studied, the overall mortality rate was 53.48%. On the basis of the severity of the acute episode, 23 patients were classified as severe or very severe; this group had the greatest number of deaths, with 17 patients. Among the remaining 20 patients, 11 were classified as having mild disease, with a single death, and 9 were classified as having moderate disease, with 4 deaths.
Source: Medical records
DISCUSSION
The prevalence of COPD depends on the geographic region and the diagnostic criteria used. (8, 9) The literature reflects a higher prevalence among men, contrary to our results where women predominated, a trend described in some studies as being due to increased smoking rates among women and greater exposure to biomass combustion products in developing countries.
Furthermore, this pattern is related to the predominance of females in the Cuban population, with a life expectancy at birth of 80.45 years compared with 76.50 years for males; similar results were reported by López Campos JL (10) and Rodríguez-Pérez I((11)), with a predominance of women in both studies of 61.80% and 55.20%, respectively.
The predominance of the white population in this study is not an unexpected finding, as a higher incidence of this disease has been demonstrated in the white population, and furthermore, the population of Pinar del Río is predominantly white.
Notably, as life expectancy increases, so does the prevalence of COPD, since it is a disease that typically manifests in older individuals. (12)
This could be linked to population aging, a greater association of risk factors, and the inherent frailty of older adults associated with a high burden of chronic and debilitating diseases, in addition to the specific characteristics of patients who meet the criteria for ICU admission and have a greater potential for complications and mortality.
In 2021, a total of 5,207 deaths from chronic lower respiratory tract diseases were reported in Cuba, with an age-adjusted mortality rate of 46.5 per 100,000 inhabitants, which was higher than that reported in 2020. The overall mortality rate in the sample is high, at 53.48%, because of its multidimensional nature associated with risk factors, stratification, and disease severity. (7)
A history of exacerbations in patients with COPD is highly important, especially if they are recurrent or lead to hospital admission. In addition to the heavy healthcare burden and high costs, they negatively impact patients’ quality of life, contribute to disease progression, and influence prognosis—factors that contribute to patient risk stratification. (13)
In a study conducted by Jiménez Sellés P (14), which included 1,210 COPD patients over the age of 40, 51.2% experienced at least one exacerbation during the 2-year study period, with an average of 4 exacerbations per patient. According to these authors, the occurrence of exacerbations is associated with age, the presence of comorbidities, and the time elapsed since diagnosis.
There are conditions or circumstances that increase the risk of prolonged hospital stays in patients with COPD, including prolonged hospitalization prior to ICU admission, age, parameters related to prior poor general health, comorbidities, the need for ventilatory support, and both community-acquired and nosocomial infections. (15)
Patients with COPD have a higher incidence of comorbidities than the general population without COPD does. It is considered a “systemic” disorder and not a disease that affects only the lungs. Cardiovascular disease is the most significant comorbidity of COPD; its association increases mortality. These chronic conditions tend to be associated with a significant increase in cardiovascular risk factors, along with an increase in the combined incidence of ischemic heart disease and heart failure. (16)
There is a close link between respiratory function and the nutritional status of critically ill patients. Malnutrition and muscle dysfunction are two key determinants of the clinical severity and prognosis of chronic obstructive pulmonary disease. The close relationship between weight loss or malnutrition and mortality has been known for years. (17)
Findings from various studies confirm that multiple clinical factors contribute to impaired physical performance in patients with COPD. In particular, frequent exacerbations can accelerate the decline in lung function by 25%. (16)
Among the most recognized triggers in the literature are respiratory infections, both viral and bacterial. The SAE describes theories supporting higher concentrations of pathogens that typically colonize the lungs during the stable phase. This increase in bacterial density leads to heightened inflammatory responses; sometimes, this process is triggered by an infection, but in other cases, the cause is noninfectious. (18)
The following groups are at higher risk of exacerbations and mortality: patients with severe or very severe COPD according to the GOLD classification; those with grade 2 dyspnea or higher if receiving treatment; and those who have had two or more moderate exacerbations or a hospital admission due to an exacerbation in the previous year. Both indices are strongly correlated and have similar prognostic capacities for mortality. (19)
Patients with COPD are estimated to experience an average of 1 to 4 exacerbations per year. However, there is significant interindividual variability, such that some patients suffer recurrent exacerbations, while others do not. (20)
The severity of COPD is associated with exacerbations, particularly mortality, when these exacerbations are severe. (20) This is relevant because not all exacerbations affect mortality to the same extent. The severity of COPD is determined not only by the characteristics of the exacerbation itself but also very directly by the patient’s baseline severity.
Santeliz J, (21) in their comparative study of the staging of patients with COPD, classified according to GOLD 2007, 2011, and 2019, and using the results obtained with the GOLD 2019 classification—which separates functional categorization (airflow limitation) from clinical classification (degree of dyspnea and history of exacerbations)—which is particularly relevant in our cohort, where owing to limited availability, we do not have airflow obstruction measurements—we can see that the results by group are very similar to our own, with groups C and D predominating and accounting for the greatest number of deaths.
Moreno A et al. (22), in their study titled “Causes of death in Patients with Severe COPD,” which included a sample of 203 patients with severe COPD at a Pulmonology Day Hospital, reported a similar mortality rate of 53.7%, incorporating severity classification based on spirometry values into their study. A total of 18.7% of patients required admission to the intensive care unit, which constituted an independent factor associated with increased mortality.
When the severity of acute episodes is correlated with mortality, a direct relationship can be observed between the most severe forms of presentation and increased mortality.
CONCLUSIONS
COPD is a progressive inflammatory lung disease that requires personalized, multidisciplinary, and dynamic intervention. Smoking is the most commonly identified causal factor. Previous hospitalizations, the need for ventilatory support, and longer hospital stays were correlated with higher mortality. The comorbidities and their combinations most relevant to disease severity were hypertension, malnutrition, diabetes mellitus, and heart disease. Clinical assessments based on dyspnea level, number of exacerbations, and evaluation of the intensity of the acute episode in the multidimensional assessment of COPD grouped the largest number of patients into the high-risk stratum.
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Declarations
Funding
No financing.
Conflict of interest
None.
Authorship contributions
Drafting – original draft: Juan Andrés Prieto Hernández, Noel Alejandro Díaz Rojas, Abel Trujillo Ledesma, Maidelyn Alonso Loaces, Jorge Luis Bouza Corrales.
Writing–review and editing: Juan Andrés Prieto Hernández, Noel Alejandro Díaz Rojas, Abel Trujillo Ledesma, Maidelyn Alonso Loaces, Jorge Luis Bouza Corrales.