Abstract
BACKGROUND:
Chronic obstructive pulmonary disease (COPD) exacerbations significantly affect morbidity, mortality, and healthcare costs. The Lancet Commission proposed a severity classification for COPD exacerbations, but its validation has not been performed. This study aims to assess the relationship between exacerbation severity scores, as defined by the Lancet Commission, and patient outcomes, including morbidity and mortality.
METHODS:
A retrospective, single-center study analyzed 240 hospitalized patients with COPD exacerbations from January 2023 to January 2024. Patients were categorized into three severity groups based on the Lancet exacerbation severity scores. Clinical and laboratory parameters, duration of hospitalization, intensive care unit (ICU) admissions, ventilatory support, and 30-day mortality rates were compared.
RESULTS:
Our study found that patients with the highest severity scores had significantly lower hemoglobin and hematocrit levels, higher pCO2 and urea levels, and longer hospital stays. The rates of noninvasive mechanical ventilation use, ICU admission, and mortality were notably higher in this group. In addition, hypoalbuminemia, anemia, lymphopenia, and elevated blood urea were linked to 30-day mortality in patients experiencing exacerbation. The receiver operating characteristic analysis showed an albumin cutoff of ≤33.3 g/L as predictive of mortality, with a sensitivity of 51.3% and specificity of 80.5%.
CONCLUSION:
This study is the first to the Lancet Commission’s severity classification in COPD exacerbations. Results indicate that this scoring system can effectively identify patients at high risk for poor outcomes. Future prospective studies are necessary to refine severity assessment criteria and incorporate biochemical markers for improved prognostication and management of COPD exacerbations.
KEYWORDS: Anemia, chronic obstructive pulmonary disease, exacerbation, hospitalization, hypoalbuminemia, Lancet Commission, mortality
Background
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death and the seventh leading cause of poor health worldwide as reported by the World Health Organization.[1] The exacerbation of COPD (ECOPD) is the most significant cause of morbidity and mortality in patients with COPD. It contributes to rapid declines in respiratory function and worsened disease status. The risk of death significantly increases, especially when ECOPD leads to hospitalization. The 1-year mortality rate following a COPD exacerbation requiring hospitalization (26.2%) is twice the 1-year mortality rate following myocardial infarction (12.3%).[2,3] Furthermore, hospitalization due to ECOPD accounts for approximately 68% of all COPD-related healthcare costs.[2] Therefore, it is essential to recognize the exacerbation as quickly as possible, accurately predict its severity, and treat it most appropriately.
Until a few years ago, exacerbations were defined in many guidelines as an increase in respiratory symptoms requiring additional treatment.[4] However, a more comprehensive and clearer definition of ECOPD, which is of great importance in the prognosis of the disease, was first presented in the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2023 report.[5] In the same way, the severity of exacerbation was assessed subjectively based on patients’ perceptions and practitioners’ treatment preferences until recently. Establishing objective and reliable scoring systems for the prompt diagnosis and assessment of exacerbation severity is crucial. Hospitalized ECOPD cases were classified using more objective criteria, considering the presence and severity of respiratory failure as outlined in the GOLD 2023 Report.[5] The Lancet COPD Commission also proposed five criteria, including clinical and laboratory characteristics, for classifying severe ECOPD in its 2022 article.[6] The presence of any of these criteria is sufficient to classify an exacerbation as severe. However, the Commission points out that these recommendations for the classification of exacerbation severity have not yet been validated. This study aimed to investigate the link between the severity of exacerbations defined by the Lancet Commission and their associated morbidity and mortality. We also investigated the factors associated with early mortality in patients hospitalized for ECOPD.
Materials and Methods
This study was planned as a single center and retrospective. Between January 2023 and January 2024, patients with ECOPD who applied to an emergency department (ED) of a university hospital and were then hospitalized in the pulmonary medicine clinic were included in the study. Patients were excluded from the analysis if they met any of the following criteria: (1) those who developed confusion or respiratory irregularities due to a central nervous system condition unrelated to the ECOPD, (2) those with lung cancer, kyphoscoliosis, obstructive sleep apnea, or obesity hypoventilation syndrome that were not related to COPD exacerbation, and (3) presence of conditions that can be confused with ECOPD, such as heart failure, pneumonia, pulmonary embolism, pneumothorax, and pleurisy. We examined the patients’ files and electronic medical records.
The patients’ characteristics, including age, gender, body mass index, smoking history, and comorbidities, were obtained from their files. The inhaler medications used by patients include long-acting beta2-agonist, long-acting muscarinic antagonist, inhaled corticosteroid, and other treatments obtained from the electronic databases. The arterial blood gas results and biochemical values of patients admitted to the ED were recorded retrospectively. Laboratory records include complete blood counts, glucose, blood urea nitrogen (BUN), creatinine, albumin, lactate dehydrogenase, C-reactive protein (CRP), troponin, sodium (Na), and potassium (K) levels. The number of hospital and/or intensive care unit (ICU) admissions due to ECOPD were also recorded.
All interventions involving noninvasive mechanical ventilation (NIMV), mechanical ventilation, ICU admissions during hospitalization, and the duration of in-hospital stays were recorded.
The Lancet Commission exacerbation severity score was evaluated according to the presence of following: (1) Use of accessory respiratory muscles or paradoxical chest wall movements, or both; (2) Clinically significant hypoxemia and new or worsening hypercapnia or respiratory acidosis; (3) Reduced alertness (e.g., confusion, lethargy, and coma); (4) Failure to respond to initial medical management; (5) Right heart failure, cardiac ischemia, hemodynamic instability, or clinically significant arrhythmia. A total severity score, ranging from 1 to 5, was calculated for each patient. We also categorized patients into three subgroups based on total severity scores as follows: Group 1 (score 1 point); Group 2 (scores 2 and 3 points); and group 3 (scores 4 and 5 points). These groups were compared regarding the study variables and exacerbation outcomes, which included length of hospital stay, ICU administration, and early mortality rates. In addition, those who deceased and those who survived within 1 month following the exacerbation were compared in terms of clinical and laboratory features.
Ethical approval for this study is obtained from the Ethics Committee.
Statistical analysis
The distribution of continuous data was tested for normality using the Shapiro–Wilk test. Data with normal distributions were presented as means ± standard deviation, and between-group comparisons were performed using parametric tests (independent samples t-test). Between-group comparisons of data without a normal distribution were performed using nonparametric tests (Mann–Whitney U-test). The categorical data were presented as absolute values and percentages. Group comparisons were performed using Fisher’s exact test and Chi-squared test. The association between study parameters and mortality was assessed by multivariable logistic regression analysis after adjustments. Receiver operating characteristic (ROC) curve analysis was performed to determine the predictive value of risk parameters for mortality. Predictability was determined by the area under the curve (AUC). A two-sided P < 0.05 is considered statistically significant. All the data were analyzed using the IBM SPSS Statistics version 20.0, Armonk, New York, USA.
Results
The study involved 240 patients with ECOPD, of whom 67.5% were male, with a mean age of 73.8 ± 11 years. A significant difference was observed in smoking history, with Groups 1 and 2 exhibiting higher pack years than Group 3 (P = 0.018). The patients in Group 3 displayed significantly lower hemoglobin and hematocrit levels than those in Groups 1 and 2 (P = 0.003 and P = 0.0007, respectively). Group 3 had significantly higher pCO2 levels, indicating greater respiratory impairment (P = 0.006). Oxygen saturation was significantly higher in Group 1 compared to Group 2 and Group 3 (P = 0.011). The bicarbonate and the urea levels were notably higher in patients belonging to Group 3 (respectively, P = 0.0002, P = 0.042). The clinical and laboratory characteristics of all patients, along with a comparison of the groups based on the Lancet severity score, are presented in Table 1.
Table 1.
The clinical and laboratory characteristics of the patients and the comparison of the groups according to the Lancet severity score.
| Variables | All patients (n=240) | Group 1 (n=43) (Lancet score=1) | Group 2 (n=160) (Lancet score=2–3) | Group 3 (n=37) (Lancet score=4–5) | P |
|---|---|---|---|---|---|
| Age (years) | 73.8±11 | 73±13 | 74±11 | 76±11 | 0.263 |
| Female/male | 78 (32.5)/162 (67.5) | 13 (30.2)/30 (69.8) | 9 (30.6)/111 (69.4) | 16 (43.2)/21 (56.8) | 0.251 |
| Smoking (pack/year) | 50.0±37.0 | 51±42 | 53±34 | 37±42 | 0.018 |
| WBC (103/μL) | 11.9±5.0 | 12±5.8 | 12±6.0 | 11±5.5 | 0.524 |
| Eosinophil (cell/μL) | 130±200 | 100±150 (0–750) | 140±240 (0–2000) | 140±300 (0–1800) | 0.264 |
| Neutrophil (103/μL) | 9.7±5.0 | 9.9±5.8 | 9.8±5.6 | 9.2±5.2 | 0.568 |
| Lymphocyte (103/μL) | 1.3±0.9 | 1.3±0.80 | 1.4±0.99 | 1.2±0.58 | 0.221 |
| Hb (g/dL) | 13.5±11.0 | 13±3.6 | 13±3.4 | 11±2.1 | 0.003 |
| Hct (%) | 38.5±6.0 | 39±8.4 | 39±6.0 | 35±6.3 | 0.0007 |
| Urea (mg/dL) | 45.8±22.8 | 41±19 | 46±23 | 51±25 | 0.042 |
| Albumin (g/L) | 36.8±5.0 | 37±5.0 | 37±5.0 | 35±5.5 | 0.128 |
| LDH (U/L) | 270.8±99.0 | 268±96 | 278±103 | 247±83 | 0.133 |
| CRP (mg/L) | 94.72±102.3 | 100±112 (0.91–463) | 93±94 (0–507) | 97±124 (0–573) | 0.815 |
| Troponin (ng/L) | 382.3±1180 | 503±1172 (8–3600) | 448±1325 (3–8900) | 43±452 (12–230) | 0.055 |
| Na (mmol/L) | 136.±6.3 | 136±5.0 | 137±4.3 | 136±12 | 0.140 |
| K (mmol/L) | 4.3±0.61 | 4.2±0.62 | 4.4±0.55 | 4.4±0.79 | 0.076 |
| pH | 7.3±0.2 | 7.4±0.1 | 7.4±0.3 | 7.4±0.1 | 0.289 |
| pCO2 (mmHg) | 42.8±12.0 | 39±9.4 | 43±12 | 49±15 | 0.006 |
| pO2 (mmHg) | 67.5±30.0 | 70±2 | 65±3 | 75±3 | 0.093 |
| O2sat (%) | 88.3±10.0 | 92±5.5 | 87±12 | 90±9.1 | 0.011 |
| HCO3 (mmol/L) | 25.9±5.0 | 24±4.2 | 26±4.9 | 29±5.7 | 0.0002 |
Continuous variables are presented as mean±SD or median (IQR) depending whether they are normally distributed or not. Categorical variables are presented as case numbers and percentages. WBC=White blood cell, Hb=Hemoglobin, Htc=Hematocrit, LDH=Lactate dehydrogenase, CRP=C-reactive protein. Arterial blood gas results=pCO2=Partial pressure of carbon dioxide, pO2=Partial pressure of oxygen, O2Sat=Oxygen saturation, HCO3=Bicarbonate, SD=Standard deviation, IQR=Interquartile range, SD=Standard deviation, IQR=Interquartile range.
When the groups were compared regarding outcomes of ECOPD, the length of hospitalization was significantly longer in patients of Group 3 than in Groups 1 and 2 (P < 0.0001, P = 0.002, respectively). The use of NIMV during hospitalization was higher in Group 3 (83.7%) compared to group 1 (23.2%) and group 2 (36.8%) (P < 0.0001). ICU admissions during the current stay were significantly higher in Group 3 (51.3%) than in Group 2 (13.1%) and Group 1 (2.3%) (P < 0.0001). The mortality rate within 30 days was significantly higher in Group 3 (29.8%) compared to Group 2 (14.4%) and Group 1 (11.7%) (P = 0.041). A comparison of the outcomes of the groups is presented in Table 2.
Table 2.
Comparison of clinical features and prognostic factors of the groups according to Lancet severity score.
| Variables | Group 1 (n=43) (Lancet score of 1) |
Group 2 (n=160) (Lancet score of 2–3) |
Group 3 (n=37) (Lancet score of 4–5) |
P |
|---|---|---|---|---|
| Use of LTOT at home | ||||
| Yes/no | 10 (23.0)/33 (77.0) | 56 (35.0)/104 (65.0) | 17 (45.9)/20 (54.1) | 0.036 |
| Use of NIVM at home | ||||
| Yes/no | 6 (13.9)/37 (86.1) | 17 (10.6)/143 (89.4) | 8 (21.6)/29 (78.4) | 0.096 |
| Hospitalization in the previous year | ||||
| Yes/no | 18 (41.8)/25 (58.2) | 56 (35.0)/104 (65.0) | 18 (48.6)/19 (51.4) | 0.134 |
| ICU admission in the previous year | ||||
| Yes/no | 4 (9.2)/39 (90.8) | 20 (12.5)/140 (87.5) | 11 (29.7)/26 (70.3) | 0.021 |
| ED admission in the previous year | ||||
| Yes/no | 31 (72.1)/12 (27.9) | 100 (62.5)/60 (37.5) | 26 (70.2)/11 (29.7) | 0.449 |
| Total days hospitalized in the ward | 6.8±3.6 | 7.8±6.4 | 11±7.9 | 0.002 |
| Total days hospitalized in the ward and ICU | 7.0±3.6 | 8.6±7.5 | 15±10 | <0.0001 |
| NIMV use during hospitalization | ||||
| Yes/no | 10 (23.2)/33 (76.8) | 59 (36.8)/101 (63.2) | 31 (83.7)/6 (16.2) | <0.001 |
| ICU admission | ||||
| Yes/no | 1 (2.3)/42 (97.7) | 21 (13.1)/139 (86.9) | 19 (51.3)/18 (48.7) | <0.001 |
| The mortality occurring within 30 days | 5 (11.7) | 23 (14.4) | 11 (29.8) | 0.041 |
Continuous variables are presented as mean±SD or median (IQR) depending whether they are normally distributed or not. Categorical variables are presented as case numbers and percentages. LTOT=Long-term oxygen therapy, NIMV=Noninvasive mechanical ventilation, ICU=Intensive care unit, ED=Emergency department, SD=Standart deviation, IQR=Interquartile range.
Thirty-nine patients were hospitalized with an ECOPD and died within 30 days of admission. While 199 patients were found to be alive, the records of two patients could not be accessed after discharge. A comparison between the surviving and deceased groups within 30 days of hospitalization for an exacerbation revealed several significant differences. The deceased group was older (P = 0.0004) and had a longer hospital stay (P = 0.0004). The use of NIMV and ICU admissions during hospitalization was higher. ED admissions in the previous year and the percentage of patients with at least one comorbidity were greater in the deceased group (<0.0001). In addition, their albumin levels were significantly lower (P = 0.0001), as were hematocrit levels (P = 0.005) and lymphocyte counts (P = 0.036). These results are provided in Table 3. Multivariate regression analysis of 30-day mortality is presented in Table 4. The ROC curve analysis of albumin levels for predicting patient outcomes showed an AUC of 0.672, a sensitivity of 51.3%, and a specificity of 80.5%. The optimal cutoff value for albumin was determined to be 33.3 g/L or lower (P = 0.001), as illustrated in Figure 1.
Table 3.
Comparison of clinical and laboratory features in the deceased and surviving groups.
| Variables | The deceased group (n=39) | The surviving group (n=199) | P |
|---|---|---|---|
| Age (years) | 79±9.3 | 73±11 | 0.0004 |
| Smoking (package/year) | 54±40 | 50±37 | 0.583 |
| Eosinophil (103/μL) | 0.070±0.11 | 0.15±0.26 | 0.061 |
| Lymphocyte (103/μL) | 1.1±0.61 | 1.4±0.95 | 0.036 |
| Hb (g/dL) | 13±4.8 | 13±9.0 | 0.634 |
| Hct (%) | 36±6.0 | 39±6.6 | 0.005 |
| Albumin (g/L) | 34±5.7 | 37±4.8 | 0.0001 |
| LDH (U/L) | 272±135 | 271±90 | 0.990 |
| CRP (mg/L) | 78 (108) | 58 (143) | 0.569 |
| Troponin (ng/L) | 48 (260) | 26 (34) | 0.086 |
| pH | 7.4±0.088 | 7.4±0.22 | 0.764 |
| pCO2 (mmHg) | 43±14 | 43±12 | 0.922 |
| pO2 (mmHg) | 69±28 | 67±30 | 0.653 |
| O2 sat (%) | 90±7.3 | 88±11 | 0.496 |
| HCO3 (mmol/L) | 25±5.7 | 26±4.8 | 0.534 |
| Duration of hospitalization (days) | 12±11 | 7.5±4.7 | 0.0002 |
| NIVM use during hospitalization (yes/no) | 22 (56.4)/17 (43.6) | 77 (38.7)/122 (61.3) | 0.019 |
| ICU admission (yes/no) | 19 (48.7)/20 (51.3) | 21 (10.6)/178 (89.5) | <0.0001 |
| LANCET score | 2.7±1.2 | 2.4±1.0 | 0.120 |
| ED admission in the previous year (yes/no) | 28 (71.8)/11 (28.2) | 128 (64.3)/71 (35.7) | <0.0001 |
| At least one comorbidity (yes/no) | 36 (92.3)/3 (7.7) | 171 (85.9)/28 (14.1) | <0.0001 |
Continuous variables are presented as mean±SD or median (IQR) depending whether they are normally distributed or not. Categorical variables are presented as case numbers and percentages. WBC=White blood cell, Hb=Hemoglobin, Htc=Hematocrit, LDH=Lactate dehydrogenase, CRP=C-reactive protein, pCO2=Partial pressure of carbon dioxide, pO2=Partial pressure of oxygen, O2 sat (%)=Oxygen saturation, HCO3=Bicarbonate, ED=Emergency department, ICU=Intensive care unit, NIMV=Noninvasive mechanical ventilation, SD=Standart deviation, IQR=Interquartile range.
Table 4.
Multivariate logistic regression analysis of 30-day mortality.
| Variables | P | OR | 95% CI |
|---|---|---|---|
| Age (years) | 0.08 | 1.04 | 1.01–1.07 |
| Male sex | 0.511 | 1.47 | 0.46–4.68 |
| WBC (×109/L) | 0.16 | 1.13 | 1.02–1.26 |
| Lymphocytes (×109/L) | 0.006 | 0.58 | 0.87–1.83 |
| Hematocrit (%) | 0.12 | 0.95 | 0.91–0.99 |
| Albumin (g/dL) | 0.001 | 0.45 | 0.27–2.74 |
| LDH (U/L) | 0.31 | 1.00 | 1.001–1.005 |
| CRP (mg/L) | 0.38 | 1.01 | 1.004–1.020 |
| Troponin (ng/mL) | 0.14 | 1.92 | 1.30–2.84 |
| pH | 0.47 | 0.03 | 0.004–0.32 |
| pCO2 (mmHg) | 0.87 | 1.04 | 1.01–1.07 |
| pO2 (mmHg) | 0.26 | 0.98 | 0.96–0.99 |
| O2 saturation (%) | 0.56 | 0.93 | 0.88–0.98 |
| HCO3 (mmol/L) | 0.16 | 0.89 | 0.80–0.98 |
| Admission to ICU during hospitalization | 0.001 | 21.11 | 3.62–123.21 |
| NIMV use during hospitalization | 0.123 | 3 | 0.74–12.14 |
| At least one comorbidity | 0.449 | 2.08 | 0.31–13.74 |
| Need for mechanical ventilation | 0.042 | 0.17 | 0.03–0.94 |
WBC=White blood cells, LDH=Lactate dehydrogenase, CRP=C-reactive protein, pCO2=Partial pressure of carbon dioxide, pO2=Partial pressure of oxygen, O2 sat (%)=Oxygen saturation, HCO3=Bicarbonate, ICU=Intensive care unit, NIMV=Non-invasive mechanical ventilation
Figure 1.
The receiver operating characteristic curve analysis of albumin levels for predicting patient outcomes. AUC: Area under the curve.
Discussion
The most significant cause of mortality for COPD patients is an exacerbation of the disease, which particularly necessitates hospitalization. To date, several approaches have been proposed to further define the ECOPD based on objective measures and criteria, in an attempt to provide a better diagnosis and management. The main reasons for these approaches are the differences among COPD patients in the perception of exacerbation symptoms and self-management skills, and physicians’ approach to exacerbation management varies according to their knowledge, experience, and resources. Furthermore, pneumonia, pulmonary embolism, and heart failure, which can be confused with ECOPD, are often overlooked. A new framework called the Rome Proposal highlighted limitations in the current severity grading of ECOPD and introduced a revised system with three severity categories: mild, moderate, and severe.[7] This classification is based on five objective variables: dyspnea, oxygen saturation, respiratory rate, heart rate, and serum CRP levels. For certain patient groups, arterial blood gas measurements may also offer more information about the patient’s current clinical status.
Similarly, the Lancet Commission noted that acute exacerbations and their severity are poorly defined, which limits effective treatment options, particularly in the low-income settings. They proposed criteria for classifying severe exacerbations of COPD and recommended eliminating the definitions of mild and moderate exacerbations, categorizing them only as severe and nonsevere. In this context, for the first time in the literature, we divided patients with severe ECOPD into three groups based on their exacerbation scores as measured by the Lancet. Our results revealed that patients with high exacerbation scores had longer hospital stays, greater respiratory challenges, and metabolic and biochemical disturbances such as higher urea levels and lower hemoglobin and hematocrit levels. Furthermore, patients with high scores had a greater percentage of requiring NIMV and ICU during their hospital stay and experienced higher mortality. Consequently, our findings indicate that the Lancet score can distinguish severe exacerbations and may predict these patients’ need for ventilatory support and intensive care.
The EXACOS-CV US study showed that the risk of death increased for 2 years following an exacerbation, peaking within the first 30 days after the event.[8] In our study, 39 patients hospitalized due to COPD exacerbations died within 30 days of admission from all-cause mortality. We identified significant differences between the deceased group and the surviving group: the deceased group was older, had higher usage of NIMV, and required more ICU resources during hospitalization, enduring longer hospital stays. In severe attacks, the need for ventilation support or ICU admission can lead to numerous complications, such as nosocomial pneumonia, which can prolong the length of stay. Conversely, an extended length of stay for various reasons can also result in these complications and increased mortality. Therefore, it is vital to plan for discharging patients with COPD exacerbations as soon as possible and with optimal care. ED admissions in the previous year and the proportion of patients with at least one comorbidity were higher among the deceased group. A Canadian study utilized health databases to establish an initial cohort of patients hospitalized for ECOPD for the first time between 1990 and 2005, indicating that patients with more comorbidities experience higher mortality rates, which aligns with our results.[9]
One of the parameters recommended by the GOLD 2023 strategy report to determine exacerbation severity in patients hospitalized due to ECOPD is that the CRP level exceeds 10 mg/L.[10] In contrast, we did not observe higher CRP levels in patients with elevated Lancet exacerbation scores or those with a fatal outcome. The levels of serum albumin, lymphocytes, hemoglobin, and hematocrit were notably lower. At the same time, urea was higher in patients displaying increased Lancet exacerbation scores or those with a fatal outcome in our study. Recent data suggest an association between BUN levels and hospital mortality in patients with ECOPD.[11] A multicenter cohort study reported that nonsurvivors with ECOPD had elevated BUN levels compared to survivors. Potential explanations include COPD patients experiencing impaired renal perfusion due to hypoxia, increased inflammation, comorbid conditions, and medication effects.[12] Our study first demonstrated the link between BUN and higher Lancet scores in patients with ECOPD. Several studies have shown a substantial correlation between survival and relative lymphocyte count in older individuals with mild to severe COPD.[13,14] Lymphopenia, an indicator of weakened immunity, raises the risk of infections, which are the leading cause of fatal COPD exacerbations, and is primarily associated with early mortality.[15] Anemia has a strong association with an increased risk of death among individuals with COPD.[16] Low hemoglobin levels are linked to increased hospitalizations and both short- and long-term mortality. Anemia represents a risk factor for death, not only in patients with COPD but also among hospitalized individuals with other chronic illnesses.[17] Hypoalbuminemia is well-documented to correlate with increased complications and poorer prognosis across various medical conditions.[18,19,20,21,22] Our findings also validated the 30-day mortality predictive value of hypoalbuminemia. The ROC curve analysis of albumin levels for predicting patient mortality showed an AUC of 0.672, a sensitivity of 51.3%, and a specificity of 80.5% in our study. The optimal cutoff value for albumin was determined to be ≤33.3 g/L for predicting mortality. We believe that levels of albumin, BUN, lymphocytes, and hemoglobin may help assess the severity of COPD exacerbations. Future prospective studies on the role of biochemical parameters in forecasting the severity of exacerbations could provide valuable insights.
There are some limitations to our study. First of all, it was a retrospective study; however, we confirmed the data manually using patients’ written files. In addition, we excluded conditions such as pulmonary embolism, pneumonia, and congestive heart failure, which should be considered in the differential diagnosis of exacerbation. Second, we did not assess respiratory function parameters such as forced expiratory volume in 1 s, which could have provided additional insights into the severity of exacerbation. Finally, our study focused on the short-term outcomes, specifically 30-day mortality. Longer-term follow-up could offer a more comprehensive understanding of the impact of our results, such as biochemical parameters.
Conclusion
This study is the first in the literature to evaluate the COPD exacerbation severity classification recommended by the Lancet Commission. It demonstrated that patients with high exacerbation scores experienced longer hospital stays, greater respiratory challenges, metabolic and biochemical disturbances, including higher urea levels and lower hemoglobin. Furthermore, patients with high scores had a higher rate of requiring NIMV and ICU during their hospital stay, along with increased mortality. The Lancet Comission’s recommendations for assessing the severity of COPD exacerbations may be confirmed and enhanced by future prospective long-term studies.
Study limitations
This study has several limitations. First, it was designed as a retrospective analysis, which may introduce inherent biases related to data collection and interpretation. Second, the study was conducted at a single center, potentially limiting the generalizability of the findings to broader populations or different clinical settings. Finally, the relatively small sample size may reduce the statistical power and limit the ability to detect subtle but clinically relevant differences.
Authors’ contributions
ESAK: searched literature, conceived the research idea, designed the research structure, performed the statistical analysis, acquired data, prepared and edited the manuscript, EEY: searched literature, prepared and edited the manuscript, designed the research structure, GM: edited and reviewed manuscript, contributed to data acquisition, SS: edited and reviewed manuscript, BE: contributed data acquisition, EG: edited and reviewed manuscript, BAY: contributed to data acquisition, CD: contributed to data acquisition, DB: contributed to data acquisition and reviewed manuscript. All authors contributed substantially to the write-up of the article and all take responsibility of the content of the publication.
Ethical statement
This study was performed in accordance with the Declaration of Helsinki. Ethical approval was obtained from The Ethics Committee of Istanbul Medeniyet University Göztepe Prof. Dr. Süleyman Yalçın City Hospital (number: 2023/0836).
Data availability statement
The participants of this study did not give written consent for their data to be shared publicly and due to the legal restrictions supporting data is not available.
Conflicts of interest
There are no conflicts of interest.
Acknowledgments
None.
Funding Statement
Nil.
References
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The participants of this study did not give written consent for their data to be shared publicly and due to the legal restrictions supporting data is not available.