Chronic obstructive pulmonary disease (COPD) is a chronic disorder that progressively impairs the respiratory system, resulting in gradual airflow limitation. The disease is primarily caused by prolonged exposure to environmental irritants such as cigarette smoke, air pollution, and occupational dust and chemicals [1]. Although no cure for COPD is known, available maintenance medications have been proven to reduce the risk of exacerbations, manage symptoms, and enhance quality of life [2]. COPD represents a significant global public health issue. As of 2019, it was estimated to affect 10.3% of the global population, equivalent to 391.9 million individuals, with 80.5% residing in low- and middle-income countries. Moreover, this prevalence is expected to increase due to population aging and heightened exposure to environmental risk factors such as smoking and air pollution [3]. The prevalence of COPD in Vietnam is estimated, according to previous studies, to range between 7% and 10% [4-6].

In developed countries, the multi-disciplinary management model is increasingly prevalent in the management of COPD. This model requires collaboration among various specialties and multiple service types in assessing, treating, and caring for COPD patients, encompassing primary healthcare, rehabilitation, respiratory services, mental health, and nutrition. Central to the multi-disciplinary management model is the principle of patient-centered care, wherein evaluations prioritize treatable traits, leading to the creation of customized intervention plans that cater to the individual needs of each patient. Interventions are coordinated across different disciplines, with an emphasis on controlling symptoms, managing risk factors for disease progression, exacerbations, and enhancing quality of life [7-9]. Prior studies have confirmed the efficacy of the multi-disciplinary COPD management model in diminishing disease burden [10-13], yet its significant resource demands limit its application primarily to developed regions. The implementation of this model in low- and middle-income countries might be impractical and could necessitate substantial modifications [14].

In Vietnam, the COPD management system features COPD management units (CMUs), distributed across three tiers integrated with the existing tiered healthcare system. These include: tier 1 as primary healthcare services; tier 2 as outpatient clinics equipped to perform basic diagnostic tests such as chest X-rays, spirometry, and blood tests; and tier 3 as regional, provincial, or city-level general hospitals with respiratory specialists and facilities for advanced diagnosis and treatment [15]. In an effort to mitigate the growing burden of COPD, Vietnam had established 245 CMUs nationwide by September 2020, and by December 2020, these units had provided care for 636,828 COPD patients [16].

Despite these efforts, the management of chronic respiratory diseases in Vietnam encounters specific challenges that distinguish it from other low- and middle-income countries. A 2021 Vietnamese qualitative study identified unique barriers to healthcare access, including complex pathways that delay diagnosis, limited patient knowledge that hinders timely care, and reliance on family support for navigationsystem [17]. Additionally, health insurance policies frequently fail to provide adequate coverage for essential diagnostic tests such as spirometry, recommended critical long-acting medications by international guidelines, and preventive measures like smoking cessation programs, pulmonary rehabilitation, and vaccinations for influenza and pneumococcal infections, which are either excluded or only minimally reimbursed [18].

Until now, no study had been conducted to assess the efficacy of these CMUs over the years. To bridge these gaps, this study aimed to evaluate the changes in exacerbation rates and other clinical outcomes among COPD patients managed at CMUs, thereby laying the groundwork for community interventions and future policy developments.

A total of 518 COPD patients were enrolled at baseline; over the 2-year follow-up, 166 were loss to follow-up (LTFU), resulting in 352 patients being included in the final analysis. The mean age was 65.94±8.19 years, with the majority being male (87.8%). Hypertension was the most prevalent comorbidity (30.1%), followed by gastroesophageal reflux disease (16.3%). The majority of participants were either former smokers (62.5%) or current smokers (21.6%). The majority of patients exhibited moderate to severe symptoms, according to the mMRC (58.5%) and CAT (93.8%) classifications, with high treatment adherence (76.4%). The prevalence of airflow obstruction classified as mild, moderate, severe, and very severe were 44.6%, 27%, 9.7%, respectively. The rates of participants with exacerbations, hospitalized exacerbations, and ICU/ED admissions were 49.7%, 42.3%, and 5.7%, respectively. No statistically significant differences were observed in sociodemographic and clinical characteristics between the LTFU group and non-LTFU group (Table 1).

Throughout the follow-up period, the number of smokers increased from 76 (21.6%) to 90 (25.6%); the proportion of patients with an mMRC score ≥2 decreased from 58.5% to 47.6%. Testing frequency increased for CBC, chest X-ray, and spirometry, with spirometry results indicating improvements as the very severe COPD category decreased from 9.7% to 5.8%. Medication usage remained largely stable, except for a reduction in short-acting beta agonist (SABA) abuse (from 33% to 19%). The percentage of patients with poor treatment adherence slightly decreased from 10.5% to 6.5%, while the number of follow-up visits per year declined from 11.75±2.14 to 7.12±2.30. A reduction was also observed in patients with hospitalized/ICU/ED exacerbations and in hospitalization days (Table 2). The annual rates for exacerbations and hospitalizations were 0.75±0.89 and 0.56±0.70 exacerbations per year, respectively, while the annual numbers of hospitalization and ICU days were 13.84±9.53 and 5.05±5.35 days per year (Supplementary Table S1).

The annual exacerbation rate was elevated in both the underweight and overweight groups compared to the normal weight cohort. The annual hospitalization rate was higher in males compared to females and was increased in the underweight group in comparison to the normal and overweight groups. Both the rates of annual exacerbations and hospitalizations were elevated in the mMRC ≥2 group, correlating with increased severity of airflow obstruction (Supplementary Table S2). Results from the Poisson regression model demonstrated that symptom severity, as assessed by mMRC, was linked to higher rates of annual exacerbations and hospitalizations, whereas the severity of airflow obstruction was related to an increase in the annual hospitalization rate. In addition, BMI was associated with an elevated annual exacerbation rate (Table 3).

Our study aimed to assess the improvement in COPD exacerbation rates among patients managed at CMUs. The study results indicated reductions in the prevalence of patients requiring hospitalization (decreased from 42.3% to 34.4%) and ICU/ED admissions (decreased from 5.7% to 0.6%). Our findings are consistent with those of previous studies conducted at CMUs and specialized COPD clinics. A 2011 study evaluating the effectiveness of specialized outpatient clinics for COPD monitored 117 patients over a 6-month period. It reported improvements in patient quality of life at the 6-month mark (St. George’s Respiratory Questionnaire score decreased from 35.6±18.9 to 28.4±16.6, p=0.018), as well as in the rates of exacerbations (decreased from 3.3 to 1.1 exacerbations per year) and hospitalizations (decreased from 1.4 to 0.48 admissions per year) [22]. EPOCONSUL (2019) was a comprehensive cross-sectional study conducted in Spain, involving 4,508 COPD patients attending general medical clinics and specialized CMUs. It revealed that patients attending specialized units exhibited more severe airway obstructions, more pronounced respiratory symptoms, and greater comorbidity rates compared to those attending general medical clinics. Compared to standard medical clinics, specialized CMUs demonstrated superior exacerbation control, with 70.5% of patients experiencing no post-treatment exacerbations compared to 56.1% (p<0.001). These units also displayed enhanced testing capabilities and better treatment adherence [23]. However, our findings should be interpreted with caution, as the observed reduction in exacerbations could be influenced by the coronavirus disease 2019 (COVID-19) pandemic. On one side, the scarcity of resources and infrastructure for COPD care might limit healthcare facilities from treating COPD patients. On the other side, respiratory symptoms common to both COPD and COVID-19 present significant challenges; these symptoms might go unreported as patients may fear community stigma, be concerned about being categorized as high-risk and needing isolation, or be erroneously referred to COVID-19 isolation and treatment facilities rather than receiving COPD care.

Our study also observed a pattern of airflow obstruction severity, characterized by a predominance of moderate to severe obstruction, analogous to data from prior studies on COPD populations in Korea [24], Spain [23], and Europe [25]. This indicates that a significant proportion of Vietnamese COPD patients present with advanced disease at the time of diagnosis, potentially influencing management strategies and outcomes.

Our study results also highlighted challenges in managing COPD patients at CMU, the first being the increase in the number of COPD patients returning to smoking during the COVID-19 epidemic. From a community perspective, smoking cessation emerged as the most effective intervention for the COPD population, as successful control of smoking habits among patients was associated with reduced frequency and severity of exacerbations [26], decreased hospitalization rates [27], and a notable improvement in quality of life [28]. Additionally, smoking cessation has been demonstrated to be the only intervention effective at improving respiratory function and survival rates in mild to moderate COPD patients [29]. In the management strategy for COPD patients, smoking cessation has proven to be more cost-effective than other interventions [30,31]. For these reasons, smoking cessation interventions, including behavioral changes and nicotine replacement therapy, are regarded as crucial elements in the treatment strategy endorsed by both the Ministry of Health and GOLD 2022 [32,33]. However, limited resources made it challenging to routinely implement smoking cessation interventions at CMUs in Vietnam. During regular check-ups, patients typically received smoking cessation advice solely from their treating physicians, rather than from professionally trained healthcare staff knowledgeable about smoking cessation practices and procedures [34,35]. Moreover, nicotine replacement therapies were not widely available in the market and were not included on the list of items covered by health insurance for reimbursement. Consequently, the outcomes of smoking cessation for patients with COPD might not achieve the desired levels of improvement.

The challenge of managing COPD patients at CMU was underscored by the diagnostic testing rates, encompassing spirometry, CBC, and chest X-ray. The study noted a decrease in spirometry/bronchodilator tests, and although there was a rise in X-ray/CBC examinations over time, still approximately one-third to half of the patients were not prescribed CBC and chest X-ray annually. Previous studies have documented similar issues with laboratory ordering in COPD management [36-38]. Spirometry delivers critical indicators for COPD management, as increased severity of dyspnea does not necessarily indicate an exacerbation, particularly in the substantial proportion of COPD patients with comorbid cardiovascular diseases, which may also cause dyspnea [39]. Moreover, spirometry serves as a robust prognostic tool, as FEV₁ is strongly associated with primary outcomes in COPD patients, including exacerbation, hospitalization, and mortality [36-38]. The absence of spirometry in COPD monitoring inevitably leads to delayed diagnosis and management, thereby exposing patients to the risk of exacerbations or severe airflow obstruction. Additionally, the eosinophil count in CBC also plays a pivotal role in COPD management, aiding in exacerbation prediction for risk stratification and guiding treatment decisions regarding inhaled corticosteroid (ICS) [40]. Owing to these roles, CBC and spirometry have been endorsed by both the Vietnamese Ministry of Health and GOLD in COPD management [32,33]. Although not a primary diagnostic and treatment monitoring tool, chest X-rays still provide vital information on various aspects including comorbidities, complications, and differential diagnosis. The infrequent use of chest X-rays in clinical practice may lead to delayed or missed diagnoses, particularly for conditions that can be confused with the chronic respiratory context of COPD, such as pleural diseases, pulmonary fibrosis, and lung cancer [41,42].

The final management challenge identified in our study was inappropriate medication use, with SABA and ICS being the predominant medications, while long-acting beta agonist constituted only a very small proportion during the study period. According to the Vietnamese Ministry of Health and GOLD, long-acting agents play a foundational role in COPD treatment. Pre-treatment eosinophil count testing is essential to identify individuals who would benefit from ICS treatment, while SABA are recommended only during exacerbations. Similar patterns of SABA and ICS dominance have been observed in previous studies on COPD management in low- and middle-income regions, primarily due to an imbalance in the availability and affordability of these medications, as well as the knowledge and prescribing practices of treating physicians [25,43,44].

Overall, our study results identified challenges in COPD management, reflecting the absence of long-acting muscarinic antagonist medications, insufficient professional smoking cessation interventions, and low rates of testing requests. The current management situation resulted from a combination of factors that persisted throughout the study period. Firstly, the study was conducted during the COVID-19 pandemic, which significantly influenced the entire socioeconomic landscape, particularly affecting the healthcare sector. Infrastructure and personnel dedicated to COPD care and management across the country were reallocated to support COVID-19 treatment efforts, leading to a severe shortage of resources for managing COPD. Secondly, the limited financial coverage by health insurance for medications, tests, and procedures posed considerable challenges for physicians and adversely affected the quality of services provided to patients. Thirdly, resource limitations at the primary level significantly contributed to the continued difficulty in effectively managing COPD patients. These resource constraints were reflective of broader challenges in non-communicable disease prevention at the primary level: healthcare personnel were often deemed inadequate and inconsistent, and the budget allocated for COPD management, primarily funded by the state, failed to meet demands. These constraints became particularly acute during the nationwide COVID-19 outbreak, while barriers resulting from improper resource allocation and shortcomings in health insurance regulations have remained static over the past decades.

There are several limitations to consider in this study. Firstly, most of the variables were retrospectively collected from within 12 months preceding the baseline and follow-up examinations, a timeframe that may be excessively lengthy and prone to recall bias. Secondly, the data did not comprehensively demonstrate the absence of long-acting medications, discrepancies in health insurance regulations, and lack of access of COPD patients to other services in the multi-disciplinary management model, including smoking cessation interventions, flu vaccination, and respiratory function rehabilitation. Additionally, the study design did not incorporate a qualitative component to further elucidate the existence and causes of these barriers. Thirdly, while the study was conducted during the COVID-19 pandemic, no adjustments were made in the design to better clarify the effects of the pandemic on the study outcomes, specifically in exploring the COVID-19 status of COPD patients. Moreover, the impact of the COVID-19 pandemic contributed to a high rate of LTFU (166 out of 518 COPD patients, or 32%), which hindered our ability to assess mortality, a critical outcome in COPD management. Fourthly, although the study observed a decrease in exacerbation and hospitalization rates attributed to CMU-based management, it did not compare data before and after the implementation of CMUs due to the nature of the study design and available data. Such a comparison would have been crucial to determining the true impact of CMU-based management on patient outcomes. Lastly, the exclusion of deceased patients who could not be followed up may have introduced a risk of survival bias to this study.

In conclusion, to our knowledge, this was the first study conducted in Vietnam to evaluate the management of Vietnamese CMU’s. The study provided important data on changes in exacerbation rates and other clinical outcomes and identified challenges in managing COPD patients at these facilities, thereby laying the groundwork for future interventions and policy changes.