The profile of COPD patients of our study revealed that they are: elderly, mainly men, usually in advanced stages of the disease and presenting multiple comorbidities. Smoking was related by 92% of patients, being probably the most common factor associated with COPD development in this study, what is in accordance to the available literature [2, 5].
Higher age is compatible with the period between the beginning of exposure (usually tobacco smoke) and the development of COPD, as less aged patients reflect probably a higher genetic predisposition or even deficiency of α1-antitrypsin [2, 20]. The prevalence of male gender is consistent with previous studies in literature, with one study indicating the presence of 83% male individuals among more than 10,000 patients followed up in a respiratory clinic in Spain [17, 21]. This finding probably reflects the higher prevalence of tobacco smoking and a higher exposure to occupational activities such as biomass combustion in male gender, which could explain the higher incidence of COPD among men [10, 22, 23]. Because of higher age, the presence of other non-respiratory comorbidities is more common in COPD patients; in our sample we observed that 72.2% of the subjects had at least one non-respiratory comorbidity, with cardiovascular diseases (coronary insufficiency, heart failure and arrhythmia) being the most prevalent ones. In the multicentric EPOCA (Enfermedad Pulmonar Obstructiva Crónica en Acción) Project, which was also dedicated to the analysis of the features of patients with COPD, the prevalence of comorbidities varied considerably according to the evaluated country, oscillating from 38.1% in Argentina to 63.4% in Spain .
The main symptom reported by the population studied was dyspnea (92%), reflex of the ventilatory limitation observed in COPD. The EPOCA study found similar results, with dyspnea being reported by 97% of the patients, followed by chronic cough (79.6%) and sputum production (70.5%) . COPD stages II and III were the most prevalent (71.7%); this probably may be explained by delayed diagnosis (sub-diagnosis) at the earlier stages, since many patients initially ascribe their effort intolerance, due to COPD, to aging and sedentarism. The PLATINO study identified that 85.7% of the 144 patients diagnosed with COPD in the metropolitan region of Sao Paulo had never received this diagnosis in their lives . Moreover, the same study observed that, among the patients previously diagnosed with COPD, 42.7% had never been counseled to stop smoking and 82.3% were not receiving the recommended pharmacologic treatment.
Regarding the use of medications for the respiratory system, it is interesting to note that almost 60% of the sample consisted of patients with stage III and IV of the GOLD classification. Based on this finding, the high prescription in our sample of patients of β2-agonists associated with long-term inhaled corticosteroids (97.8%) and tiotropium (31.7%) is easily explicable.
Similarly, also the great use of methylxanthines among patients (85%) can be explained. The GOLD guidelines point out that inhaled bronchodilators, where available, should be used as first-line treatment in COPD, rather than oral bronchodilators, including methylxanthines. However, the same guidelines emphasize that methylxanthines can and should be considered in the treatment of patients with COPD who remain symptomatic despite the use of inhaled bronchodilators such as long-acting β2-agonists association and tiotropium. Furthermore, methylxanthines are low cost medications in Brazil, compared to some classes of inhaled bronchodilators, which may have contributed to the prescription above expectations, according to recommendations from international guidelines.
The presence of LTOT in our sample is consistent with previous studies, which reported that around 25% of the followed subjects with COPD use LTOT [13, 21, 25]. The high frequency of LTOT among these patients is justified by the loss in lung function and the ventilation/perfusion mismatch, especially in the most advanced phases of COPD [2, 13].
We observed that almost one-third of the patients use digitalic drugs daily; this is probably related to left ventricle systolic dysfunction (LVSD) or even right failure due to corpulmonale. A recent systematic review revealed that the connection between COPD and LVSD is probably much more prevalent than previously estimated; superimposition rates between these two diseases varied from 10% to 46%, especially during periods of COPD exacerbation . In our sample, corpulmonale was identified in 30 patients (16.6%), whereas the presence of LVSD was suggested in 20 patients (11.1%), according to echocardiographic findings.
We also point out the high incidence of systemic arterial hypertension (55%) in the evaluated subjects (average age 67.7 years), since the prevalence of this comorbidity (55%) increases linearly with age [26, 27]. Besides that, many patients were using diuretics specifically to ameliorate edema due to corpulmonale, or angiotensin-converting enzyme (ACE) inhibitors due to LSVD, thus explaining the use of antihypertensives (including diuretics) in 155 patients (86.1%).
It is important to emphasize that almost 20% of the patients took regularly antidepressants, a possible direct reflex of patients’ compromised health status and quality of life . In this context, it is interesting to quote a recent case–control study with more than 35,000 patients with COPD which identified that the existence of COPD itself doubles the risk of depression (OR 2.01, IC95% 1.45-2.78) . Another finding of concern in our study is the fact that the evaluated patients took many different types of drugs, an average of at least four medications a day. This is clinically relevant, since COPD patients are usually elderly patients, who frequently experience visual, hearing, and even cognitive deficits, which could possibly reduce their compliance to these medications, especially when they are not adequately assisted by their relatives .