This is according to an American study. Its authors recommend screening for diabetes, arterial hypertension and cardiovascular disease in patients with COPD. The study, to be published in the forthcoming issue of the European Respiratory Journal (ERJ), the scientific publication of the European Respiratory Society, finds that chronic obstructive pulmonary disease (COPD) is often associated with other serious illnesses.
Conversely, a patient with diabetes or arterial hypertension should also be screened for COPD and other respiratory conditions, according to the study’s authors.
COPD, which includes chronic bronchitis and emphysema, is increasingly prevalent throughout the world. This serious respiratory disease, caused largely by smoking, could become the third most common cause of death in Western countries by 2020, according to calculations by the World Health Organization (WHO).
In view of this danger, considerable efforts are under way to improve management and prevention of COPD. In particular, researchers are attempting to identify which illnesses are frequently linked with COPD and assess their impact on the way the disease progresses.
Among them are David Mannino (Department of Preventive Medicine and Environmental Health, University of Kentucky, Lexington, USA) and his team, who set out to determine what links COPD to cardiovascular disease, hypertension and diabetes, and to assess to what degree the simultaneous presence of several diseases (comorbidity) could affect hospitalisation and mortality rates.
Over 20,000 patients monitored for five years
For their project, two existing databases were combined. The total of 20,296 subjects were classified according to the severity of their COPD, using a scale based on the GOLD (Global Initiative for Chronic Obstructive Lung Disease) classification. This involves five stages, from 0 (respiratory symptoms such as chronic cough and expectoration, but without reduction of respiratory function) to 4 (very severe disease with major anomalies revealed by spirometric testing).
In each group of patients, the authors analyzed the presence or absence of diabetes, arterial hypertension, or a cardiovascular disease, including angina pectoris, antecedents of myocardial infarction, heart failure, stroke and transient ischaemic attack (TIA). They also noted the levels of hospitalization and mortality over the five-year monitoring period of the studies. Over half of patients have a comorbidity
Mannino and his team report in the ERJ article that, having analyzed each of the groups for comorbidities, they found over half of the COPD patients to be suffering from an associated condition.
This was particularly striking among patients with one of the severe forms of COPD (GOLD stage 3 or 4), for whom the risk of diabetes was increased by 50%, hypertension by 60% and cardiovascular disease by 140%. In total, less than half of COPD patients (48.9%) did not have a comorbidity. Over one-third (7,359, or 36.3%) had a single comorbidity, while 2,597 (12.8%) had two. There were even 415 patients (2%) with all three.
What is more, the authors emphasis, the risk of hospitalization during the five-year study period was significantly higher for those with one or more comorbidities.
Strangely, though, the association with cardiovascular disease appears to be independent of the severity of the respiratory condition: "the risk of cardiovascular disease is the same in patients with severe COPD and those with only early signs of the condition", Mannino comments.
He believes, therefore, that there would be benefits from systematic screening for cardiovascular disease, hypertension and diabetes in COPD patients, and vice versa.
"Prevalence and outcomes of diabetes, hypertension, and cardiovascular disease in COPD."
D.M. Mannino, D. Thorn, A. Swensen, F. Holguin: Eur Respir J 2008, doi:10.1183/09031936.00012408 Click here to view abstract online.