Chronic Obstructive Pulmonary Disease (COPD) Often Associated With Other Illnesses

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, one from the
ARIC (Atherosclerosis Risk In Communities) cohort and the other from
the Cardiovascular Health Study (CHS). Launched in the late 1980s by
the US National Institutes of Health, both studies included thousands
of subjects, aged over 65 for the CHS and from 45 to 64 for ARIC.



Mannino's team only studied patients for whom adequate pulmonary
function data were available, selecting 15,341 volunteers from the
ARIC cohort and 4,955 from the CHS.



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 analysed 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 hospitalisation and mortality over the
five-year monitoring period of the studies.



Over half of patients have a comorbidity



The results published by the ERJ provide food for thought.
A total of 530 patients were in one of the more severe COPD
categories (GOLD 3 or 4), with another 2,076 suffering from moderate
COPD (GOLD 2) and 2,892 for whom the disease was just beginning (GOLD 1).


A further 4,511 subjects could be considered as potentially at risk
(GOLD 0) and 2,868 others were found by functional respiratory
testing to be suffering from restrictive syndrome (excessively small
lung volume).


Finally, the remaining 7,419 subjects, or approximately one-third of
the participants, could be classed as "normal" in terms of
respiratory function.



Mannino and his team report in the ERJ article that, having analysed
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%.


Results are similar for the group of non-COPD patients with
restrictive syndrome.


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 emphasise, the risk of hospitalisation
during the five-year study period was significantly higher for those
with one or more comorbidities.



The association between COPD and cardiovascular disease has not been
completely elucidated.


It could arise from a number of factors, including chronic infection,
inflammation or a shared risk factor, such as smoking.


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.




Title Of The Original Article

"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.


The European Respiratory Journal is the peer-reviewed scientific publication of the European Respiratory Society (more than 8,000 specialists in lung diseases and respiratory medicine in Europe, the United States and Australia).


European Respiratory Journal