Patients with chronic obstructive pulmonary disease (COPD) have worse outcomes following myocardial infarction (MI) compared with other patients, with a two-fold increased risk of death at one year, a US study has found.
According to the study – by Professor John Spertus, of the University of Missouri at Kansas City, and colleagues – COPD is common among MI patients and forms a barrier to optimal therapy after MI.
The authors explain: “For instance, beta blockers have been shown to improve survival and decrease angina frequency, yet may be withheld from patients with COPD out of fear of promoting bronchospasm.”
The researchers set out to improve understanding of the link between COPD, patients’ health status (symptoms, function, quality of life) and long-term mortality after MI.
To do this, they prospectively studied 2,481 MI patients’ responses to the disease-specific Seattle Angina Questionnaire (SAQ) and generic Short Form 12 (SF-12), at baseline and then one year later.
The SAQ quantifies five domains of coronary disease, including angina frequency and quality of life, and the researchers categorised each scale into “clinically meaningful” ranges. For example, since a major goal of treatment is the elimination of angina, frequency of the latter was dichotomised into “no angina” or “any angina”. Meanwhile, the SF-12 provides a generic measurement of overall physical and mental health.
COPD was common, affecting 387 patients (15.6%, or one patient in six), and was associated with significantly greater one-year mortality (15.8% vs 5.7%, p<0.001). In addition, patients with COPD were much more likely than those without it to be rehospitalised in the year after MI (48.7% vs 38.6%, p<0.001).
After adjusting for baseline differences, one-year mortality remained substantially higher in patients with COPD than without it, at a hazard ratio (HR) of 2.00.
Patients with and without COPD had substantial baseline health status impairment. But while both groups’ health status improved, the COPD patients reported worse one-year health status than those without COPD, with SAQ quality-of-life domain scores an average 2.53 points lower and SF-12 scores an average 1.83 points lower.
There was a trend towards a greater risk of one-year angina in patients with COPD, with a relative risk of 1.12.
“Our data suggest that patients with acute MI and COPD have a substantially worse prognosis in terms of mortality and health status that warrant careful attention at the time of hospital discharge and during follow-up,” the authors conclude.