WASHINGTON — The development of acute coronary syndrome was eight times more common among 206 patients hospitalized with community-acquired bacterial pneumonia than among 395 hospitalized controls in a 7-year study.
Moreover, the risk of having an acute coronary event was 45 times greater among the pneumonia patients in the first 15 days after admission—and more than 100 times greater during the first 3 days—than it was during either the previous or subsequent year.
“The association between bacterial pneumonia and the development of ACS is so striking that a causal relation is suggested,” Dr. Vicente Corrales-Medina and his associates wrote in a poster presented at the jointly-held annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and the annual meeting of the Infectious Diseases Society of America (IDSA).
Several previous studies have suggested an association between acute infections—including those of the respiratory, gastrointestinal, and urinary tract—and the occurrence of ACS in the days and weeks after the infection. Most of those studies have not clearly defined or confirmed the infections, however, Dr. Corrales-Medina of the infectious diseases department of the Michael E. DeBakey VA Medical Center and Baylor College of Medicine, Houston, said in an interview.
Researchers in the current study enrolled patients hospitalized at the Houston VA Medical Center during 2000–2006. Study participants had either clinical and radiologic evidence for pneumonia and one blood culture yielding Streptococcus pneumoniae or Haemophilus influenzae, or a clinical syndrome of pneumonia, radiologic documentation of a new pulmonary infiltrate, a sputum sample showing more than 10 inflammatory cells per epithelial cell with predominance of gram-positive cocci in pairs or gram-negative coccobacilli, and a culture yielding pneumococci or H. influenzae with no other likely bacterial pathogens.
Case controls were patients whose reason for admission was not an elective or therapeutic procedure and whose admission diagnosis was different from pneumonia or ACS. Final diagnoses of ACS were determined by a senior cardiologist.
Of the 206 cases of pneumonia, 144 were due to S. pneumoniae and 62 to H. influenzae.
There were 22 (10.7%) cases of ACS in the group with community-acquired pneumonia (CAP) and 6 (1.5%) in the controls, a significant difference with an odds ratio of 7.8. The odds ratio was 7.0 for cases of CAP caused by S. pneumoniae and 9.6 for those caused by H. influenzae.
Dr. Corrales-Medina stated that he had no financial disclosures.