ORLANDO — Infection following acute hospitalization for ST-segment elevation myocardial infarction was linked with prolonged hospitalization and significantly increased risk of death, in a review of patients in Florida hospitals in 2006.
The incidence of in-hospital infection among the 11,879 patients for ST-segment elevation myocardial infarction (STEMI) was 17%, with more than a third of these patients having two or more infections while hospitalized, Michelle C. Nash and her associates reported in a poster at the annual scientific sessions of the American Heart Association. The most common infections were urinary tract (in 6%), pneumonia (5%), surgical site (4%), and bloodstream (3%). Other infections collectively affected another 4% of the patients.
Among STEMI patients without an infection, 16% had a length of stay of 7 days or more. The percentage of infected patients who required hospitalization for a week or longer ranged from a low of 45% in those with surgical site infections to a high of 76% in those with bloodstream infections, said Ms. Nash, a researcher in the department of epidemiology and biostatistics at the University of South Florida in Tampa, and her associates (see table, p. 24).
In addition, while surgical site and some other infections led to mortality rates nearly identical to the 7% rate in STEMI patients who never developed an infection, other types of infection led to a substantially increased in-hospital mortality rate, such as the 31% rate in patients with bloodstream infections and the 20% rate in those with pneumonia.
In-hospital infections boosted the risk that STEMI patients would need mechanical ventilation or would develop renal failure or heart failure. “Notably, patients with miscellaneous infections, not those with pneumonia, had the greatest risk for mechanical ventilation” at 25%, compared with 5% in patients who developed pneumonia, the researchers said.
Their analysis also examined demographic and clinical features that appeared to be linked with an increased susceptibility to infection. The pattern of factors significantly associated with infection varied depending on infection site.
▸ Bloodstream infection. Patients treated with an indwelling arterial or venous catheter and those on dialysis were at increased risk for bloodstream infections. Both of these factors boosted the risk for a bloodstream infection by nearly sevenfold, compared with STEMI patients who did not receive these treatments. Other risk factors included chronic obstructive pulmonary disease (COPD), valve disorders, and blood transfusion, each of which roughly doubled the risk for a bloodstream infection.
▸ Pneumonia. Major risk factors for pneumonia included chronic bronchitis, an indwelling arterial or venous catheter, and dialysis, each of which quadrupled the risk. Other significant risk factors included alcohol abuse and COPD—each of which more than doubled the risk—and chronic kidney disease and an operative procedure, each of which raised the risk for pneumonia by about 50%.
▸ Surgical site infection. Cardiac catheterization and dialysis each raised the rate of surgical site infection by more than 2.5-fold, compared with STEMI patients not receiving these procedures. Other significant risk factors included an indwelling arterial or venous catheter and blood transfusion, which boosted the risk by 50%–100%. Two factors were found to significantly reduce the rate of surgical site infections: Percutaneous coronary intervention cut the risk by more than a third, and cigarette smoking cut the infection risk by 30%.
▸ Urinary tract infection. Female gender had the biggest impact on the risk of urinary tract infections, boosting the risk by nearly 2.5-fold. Dialysis also raised the risk more than twofold. Several other factors significantly raised the risk for urinary tract infection by 47%–94%: COPD, diabetes, chronic kidney disease, an operative procedure, an indwelling arterial or venous catheter, and blood transfusion. In addition, the risk for a urinary tract infection rose by a significant 27% for every 5-year increment in age. Finally, cigarette smoking significantly cut the risk by a third.
Ms. Nash and her associates said that they had no financial support from commercial sources to disclose.
Elsevier Global Medical News