SAN DIEGO – , results from a large retrospective cohort study found.
In a poster abstract presented at an international conference of the American Thoracic Society, researchers led by, noted that ventilator-associated pneumonia is one of the most common hospital-acquired infections in intensive care units and affected an estimated 9%-27% of all intubated patients. “While data are readily available surrounding mortality associated with VAP, scant data are available on outcomes associated with any type of pneumonia requiring intubation and mechanical ventilation (MV) caused by gram-negative organisms,” they wrote.
In an effort to describe mortality rates and associated risk factors for intubated and MV patients diagnosed with gram-negative pneumonia, Dr. Lodise of the Albany (N.Y.) College of Pharmacy and Health Sciences and his associates conducted a retrospective cohort study of data from the(HCUP) National Readmission Database (NRD). HCUP is the largest source of hospital care data in the United States, accounting for 49.3% of the total U.S. resident population and 49.1% of U.S. hospitalizations. The researchers included patients at least 18 years of age who were hospitalized with a primary or secondary diagnosis of gram-negative pneumonia between Feb. 1, 2013, and Nov. 30, 2013. They excluded index hospitalizations with a primary or secondary diagnosis of viral pneumonia, fungal pneumonia, atypical organisms, gram-positive bacterial pneumonia, or pneumonia occurring secondary to an infectious disease. They examined mortality rates descriptively and modeled them via adjusted multivariate logistic regression to evaluate the impact of baseline characteristics and comorbidities on risk of mortality. All analyses incorporated sample weights to increase generalizability and allow for extrapolation to the entire U.S. population.
A total of 32,683 patients met all study criteria. Of these, 2,323 (7.1%) had a primary diagnosis and 30,360 (92.9%) had a secondary diagnosis for gram-negative pneumonia. Their mean age was 64 years, and 61.1% were male. In all, 7,928 patients (24.3%) died during hospitalization. Multivariate analysis revealed that patients with concomitant sepsis had the highest risk of mortality (odds ratio, 2.60), followed by patients aged 65 years and older (OR, 1.88) and those with any prior hospitalization within 30 days (OR, 1.34). Comorbidities upon admission with highest risk of mortality included cancer (OR, 2.45), liver disease (OR, 1.91), AIDS/HIV (OR, 1.59), renal disease (OR, 1.33), and congestive heart failure (OR, 1.15). Diabetes was found to have a decreased risk of mortality, with an OR of 0.80. “However, a majority of patients with diabetes had no complications; thus, these patients may be representative of a less severe patient population,” Dr. Lodise and his associates noted in the poster.
They acknowledged certain limitations of the study, including the potential for coding errors. They also pointed out the HCUP NRD does not contain treatment-specific information, drugs administered or treatment patterns during hospitalization, the number of days patients spent in the ICU, or the number of days on ventilation, “which can influence outcomes in pneumonia patients.” In addition, the study did not attempt to determine cause of death. “Death may have been due to combinations of factors separate from pneumonia,” they wrote.
Bayer Healthcare Pharmaceuticals funded the study. Dr. Lodise reported having no financial disclosures.
SOURCE: Lodise T. et al. ATS 2018, .