Abstract
Hospital-acquired pneumonia is the most common health care-associated infection in the United States. Most cases occur in nonventilated patients, but many hospitals track hospital-acquired pneumonia only in ventilated patients because of the complexity and subjectivity of conducting surveillance for large numbers of nonventilated patients. To propose and assess potentially objective, efficient, and reproducible surveillance definitions for nonventilator hospital-acquired pneumonia (NV-HAP) using routine clinical data stored in electronic health record systems. This cohort study was conducted in 2 tertiary referral and 2 community hospitals in Massachusetts between May 31, 2015, and July 1, 2018. All nonventilated patients aged 18 years or older who were admitted to these hospitals were included (N = 310 651). Ten candidate definitions for NV-HAP based on clinically meaningful combinations of 6 potential surveillance criteria were proposed: worsening oxygenation, temperature higher than 38 °C (fever), abnormal white blood cell count of less than 4000/μL or more than 12 000/μL, performance of chest imaging, submission of respiratory specimen for culture, and 3 or more days of new antibiotics. Incidence rates, lengths of stay, hospital mortality rates, and odds ratios (ORs) for time to discharge and mortality compared with those of matched controls were calculated for each candidate definition. The ORs were adjusted for demographics, clinical service, comorbidities, and severity of illness. The study analyzed 310 651 patients with 489 519 admissions, including 205 054 patients with 311 484 admissions of 3 or more days. Among the patients with 311 484 admissions, the mean (SD) patient age was 58.3 (19.3) years and 176 936 (56.8%) were of women. Incidence rates for candidate definitions per 100 admissions ranged from 3.4 events for worsening oxygenation alone to 0.9 event for worsening oxygenation and at least 3 days of new antibiotics to 0.6 event for worsening oxygenation, at least 3 days of new antibiotics, fever, abnormal white blood cell count, and performance of chest imaging. Crude mortality rates ranged from 16.1% (n = 2643) for patients with worsening oxygen alone to 27.7% (n = 868) for patients with worsening oxygenation, at least 3 days of antibiotics, fever or abnormal white blood cell count, and chest imaging. Patients who met NV-HAP candidate definitions remained in the hospital for twice as long as their matched controls (adjusted ORs ranged from 1.8 [95% CI, 1.7-1.8] to 2.1 [95% CI, 2.0-2.1]) and were 4 to 6 times as likely to die in the hospital (adjusted ORs ranged from 3.8 [95% CI, 3.5-4.0] to 6.5 [95% CI, 5.2-8.2]). Agreement between candidate definitions and clinical diagnoses was fair (κ = 0.33). These findings suggest that objective surveillance for NV-HAP using electronically computable definitions that incorporate common clinical criteria is feasible and generates incidence, mortality, and adjusted ORs for hospital mortality similar to estimates from manual surveillance. These definitions have the potential to facilitate widespread, automated surveillance for NV-HAP and thus inform the development and evaluation of prevention programs.
Highlights
Incidence rates for candidate definitions per 100 admissions ranged from 3.4 events for worsening oxygenation alone to 0.9 event for worsening oxygenation and at least 3 days of new antibiotics to 0.6 event for worsening oxygenation, at least 3 days of new antibiotics, fever, abnormal white blood cell count, and performance of chest imaging
Patients who met nonventilator hospital-acquired pneumonia (NV-HAP) candidate definitions remained in the hospital for twice as long as their matched controls and were 4 to 6 times as likely to die in the hospital
The incidence of NV-HAP varied by candidate definition, ranging from 3.4 events per 100 admissions for patients with worsening oxygenation alone to 0.9 event per 100 admissions for patients with worsening oxygenation and at least 3 days of new antibiotics to 0.6 event per 100 admissions for patients with worsening oxygenation, at least 3 days of antibiotics, fever or abnormal white blood cell (WBC) count, and performance of chest imaging (Table 3)
Summary
Hospital-acquired pneumonia is the most common health care–associated infection in the United States, affecting approximately 1% of hospitalized patients, two-thirds of whom are not receiving mechanical ventilation when pneumonia begins.[1,2,3] Crude mortality rates for patients with nonventilator hospital-acquired pneumonia (NV-HAP) range between 15% and 30%, which are similar to or higher than the rates associated with ventilator-associated pneumonia.[3,4,5,6,7,8,9] Most hospitals, do not have formal surveillance or prevention programs for NV-HAP.[3,10,11,12]One of the major barriers to creating surveillance and prevention programs for NV-HAP is the complexity and subjectivity of the surveillance definitions published by the US Centers for Disease Control and Prevention (CDC).[13]. Hospital-acquired pneumonia is the most common health care–associated infection in the United States, affecting approximately 1% of hospitalized patients, two-thirds of whom are not receiving mechanical ventilation when pneumonia begins.[1,2,3] Crude mortality rates for patients with nonventilator hospital-acquired pneumonia (NV-HAP) range between 15% and 30%, which are similar to or higher than the rates associated with ventilator-associated pneumonia.[3,4,5,6,7,8,9] Most hospitals, do not have formal surveillance or prevention programs for NV-HAP.[3,10,11,12]. In contrast to ventilator-associated pneumonia surveillance, almost every patient in the hospital must be tracked for NV-HAP rather than just the relatively small number of patients receiving mechanical ventilation. The sensitivity of coding for NV-HAP is only between 40% and 60%, and the positive predictive value is between 30% and 50%.3,20,21
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