Risk Factors for Death from Psychiatric Hospital-acquired Pneumonia

OBJECTIVES: Pneumonia is a major cause of death among inpatients at psychiatric hospitals. Psychiatric hospital-acquired pneumonia (PHAP) is defined as pneumonia developed in inpatients at psychiatric hospitals. PHAP is a type of nursing and healthcare-associated pneumonia (NHCAP). The purpose of this study was to clarify the risk factors for mortality among PHAP patients. METHODS: We retrospectively reviewed the clinical files of patients transferred to Tokyo Metropolitan Matsuzawa Hospital from psychiatric hospitals for PHAP treatment during the 10-year period from September 2007 to August 2017. We analyzed the clinical differences between the survivors and non-survivors and assessed the usefulness of severity classifications (A-DROP, I-ROAD, and PSI) in predicting the prognosis of PHAP. RESULTS: This study included a total of 409 PHAP patients, 87 (21.3%) of whom expired and 322 (78.7%) of whom survived. The mortality rates, according to the A-DROP classifications, were 4.9% in the mild cases, 21.6% in the moderate cases, 40.7% in the severe cases, and 47.6% in the very severe cases. The mortality rates, according to the I-ROAD classifications, were 9.5% in group A, 34.7% in group B, and 36.2% in group C. The mortality rates, according to the PSI classifications, were 0% in class II and III, 23.1% in class IV, and 44.9% in class V. The mortality rate increased as the severity increased. We identified 3 factors (age ≥65 years, body mass index ≤18.5 kg/m(2), and bilateral pneumonic infiltration) as significant predictors of mortality. We therefore added two factors (body mass index ≤18.5 kg/m(2) and bilateral pneumonic infiltration) to the A-DROP classification and established a modified A-DROP classification with a range of 0 to 7. The area under the receiver operation characteristic curves for predicting mortality were 0.699 for the A-DROP classification and 0.807 for the modified A-DROP classification. CONCLUSION: The mortality rate in PHAP patients tended to increase with increasing classifications of severity. The modified A-DROP classification may be useful for predicting the prognosis of PHAP patients.