Delayed Antibiotic Treatment in Community-acquired Pneumococcal Pneumonia. Analysis of Risk Factors and Impact on the Outcome.

In this retrospective cohort study, we plan to include all patients presenting with a community-acquired pneumococcal pneumonia at the University Hospital of Zurich between January 1, 2006 and June 30, 2012 (6½ years). The patients will be identified either with one or more blood culture pairs positive for S. pneumoniae or with a positive pneumococcal urine antigen assay in combination with the clinical diagnosis of CAP, which was based on the presence of select clinical features (e.g., cough, fever, sputum production, and pleuritic chest pain) and is supported by imaging of the lung, usually by chest radiography according to Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of CAP in adults [11].

CAP is not considered if the patient is discharged from a hospital less than 7 days before the current hospital admission, if the first blood culture or urinary antigen assay is obtained more than 1 week after hospital admission, or if the patient has no clinical diagnosis of CAP at the time of admission. Patients referred from or transferred to another hospital are excluded.

After identification of eligible patients upon microbiological results, medical records are reviewed using a standardized data collection questionnaire. Comorbidity is determined using the Charlson comorbidity index [10]. Additionally, all patients are classified according to the multimorbidity patterns proposed by Holden et al. [12]. These are:

1. arthritis, osteoporosis, other chronic pain, bladder problems, and irritable bowel;
2. asthma, chronic obstructive pulmonary disease, and allergies;
3. back/neck pain, migraine, other chronic pain, and arthritis;
4. high blood pressure, high cholesterol, obesity, diabetes, and fatigue;
5. cardiovascular disease, diabetes, fatigue, high blood pressure, high cholesterol, and arthritis; and
6. irritable bowel, ulcer, heartburn, and other chronic pain.

Time calculation is based upon the moment of emergency room (ER) admission.