Data collection
At baseline, both demographic and clinical variables were collected for each patient. Severity was assessed using the PSI scale (pneumonia severity index)18. Comorbidity was collected using the Charlson comorbidity index19 and autonomy in activities of daily living was measured using the Katz index20. Vital signs were collected daily to assess clinical stability. Clinical cure and symptoms of pneumonia were assessed using a validated questionnaire21. Originally follow-up for all patients took place for up to 30 days, this period was extended to one year in this new study.
The main outcome variables that this study assessed were mortality at 90 days, 180 days, and 1 year, as well as new admissions that took place after the 30-day clinical trial follow-up and up to 1 year of index admission. Similarly, the occurrence of cardiovascular events was assessed during that same period of time, defined as the occurrence of hypertension, cardiac arrhythmia, valvulopathy, heart failure, coronary heart disease, decompensation of previous heart disease, intermittent claudication, thrombosis, embolism or stroke. The principal investigator at each hospital reviewed the medical records to confirm the occurrence of complications, in addition to conducting phone consultations when considered necessary. Patients or the public were not involved in the design, or conduct, or reporting, or dissemination plans of our research.
On the other hand, a subanalysis was carried out in one of the hospitals, where biomarker levels were measured at admission, at 5 days and at 30 days. PCR levels quantified by immunoturbidimetry with an analytical sensitivity of 1 mg/L were analyzed. PCT was analyzed via electrochemiluminescence, with an analytical sensitivity of 0.02 ng/mL and 5 pg/mL respectively. On the other hand, ProADM was analyzed via sandwich immunoassay using TRACE (time-resolved amplified cryptate emission) technology with an analytical sensitivity of 0.05 nmol/L.