Clinical Pathway Based on Procalcitonin Levels for the Management of Community-acquired Pneumonia in Outpatients
Clinical Pathway Based on Procalcitonin Levels for the Management of Community-acquired Pneumonia in Outpatients
A clinical protocol was developed for the management of adult outpatients with
 community-acquired pneumonia (CAP) and Pneumonia Severity Index risk classes I-II. Patients
 are assigned to oral azithromycin or levofloxacin according to procalcitonin (PCT) levels
 measured with a rapid point-of-care method. When PCT levels are <0.5 ng/ml, azithromycin, 500
 mg/day is given orally for 5 days; if PCT is ≥0.5 ng/ml, levofloxacin, 500 mg/day is given
 orally for 7 days
A clinical protocol was developed in collaboration with the hospital's Emergency Department
 for the management of adult outpatients with community-acquired pneumonia (CAP). Patients are
 assigned to 2 treatment categories according to the plasma procalcitonin (PCT) values.

 Treatment assignment:

 1. PCT<0.5 ng/ml: azithromycin, 500 mg/day orally for 5 days

 2. PCT≥0.5ng/ml: levofloxacin, 500 mg/day orally for 7 days

 Laboratory and microbiological studies:

 In the ED, patients with signs and symptoms of pneumonia have a blood sample collected for
 routine biochemical and hematological determinations, and PCT concentration measurement.

 Rapid testing for the determination of PCT are performed with BRAHMS PCT-Q, an
 immunochromatografic test for the semi-quantitative detection of PCT in serum (BRAHMS GmbH,
 16761 Hennigsdorf, Germany). PCT concentration ranges are the following: <0.5 ng/ml; ≥ 0.5
 ng/ml; ≥2 ng/ml; ≥10 ng/ml.

 The etiological diagnostic workup includes obtaining sputum samples from patients with
 productive cough, and a urine sample for detection of S. pneumoniae and Legionella
 pneumophila serogroup 1 antigens by immunochromatographic assays (Binax NOW, Alere Healthcare
 SLU, Spain). Only qualified sputum samples, as defined according to standard criteria
 (presence of >25 WBC and <10 squamous cells per low-power magnification field [x10]) are
 evaluated. Serum samples (obtained during the acute stage of illness and 4 weeks later) are
 collected and frozen at -80ºC for ulterior serological testing. An indirect chemiluminescent
 immunoassay (VirClia® Monotest, Vircell, S.L., Granada, Spain) is performed to detect IgG
 antibodies against Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila
 and Coxiella burnetii. Calculation of cutoff values and interpretation of the results are
 performed in accordance with the instructions of the manufacturer. The diagnostic criteria
 are either a seroconversion (index value from negative to positive) or a significant increase
 in the index value (≥threefold) in paired samples. All assays are performed and analyzed
 blindly by the same person.

 Follow-up and outcome measures:

 After treatment has been assigned, patients are referred to the outpatients clinic, where
 they are seen within the following 24 hours (Visit 2). A phone visit (Visit 3) is scheduled
 on day 7, and the last programmed visit on day 30 at the clinic (Visit 4). Patients are
 instructed to visit the outpatients' clinic if their clinical status worsens or fever
 persists more than 48 hours after the first visit. Cure is defined as an improvement or lack
 of progression of baseline radiographic findings at the end of therapy (EOT) and resolution
 of signs, including chest X-Ray, and symptoms of pneumonia at visit 4. Failure is defined as
 persistence or progression of signs and symptoms or progression of radiological signs of
 pneumonia at EOT, persistent infiltrate on X-Ray at visit 4, and initiation within 2 calendar
 days of the initial antibiotic therapy of a different potentially effective antibiotic, death
 on or after day 3 attributable to primary infection, or relapsed infection at visit 4.
 Antibiotic change requirement due to toxicity, and need for hospital admission is also
 recorded.

 In addition to the short-term outcome, the long-term (3-year) outcome of the patients is
 assessed through a structured telephone interview.
Inclusion Criteria:

 -  Fever with or without respiratory symptoms

 -  New infiltrate on chest radiograph

 -  Pneumonia Severity Index (PSI) score ≤ 70 (risk classes I and II).

 Exclusion Criteria:

 -  PSI risk classes III-V

 -  Age ≥65 years

 -  Comorbidity (diabetes, chronic obstructive pulmonary disease, chronic renal disease,
 neoplasia, immunosuppression including HIV infection, chronic heart failure or
 cirrhosis)

 -  White blood cell count ≥20.0 x 109/L

 -  Pleural effusion

 -  Bilateral infiltrates

 -  Previous failure or allergy to macrolides or quinolones

 -  Need for oxygen therapy -