An interventional study of Expanded Diagnostic Strategy and Conventional Diagnostic Strategy in Acute Respiratory Infection, sponsored by Santiago Lopez Gil. Not yet recruiting at 1 site in Spain. Open to participants aged 65 Years and older. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Santiago Lopez Gil · Not applicable, Interventional, and Treatment
This study will evaluate whether an expanded diagnostic strategy can reduce antibiotic use in patients aged 65 years or older who are hospitalized with community-acquired acute respiratory infection, without negatively affecting clinical outcomes.
The expanded diagnostic strategy combines multiplex respiratory polymerase chain reaction (PCR), serial procalcitonin measurements, and bedside lung ultrasound. The results of these tests will be integrated to support decisions about antibiotic treatment.
The study will compare the expanded diagnostic strategy with conventional diagnostic management. The main outcome will be the total duration of antibiotic therapy. The study will also assess the use of high-impact antibiotics, microbiological diagnosis, hospital and intensive care unit stay, complications, mortality, recurrence of infection, hospital readmissions, detection of multidrug-resistant microorganisms, and antibiotic-related adverse events.
This is a pragmatic, controlled, open-label, cluster-randomized crossover trial conducted in two hospital wards at Hospital General Universitario de Elche, Spain. The study population will consist of patients aged 65 years or older hospitalized with community-acquired acute respiratory infection.
The two hospital wards will constitute the study clusters. During the first two-month study period, one ward will be randomly assigned to the expanded diagnostic strategy and the other to the conventional diagnostic strategy. After a two-month washout period, the ward-level strategies will be crossed over for a second two-month study period. Individual participants will receive only the diagnostic strategy assigned to their hospital ward during the corresponding study period.
The expanded diagnostic strategy will include multiplex respiratory PCR using the BIOFIRE Pneumonia Panel plus, including detection of selected antimicrobial resistance genes; bedside lung ultrasound using the BLUE protocol; and serial procalcitonin measurements. The results will be integrated into a predefined diagnostic and therapeutic algorithm to support decisions regarding antibiotic initiation, continuation, modification, de-escalation, and discontinuation.
Participants assigned to the conventional diagnostic strategy will receive usual diagnostic assessment and antimicrobial management. Etiological diagnostic tests will be performed according to routine clinical practice and at the discretion of the treating physician.
The primary objective is to determine whether the expanded diagnostic strategy reduces the total duration of antibiotic therapy compared with conventional diagnostic management. Secondary assessments will include high-impact antibiotic use, antibiotic escalation and de-escalation, microbiological diagnosis and time to diagnosis, detection of multidrug-resistant microorganisms, infectious complications, hospital and intensive care unit length of stay, intensive care unit admission, in-hospital and 30-day mortality, recurrence of infection requiring antimicrobial therapy, 30-day hospital readmission, and antibiotic-related adverse events.
An exploratory economic evaluation of the expanded diagnostic strategy is also planned from the perspective of the Spanish National Health System.
2,072 studies on the registry are indexed under Pneumonia; 286 are open to participants now.
This study's planned enrollment of 406 is above the median of 107 across 1,263 interventional studies indexed under Pneumonia.
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Exclusion Criteria:
Participants receive an expanded diagnostic strategy in addition to conventional diagnostic assessment. The strategy includes multiplex respiratory PCR, bedside lung ultrasound, and serial procalcitonin measurements. Results are integrated into a predefined diagnostic and therapeutic algorithm to support decisions regarding antibiotic initiation, continuation, modification, de-escalation, and discontinuation.
Diagnostic Test: Expanded Diagnostic Strategy
Participants receive conventional diagnostic assessment and antimicrobial management according to usual clinical practice. Etiological diagnostic tests may be performed at the discretion of the treating physician.
Diagnostic Test: Conventional Diagnostic Strategy
A protocolized diagnostic strategy combining multiplex respiratory PCR using the BIOFIRE Pneumonia Panel plus, bedside lung ultrasound using the BLUE protocol, and serial procalcitonin measurements. Diagnostic results are integrated into a predefined algorithm to support decisions regarding antibiotic initiation, continuation, modification, de-escalation, and discontinuation.
Conventional diagnostic assessment and antimicrobial management according to usual clinical practice. Etiological diagnostic tests are performed at the discretion of the treating physician.
Total Duration of Antibiotic Therapy
Total antibiotic exposure, calculated as the sum of days of therapy for all antibiotics received for the index acute respiratory infection, including antibiotic therapy administered during hospitalization and antibiotic therapy prescribed at hospital discharge. Each antibiotic received on a given calendar day contributes one day of therapy; therefore, days of concomitant antibiotic therapy are counted separately for each antibiotic.
Time frame: From hospital admission through 30 days after hospital discharge
Duration of High Impact Antibiotic Therapy
Total exposure to high-impact antibiotics, calculated as the sum of days of therapy for all high-impact antibiotics received for the index acute respiratory infection. High-impact antibiotics are predefined as levofloxacin, moxifloxacin, piperacillin-tazobactam, ceftaroline, ceftobiprole, cefiderocol, cefepime, ceftazidime-avibactam, ceftolozane-tazobactam, carbapenems, vancomycin, and linezolid. Each antibiotic received on a given calendar day contributes one day of therapy; concomitant antibiotics are counted separately.
Time frame: From hospital admission through 30 days after hospital discharge
Antibiotic De-escalation
Proportion of participants in whom antibiotic therapy is de-escalated during the index hospitalization or after discharge. Antibiotic de-escalation is defined as switching from a high-impact antibiotic to a low-impact antibiotic or discontinuing antibiotic therapy, according to the predefined classification in the study protocol.
Time frame: From hospital admission through 30 days after hospital discharge
Antibiotic Escalation
Proportion of participants requiring escalation to high-impact antibiotic therapy for the index acute respiratory infection. Antibiotic escalation is defined as the need to change to an antibiotic classified as high-impact according to the predefined classification in the study protocol.
Time frame: From hospital admission through 30 days after hospital discharge
Pathogen Detection by Pneumonia Panel PCR
Proportion of participants in whom at least one pathogen is detected by the multiplex pneumonia panel PCR performed on a respiratory sample.
Time frame: Within the first 24 hours after hospital admission
Time to Microbiological Diagnosis
Time in hours from hospital admission to the availability of the microbiological result establishing the microbiological diagnosis.
Time frame: From hospital admission to hospital discharge (assessed at 30 days after discharge)
Detection of Multidrug-Resistant Microorganisms
Proportion of participants in whom at least one multidrug-resistant microorganism is detected in any microbiological sample. Multidrug-resistant microorganisms are defined as methicillin-resistant Staphylococcus aureus (MRSA); Enterobacterales producing extended-spectrum beta-lactamases (ESBL), AmpC beta-lactamases, or carbapenemases; Pseudomonas aeruginosa resistant to at least one antibiotic in each of the following classes: penicillins, cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides; carbapenem-resistant Acinetobacter baumannii; and Stenotrophomonas maltophilia.
Time frame: From hospital admission through 30 days after hospital discharge
Respiratory Infection-Related Complications
Proportion of participants who develop at least one complication related to the index acute respiratory infection, including empyema, sepsis, lung abscess, acute respiratory distress syndrome, multiorgan failure, or venous thromboembolism.
Time frame: From hospital admission through 30 days after hospital discharge
Hospital Length of Stay
Total number of days from hospital admission to hospital discharge.
Time frame: From hospital admission to hospital discharge (assessed at 30 days after discharge)
Intensive Care Unit Admission
Proportion of participants requiring admission to the intensive care unit (ICU) during the index hospitalization.
Time frame: From hospital admission to hospital discharge (assessed at 30 days after discharge)
Intensive Care Unit Length of Stay
Total number of days spent in the intensive care unit (ICU) during the index hospitalization among participants requiring ICU admission.
Time frame: From hospital admission to hospital discharge (assessed at 30 days after discharge)
In-Hospital Mortality
Proportion of participants who die from any cause during the index hospitalization.
Time frame: From hospital admission to hospital discharge (assessed at 30 days after discharge)
30-Day Mortality After Hospital Discharge
Proportion of participants who die from any cause within 30 days after hospital discharge.
Time frame: Within 30 days after hospital discharge
Recurrence of Respiratory Infection Requiring Antibiotic Therapy
Proportion of participants who develop a new episode of respiratory infection requiring a new course of antibiotic therapy during the index hospitalization or within 30 days after hospital discharge.
Time frame: From hospital admission through 30 days after hospital discharge
30-Day Hospital Readmission
Proportion of participants requiring hospital readmission for any cause within 30 days after hospital discharge.
Time frame: Within 30 days after hospital discharge
Antibiotic-Related Adverse Events
Proportion of participants who experience at least one adverse event considered related to antibiotic therapy, including phlebitis and Clostridioides difficile infection.
Time frame: From hospital admission through 30 days after hospital discharge
Healthcare Costs
Total direct healthcare costs associated with antimicrobial therapy and the diagnostic procedures included in the expanded diagnostic strategy. Costs will include antimicrobial therapy, serial procalcitonin measurements, bedside lung ultrasound, and multiplex pneumonia panel PCR testing.
Time frame: From hospital admission through 30 days after hospital discharge
Cramér's V Coefficient for Association Between Lung Ultrasound BLUE Profile and Microbiological Diagnostic Category
The association between the presence or absence of a pneumonia-compatible lung ultrasound BLUE profile (ultrasound profile present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Cramér's V Coefficient for the Association Between PLAPS and Microbiological Diagnostic Category
The association between the presence or absence of posterolateral alveolar and/or pleural syndrome (PLAPS) on lung ultrasound (PLAPS present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Cramér's V Coefficient for the Association Between B' Profile and Microbiological Diagnostic Category
The association between the presence or absence of a B' lung ultrasound profile (B' profile present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Cramér's V Coefficient for the Association Between A/B Profile and Microbiological Diagnostic Category
The association between the presence or absence of an A/B lung ultrasound profile (A/B profile present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Cramér's V Coefficient for the Association Between C Profile and Microbiological Diagnostic Category
The association between the presence or absence of a C lung ultrasound profile (C profile present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Cramér's V Coefficient for the Association Between Pleural Effusion and Microbiological Diagnostic Category
The association between the presence or absence of pleural effusion on lung ultrasound (pleural effusion present/absent) and microbiological diagnostic category (bacterial, viral, mixed bacterial-viral, or no microbiological diagnosis) will be measured using Cramér's V coefficient. Lung ultrasound will be performed according to the BLUE protocol, and microbiological categories will be determined using tests performed during the index hospitalization. Cramér's V will be calculated from a 2 × 4 contingency table, yielding a single unitless numerical value ranging from 0 (no association) to 1 (maximum association). Participants with insufficient microbiological data will be excluded. Diagnostic category distributions according to ultrasound findings will also be reported descriptively.
Time frame: During the index hospitalization, with final outcome assessment at 30 days after hospital discharge
Plan to share: No — Individual participant data are not planned to be shared because a formal data-sharing plan has not been established for this study. Any future requests for data access would be evaluated in accordance with institutional policies, ethical requirements, and applicable data protection regulations.
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