Evaluating the Use of an App in Pleural Disease: Algorithm-supported Clinical Decision Making Versus Usual Care (APPLAUS)

Evaluating the Use of an App in Pleural Disease: Algorithm-supported Clinical Decision Making Versus Usual Care: a Multicentre, Stepped-wedge Cluster-randomised Controlled Trial to Reduce Number of Days in Hospital.

Pleural disease is a group of conditions that affect the membrane around the lungs. These conditions-fluid around the lungs, infections, cancer, and collapsed lung-are common and can cause serious illness. They often lead to long hospital stays, emergency admissions, and reduced quality of life. In Denmark and worldwide, the number of patients with pleural disease is rising, and the treatment is costly for the healthcare system.

How long patients stay in the hospital depends on the type of pleural disease. Some stay less than a week, while others remain for several weeks, especially if complications occur. Research shows that early diagnosis and treatment based on clinical guidelines can shorten hospital stays and improve outcomes.

In the UK, many hospitals have created dedicated pleural clinics run by specialists. These clinics help ensure that patients receive fast, consistent, and evidence based care, and they have reduced the number of days patients spend in hospital. In Denmark, however, such clinics are rare. A recent national survey showed that many Danish hospitals do not follow current pleural disease guidelines, and many lack clear pathways for diagnosing and treating these patients. As a result, patients may receive suboptimal care.

This project aims to close that gap. The goal is to develop an easy to use, guideline based decision tool that supports doctors in emergency, medical, and surgical departments. The tool will guide clinicians from the moment a patient arrives until discharge, helping them choose the right tests and treatments at the right time. By making expert knowledge accessible to non specialists, the project hopes to improve patient care, reduce complications, and shorten hospital stays.

Ultimately, the project seeks to ensure that all patients with pleural disease in Denmark receive fast, safe, and evidence based treatment-no matter where they are admitted.

Study Overview

• Status: Enrolling by invitation
• Conditions: Pleural Diseases; Pleural Effusion; Pleural Infection; Pneumothorax Spontaneous Secondary; Pneumothorax Spontaneous Primary
• Intervention / Treatment: Other: Usual care; Behavioral: Clinical decision-making support tool

• Study Type: Interventional
• Enrollment (Estimated): 828
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Aalborg, Denmark, 9000
    • Aalborg University Hospital
  • Aarhus, Denmark, 8200
    • Aarhus University Hospital
  • Amager, Denmark, 2300
    • Amager Hospital
  • Esbjerg, Denmark, 6700
    • Esbjerg Hospital
  • Hillerød, Denmark, 3400
    • North Zealand Hospital, Hillerød
  • Hvidovre, Denmark, 2650
    • Hvidovre Hospital
  • Kolding, Denmark, 6000
    • Kolding Hospital
  • Køge, Denmark, 4600
    • Zealand University Hospital, Køge
  • Odense, Denmark, 5000
    • Odense University Hospital
  • Slagelse, Denmark, 4200
    • Slagelse Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

One or more of the following, relevante ICD-10 codes for either spontaneous pneumothorax, pleural effusion or pleural infection.

Spontaneous pneumothorax:

• DJ93
• DJ930
• DJ931
• DJ938
• DJ939

Pleural effusion:

• DJ90
• DJ909
• DJ919
• DJ91
• DJ940
• DJ948
• DJ948A
• DJ949
• DC782

Pleural infection:

• DJ86
• DJ860
• DJ860

Exclusion Criteria:

• Traumatic pneumothorax (including iatrogenic pneumothorax)
• Hemothorax

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Usual care; Usual provided care for patients with spontaneous pneumothorax, pleural effusion or pleural infection. All clusters begin in this condition before transitioning to the intervention as part of the stepped-wedge schedule.	Other: Usual care; Care supported by a clinical decision-support tool delivered via a smartphone app.
Experimental: Clinical decision-making support tool; Care supported by the clinical decision-making app. Clusters transition to this condition at predefined time points according to the stepped-wedge design.	Behavioral: Clinical decision-making support tool; Care for patients with spontaneous pneumothorax, pleural effusion or pleural infection when supported by a clinical decision-support tool, in the form of a smartphone app.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Length of hospital stay (days)	Number of days from hospital admission to hospital discharge.	From hospital admission through hospital discharge (up to 90 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correct pneumothorax subtype classification	Whether the pneumothorax subtype was correctly classified during the index hospital admission according to predefined diagnostic criteria (yes/no).	During index hospital admission (up to 90 days after admission)
Number of participants receiving each initial pneumothorax management strategy	Number of participants managed with either conservative care, needle aspiration, chest tube insertion, or ambulatory device insertion	Within 24 hours from hospital admission
Chest tube size	Diameter of chest tube used for treatment of spontaneous pneumothorax, reported in French units (Fr).	Periprocedural.
Number of participants with persistent air leak (>7 days)	Number of participants with ongoing air leak through the chest drainage system for more than 7 days after chest tube insertion (yes/no)	From chest tube insertion until resolution of air leak or up to 90 days
Number of participants undergoing high-resolution computed tomography (HRCT)	Number of participants who underwent high-resolution computed tomography (HRCT) during hospital admission or within 90 days after discharge, recorded as yes/no	During index hospital admission
Number of participants receiving complete recommended diagnostic work-up for unilateral pleural effusion	Assessment of whether recommended blood tests (full blood count, C-reactive protein, renal function tests, liver function tests, and albumin) and pleural fluid analyses (pH or glucose, LDH, leukocyte differential count, microbiology culture and sensitivity analysis, and cytology) were performed in participants with unilateral pleural effusion.	At end of index hospital admission (up to 90 days).
Chest tube size	Chest tube size (French gauge, Fr) used for pleural effusion drainage	Periprocedural
Definitive cause for pleural effusion	Was a definitive cause for the cause of pleural effusion established.	During hospital admission or within 90 days after discharge.
Definitive pleural procedure	Definitive pleural procedure within 90 days of admission due to pleural effusion.	During hospital admission or within 90 days after discharge.
Number of participants receiving complete recommended diagnostic work-up for suspected pleural infection	Assessment of whether recommended blood tests (full blood count, C-reactive protein, renal function tests, liver function tests, and albumin) and pleural fluid analyses (pH or glucose, LDH, leukocyte differential count, microbiology culture and sensitivity analysis, and cytology) were performed in participants with suspected pleural infection.	Up to 90 days
Chest tube diameter of chest tubes used for pleural infection.	Diameter of chest tube used for drainage of pleural infection, reported in French units (Fr).	Periprocedural.
Number of participants receiving intrapleural enzyme therapy (IET) for pleural infection.	Assessment of whether intrapleural enzyme therapy (IET) was administered in participants with pleural infection despite chest tube drainage.	Up to 90 days.
Length of antibiotic treatment	Total length of antibiotic treatment (both intravenously and orally) for pleural infection.	During hospital admission or within 90 days after discharge.

Collaborators and Investigators

• Sponsor: Zealand University Hospital
• Investigators: Principal Investigator: Casper Jensen, MD, Lungemedicinsk Forskningsenhed (PLUZ), Institut for Regional Sundhedsforskning, Syddansk Universitet

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2026
• Primary Completion (Estimated): October 15, 2026
• Study Completion (Estimated): October 15, 2026

Study Registration Dates

• First Submitted: March 20, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 4, 2026

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Pleural Effusion; Pneumothorax; Pleural Diseases
• Other Study ID Numbers: p-2024-17577

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No