OPTIMIZE-ILD-1: A Randomized, Pragmatic, Parallel-Group Trial Evaluating the Impact of an Optimized Diagnostic Circuit on Time to Diagnosis in Patients With Suspected Interstitial Lung Disease
The OPTIMIZE-ILD-1 trial is a prospective, randomized, open-label clinical trial designed to evaluate the impact of a coordinated diagnostic pathway on patients with suspected interstitial lung disease (ILD). In routine clinical practice, diagnostic workflows for ILD are frequently fragmented, involving multiple independent appointments that can lead to significant delays and increased burden for patients and caregivers. This study compares the standard diagnostic pathway against an optimized circuit where core diagnostic procedures-such as high-resolution CT, pulmonary function tests, and laboratory panels-are pre-bundled and scheduled within a coordinated and compressed timeframe. All eligible patients referred for suspected ILD are included consecutively to ensure a pragmatic, real-world representation of the referral population. The primary objective is to measure the time to diagnostic communication, defined as the duration from randomization to the date the patient is formally informed of the final diagnosis following a multidisciplinary team (MDT) consensus. Secondary objectives include assessing the time to MDT diagnosis, the time to treatment initiation (when clinically indicated), socioeconomic cost-burden, and the environmental carbon footprint of the diagnostic journey. Furthermore, the study evaluates health-related quality of life, psychological distress, and clinical frailty, while exploring factors such as language proficiency as determinants of diagnostic equity. Caregiver-related outcomes, including burden and experience measures, are contingent upon the presence of a primary caregiver and the provision of their independent informed consent. The design of this protocol was informed by a patient focus group and is officially endorsed by the 'AIRE' Associació Catalana de Malalts i Trasplantats Pulmonars, ensuring a patient-centered approach that prioritizes the diagnostic journey's efficiency and human impact.
• Age 18 years or older.
• Referral for suspected or undiagnosed interstitial lung disease (ILD).
• Incomplete interstitial lung disease diagnostic work-up at the time of referral (previous chest computed tomography or partial blood tests allowed, but not complete pulmonary function testing or the full ILD diagnostic laboratory panel).
• Presence of at least one radiological finding suggestive of interstitial lung disease on chest X-ray or chest computed tomography (including reticulation, ground-glass opacities, traction bronchiectasis or honeycombing) that cannot be explained by other diseases.
• Presence of at least one functional abnormality compatible with interstitial lung disease (reduced forced vital capacity or reduced diffusing capacity for carbon monoxide) that cannot be explained by other diseases.
• Presence of at least one physical examination finding suggestive of interstitial lung disease (persistent bibasilar crackles or digital clubbing) that cannot be explained by other diseases.
• Presence of symptoms such as persistent or progressive shortness of breath or chronic cough, only when accompanied by at least one radiological, functional or semiological criterion above.
• History of relevant environmental exposure, occupational exposure, autoimmune disease, or suspected drug or radiation toxicity, only when accompanied by at least one radiological, functional or semiological criterion above.
• Family history of interstitial lung disease in a first-degree relative, only when accompanied by at least one radiological, functional or semiological criterion above.
• Ability to provide informed consent.