"Breathlessness Diagnostics in a Box" (BiaB) for Primary Care. A Multi-country Quality Improvement Project Using a Randomized Stepped-wedge Design

This is a prospective interventional study using a stepped-wedge cluster design with a usual care period followed by an intervention period. Participating general practice sites are assigned to one of five predefined sequences determining the timing of transition from usual care to the BiaB intervention. All sites start in the usual care phase and sequentially transition to the intervention phase according to the study schedule. The primary objective of the study is to assess whether use of BiaB shortens the time to diagnosis in patients presenting with breathlessness, compared with usual care without BiaB. Secondary objectives include evaluating whether BiaB increases the number of new diagnoses of chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD), and assessing the usability and efficiency of the BiaB tool. The study is conducted in general practice settings in the Netherlands, Spain, and Portugal, with a total of 45 sites. Each site participates for a total duration of 40 weeks. Patients attend a single study visit and may complete up to four quarterly questionnaires over a maximum follow-up of one year. Data are collected during routine clinical care, from electronic medical records, and via questionnaires completed by patients and healthcare professionals. Data from the usual care period, and where available retrospective data, are used as control data for comparison with the intervention period.