Lifestyle, Dietary Habits, and Modifiable Risk Factors in Patients with Acute Pulmonary Embolism: Protocol for a Prospective Observational Study with Development and Validation of a Composite Lifestyle and Nutrition Questionnaire

Background/Objectives: Modifiable lifestyle factors are established determinants of venous thromboembolism risk, but their relationship with the severity and early course of acute pulmonary embolism (PE) is poorly characterized, and no validated Romanian-language instrument captures these domains in the acute PE setting. This protocol describes a prospective observational study with two distinct components: (i) a measurement component that develops and validates the Pulmonary Embolism Lifestyle and Nutrition Questionnaire (PE-LNQ), a composite patient-completed instrument, and (ii) a clinical component that analyzes the associations between lifestyle factors, routine clinical and laboratory data, and the severity and early outcomes of acute PE. Methods: Phase 1 comprises cross-cultural adaptation, content validation, piloting, and COSMIN-based psychometric evaluation. Its primary endpoints are test–retest reliability (ICC ≥ 0.70) and confirmation of ≥ 75% of a priori construct-validity hypotheses, including convergent validity against measured anthropometry and routine biomarkers. Phase 2 enrolls consecutive adults with CTPA-confirmed acute PE in a staged design (minimum 220 patients single-center; approximately 400 with a planned multicenter extension). The primary clinical endpoint is intermediate-/high-risk PE (vs. low risk) by sPESI/PESI, with the ordinal PESI class (I–V) as the key secondary endpoint. Severity data and a pre-specified panel of routine admission laboratory parameters are extracted from the medical record without study-specific sampling; patients are followed for in-hospital, 3-, and 6-month adverse events. The confirmatory analysis is multivariable logistic regression; ordinal, survival, incremental-value, and biomarker analyses are pre-specified as secondary or exploratory. Expected Results: The PE-LNQ is expected to show adequate reliability and validity, and less favorable lifestyle profiles to be associated with higher severity class and more early adverse events. Conclusions: This study will deliver a validated, freely reusable instrument and clarify the prognostic relevance of modifiable lifestyle factors, supporting their integration into risk assessment and secondary prevention.