The lipedema common case report form as a research tool: standardizing lipedema data collection.

Lipedema is a chronic adipose tissue condition that primarily affects women. Despite increasing recognition of lipedema, the condition remains poorly understood and lacks standardized diagnostic criteria or confirmatory tests. Variability in definitions and measurement across clinical and research settings impedes comparability across studies, constraining the evidence base needed to support future advances in clinical practice and patient care. To address challenges associated with inconsistent definitions and data collection, the Lipedema Foundation (LF) partnered with clinicians, researchers, and biostatisticians to develop a Lipedema Common Case Report Form (CCRF). The CCRF was designed to be a research data harmonization tool and is not intended to define diagnostic standards or guide clinical treatment decisions. Its development involved review of published lipedema clinical guidelines and collaborative work to define data elements and attributes for inclusion. When they existed, validated or standardized measures were incorporated directly. When no suitable standardized measures were available, an iterative and collaborative process was used to develop lipedema-specific Common Data Elements (CDEs). The initial version of the CCRF was piloted in participants with and without lipedema, and updates based on participant and clinician feedback were incorporated into the CCRF. A biostatistical review evaluated data completeness, quality, and structure, leading to additional refinements. The final Version 1 instrument consists of 682 CDEs organized into four classifications: (1) Core, (2) Supplemental Highly Recommended, (3) Supplemental, and (4) Exploratory. The current version is prepared for dissemination in the field. By disseminating the CCRF broadly and encouraging adoption in all lipedema research beginning in 2026, including all newly initiated LF-funded projects, LF intends to evaluate its use with grantees and iterate systematically to achieve consistent and comparable data collection. The CCRF provides a structured framework for harmonized data collection that may facilitate comparability across studies and support future development of standardized diagnostic and research methodologies.