A Study of Incidence, Treatment Patterns, and Outcomes in Transfusion-dependent Lower-risk Myelodysplastic Syndromes in Spain

Inclusion criteria

• Age ≥18 years at the time of lower-risk myelodysplastic syndromes (LR-MDS) diagnosis.
• Documented diagnosis of LR-MDS identified through International Classification of Diseases (ICD) 9 codes recorded in medical history. In addition, recorded diagnosis of MDS with an explicitly documented International Prognostic Scoring System (IPSS) category of low or intermediate-1 and/or revised IPSS category of very low or low at or around the index date.
• Evidence of transfusion dependence, defined as receiving ≥2 red blood cell (RBC) units within an 8-week interval, occurring within the selection window (January 1, 2021, to May 31, 2025, or the latest date ensuring detectable follow-up).
• Active participants in BIG-PAC®, defined as ≥1 claim of any kind within 12 months prior to or on the index date (baseline period).
• A minimum of 6 months of follow-up data available after the index date, unless the patient dies earlier

Exclusion criteria

• Diagnosis of high-risk MDS (HR-MDS) or another hematologic malignancy (e.g., acute myeloid leukemia) before the index date.
• Documented transformation to acute myeloid leukemia (AML) or HR-MDS occurring before initiation of first-line treatment.
• Participation in interventional clinical trials during the period of first-line treatment.
• Presence of anemia secondary to non-MDS-related causes, such as nutritional deficiencies, advanced chronic kidney disease, or active bleeding, when such conditions preclude accurate attribution of transfusion dependence to MDS.
• Lack of sufficient clinical history, defined as <12 months of observable data before the index date.
• Have missing key variables, e.g., age or sex.
• Incomplete or inconsistent clinical information that prevents reliable evaluation of key study variables, including transfusion dependence status, treatment patterns, or outcomes.