The purpose of this study is to understand the incidence of transfusion dependent lower-risk myelodysplastic syndromes (TD LR-MDS) and describing real-world first-line treatment patterns, healthcare resource utilization, and associated clinical outcomes in adult patients with TD LR-MDS 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.

The study population will consist of adult participants diagnosed with transfusion dependent lower-risk myelodysplastic syndromes (TD LR-MDS) identified in Spain using the BIG-PAC® database