Table 2. Characteristics of observational studies included in the meta-analysis.
| Authors | Country | Samplea | Median age, years | Classification used for diagnosis | MDS subtypes | Patients' IPSS | Serum ferritin cut-off (ng/ml) | Exposed/Not exposed | Variables of adjustment | Outcome(RR, 95%CI) | Median follow-up time, months |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chee et al. 2008 | USA | 77 | 73 | FAB | RARS | Low, IM-1, IM-2 | ≥1000 | 14/63 | RBC transfusion | OS (1.21, 0.39–3.75) | 36 |
| Cermak et al. 2009 | Czech Republic | 137 | 49.4 | WHO | RA, RARS, RCMD, RS-RCMD, 5q | Low, IM-1, IM-2 | ≥2000 | 55/52 | RBC transfusion, corticosteroid and/or cyclosporine A therapy, oral iron chelator therapy, multilineage dysplasia | OS (3.57,1.51–8.47) | - |
| Park et al. 2011 | France | 318 | 77 | WHO | RA, RARS, RCMD, RS-RCMD, RAEB, 5q | Low, IM-1 | ≥300 | 153/165 | Hb level, gender, ringed sideroblasts, platelets, MCV, sEPO level, WHO classification | LFS (1.76, 0.86–3.62) OS (0.91, 0.57–1.43) | 31 |
| ≥1000 | 32/286 | LFS (1.81, 0.55–5.91) OS (0.85, 0.4–1.81) | |||||||||
| Kikuchi et al. 2012 | Japan | 47 | - | WHO | RC, RCMD, RAEB | Low, IM-1, IM-2, High | ≥300 | 19/28 | None | LFS (4.75,0.85–26.51) OS (3.44, 1.14–10.36) | 50 |
| ≥500 | 10/37 | LFS (21.16, 2.06–217.1) OS (1.9, 1.03–3.5) | |||||||||
| Komrokji et al. 2012 | USA | 767 | 69 | WHO | RA, RARS, RCMD, RAEB, MDS-u | Low, IM-1, IM-2, High | ≥1000 | - | RBC transfusion, age, IPSS | OS (1.4, 1.1–1.9) | 35 |
| Li et al. 2013 | China | 1912 | 50 | WHO | RA, RARS, RCMD, RAEB, 5q, MDS-u | IM-1 | ≥500 | 74/117b | RBC transfusion, age, gender, Hb level, platelets, absolute neutrophil level percentage of bone marrow blasts, karyotipe, cellularity of bone marrow biopsy, grade of bone marrow fibrosis | Total sample OS (3.53, 1.9–6.6) Transfused patients OS (2.88, 1.61–5.13) Non-transfused patients OS (3.36, 1.51–7.49) | 21 |
FAB: French-American-British; WHO: World Health Organization; MDS: Myelodysplastic syndrome; RA: Refractory anemia; RARS: refractory anemia with ring sideroblasts; RC: refractory cytopenia with unilineage dysplasia; RCMD: refractory cytopenia with multilineage dysplasia; RS-RCMD: refractory cytopenia with multilineage dysplasia with ring sideroblasts; RAEB: refractory anemia with excess blasts; 5q: 5q syndrome; MDS-u: MDS unclassified; IPSS: International Prognostic Scoring System. Low (Low risk):0; IM-1(Intermediate risk-1): 0.5–1; IM-2 (Intermediate risk-2): 1.5–2; High (High risk): ≥2.5; RBC: red blood cells; Hb: hemoglobin; MCV: mean corpuscular volume; sEPO: serum erythropoietin; OS: Overall survival; LFS: leukemia free survival.
aAll studies were designed as retrospective cohort.
bThe reported number refers to the total sample including both transfused and non-transfused patients. The separate number of subjects included in the transfused and in the non-transfused group, according to the exposure, was not available in the study.