Improved prognostic stratification power of CIBMTR risk score with the addition of absolute lymphocyte and eosinophil counts at the onset of chronic GVHD

The CIBMTR chronic graft-versus-host disease (cGVHD) risk score can be refined and improved for better prognostic stratification. Three hundred and seven consecutive patients diagnosed with cGVHD by the NIH consensus criteria were retrospectively reviewed and had the CIBMTR risk score applied and analyzed. The CIBMTR risk score was successfully validated in our cohort (n = 307). The 3-year overall survival (OS) rates in each risk group (RG) were 82.5 ± 11.3% (RG1), 79.4 ± 3.0% (RG2), 71.8 ± 6.3% (RG3), and 27.3 ± 13.4% (RG4). A significantly lower OS rate and higher non-relapse mortality (NRM) were noted in RG4 compared to the other RGs. However, there were no differences in OS or NRM among RG1 to 3. To improve prognostic stratification power of the CIBMTR risk score, we incorporated the absolute lymphocyte (ALC) and eosinophil count (EC) at time of cGVHD into the CIBMTR risk score. Lower ALC (<1.0 × 10⁹/L, HR 1.94, p = 0.014) and lower EC (<0.5 × 10⁹/L, HR 3.27, p = 0.014) were confirmed as adverse risk factors for OS. Patients were stratified into four revised risk groups (rRG). The 3-year OS rates were 93.3 ± 6.4% (rRG1, score 0–3), 84.9 ± 3.4% (rRG2, score 4–6), 70.9 ± 4.4% (rRG3, score 7–9), and 32.0 ± 1.1% (rRG4, score ≥ 10) (p < 0.001). The 3-year NRM rates were 0.0% (rRG1), 6.7 ± 0.4% (rRG2), 18.4 ± 0.7% (rRG3), and 57.7 ± 5.1% (rRG4) (p < 0.001). The revised CIBMTR risk score was superior to the original CIBMTR risk score for OS (p < 0.001). The revised CIBMTR risk score including ALC and EC at the onset of cGVHD improved the prognostic stratification power of the CIBMTR risk score for long-term outcomes.