Adjusting diffusing capacity for anemia in patients undergoing allogeneic HCT: a comparison of two methodologies

Area of Science:

• Pulmonary Medicine
• Hematology
• Transplantation Science

Background:

• Diffusing capacity of the lungs for carbon monoxide (DLCO) measurements are influenced by hemoglobin levels.
• Two common equations adjust DLCO for hemoglobin: Cotes (ATS/ERS recommended) and Dinakara (used in HCT-CI).
• The comparative prognostic value of these adjustment methods in allogeneic HCT recipients is not well-established.

Purpose of the Study:

• To compare the prognostic accuracy of Cotes and Dinakara DLCO adjustment methods.
• To determine which method better predicts non-relapse mortality and overall survival post-allogeneic HCT.

Main Methods:

• Retrospective analysis of 1273 adult patients undergoing allogeneic HCT with pre-transplant DLCO and hemoglobin.
• Competing risk analysis was used to assess non-relapse mortality.
• Multivariable analyses adjusted for demographics, hematologic variables, cardiac function, and FEV1.

Main Results:

• Cotes-DLCO was 85.6% predicted, Dinakara-DLCO was 103.6% predicted; Cotes-DLCO was lower in anemic patients.
• Cotes-DLCO adjustment improved prediction of non-relapse mortality for mild and moderate impairment.
• Cotes-DLCO predicted 1-year overall survival, while Dinakara-DLCO did not.

Conclusions:

• The Cotes method may underestimate DLCO in anemic HCT patients, whereas Dinakara may overestimate it.
• The Cotes method demonstrates superior prognostic capability for survival outcomes compared to the Dinakara method in allogeneic HCT.
• These findings support the use of the Cotes method for DLCO adjustment in HCT recipients for improved risk stratification.