METHODS
This was a retrospective study where data was collected from chart
review of patients who underwent their first hematopoietic stem cell
transplant at Riley Hospital for Children. A database maintained by the
Pediatric Stem Cell Transplant Program was used and contained
information on patients who underwent stem cell transplant from January
1, 2007 to April 30th, 2017. The database provided
information such as demographics, date of diagnosis, and type of
oncologic diagnosis. Additional inclusion criteria for the study were as
follows: patients who performed pre-transplant DLCO that met American
Thoracic Society (ATS) criteria, and a hemoglobin recorded within 7 days
of their pulmonary function testing. This study was approved by the
Indiana University Institutional Review Board.
Information on patients’ demographics, primary disease, pre-transplant
pulmonary function tests, and chest imaging prior to transplant was
compiled in an Indiana School of Medicine RedCap database.
Post-transplant data collected included additional transplants, relapse
status, graft versus host disease (GVHD) status, all post-transplant PFT
data, mortality, and pulmonary complications. Post-transplant data was
collected, including mortality data at one and three years. Pulmonary
complications were defined as documented and treated pulmonary
infections as well as clinically significant abnormal chest imaging.
Mortality was defined as death by any cause.
Paired t-tests and ANOVA models were used to define any differences
between the two equations at baseline and when stratifying by Hgb level.
Logistic regression models were used to determine associations between
the Dinakara and Cotes equation with mortality at one- and three-years
post-transplant. Results were reported as odds ratios with 95%
confidence intervals and p-values. Two sample t-test statistical
analysis were then used to compare PFT’s and hemoglobin correction
equations with and without pulmonary complications. Spirometry data were
reported as z-scores while DLCOHgb values were reported
as percent predicted values and p-values produced from student’s t- test
were used for comparison. The Global Lungs Initiative reference
equations for used for spirometry, and data from Kim et al. were used
for DLCO reference equations. All analyses were performed using SAS v9.4
and all analytic assumptions were verified.