Seminar 12 Bone Marrow Transplantation for Leukemia Rhajiv

Seminar #12 Bone Marrow Transplantation for Leukemia Rhajiv Ratnatunga Honors STAT 1000

Basics �Bone marrow transplantation is one of the most common treatments for acute leukemia.

Purpose of Study � The purpose of this study was to consider the effects of bone marrow transplantation with a radiationfree conditioning regimen. � Patients were given different drugs in two groups at four different hospitals (two in US and two in Australia) � 137 patients were studied (97 in the US and 40 in Australia) from 1984 to 1989.

Study design �This study was…. a) Retrospective observational study b) Prospective observational study c) Experiment c – This was an experiment because the experimenters controlled different variables (specifically, the types of drugs given) in order to see their effect on recovery from or relapse into acute leukemia. The study was two sample since the study looked at the effects of two independent drug treatments.

Importance of age �The experimenters grouped individuals into many different risk categories. �Donor age and recipient age was one of the risk categories.

Explanatory vs. Response �Since we start with a recipient who needs a donor. . . The explanatory variable is The response variable is recipient age donor age.

Scatter plot with regression The regression equation is Recipient = 8. 89 + 0. 684 Recipients S = 6. 55008 R-Sq = 54. 0% r =. 734846 (fairly strong + relationship)

Interpretation of slope �Positive slope of. 790 means that for every additional year in the age of the donor, we expect the age of the recipient to go up around 9. 6 months. �Fairly strong positive correlation supports this relationship.

Interpretation of intercept �None of the recipients were less than 1 year old �Intercept is of no interpretive value since it deals with a recipient age of 0

Interpretation of S value �The s value of 6. 55008 meant that ages predicted by the regression line tended to be off on average by around 6. 5 years from the actual ages. �This difference makes sense when looking at the r value of the correlation r =. 734846 (fairly strong + relationship)

Another reason Why are ages positively correlated? �Bone marrow transplantation need exact matches of Human leukocyte antigen �Highest percentage of matches found among…. Siblings

Age difference Bimodal Parent donation vs. Sibling donation

Sample or Population � Was this study reported from a sample or population? Sample

Bias �The experimenters tried to categorize risk factors prior to transplantation in order to reduce confounding variables. �Objective determinations such as “death” and “remission” do not involve bias.