Table 1:

Barriers to hematopoietic cell transplantation

Article	Study design	Study population	Sample size	Age data reported	Age definitionsa (continuous or categorical, cut-off)	Types of transplant	Data source	Barriers	No associations found
Adrianzen Herrera 201918	Retrospective	Adult T-cell leukemia-lymphoma	88	Median: 56 years (range 28–87)	Categorical (<40, 41–60, or >61)	Allogeneic	EMR of Montefiore Bronx	Socioeconomic status, donor/human leukocyte antigen-subtype availability, insurance, patient preference, Poor understanding or medical non-compliance, cancer type, disease status	Age, performance status
Al-Hamadani 201412	Retrospective	Multiple myeloma	137,409	N/A	Categorical (<65, 65–75, or >75)	Autologous	NCDB	Race, socioeconomic status, age, insurance, distance to transplant center/residence, year diagnosed, academic vs. community, bed size	Gender/Sex, comorbidity
Barker 201019	Prospective	Acute leukemia, MDS, myeloproliferative disease, NHL, CLL, prolymphocytic leukemia, HL, MM, or severe AA	553	Median: 47 years (range 0.9–73)	-	Allogeneic	- NMDP for URD - Bone Marrow Donors Worldwide, NMDP and New York Blood Center for Cord Blood	Donor/human leukocyte antigen-subtype availability, race	None
Berman 199237	Retrospective	AML	350	35–46% of patients were aged ≤40 years	-	Allogeneic	MSKCC	Comorbidity, patient preference, disease status	None
Bhatt 201810	Retrospective	AML	17,555	Median: 68 years (range 61–75)	Categorical (60–65, 66–70, or 71–75)	Autologous and allogeneic	NCDB	Race, socioeconomic status, age, insurance, comorbidity, distance to transplant center/residence, year diagnosed, academic vs community	Gender/Sex, time from diagnosis to initial therapy initiation
Bierenbaum 201220	Retrospective	AML	504	White: median 60.8 years; Black: median 54.4 years	Categorical (<60 or ≥60)	Autologous and allogeneic	UMGCC	Race, age, donor/human leukocyte antigen-subtype availability, substanceuse disorder, comorbidity, performance status, patient preference, disease status	Time from diagnosis to referral
Cho 200638	Retrospective	ALL, CLL, AML, CML, Hodgkin’s, NHL	Leukemia: 2,899; Lymphoma: 3,536	Leukemia: median 37 years; Lymphoma: median 46 years	Continuous	Autologous and allogeneic	Arizona Hospital Inpatient Discharge Data Public Release File	Age, insurance, comorbidity, cancer type, academic vs community, bed size	Gender/Sex, race
Costa 201521	Retrospective	MM	22,462	Median: 71 years (range 61–81)	Continuous	Autologous	SEER	Gender/Sex, race, age	None
Delamater 201622	Cross-sectional	All HCT indications	306,675,006	76% aged ≥18 years	Categorical(0–9, 10–17, 18–29, 30–44, 45–59, 60–74, or ≥75)	Autologous and allogeneic	2010 US Census Block Group Data	Race, age, distance to transplant center/residence	Gender/Sex
Fiala 201723	Retrospective	MM	20,916	Median: 77.1 years	Continuous	Autologous and allogeneic	SEER-Medicare linked database	Gender/Sex, race, socioeconomic status, age, insurance, comorbidity, performance status, year diagnosed	Distance to transplant center/residence
Getta 201724	Retrospective	MDS	362	Median: 65 years (range 20–75)	Categorical (<40, 40–64, or ≥65)and (<65 or ≥65)	Allogeneic	MSKCC	Age, comorbidity, physician perception of risk, performance status, patient preference, disease risk, disease status, year diagnosed	Gender/Sex, marital status, race, insurance, socioeconomic status, distance to transplant center/residence
Hwang 200439	Retrospective	ALL, CLL, AML, CML, and other leukemias	6,574	N/A	Categorical (0–17, 18–64, or ≥65)	Autologous and allogeneic	Texas Hospital Inpatient Discharge Public Use Data File	Gender/Sex, age, comorbidity, cancer type	Race, insurance
Jabo 201725	Retrospective	ALL, AML	ALL: 367; AML: 3,657	ALL: 68% aged ≥60 years; AML: 89% aged ≥60 years	Categorical (15–39, 40–59, or ≥60)	Allogeneic	California Cancer Registry	marital status, race, socioeconomic status, age, year diagnosed	Gender/Sex, distance to transplant center/residence
Joshua 201026	Retrospective	AML, ALL, CML, NHL, MM	27,725	16% aged 6069 years; 29% aged 5059 years; 24% aged 4049 years 13% aged 3039 years; 8% aged 20–29 years; 10% aged 019 years	-	Allogeneic	SEER and CIBMTR	Gender/Sex, race	None
Kollman 200111	Cross-sectional	CML, AML, ALL, other leukemia, MDS, AA, and other malignant and non-malignant diseases	544 (Physician s, patients, and transplant center coordinators)	Median 29 years (range 0–65)	-	Allogeneic	NMDP	Donor/human leukocyte antigen-subtype availability, insurance, physician perception of risk, patient preference, Disease status, other treatment options	None
Mehta 200336	Retrospective	ALL, AML, CML	Not provided	N/A	-	Allogeneic	CIBMTR and SEER	Gender/Sex	Cancer type
Mitchell 199740	Retrospective	All types of leukemia and lymphoma	Leukemia: 15,116; Lymphoma: 23,304	Median: 30.7 years	Continuous	Autologous and allogeneic	Inpatient Hospital Discharge Database (California, Maryland, New York, Massachusetts), Bureau of the Census	Insurance, year diagnosed, cancer type, age, race	Gender/Sex
Mitchell 201527	Retrospective	All types of leukemia and lymphoma	Leukemia: 5,721; Lymphoma: 9,137	Leukemia: 36.7 years (SD 20.9), lymphoma: 47.5 years (SD 13.6)	Continuous	Autologous and allogeneic	California Office of Statewide Planning and Development	Race, socioeconomic status, age, insurance, distance to transplant center/residence, cancer type	Gender/Sex
Patel 201528	Retrospective	AML	11,084	43% 6180 years, 18% >80 years	Categorical (<21, 21–40, 41–60, 61–80, or >80)	Autologous and allogeneic	California Cancer Registry research database, Office of Statewide Health Planning and Development	Race, age, comorbidity, disease risk	Gender/Sex
Paulson 201929	Retrospective	AML, ALL, MDS	3,147	Not provided	-	Allogeneic	SEER and CIBMTR	Socioeconomic status	Race, social support, distance to transplant center/residence
Pidala 201330	Retrospective	ALL, AML, MDS, myeloproliferative disorder, MM, Non-Hodgkin lymphoma, Hodgkin lymphoma, CLL, severe AA, PNH	531	50–51 years (range 17–72)	Continuous	Allogeneic	Blood and Marrow Transplantation Program at Moffitt Cancer Center	Race, age, donor/human leukocyte antigen-subtype availability, insurance, comorbidity, social support, patient preference, disease status, other treatment options, psychiatric disability	Gender/Sex, performance status, CMV serologic status
Pidala 201331	Cross-sectional	CML, ALL, AML, MDS	113 (Physicians)	N/A	Categorical (35–40, 45–50, 50–55, 55–60, 60–65, 65–70, 70–75, or >75)	Allogeneic	AMA Master file	Gender/Sex, race, age, insurance, psychiatric disability, substance use disorder, comorbidity, physician perception of risk, social support, distance to transplant center/residence, other treatment options, language, poor understanding or medical non-compliance, academic vs. community, physician experience with transplant	Donor/human leukocyte antigen- subtype availability
Preussler 201432	Cross-sectional	All HCT Indications	47 states	N/A	-	Allogeneic	State Medicaid website	Insurance	None
Preussler 201633	Mixed-method	All HCT Indications	Focus group: 15, Survey: 133 (Social workers)	N/A	-	Autologous and allogeneic	N/A	Insurance, social support	None
Pulte 201334	Retrospective	AML, ALL	ALL: 3148, AML:11,735	ALL: 38–39 years, AML:68–69 years	-	Autologous and allogeneic	SEER	Race	None
Schriber 201735	Retrospective	MM	24,102	N/A	Categorical (<45, 45–60, or 61–75)	Autologous	CIBMTR	Gender/Sex, race, age	None

Abbreviations: AA, aplastic anemia; ALL, acute lymphoblastic leukemia; AMA, American Medical Association; AML, acute myeloid leukemia; CLL, chronic lymphocytic leukemia; CML, chronic myeloid leukemia; CMV, cytomegalovirus; HCT, hematopoietic cell transplantation’ HL, Hodgkin’s lymphoma; EMR, electronic medical records; IBMTR, International Bone Marrow Transplant Registry; MDS, myelodysplastic syndrome; MM, multiple myeloma; NCDB, National Cancer Database; NHL, non-Hodgkin’s lymphoma; NMDP, National Marrow Donor Program; MSKCC, Memorial Sloan Kettering Cancer Center; PNH, paroxysmal nocturnal hemoglobinuria; SCT, stem cell transplantation; SEER, Surveillance, Epidemiology, and End Results Program; UMGCC, University of Maryland Greenebaum Cancer Center; URD, unrelated donor

^aStudies that assessed age as a barrier