Table I.

Association of patient demographics with minimal residual disease after induction therapy

Presenting feature	No. of patients	Induction I MRD status			Induction II MRD status
		Positive	Negative	P	Positive	Negative	P
Age (years)
< 10	108	33	68	<0.001	20	80	< 0.001
≥ 10	100	38	58		18	75
Leucocyte counts (x 109/l)
< 50	153	51	97	0.49	28	117	0.84
≥ 50	55	20	29		10	38
Sex
Male	117	42	70	0.66	22	88	1.0
Female	91	29	56		16	67
Race
White	146	49	90	0.75	28	107	0.16
Black	38	12	24		9	27
Other	23	9	12		1	20
FAB Subtype				0.01			0.32
M0	2	1	1	1.0	0	2	1.0
M1	23	15	7	0.002	6	14	0.24
M2	35	10	25	0.34	5	29	0.47
M4	55	18	37	0.62	10	44	1.0
M5	52	10	35	0.034	6	39	0.29
M6	2	1	1	1.0	1	1	0.36
M7 (AMKL)	25	9	14	0.82	5	18	0.78
NA	14	7	6	0.23	5	8	0.14
Karyotype				<0.001			<0.001
t (9;11)	15	4	11	0.58	2	13	0.74
11q23 non-t(9;11)	25	5	17	0.24	2	20	0.26
t(1;11)	2	2	0	0.13	0	2	1.0
t(4;11)	1	0	0	NA	0	0	NA
t(6;11)	2	0	2	0.54	0	2	1.0
t(10;11)	9	0	9	0.028	1	8	1.0
t(11;19)	9	2	5	1.0	1	6	1.0
Other 11q23	2	1	1	1.0	0	2	1.0
t (8;21)	30	6	24	0.062	1	28	0.02
inv (16)/t(16;16)	25	0	25	<0.001	0	25	0.005
t(1;22)	5	0	4	0.30	0	4	1.0
Normal	49	28	19	<0.001	14	31	0.034
Other	54	25	25	0.026	17	32	0.004
NA	5	3	1	0.13	2	2	0.17
FLT3 status
ITD	27	20	6	<0.001	13	12	< 0.001
Mutation	8	1	6		1	6
Wild-type	158	46	105		23	125
Unknown	15	4	9		1	12
Study Arm
High-dose Ara-C	99	29	64	0.19	15	76	0.37
Low-dose Ara-C	109	42	62		23	79

MRD, minimal residual disease; FAB, French-American-British classification; ITD, internal tandem duplication; NA, not available; AMKL, acute megakaryoblastic leukaemia; Ara-C, cytarabine.

Total numbers may be unequal due to incomplete data. The exact χ² test was used to compare categorical features and MRD status.