Comparison of three screening tests for autism in preterm children with birth weights less than 1,500 grams

Figures & data

Table 1 Family and child characteristics of the preterm population (age 2 years)

Sample	Mean (SD) or frequency (%)			Statistics
	Total (N=157)	With ASD diagnosis (N=13)	Without ASD diagnosis (N=121)
Maternal
Age at delivery (years)	32.6 (4.4)	32.3 (3.2)	32.7 (4.3)	U=829.5, df=1, P=0.749
Education
Elementary	2 (1.3%)	0 (0%)	1 (0.8%)	χ^2=0.637, df=2, P=0.727
High school	89 (56.7%)	6 (46.2%)	68 (56.2%)
University	65 (41.4%)	7 (53.8%)	52 (43.0%)
Unknown	1 (0.6%)	0 (0%)	0 (0%)
Paternal
Age at delivery (years)	34.8 (4.9)	33.5 (2.9)	35.0 (4.8)	U=898, df=1, P=0.315
Education
Elementary	1 (0.6%)	0 (0%)	1 (0.8%)	χ^2=0.904, df=2, P=0.636
High school	90 (57.3%)	9 (69.2%)	66 (54.5%)
University	61 (38.9%)	4 (30.8%)	51 (42.2%)
Unknown	5 (3.2%)	0 (0%)	3 (2.5%)
Child
Birth weight (g)	1,034.1 (283.4)	964.5 (300.4)	1,042.2 (282.3)	U=898.5, df=1, P=0.402
Birth length (cm)	35.6 (3.6)	35.6 (4.1)	35.5 (3.5)	U=243, df=1, P=0.883
Gestational age (weeks)	28.2 (2.6)	26.9 (2.0)	28.3 (2.5)	U=1,071, df=1, P=0.033
Stay in hospital (days)	75.8 (29.7)	89.5 (23.9)	75.4 (29.2)	U=357.5, df=1, P=0.042
Use of corticoids	39 (24.8%)	5 (38.5%)	27 (22.3%)	χ^2=0.914, df=2, P=0.339

Abbreviations: SD, standard deviation; ASD, autism spectrum disorders; N, number of children.

Table 2 Comparison of screening tools used in the preterm population (age 2 years)

Screening tool	N	Positive screens	Negative screens
M-CHAT	157	28 (17.8%)	129 (82.2%)
CSBS-DP-ITC	155	42 (27.1%)	113 (72.9%)
ITSP	154	22 (14.3%)	132 (85.7%)

Notes: Cochran’s Q-test for all three screening tools: Q=9.77, df=2, P=0.008; paired Wilcoxon sign test FDR (false discovery rate adjusted for multiple testing): CSBS-DP-ITC vs ITSP (P=0.022), CSBS-DP-ITC vs M-CHAT (P=0.022), M-CHAT vs ITSP (P=0.522).

Abbreviations: N, number of screened children; M-CHAT, Modified Checklist for Autism in Toddlers; CSBS-DP-ITC, Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist; ITSP, Infant/Toddler Sensory Profile.

Table 3 Psychometric values of three screening test for autism based on ROC analysis

	Specificity	Sensitivity	PPV	NPV	Accuracy
Single test use
M-CHAT (N=134)	0.926	0.692	0.500	0.966	0.903
CSBS-DP-ITC (N=132)	0.849	0.846	0.379	0.981	0.848
ITSP (N=133)	0.942	0.462	0.462	0.942	0.902
Combined use of the tests with requested positivity in at least
One of the tests (N=131)	0.797	1.000	0.351	1.000	0.817
Two of the tests (N=131)	0.924	0.769	0.526	0.973	0.908
All three tests (N=131)	0.992	0.231	0.750	0.921	0.916

Notes: Due to missing data, ROC calculations for some tests did not include the full number of 134 probands.

Abbreviations: ROC, receiver operating characteristic; M-CHAT, Modified Checklist for Autism in Toddlers; CSBS-DP-ITC, Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist; ITSP, Infant/Toddler Sensory Profile; PPV, positive predictive value; NPV, negative predictive value; N, number of probands whose data entered the ROC analysis.