Predicting Autism Diagnoses Dimensional Parent Report Measures Improve Autism Identification at the 18 Month Visit Raymond Sturner, MD1,3, Barbara Howard, MD1,2, Paul Bergmann4, Kerry Bet2, Lydia Stewart3, Ruth Williams2 1Pediatrics, Johns Hopkins U. S. of. Med., Balt., MD, United States, 2Total Child Health, 3Ctr. For Promotion of Child Dev., 4Foresight Logic BACKGROUND RESULTS RESULTS The M-CHAT-R is the most commonly used screen for autism but has some limitations: Requires a follow-up interview for positive cases Data suggests the PPV is lower at 18 mo. than 24 mo. in community samples (0.28) younger; (0.61) older (Pandey, et al., 2008); (0.36) younger; (0.69) older (Sturner, et al., 2017) Lack of screen negative controls in validation studies Limited sensitivity in community settings: as follow up of 18 month olds identifies only 1/3 of ASD found at 9 years Higher rates of item failures in younger than older toddlers (N= 73,500) (Sturner, et al., 2017) All items are scored the same at all ages but later acquired items (after 12 months) had higher probability rates for item failure M-CHAT-R uses the same items and same scoring for all ages. Q-CHAT & POSI are screens with dimensional response options but are scored as pass/fail rather than capturing the graded responses. Individual screens: M-CHAT-R/F was more Specific (0.81) than Q-CHAT (0.67) & POSI (0.76) but less Sensitive than POSI (0.48 v. 0.60). Positive Predictive Values are low, esp. for Q-CHAT (0.11) but also POSI (0.26) Dimensional scoring: Alternative scoring of Q-CHAT and POSI using AUC was calculated using the full range of response options (D). Dimensional scoring (D) greatly improved prediction making DQ-CHAT (0.77) equivalent to the DPOSI (0.79). Dimensional scoring had little effect on the POSI. Combining tools: Combining DQ-CHAT and DPOSI significantly improved Sensitivity (0.62 v 0.48) while maintaining Specificity (0.81 v. 0.81)and PPV (0.37 v. 0.32) comparable to M-CHAT-R/F . Demographics Child’s Age Mean: 18.01 months (SD: 0.58); range (16.03 – 19.91) Child Gender Female: 27%; Male: 70% Child Race White: 77%; Af. Am: 19 %; Asian: 12%; Pac. Isl. 1.5%; Nat. Am. 0.5%; Other: 4.6%; Ethnicity Hispanic: 7%; Non-Hispanic: 90%; Respondent Bio. Mother: 90%; Bio. Father: 6.6%; Adopt Mother: 1%; Respondent Age 34 years (SD: 4.2) Range: 24 - 46 Respondent Educ. HS/GED: 4%; Some College: 9%; Assoc.: 5% Bachelors: 37%; Masters: 33%; Prof. 3%; Doctoral: 5% Respondent Race White: 76%; Af. Am.; 14%; Asian; 7%; Other: 4%; Pac. Isl. 0.5% Nat Am.:0.5% Respondent Ethnicity Hispanic 7%; Non-Hispanic: 91%; Predicting Autism Diagnoses Screen Sensitivity Specificity PPV M-CHAT-R 0.77A [0.60 – 0.89] 0.59A [0.52 – 0.67] 0.26 [0.18 – 0.36] M-CHAT-R/F 0.48A,B,C,D [0.32 – 0.65] 0.81A,B,C [0.74 – 0.86] 0.32 [0.20 – 0.46] D/QCHAT 0.77B [0.59 – 0.88] 0.54B [0.46 – 0.61] 0.23B [0.16 – 0.32] D/POSI 0.79C [0.61 – 0.90] 0.56C [0.48 – 0.63] 0.24 [0.17 – 0.34] D/(QCHAT+POSI) 0.62D [0.44 – 0.77] 0.81 0.37 [0.25 – 0.51] OBJECTIVES Enrollment Flow To compare the predictive utility of the M-CHAT-R & M-CHAT-R with Follow Up (M-CHAT-R/F) to Q-CHAT and POSI with and without dimensional scoring and to a combination of these tools with similar length to the M-CHAT. METHODS Parents completed the M-CHAT-R and the Q-CHAT for scheduled 18 month pediatric visits via an online system. M-CHAT-R/F used doctor prompts (Sturner, et. al., 2016), Data from MD, NC & MA Children with positive screens (117) on either the M-CHAT-R or Q-CHAT and age and practice matched controls (79) were recruited. Parents completed the POSI after recruitment. Diagnostic evaluations used ADOS-2 (ASD) & Mullen (DQ) MedStar IRB managed conflict and approved the study with screening portion exempt. CONCLUSIONS A combination of dimensional scoring combining Q-CHAT and POSI resulted in a 17 item screen that had better sensitivity than the others with equivalent specificity to the M-CHAT-R/F without need for a follow-up interview, but none of these screens improved the known problem of low PPV at this age. LIMITATIONS This study was unusual in testing screen negative children, but is not fully generalizable as negatives participated at a lower rate. ACKNOWLEDGMENTS Funding by NIMH 4R44MH085399. Acknowledgments: Carrie Allison; Simon Baron-Cohen; Ellen Perrin; Christopher Sheldrick Drs. Sturner and Howard have a financial interest in the online system (CHADIS) used. REFERENCES By request- rsturner@jhmi.edu