September 2019 HSC Section 1 Congenital and Pediatric Problems

Original Investigation Research

Influence of Surgical Procedures and General Anesthesia on Child Development Before Primary School Entry

Figure. Study Flow Diagram

259062 Unique records identified in EDI-ICES database

42393 Excluded a

32100 Not born in Canada

4718 Behavioral or learning disability 4438 Ineligible interventions 1232 Cardiology or cardiovascular service

216669 Eligible children in EDI-ICES database

160021 Children without surgical procedures

56648 Children with surgical procedures

29443 Ineligible procedures

27205 Children with eligible surgery

The EDI-ICES database consists of Early Development Instrument (EDI) data housed at the Institute for Clinical Evaluative Sciences (ICES), Toronto, Ontario, Canada. a Some children had multiple reasons for exclusions.

10897 Sibling pairs identified

367 Pairs with both siblings exposed to surgery

2346 Pairs with 1 sibling exposed to surgery

8184 Pairs with no sibling exposed to surgery

of impaired child development (eg, a history of fetal interven- tion, radiation therapy, brachytherapy, pharmacotherapy, or chemotherapy and those followed by a cardiology or cardio- vascular service), and children who had behavioral, learning, or developmental problems recorded in the EDI were first excluded ( Figure ). Children with EDI-recorded behavioral, learning, or developmental problems were excluded in the primary analysis because the time of diagnosis relative to ex- posure could not be confirmed, and the tendency for in- creaseduseof healthcare services among this populationcould introduce a risk of selection bias. Procedures were identified by exclusion using either Canadian Classification of Health In- terventions therapeutic intervention codes or Canadian Clas- sification of Diagnostic, Therapeutic, and Surgical Procedures codes (eTable 1 in the Supplement ). Siblingswith the samebirth mother were identified from the mother’s ICES number—a unique confidential identifier assigned to each individual for use across ICES databases—from the hospital admission at the time of the child’s birth. Sibling pairs were then classified by exposure to surgery (both siblings had surgery, neither sib- ling had surgery, or only 1 sibling had surgery). Exposures and Outcomes The primary outcome was early developmental vulnerabil- ity, defined as anymajor domain of the EDI in the lowest 10th percentile of the Ontario population. 26 Secondary outcomes included performance in major EDI domains and a multiple challenge index, defined as vulnerability in at least 9 subdo- mains of the EDI. 21 Normative data for the Ontario popula- tionweredeterminedusing the first (2004 through2006) cycle of the EDI. 25

Covariates Demographic characteristics available included aboriginal sta- tus, age at completion of EDI, age at the time of first surgery, eldest sibling status (among all siblings in the same family), median neighborhood household income quintile, rurality of residence, and sex. Birth characteristics included gestational age at birth, mother’s age at birth, and multiple births; surgi- cal admission characteristics included admission category (elective, newborn, or urgent), cumulative length of hospital stay, type of surgery, and physiological complexity of surgi- cal procedures (based on the relative value guide for anesthe- sia billing). Relative value guides for billing are validated for discriminating the physiological complexity of surgical pro- cedures. Similar to previous studies, the physiological com- plexity of surgical procedures in this Ontario-based cohort was classified using anesthesia basic unit values for individual Canadian Classification of Health Interventions therapeutic in- tervention codes in the 2015 Ontario Health Insurance Plan Schedule of Benefits, 27 and surgical procedures with nomore than 7 basic units were classified as nonphysiologically complex. 28,29 Examples of commonly performed surgical procedures with no more than 7 basic units include tonsillec- tomy (6 basic units), herniotomy (6-7 basic units), and circum- cision (6 basic units). Statistical Analysis Data were analyzed fromDecember 13, 2017, through July 27, 2018. Baseline characteristics of sibling groups were reported using standard descriptive statistics and compared using 2-tailed t tests and χ 2 tests as appropriate. Unadjusted differ- ences in EDI outcomes were estimated for each of the sibling

(Reprinted) JAMA Pediatrics Published online November 5, 2018

jamapediatrics.com

© 2018 American Medical Association. All rights reserved.

17