Supplementary Material for: Neonatal Adverse Outcomes Among Hospital Livebirths in Canada: A National Retrospective Study

Introduction: In Canada, newborn morbidity far surpasses mortality. The Neonatal Adverse Outcome Indicator (NAOI) summarizes neonatal morbidity, but Canadian trend data are lacking. Methods: This Canada-wide retrospective cross-sectional study included hospital livebirths between 24-42 weeks’ gestation, from 2013-2022. Data were obtained from the Canadian Institute of Health Information’s Discharge Abstract Database, excluding Quebec. The NAOI included 15 newborn complications (e.g., birth trauma, intraventricular hemorrhage or respiratory failure) and seven interventions (e.g., resuscitation by intubation and/or chest compressions), adapted from Australia’s NAOI. Rates of NAOI were calculated by gestational age. Unadjusted rate ratios (RR) and 95% confidence interval (CI) were calculated for neonatal mortality, NICU admission, and extended hospital stay, each in relation to the number of NAOI components present (0, 1, 2, 3, 4 or ≥5). Results: Among 2,821,671 newborns, the NAOI rate was 7.6%. NAOI increased from 7.3% in 2013 to 8.0% in 2022 (p&lt;0.01). NAOI prevalence was highest in the most preterm infants. Compared to no NAOI, RRs (95% CI) for mortality were 8.5 (7.6-9.5) with 1, 118.1 (108.4-128.4) with 3, and 395.3 (367.2-425.0) with ≥5 NAOI components. Respective RRs for NICU admission were 6.7 (6.6-6.7), 11.2 (10.9-11.3) and 11.9 (11.6-12.2), and RR for extended hospital stay were 6.6 (6.4-6.7), 12.2 (11.7-12.7) and 26.4 (25.2-27.5). International comparison suggested that Canada had a higher prevalence of NAOI. Conclusion: The Canadian NAOI captures neonatal morbidity using hospitalization data, and is associated with neonatal mortality, NICU admission, and extended hospital stay. Newborn morbidity may be on the rise in recent years.引言：在加拿大，新生儿发病率远高于死亡率。新生儿不良结局指标（Neonatal Adverse Outcome Indicator, NAOI）可用于综合反映新生儿发病情况，但目前缺乏该国的相关趋势数据。 方法：这项覆盖加拿大全国的回顾性横断面研究纳入了2013年至2022年间孕周24~42周的住院活产儿。数据来源于加拿大卫生信息研究所（Canadian Institute of Health Information）的出院摘要数据库，但排除了魁北克省的相关数据。本研究采用的新生儿不良结局指标改编自澳大利亚的同类指标，包含15项新生儿并发症（如产伤、脑室内出血或呼吸衰竭）及7项干预措施（如气管插管复苏和/或胸外按压）。研究按孕周计算了新生儿不良结局指标的发生率。针对新生儿死亡率、新生儿重症监护病房（Neonatal Intensive Care Unit, NICU）收治率及延长住院时间，分别根据存在的新生儿不良结局指标组分数量（0、1、2、3、4或≥5项）计算了未校正率比（Unadjusted Rate Ratio, RR）及95%置信区间（95% Confidence Interval, CI）。 结果：在2821671名新生儿中，新生儿不良结局指标的发生率为7.6%。该指标的发生率从2013年的7.3%上升至2022年的8.0%（p<0.01）。新生儿不良结局指标的患病率在极早早产儿中最高。与无新生儿不良结局指标组分的新生儿相比，存在1项组分时死亡率的未校正率比（95% CI）为8.5（7.6~9.5），存在3项时为118.1（108.4~128.4），存在≥5项时为395.3（367.2~425.0）。新生儿重症监护病房收治率对应的未校正率比分别为6.7（6.6~6.7）、11.2（10.9~11.3）及11.9（11.6~12.2），延长住院时间对应的未校正率比分别为6.6（6.4~6.7）、12.2（11.7~12.7）及26.4（25.2~27.5）。国际对比显示，加拿大的新生儿不良结局指标患病率更高。 结论：基于住院数据构建的加拿大新生儿不良结局指标可反映新生儿发病情况，且与新生儿死亡率、新生儿重症监护病房收治率及延长住院时间显著相关。近年来加拿大新生儿发病率或呈上升趋势。