Table 1. Summary Characteristics of Included Studies.
| Source | Study design (country) | Setting; coverage | Study years (follow-up, y) | No. of participants | Sex and age | No. of fatal cases | Main outcome(s) | Causes of death | Comparator |
|---|---|---|---|---|---|---|---|---|---|
| Kuperman et al,33 1988 | Retrospective cohort (US) | Inpatient; population-based | 1970-1985 (9.1) | 110 People with ADHD | 20.0% Female; mean age, 12.3 y at admission and 22.1 y at follow-up | 1 | Specific cause of death | Yes | General population |
| Pickett et al,13 2006; Shavelle et al,34 2001; Shavelle et al,35 1998 | Retrospective cohort (US) | Community; population-based | 1983-1997 and 1998-2002 (9.5) | 13 111 People with ASD | 20.6% Female; most aged ≥4 y at first evaluation | 280 | All-cause and specific cause of death | Yes | General population |
| Barkley et al,36 2008; Barkley et al,37 1990 | Retrospective cohort (US) | Outpatient; health services | 1979-1996 (17) | 158 People with ADHD and their parents | 9% Female; aged ≥4 y at first evaluation and 21 y at follow-up | 3 | All-cause and specific cause of death | Yes | Participants without hyperactivity |
| Mouridsen et al,38 2008; Isager et al,39 1999 | Retrospective cohort (Denmark) | Inpatient; population-based | 1960-2006 (35.5) | 341 People with ASD | 24.9% Female; mean age, 7.5 y at admission and 43.4 y at follow-up | 26 | All-cause and specific cause of death | Yes | General population |
| Gillberg et al,40 2010 | Prospective cohort (Sweden) | Community; population-based | 1962-2008 (33.2) | 120 People with ASD | 29.2% Female; early childhood at admission and mean age, 33.2 y at follow-up | 9 | All-cause and specific cause of death | Yes | General population |
| Klein et al,41 2012 | Prospective cohort (US) | Community; school-based | 1970-NA (33) | 207 People with ADHD | All male; mean age, 8.3 y at first evaluation and 41 y at follow-up | 15 | All-cause of death | No | Participants without ADHD |
| Barbaresi et al,42 2013 | Prospective cohort (US) | Community; population-based | 1976-2009 (NA) | 367 People with ADHD | 28.0% Female; mean age, 10.4 y at diagnosis and 27.0 y at follow-up | 7 | All-cause and specific cause of death | Yes | Participants without ADHD |
| Bilder et al,14 2013 | Retrospective cohort (US) | Community; population-based | 1982-2011 (25) | 305 People with ASD and their siblings | 25.2% Female; mean age, 10.8 y at diagnosis and 35.8 y at follow-up | 29 | All-cause and specific cause of death | Yes | General population; siblings |
| Fairthorne et al,43 2014 | Retrospective cohort (Australia) | Community; population-based | 1983-2010 (NA) | 2041 Mothers of children with ASD | All women; 77% aged 20-34 y with mean age at death of 42 y | 24 | All-cause and specific cause of death | Yes | Participants without ASD or intellectual disability |
| Dalsgaard et al,16 2015; Scott et al,44 2017 | Retrospective cohort (Denmark) | Community; population-based | 1981-2013 (32) | 32 061 People with ADHD | 26.4% Female; mean age, 12.3 y at diagnosis | 107 | All-cause and specific cause of death | Yes | General population |
| Koisaari et al,45 2015 | Prospective cohort (Finland) | Community; health services (maternity hospital) | 1971-2004 (40) | 122 People with ADHD | 29.5% Female; aged ≥5 y at first evaluation and mean age of 40 y at follow-up | 11 | All-cause and specific cause of death | Yes | Participants without ADHD |
| Hetchtman et al,46 2016 | Prospective cohort (US) | Community; school-based | 1992-2008 (16) | 476 People with ADHD | 19.7% Female; mean age, 8.5 y at diagnosis and 24.7 y at follow-up | 11 | All-cause and specific cause of death | Yes | Participants without ADHD |
| Hirvikoski et al,47 2016 | Retrospective case-cohort/case-control (Sweden) | Mixed; population-based | 1987-2009 (NA) | 27 122 People with ASD | 31.1% Female; mean age, 19.8 y at diagnosis | 706 | All-cause and specific cause of death | Yes | General population |
| Hosking et al,48 2016 | Retrospective cohort (UK) | Outpatient; population-based | 2009-2013 (3) | 1532 People with ASD | 58.1% Female; mean age, 39.9 y at follow-up | 15 | All-cause of death | No | General population |
| London and Landes,18 2016 | Retrospective cohort (US) | Community; population-based | 2007-2011 (4) | 654 People with ADHD | 54.4% Female; mean age, 47.6 y at follow-up | 13 | All-cause and specific cause of death | Yes | General population |
| Schendel et al,49 2016 | Prospective cohort (Denmark) | Community; population-based | 1980-2013 (NA) | 20 492 People with ASD | 22.4% Female; most aged >9 y at diagnosis with median age of 19.0 y at death | 68 | All-cause and specific cause of death | Yes | General population |
| Chen et al,19 2019 | Prospective cohort (Taiwan) | Mixed; population-based | 2000-2013 (14) | 275 980 People with ADHD | 24.1% Female; mean age, 9.6 y at evaluation | 727 | All-cause and specific cause of death | Yes | General population |
| Hwang et al,21 2019 | Retrospective cohort (Australia) | Community; population-based | 2001-2015 (NA) | 35 929 People with ASD | 20.5% Female; age ranged, 5-64 y and mean age, 35.0 y at death | 244 | All-cause and specific cause of death | Yes | General population |
| Kirby et al,50 2019 | Retrospective cohort (US) | Community; population-based | 1998-2017 (20) | 16 904 People with ASD | 24.0% Female; mean age, 18.4 y at follow-up | 49 | Specific cause of death | Yes | General population |
| Sun et al,17 2019 | Prospective cohort (Sweden) | Community; population-based | 1983-2013 (11.1) | 86 670 People with ADHD | 33.2% Female; mean age, 14.3 y at diagnosis | 424 | All-cause and specific cause of death | Yes | General population |
| Yeh et al,51 2019 | Retrospective case-control (US) | Mixed; population-based | 2000-2013 (NA) | 4416 People with ADHD | 22.5% Female; most aged 40-64 y at evaluation | 67 | Specific cause of death | Yes | General population |
| Fitzgerald et al,52 2019 | Retrospective cohort (Denmark) | Community; population-based | 1995-2014 (21.5) | 32 540 People with ADHD | 30.8% Female; mean age, 21.5 at follow-up | 35 | Specific cause of death | Yes | General population |
| Akobirshoev et al,53 2020 | Retrospective cohort (US) | Inpatient; population-based | 2004-2014 (NA) | 34 237 People with ASD | 24.7% Female; mean age, 33.1 y at evaluation | 462 | All-cause of death | No | General population |
| Jokiranta-Olkoniemi et al,54 2021 | Retrospective cohort (Finland) | Mixed; population-based | 1987-2015 (NA) | 4695 People with ASD | 20.4% Female; mean age, 8.0 y at diagnosis | 53 | All-cause and specific cause of death | Yes | Participants without ASD |
| Huang et al,55 2021 | Retrospective cohort (Taiwan) | Mixed; population-based | 2000-2015 (8.1) | 6599 People with ASD | 22.8% Female; mean age, 11.9 y at evaluation | 119 | All-cause of death | No | General population |
| Kõlves et al,56 2021 | Retrospective cohort (Denmark) | Community; population-based | 1995-2016 (NA) | 35 020 People with ASD | 26.6% Female; most aged 10-29 y | 53 | Specific cause of death | Yes | General population |
| Smith et al,15 2021 | Retrospective cohort (Scotland, UK) | Community; school-based | 2008-2015 (3.9) | 9754 People with ASD | 14.0% Female; most aged 10-19 y | 6 | All-cause of death | No | Participants without ASD |
Abbreviations: ADHD, attention-deficit/hyperactivity disorder; ASD, autism spectrum disorder; NA, not available.