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Risk of motor vehicle collisions after methadone use

  1. Ya-Hui Yang
  2. Pei-Shan Ho
  3. Trong-Neng Wu
  4. Peng-Wei Wang
  5. Chun-Hung Richard Lin
  6. Jui-Hsiu Tsai  Is a corresponding author
  7. Yue Leon Guo  Is a corresponding author
  8. Hung-Yi Chuang  Is a corresponding author
  1. Department of Health-Business Administration, Fooyin University, Taiwan
  2. Division of Medical Statistics and Bioinformatics, Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
  3. Department of Oral Hygiene, College of Dental Medicine, Kaohsiung Medical University, Taiwan
  4. Department of Healthcare Administration, Asia University, Taiwan
  5. Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
  6. Department of Computer Science and Engineering, National Sun Yat-sen University, Taiwan
  7. Department of Psychiatry, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taiwan
  8. Ph.D. Program in Environmental and Occupation Medicine, (Taiwan) National Health Research Institutes and Kaohsiung Medical University, Taiwan
  9. Tzu Chi University, Taiwan
  10. Environmental and Occupational Medicine, National Taiwan University College of Medicine and NTU Hospital, Taiwan
  11. Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan
  12. Department of Public Health, Kaohsiung Medical University, Taiwan
Research Article
Cite this article as: eLife 2021;10:e63954 doi: 10.7554/eLife.63954
3 figures, 2 tables and 1 additional file


Flow chart of participant selection.
Crude incidence rates (CIRs) of motor vehicle collisions annually among the general adult population, adult opiate users, and patients receiving methadone maintenance treatment (MMT).

The CIRs of motor vehicle collisions in Taiwan during 2009–2016 among the general adult population, adult opiate users, and adults receiving MMT are shown. The CIRs of motor vehicle collisions in the general adult population slightly increased from 19.2 per 1000 person-years in 2009 to a peak of 30.6 per 1000 person-years in 2014 but steadily decreased to 30.3 per 1000 person-years in 2016. Over the follow-up period, the CIRs of motor vehicle collisions in adult opiate users followed a similar trend—from 28.2 to 46.8 per 1000 person-years. In the general adult population receiving MMT, the highest CIR of motor vehicle collisions was noted in 2012 (58.7 per 1000 person-years), with a wide range of 37.5–58.7 per 1000 person-years. Overall, the CIRs of motor vehicle collisions from 2009 to 2016 were the lowest in the general adult population, followed by those in adult opiate users, and they were the highest in adults receiving MMT.

The Kaplan–Meier curve of motor vehicle collision-free between opiate users receiving methadone maintenance treatment and those not receiving in long-term (7 years, upper panel) and short-term (100 days, lower panel) follow-up.


Table 1
Baseline characteristics of opiate users in Taiwan, 2010–2016.
n = 1012
n = 2024
Age, mean (SE), years37.7 (8.1)37.7 (8.1)1.000
Length of time on opiate users’ registry, mean (SE), months15.3 (15.4)15.3 (15.4)1.000
Sex, n (%)1.000
Education status, n (%)<0.001
Elementary school (1–6 years)91(9.0)115(5.7)
High school (7–12 years)896(88.5)1832(90.5)
College or more (>12 years)25(2.5)77(3.8)
Income level, n (%)<0.001
≦15,000 (New Taiwan $)615(60.8)1394(68.9)
Urbanity, n (%)0.240
Past history of, n (%)
Motor vehicle collision339(33.5)623(30.8)0.129
Driving under the influence67(6.6)106(5.2)0.121
Antidepressant use85(8.4)104(5.1)<0.001
Benzodiazepine (Z-drug) use643(63.5)369(18.2)<0.001
Occurrence of
Motor vehicle collision, n (%)66(6.5)45(2.2)<0.001
Duration*, mean (SE), days234.8 (295.0)226.7 (287.7)0.886
  1. *Length of time from the index date to motor vehicle collision event after the index date, death, end of follow-up in registry, or the end of 2016.

    MMT: methadone maintenance treatment.

Table 2
Independent predictors of motor vehicle collisions among opiate users receiving methadone maintenance treatment (MMT).
VariablesCrude hazard ratio
(95% CI)
pAdjusted hazard ratio
(95% CI)
Education status
Elementary school1.00-1.00-
High school0.90 (0.50, 1.64)0.7271.06 (0.53, 2.12)0.875
College or more0.83 (0.26, 2.60)0.7431.05 (0.28, 3.95)0.942
Income level (New Taiwan $)
≦15,0001.27 (0.87, 1.86)0.2201.14 (0.77, 1.67)0.516
Suburban0.62 (0.15, 2.50)0.5000.76 (0.19, 3.10)0.700
Rural1.68 (1.14, 2.46)0.0091.56 (1.05, 2.32)0.027
Past history of
Motor vehicle collision (vs. no)1.70 (1.17, 2.48)0.0061.41 (0.94, 2.10)0.097
Driving under the influence (vs. no)2.26 (1.26, 4.01)0.0060.61 (0.33, 1.13)0.116
Antidepressant use (vs. no)2.25 (1.28, 3.93)0.0051.70 (0.95, 3.05)0.076
Benzodiazepine (Z-drug) use (vs. no)1.62 (1.09, 2.42)0.0181.25 (0.82, 1.91)0.296
Occurrence of motor vehicle collision
MMT (vs. non-MMT)3.00 (2.05, 4.38)<0.0012.75 (1.87, 4.04)<0.001

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