Risk of motor vehicle collisions after methadone use
Figures

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.
Tables
Baseline characteristics of opiate users in Taiwan, 2010–2016.
Characteristics | MMT n = 1012 | Non-MMT n = 2024 | p | |||
---|---|---|---|---|---|---|
Age, mean (SE), years | 37.7 (8.1) | 37.7 (8.1) | 1.000 | |||
Length of time on opiate users’ registry, mean (SE), months | 15.3 (15.4) | 15.3 (15.4) | 1.000 | |||
Sex, n (%) | 1.000 | |||||
Male | 866 | (85.6) | 1732 | (85.6) | ||
Female | 146 | (14.4) | 292 | (14.4) | ||
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 | |||||
Urban | 701 | (69.3) | 1453 | (71.8) | ||
Suburban | 27 | (2.7) | 60 | (3.0) | ||
Rural | 284 | (28.1) | 511 | (25.3) | ||
Past history of, n (%) | ||||||
Motor vehicle collision | 339 | (33.5) | 623 | (30.8) | 0.129 | |
Driving under the influence | 67 | (6.6) | 106 | (5.2) | 0.121 | |
Antidepressant use | 85 | (8.4) | 104 | (5.1) | <0.001 | |
Benzodiazepine (Z-drug) use | 643 | (63.5) | 369 | (18.2) | <0.001 | |
Occurrence of | ||||||
Motor vehicle collision, n (%) | 66 | (6.5) | 45 | (2.2) | <0.001 | |
Duration*, mean (SE), days | 234.8 (295.0) | 226.7 (287.7) | 0.886 |
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*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.
Independent predictors of motor vehicle collisions among opiate users receiving methadone maintenance treatment (MMT).
Variables | Crude hazard ratio (95% CI) | p | Adjusted hazard ratio (95% CI) | p | ||
---|---|---|---|---|---|---|
Education status | ||||||
Elementary school | 1.00 | - | 1.00 | - | ||
High school | 0.90 (0.50, 1.64) | 0.727 | 1.06 (0.53, 2.12) | 0.875 | ||
College or more | 0.83 (0.26, 2.60) | 0.743 | 1.05 (0.28, 3.95) | 0.942 | ||
Income level (New Taiwan $) | ||||||
≦15,000 | 1.27 (0.87, 1.86) | 0.220 | 1.14 (0.77, 1.67) | 0.516 | ||
Urbanity | ||||||
Urban | 1.00 | - | 1.00 | - | ||
Suburban | 0.62 (0.15, 2.50) | 0.500 | 0.76 (0.19, 3.10) | 0.700 | ||
Rural | 1.68 (1.14, 2.46) | 0.009 | 1.56 (1.05, 2.32) | 0.027 | ||
Past history of | ||||||
Motor vehicle collision (vs. no) | 1.70 (1.17, 2.48) | 0.006 | 1.41 (0.94, 2.10) | 0.097 | ||
Driving under the influence (vs. no) | 2.26 (1.26, 4.01) | 0.006 | 0.61 (0.33, 1.13) | 0.116 | ||
Antidepressant use (vs. no) | 2.25 (1.28, 3.93) | 0.005 | 1.70 (0.95, 3.05) | 0.076 | ||
Benzodiazepine (Z-drug) use (vs. no) | 1.62 (1.09, 2.42) | 0.018 | 1.25 (0.82, 1.91) | 0.296 | ||
Occurrence of motor vehicle collision | ||||||
MMT (vs. non-MMT) | 3.00 (2.05, 4.38) | <0.001 | 2.75 (1.87, 4.04) | <0.001 |