Table 2. Adjusted Associations Between Opioid Prescribing Patterns and Opioid Overdose Risk.
| Variable | AOR (95% CI) | Average Marginal Effect (95% CI)a |
|---|---|---|
| Daily opioid dosage categoryb | 1.18 (1.05 to 1.31) | 0.19 (0.06 to 0.32) |
| Concurrent benzodiazepine use | 1.83 (1.24 to 2.71) | 0.71 (0.24 to 1.19) |
| Extended-release or long-acting opioid use | 2.01 (1.16 to 3.46) | 0.82 (0.17 to 1.48) |
| Recent opioid use within 180 d | 1.38 (1.02 to 1.86) | 0.38 (0.02 to 0.74) |
| Age, in single y | 1.02 (0.97 to 1.08) | 0.02 (–0.04 to 0.09) |
| Female | 1.00 (0.77 to 1.29) | 0.00 (–0.30 to 0.30) |
| Urban residence | 1.43 (0.97 to 2.13) | 0.38 (0.01 to 0.74) |
| US census region (vs Northeast) | ||
| Midwest | 1.11 (0.74 to 1.66) | 0.13 (–0.39 to 0.65) |
| South | 0.83 (0.56 to 1.23) | –0.21 (–0.68 to 0.26) |
| West | 0.98 (0.63 to 1.52) | –0.03 (–0.56 to 0.51) |
| Mental health disorder | 3.14 (2.40 to 4.12) | 1.67 (1.17 to 2.17) |
| Substance use disorder | 3.36 (2.41 to 4.69) | 2.29 (1.34 to 3.24) |
| Other chronic condition | 1.21 (0.91 to 1.59) | 0.22 (–0.11 to 0.56) |
| Study year (vs 2009) | ||
| 2010 | 0.88 (0.50 to 1.54) | –0.15 (–0.79 to 0.50) |
| 2011 | 1.18 (0.69 to 2.01) | 0.21 (–0.47 to 0.89) |
| 2012 | 1.01 (0.59 to 1.73) | 0.01 (–0.64 to 0.66) |
| 2013 | 0.72 (0.40 to 1.32) | –0.33 (–0.97 to 0.31) |
| 2014 | 1.12 (0.63 to 1.99) | 0.15 (–0.57 to 0.87) |
| 2015 | 1.03 (0.56 to 1.89) | 0.04 (–0.70 to 0.77) |
| 2016 | 1.00 (0.53 to 1.86) | 0.00 (–0.75 to 0.74) |
| 2017 | 0.90 (0.41 to 1.97) | –0.13 (–1.00 to 0.75) |
Abbreviation: AOR, adjusted odds ratio.
Average marginal effect is the absolute difference in probability of overdose associated with a 1-unit increase in the variable, holding other variables at their observed values (expressed as changes in the overdose date per 100 000 person-days). For categorical variables, such as US census region, average marginal effect represents the difference in probability of overdose relative to the reference category.
Daily opioid dosage category was represented by a variable with values of 1 to 5, with 1 corresponding to less than 30, 2 corresponding to 30 to 59, 3 corresponding to 60 to 89, 4 corresponding to 90 to 119, and 5 corresponding to 120 or more morphine milligram equivalents per day. The AOR refers to a 1-unit increase in daily opioid dosage category.