Table 3. Interrupted Time-Series Poisson Regression Models of the Associations of Postoverdose Programs With the Outcomes of Opioid Fatality Rate and Opioid Emergency Response Rate in Massachusetts From January 2013 to June 2019a.
| Exposure variables | Adjusted model 1b | |||
|---|---|---|---|---|
| Opioid fatality rate | Opioid overdose emergency response rate | |||
| β | P value | β | P value | |
| Intercept | −0.097 | .94 | 1.468 | .36 |
| Change in the outcome level after program | 0.069 | .20 | 0.095 | .06 |
| Change in trend per quarter after program | −0.016 | .003 | −0.017 | .007 |
| Trend per quarter before program | −0.006 | .18 | 0.020 | <.001 |
| Age, % | ||||
| 25-44 y | 0.009 | .33 | 0.009 | .51 |
| 45-54 y | 0.039 | .04 | 0.044 | .05 |
| 55-64 y | 0.012 | .45 | 0.010 | .64 |
| ≥65 y | −0.012 | .25 | −0.020 | .29 |
| Male sex, % | 0.010 | .60 | 0.007 | .78 |
| Race and ethnicity, % | ||||
| African American/Black | −0.009 | .19 | 0.0004 | .97 |
| American Indian/Alaska Native | 0.016 | .73 | 0.068 | .23 |
| Asian | −0.010 | .19 | 0.005 | .66 |
| Hispanic/Latinx | −0.005 | .19 | 0.003 | .51 |
| Pacific Islander | 0.090 | .80 | −0.269 | .43 |
| White | −0.007 | .24 | 0.002 | .78 |
| High school education or less, % | 0.014 | <.001 | 0.019 | <.001 |
| Vacancy units, per 1000 population | 0.002 | <.001 | 0.002 | .03 |
| Naloxone kits distributed by OEND program, per 1000 population | −0.016 | .46 | 0.068 | <.001 |
| Municipality programs | ||||
| Public safety equipped with naloxone | 0.051 | .39 | 0.140 | .10 |
| Drug court or a jail diversion program | −0.108 | .08 | −0.015 | .87 |
| MOAPC program established | 0.017 | .71 | 0.161 | .007 |
| Drug arrests, per 1000 population | 0.019 | .70 | 0.098 | <.001 |
| Releases from incarceration, per 1000 population | −0.213 | .26 | 0.230 | .09 |
| BSAS methadone admissions, per 1000 population | −0.099 | .07 | 0.008 | .79 |
| BSAS residential admissions, per 1000 population | 0.110 | <.001 | 0.054 | .008 |
| Fentanyl-related deaths among opioid-related deaths, % | 0.014 | <.001 | 0.002 | <.001 |
| Patients with buprenorphine prescription for OUD, per 1000 population | 0.022 | .007 | 0.010 | .26 |
Abbreviations: BSAS, Massachusetts Bureau of Substance Addiction Services; MOAPC, Massachusetts Opioid Abuse Prevention Collaborative; OEND, opioid education and naloxone distribution; OUD, opioid use disorder.
Municipality quarterly data of opioid fatality rate per 100 000 population were available from the first quarter of 2013 to the second quarter of 2019. Data on opioid emergency response rate per 100 000 population were available from the first quarter of 2014 to the second quarter of 2019 according to the Massachusetts Ambulance Trip Record Information System.
Adjusted model 1 was a generalized estimating equations Poisson model with municipality-quarters as unit of analysis assessing the pre-post level change in the outcome and the slope change after program implementation while accounting for the trend of preintervention period and a variety of municipal-level covariates, including age group (<25, 25-44, 45-54, 55-64, and ≥65 years), male sex, race and ethnicity (African American/Black, American Indian/Alaska Native, Asian, Hispanic/Latinx, Pacific Islander, White, and other), high school education or less, vacancy units, naloxone kits distributed by Massachusetts OEND program, public safety equipped with naloxone, presence of a drug court or jail diversion program, drug arrests, releases from incarceration, BSAS methadone treatment admissions and residential admissions, Massachusetts Prescription Monitoring Program patient rate of buprenorphine prescriptions indicated for OUD, presence of Massachusetts Opioid Abuse Prevention Collaborative, and proportion of fentanyl-related deaths, without accounting for municipal-level fixed effects. Robust SEs were used to account for the clustering of repeated quarterly measures at municipal level.