Table 9 Studies reporting measures of fatal and non-fatal overdose

(S2) Aldabergenov et al., 2022 [70]

Methadone-related deaths among people prescribed methadone

44 (95% CI: 37–50)^a

55^b

NR

 ≥ 0.05*

NR

Favours control

Mixed

Buprenorphine-related deaths among people prescribed buprenorphine

2016: 1

2017: 1

2018: 1

2019: 1^c

2020: 1^d

NR

NR

NR

None

(S3) Amram et al., 2021 [71]

Emergency department visits related to overdose

16^e

15^f

Chi-square, McNemar’s chi-square or Fisher’s exact test

1

NR

Favours intervention

Positive

Odds of emergency department visit per one-dose difference in total take-home doses after regulatory changes

NR

NR

Generalized linear model with binary logistic function

1.73

Adjusted OR: 0.94 (0.86–1.03)

Favours intervention

(S6) Corace et al., 2022 [74]

Self-reported opioid overdose(s) with or without emergency department visit

13%^g

16%^h

Chi square test

0.54

χ2: 0.37

Favours control

Negative

(S8) Ezie et al., 2022 [76]

“Overdose”, details not specified

2%^e

0.7%^f

Chi square test

 > 0.05

NR

Favours intervention

Positive

(S13) Gomes et al., 2022 [81]

Non-fatal opioid overdosesⁱ among clients receiving daily methadone at baseline

9.5% per person-year^k

6.9%/person-year^l

Cox proportional-hazards model

 < 0.05*

Weighted HR: 0.73 (95% CI: 0.56–0.96)

Favours intervention

Mixed

Non-fatal opioid overdosesⁱ among clients receiving 5–6 take-home doses of methadone at baseline

1.8%/person-year^k

1.4%/person-year^m

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 0.80 (95% CI: 0.50–1.28)

Favours intervention

Fatal opioid overdoses^j among clients receiving daily methadone at baseline

0.5% per person-year^k

0.6%/person-year^l

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 1.26 (95% CI: 0.48–3.33)

Favours control

Fatal opioid overdoses^j among clients receiving 5–6 take-home doses of methadone at baseline

0.3%/person-year^k

NR^m,n

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 0.48 (95% CI: 0.16–1.45)

Favours intervention

Non-fatal opioid overdosesⁱ among clients receiving daily buprenorphine/ naloxone at baseline

3.5%/person-year^k

6.5%/person-year^m

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 1.86 (95% CI: 0.70–4.92)

Favours control

Non-fatal opioid overdosesⁱ among clients receiving 5–6 take-home doses of buprenorphine /naloxone at baseline

1.4%/person-year^k

1.7%/person-year^m

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 1.23 (95% CI: 0.58–2.63)

Favours control

(S17) Joseph et al., 2021 [85]

Non-fatal overdoses^o

2^e

6^f

NR

NR

NR

Favours control

Mixed

Fatal overdoses^o

1^e

0^f

NR

NR

NR

Favours intervention

(S26) Nguyen et al., 2021 [94]

Fatal overdoses^t among clients “established” in care without take-home doses at baseline

0.5%^q

0.6%^r

NR

 ≥ 0.05*

NR

Favours control

Mixed

Fatal overdoses^p among clients “established” in care with take-home doses at baseline

4.1%^s

0.8%^t

NR

 ≥ 0.05*

NR

Favours intervention