Skip to main content

Table 5 Studies reporting measures of retention

From: The impact of relaxing restrictions on take-home doses during the COVID-19 pandemic on program effectiveness and client experiences in opioid agonist treatment: a mixed methods systematic review

Study

Measure

Control Group

Intervention Group

Statistical Test or Model

p-value

Estimate of Effect

Direction of Effect

Overall Effect Direction

(S7) Cunningham et al., 2022 [75]

Retention in treatment at 90 daysa

42.9%b

68.0%c

Chi square or Fisher exact test

 < 0.05

NR

Favours intervention

Positive

(S9) Farid et al., 2022 [77]

“Retention”

68.1%d

(a) 72.9%

(b) 82.7%

(c) 87.3%e

NR

NR

NR

Favours intervention

Positive

(S11) Garg et al., 2022 [79]

Immediate changef in weekly prevalence of treatment discontinuation following intervention among clients stable on OAT

NA

NA

Autoregressive integrated moving average (ARIMA) model

0.93

Step change: -0.01% (95% CI -0.14–0.12%)

Favours intervention

Mixed

Gradual changeg in weekly prevalence of treatment discontinuation following intervention among clients stable on OAT

NA

NA

Autoregressive integrated moving average (ARIMA) model

0.72

Slope change: 0.00% (95% CI -0.01–0.02%)

No difference

Immediate changef in weekly prevalence of treatment discontinuation following intervention among clients not stable on OAT

NA

NA

Autoregressive integrated moving average (ARIMA) model

0.82

Step change: -0.31% (-3.04–2.43%)

Favours intervention

Gradual changeg in weekly prevalence of treatment discontinuation following intervention among clients not stable on OAT

NA

NA

Autoregressive integrated moving average (ARIMA) model

0.63

Slope change: 0.04% (95% CI: -0.12–0.20%)

Favours control

(S13) Gomes et al., 2022 [81]

OAT discontinuationh among people receiving daily methadone at baseline

63.6% per person-yeari

51.0% per person-yearj

Cox proportional-hazards model

 < 0.05*

Weighted HR: 0.80 (95% CI: 0.72–0.90)

Favours intervention

Positive

OAT discontinuationh among people receiving 5–6 take-home doses of methadone at baseline

19.6% per person-yeari

14.1% per person-yearj

Cox proportional-hazards model

 < 0.05*

Weighted HR: 0.72 (95% CI 0.62–0.84)

Favours intervention

OAT discontinuationh among people receiving daily buprenorphine/naloxone at baseline

93.2% per person-yeari

85.1% per person-yearj

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 0.91 (95% CI 0.68–1.22)

Favours intervention

OAT discontinuationh among people receiving 5–6 take-home doses of buprenorphine/naloxone at baseline

30.8% per person-yeari

26.0% per person-yearj

Cox proportional-hazards model

 ≥ 0.05*

Weighted HR: 0.85 (95% CI 0.70–1.01)

Favours intervention

(S15) Hoffman et al., 2022 [83]

Treatment discontinuation among people in treatment < 90 days

13%k

26%l

Wilcoxon rank sum test; Pearson's Chi-squared test

0.047

NR

Favours control

Negative

Treatment discontinuation among people in treatment 90–180 days

9.4%k

19%l

Wilcoxon rank sum test; Pearson's Chi-squared test

0.090

NR

Favours control

Treatment discontinuation among people in treatment > 180 days

11%k

12%l

Wilcoxon rank sum test; Pearson's Chi-squared test

0.7

NR

Favours control

Odds of treatment discontinuation per percentage point in take-home dosing above expectedm

NR

NR

Random effects logistic regression model

0.003

Adjusted OR: 0.97 (95% CI 0.95, 0.99)

Favours intervention

(S26) Nguyen et al., 2021 [94]

60-day retention among new intakes

63%k

69%l

Two-tailed t-test

0.26

NR

Favours intervention

Positive

(S31) Roy et al., 2023 [99]

Treatment disruptions among stably treated clientsn at 1 week post-initial pandemic period

1.3%k

NR

Segmented regression interrupted time series model

 < 0.05

Relative change from baseline trend:

(a) Disruptions ≥ 7 days: -12.6 (95% CI: -16.6,-8.5)

(b) Disruptions ≥ 14 days: -9.7 (95% CI: -15.1,-4.3)

(c) Disruptions ≥ 28 days: -11.6 (95% CI: -14.7,-8.5)

Favours intervention

Positive

Treatment disruptions among stably treated clientsn at 26 weeks post-initial pandemic period

1.0%k

NR

Segmented regression interrupted time series model

 < 0.05

Relative change from baseline trend:

(a) Disruptions ≥ 7 days: -17.0 (95% CI: -19.4,-14.6)

(b) Disruptions ≥ 14 days: -10.2 (95% CI: -15.7,-4.8)

(c) Disruptions ≥ 28 days: -15.5 (95% CI: -18.9,-12.1)

Favours intervention

Treatment disruptions among stably treated clientsn at 52 weeks post-initial pandemic period

0.6%k

NR

Segmented regression interrupted time series model

 < 0.05

Relative change from baseline trend:

(a) Disruptions ≥ 7 days: -21.6 (95% CI: -25.6,-17.7)

(b) Disruptions ≥ 14 days: -10.8 (95% CI:-16.3,-5.3)

(c) Disruptions ≥ 28 days: -27.3 (95% CI:-33.0,-21.6)

Favours intervention

  1. Where adjusted and unadjusted effect estimates were reported, we present adjusted estimates. Where weighted and unweighted effect estimates were reported, we present weighted estimates. In no case did this change the estimated direction of effect
  2. Acronyms: HR hazard ratio, NR not reported, OR odds ratio, RR relative risk
  3. *Not reported in the original study; inferred or calculated by authors
  4. aRetention defined as active buprenorphine prescription at least 90 days after treatment initiation
  5. bControl group: OAT clients initiating treatment after referral before pandemic
  6. cIntervention group: OAT clients initiating treatment after referral during pandemic
  7. dControl group: OAT clients from Jul.–Dec. 2019
  8. eIntervention groups: OAT clients from (a) Jan.-Jun. 2020, (b) Jul.-Dec. 2020, and (c) Jan.-Mar. 2021
  9. fThe step transfer function was used to test for immediate change
  10. gThe ramp transfer function used to test for gradual change
  11. hOAT discontinuation defined as a gap in therapy exceeding 14 days
  12. iControl group: OAT clients with no change in take-home doses during pandemic
  13. jIntervention group: OAT clients with increased take-home doses during pandemic
  14. kControl group: OAT clients pre-pandemic
  15. lIntervention group: OAT clients post-pandemic
  16. mAnalysis limited to OAT clients with at least three months of pre-pandemic data and one month of post-pandemic data
  17. n “Stable clients” defined as clients with six months or more of buprenorphine prescriptions without a treatment disruption. “Treatment disruptions” defined as gaps of 28 days
Back to article page

Substance Abuse Treatment, Prevention, and Policy

ISSN: 1747-597X