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Table 2 Participants’ percentage of abstinence during maintenance dose period (Missing = Positive)

From: Examining the benefit of a higher maintenance dose of extended-release buprenorphine in opioid-injecting participants treated for opioid use disorder

Participants’ percentage of abstinence

Maintenance dose groups

BUP-XR 300/300 mg

BUP-XR 300/100 mg

Difference (95% CI)a 300–100 mg

P valueb

Opioid-injecting participants

N

63

66

  

Weeks 10–25

Unadjusted

Mean (SE)

58.2% (4.62%)

44.0% (4.75%)

14.20% (1.22, 27.18%)

0.0320

Risk adjusted

Mean (SE)

59.6% (5.19%)

46.6% (5.34%)

13.04% (− 1.56, 27.64%)

0.0800

Weeks 14–25

Unadjusted

Mean (SE)

59.5% (4.79%)

42.6% (4.78%)

16.97% (3.71, 30.24%)

0.0122

Risk adjusted

Mean (SE)

61.5% (5.35%)

45.0% (5.40%)

16.48% (1.58, 31.37%)

0.0074

Weeks 18–25

Unadjusted

Mean (SE)

60.7% (4.85%)

42.0% (4.83%)

18.67% (5.25, 32.09%)

0.0064

Risk adjusted

Mean (SE)

62.9% (5.26%)

44.2% (5.39%)

18.65% (3.90, 33.41%)

0.0132

Non-injecting opioid participants

N

92

90

  

Weeks 10–25

Unadjusted

Mean (SE)

46.6% (4.22%)

56.3% (3.99%)

− 9.65% (− 21.03, 1.73)

0.0966

Risk adjusted

Mean (SE)

44.2% (4.56%)

54.3% (4.19%)

− 10.06% (− 22.20, 2.08)

0.1044

Weeks 14–25

Unadjusted

Mean (SE)

46.0% (4.41%)

54.9% (4.19%)

− 8.89% (− 20.81, 3.02)

0.1435

Risk adjusted

Mean (SE)

43.3% (4.78%)

53.0% (4.33%)

− 9.66% (− 22.31, 2.99)

0.1343

Weeks 18–25

Unadjusted

Mean (SE)

45.2% (4.55%)

53.8% (4.28%)

− 8.51% (− 20.75, 3.74)

0.1735

Risk adjusted

Mean (SE)

42.4% (4.91%)

51.8% (4.40%)

− 9.41% (− 22.34, 3.52)

0.1536

  1. N No. of participants in the analysis set
  2. Each participant’s percentage abstinence was calculated after the first (weeks 10–25), second (weeks 14–25), and third (weeks 18–25) maintenance doses as the proportion (%) of negative opioid use results among the corresponding 16, 12, and 8 weekly assessments, respectively. Missing = Positive: the missing UDS or missing self-report for illicit opioid use at a specific scheduled visit was imputed as positive for that visit. The risk-adjusted analysis compared the 100-mg versus 300-mg maintenance dose groups via inverse propensity weighting using propensity scores
  3. CI confidence interval, SE standard error, UDS urine drug screen
  4. aGroup mean (SE) and 95% CI of difference in group mean was based on the general linear model Robust Sandwich variance estimator
  5. bP value was based on the Wald test