Retention in clinical trials after prison release: results from a clinical trial with incarcerated men with HIV and opioid dependence in Malaysia

Figures & data

Figure 1 Study flow diagram.

Table 1 Participant characteristics at enrollment by treatment group (N = 296)

	HHRP-M^a			Methadone^a
Variable	Treatment (n = 148) n (% )	Control (n = 148) n (%)	p Value^b	Treatment (n = 218) n (%)	Control (n = 78) n (%)	p Value^b
Demographic and social characteristics
Mean age, years (SD)	38.9 ± 6.9	39.2 ± 6.5	0.80	38.7 ± 6.6	40.1 ± 6.7	0.23
Completed upper secondary education	45 (30.4)	47 (31.8)	0.80	70 (32.1)	22 (28.2)	0.52
Stable housing before incarceration^c	104 (70.3)	97 (65.5)	0.38	148 (67.9)	53 (67.9)	0.99
Incarceration factors
Mean years of prison sentence (SD)	3.1 ± 4.4	2.6 ± 3.9	0.58	2.8 ± 4.0	3.2 ± 4.6	0.83
Relocation status^d	13 (8.80)	14 (9.50)	0.84	18 (8.3)	9 (11.5)	0.39
Psychosocial characteristics
Social support mean score (SD)	50.6 ± 20.4	50.1 ± 18.8	0.94	50.1 ± 19.2	51.1 ± 20.8	0.33
HIV stigma mean score (SD)	99.6 ± 12.0	97.8 ± 11.7	0.21	98.6 ± 12.2	99.0 ± 11.1	0.99
Mean health-related quality of life score (SD)	61.3 ± 16.0	60.4 ± 14.6	0.22	61.2 ± 16.0	59.8 ± 13.2	0.54
Clinical characteristics
Mean years since HIV diagnosis (SD)	8.4 ± 5.2	8.1 ± 5.5	0.73	8.5 ± 5.4	7.8 ± 5.2	0.61
Mean CD4^+ T-cells/µL (SD)	442 ± 275	460 ± 293	0.99	439 ± 277	483 ± 301	0.38
Have previously been prescribed antiretroviral therapy	26 (17.6)	33 (22.3)	0.31	41 (18.8)	18 (23.1)	0.42
Mean Depression score (SD)	12.6 ± 6.6	12.2 ± 6.8	0.48	12.1 ± 6.2	13.2 ± 7.9	0.59
Substance use
Mean Addiction severity score (SD)	0.26 ± 0.10	0.27 ± 0.10	0.64	0.26 ± 0.10	0.30 ± 0.10	<0.01
Alcohol use disorder	26 (17.6)	23 (15.5)	0.64	34 (15.6)	15 (19.2)	0.46
Lifetime drug injection	131 (88.5)	140 (94.6)	0.06	199 (91.3)	72 (92.3)	0.78
Pre-incarceration heroin use	143 (96.6)	133 (89.9)	0.03	202 (92.7)	74 (94.9)	0.61
Pre-incarceration amphetamine use	81 (54.7)	84 (56.8)	0.73	124 (56.9)	41 (52.6)	0.51

^aSome subjects were allocated to receive both methadone and HHRP-M.

^bChi-squared/Fishers exact p value reported for categorical predictors; KS test p value reported for continuous predictors.

^cVariable assessed for the 30 days before incarceration.

^dParticipant was subject to legally enforced relocation to another Malaysian state after prison release.

SD: standard deviation; HHRP-M: Holistic Health Recovery Program, Malaysia; ART: antiretroviral therapy.

Table 2 Estimated effects of HHRP-M and pre-release methadone initiation on reenrollment (completion of ≥ 1 post-release study visit) within 12 months of prison release

Treatment effect estimator	HHRP-M		Methadone
	Estimate	95% CI	Estimate	95% CI
Unadjusted estimator
Difference in means	13.5%	3.8, 23.2%^b	10.0%	−2.5, 22.6%^c
Adjusted estimators^a
Outcome regression (OLS)	12.9%	3.1, 22.5%	10.2%	−1.8, 22.9%
Inverse probability weighting	13.1%	2.8, 23.6%	12.1%	−4.9, 29.8%
Doubly-robust	12.8%	2.6, 23.0%	10.4%	−5.8, 26.4%

^aAdjusting for all covariates shown in Table 1; standard errors estimated with the non-parametric bootstrap.

^bNon-parametric variance estimator.

^cT-statistic based confidence interval.

CI: confidence interval; OLS: ordinary least squares.

Table 3 Estimated effects of HHRP-M and pre-release methadone initiation on post-release retention across all time points using generalized estimating equations

	Unadjusted				Adjusted
Variable	Model 1		Model 2		Model 3
	β (95% CI)	p Value	β (95% CI)	p Value	β (95% CI)	p Value
Interventions
HHRP-M	0.06 (−0.02, 0.15)	0.160			0.05 (−0.01, 0.13)	0.220
Methadone			0.09 (−0.001, 0.20)	0.053	0.10 (0.008, 0.20)	0.034
Demographic
Mean age					0.003 (−0.004, 0.01)	0.391
Completed upper secondary education					0.08 (−0.006, 0.17)	0.067
Length of prison sentence					−0.008 (−0.01, 0.002)	0.112
Relocation status^a					−0.43 (−0.51, −0.34)	<0.001
Psychosocial factors
Stable housing^b					−0.01 (−0.11, 0.08)	0.783
Social support score					0.002 (−0.001, 0.004)	0.173
HIV stigma score					−0.003 (−0.007, 0.001)	0.113
Clinical factors
SF-36 general health					−0.001 (−0.004, 0.002)	0.436
Years since HIV diagnosis					0.001 (−0.007, 0.009)	0.781
CD4^+ T-cells/µL^c					0.004 (−0.01, 0.02)	0.621
ART experienced					−0.02 (−0.13, 0.08)	0.707
Depression score					0.008 (−0.0002, 0.01)	0.055
Substance use
Addiction severity score					0.03 (−0.40 –0.46)	0.895
Alcohol use disorder					0.01 (−0.09, 0.12)	0.790
Lifetime drug injection					−0.09 (−0.25, 0.05)	0.221
Pre-incarceration heroin use					0.08 (−0.09, 0.25)	0.372
Pre-incarceration methamphetamine use					−0.08 (−0.16, 0.006)	0.069
Study-related factors
Elapsed time^d					−0.002 (−0.006, 0.002)	0.392

^aParticipant was subject to legally enforced relocation to another Malaysian state after prison release.

^bVariable assessed for the 30 days before incarceration.

^cCoefficients represent 100-cell/µL change in baseline count.

^dElapsed time between study start date and participant enrollment date.

β: unstandardized coefficients; CI: confidence interval.

Table 4 Estimated effects of HHRP-M and pre-release methadone initiation on sustained retention, defined as completion of all 12 monthly follow-up visits ^a

Treatment effect estimator	HHRP-M		Methadone
	Estimate	95% CI	Estimate	95% CI
Unadjusted estimator
Difference in means	3.4%	−5.3, 12.0%^b	7.8%	−1.5, 17.1%^c
Adjusted estimators^a
OLS	3.6%	−5.4, 12.5%	9.5%	−0.5, 19.5%
Inverse probability weighting	3.1%	−6.1, 12.7%	11.3%	2.6, 19.5%
Doubly-robust	2.7%	−6.1, 11.6%	11.0%	2.0, 20.6%

^aAdjusting for all covariates shown in Table 1; standard errors estimated with the non-parametric bootstrap.

^bNon-parametric variance estimator.

^cT-statistic based confidence interval.

CI: confidence interval; OLS: Outcome regression.

Figure 2 Retention of study participants after prison release by treatment allocation.