Randomized clinical trial of the effects of screening and brief intervention for illicit drug use: the life shift/shift gears study

Table 2 Outcomes of Life Shift/Shift Gears using complete cases (n=292) and imputed cases (n = 694)

Means (SE) or percent
Outcome	*Life Shift* intervention		*Shift Gears* control		p value for group ×; time interaction or Wald χ²
	Baseline	Follow-up	Baseline	Follow-up
Past 30 day drug abstinence at follow-up (%)^b
Self-reported		12.5 (3.2)		12.0 (3.1)	.888
Biologically validated^c		7.0 (2.5)		2.0 (1.2)	.074
Self-reported drug use – ASI Composite Score (0-1)
Complete cases	.059 (.008)	.068 (.010)	.055 (.007)	.095 (.010)	.035^a
Imputed	.070 (.005)	.075 (.006)	.068 (.006)	.085 (.007)	.124^a
Medical problems – ASI Composite Score (0-1)
Complete cases	.639 (.021)	.176 (.038)	.696 (.020)	.280 (.036)	.404^a
Imputed	.65 (.013)	.219 (.023)	.669 (.014)	.248 (.024)	.627^a
Psychiatric problems – ASI Composite Score (0-1)
Complete cases	.287 (.031)	.250 (.029)	.292 (0.27)	.243 (.025)	.734^a
Imputed	.264 (.017)	.239 (.016)	.272 (.017)	.228 (.017)	.404^a
Alcohol use – ASI Composite Score (0-1)
Complete cases	.127 (.018)	.124 (.016)	.106 (.017)	.106 (.015)	.888
Imputed	.126 (.011)	.115 (.009)	.126 (.012)	.112 (.010)	.808
Past 6 mo. health care utilization
No. of ED visits^d	.528 (.106)	.828 (.129)	.549 (.111)	.806 (.135)	.826^a
No. of hospitaliz.^e	.196 (.094)	.261 (.111)	.146 (.099)	.317 (.117)	.479
No. of days hosp.^e	1.26 (.607)	1.60 (643)	1.43 (.643)	2.56 (.681)	.335^a
Driving and traffic risk scores
Complete cases	.975 (.068)	.831 (.070)	.840 (.064)	.907 (.066)	.057
Imputed	1.00 (.045)	.935 (.042)	.837 (.048)	.897 (.045)	.165

^aSignificant time main effect, p < .05.
^bImputation not available for dichotomous outcomes, therefore, analyses based on 292 complete cases.
^cThose followed and reporting 0 drug use but who did not provide a hair sample for any reason; assumed to be nonabstinent.
^dData available for 602 patients.
^eSite 2 only; data available for 97 patients.

ISSN: 1940-0640