Skip to main content
. Author manuscript; available in PMC: 2015 Jul 2.
Published in final edited form as: JAMA Psychiatry. 2014 May;71(5):547–556. doi: 10.1001/jamapsychiatry.2013.4546

Table 4.

Results From Negative Binomial Hurdle Models

Covariatea Days of Use Among Those Who Used
Logistic Portion Predicting Nonuse and Nonheavy Drinking
B (SE) IRRb B (SE) ORb
3-mo Drug use days
 Contrast 1: TAU (−) vs RP/MBRP (+) −0.06 (0.18) 0.94 0.11 (0.12) 1.12
 Contrast 2: RP (−) vs MBRP (+) 0.48 (0.25) 1.61 −0.02 (0.12) 0.98
 Age −0.07 (0.04) 0.94 0.01 (0.02) 1.01
 Treatment history 0.06 (0.36) 1.06 −0.10 (0.09) 0.90
 SDS baseline −0.03 (0.18) 0.97 −0.06 (0.04) 0.94
 Treatment hours −0.002 (0.05) 0.99 0.07 (0.02)c 1.08c
 Treatment site, coded 0, 1 −1.47 (1.15) 0.23 −0.58 (0.32) 0.56
6-mo Drug use days
 Contrast 1: TAU (−) vs RP/MBRP (+) −0.44 (0.44) 0.65 0.24 (0.12)c 1.28c
 Contrast 2: RP (−) vs MBRP (+) 0.52 (0.69) 1.68 −0.05 (0.18) 0.95
 Age −0.02 (0.15) 0.98 0.000 (0.02) 1.00
 Treatment history −0.25 (0.88) 0.78 −0.08 (0.09) 0.92
 SDS baseline 0.21 (0.13) 1.23 −0.07 (0.04) 0.93
 Treatment hours −0.01 (0.06) 0.99 0.07 (0.03)c 1.08c
 Treatment, coded 0, 1 −0.79 (0.80) 0.44 0.47 (0.35) 1.59
12-mo Drug use days
 Contrast 1 TAU (−) vs RP/MBRP (+) −0.24 (0.15) 0.79 0.09 (0.16) 1.09
 Contrast 2: RP (−) vs MBRP (+) −0.37 (0.16)c 0.69c 0.21 (0.18) 1.24
 Age −0.09 (0.04)c 0.91c 0.02 (0.02) 1.02
 Treatment history −0.29 (0.28) 0.75 0.19 (0.17) 1.22
 SDS baseline 0.11 (0.06) 1.12 −0.15 (0.09) 0.86
 Treatment hours −0.02 (0.02) 0.98 0.01 (0.02) 1.01
 Treatment site, coded 0, 1 −0.25 (0.42) 0.78 0.30 (0.49) 1.35
3-mo Heavy drinking days
 Contrast 1: TAU (−) vs RP/MBRP (+) 0.33 (0.47) 1.40 0.12 (0.11) 1.12
 Contrast 2: RP (−) vs MBRP (+) −0.02 (0.30) 0.98 0.25 (0.15) 1.28
 Age −0.05 (0.02)c 0.95c −0.03 (0.02) 0.97
 Treatment history 0.49 (0.78) 1.64 −0.13 (0.12) 0.88
 SDS baseline −0.16 (0.31) 0.85 −0.04 (0.05) 0.96
 Treatment hours −0.20 (0.11) 0.82c 0.09 (0.02)c 1.09c
 Treatment site, coded 0, 1 −1.81 (1.03) 0.16c −1.03 (0.36)c 0.36c
6-mo Heavy drinking days
 Contrast 1: TAU (−) vs RP/MBRP (+) −0.37 (0.09)c 0.69 0.23 (0.09)c 1.26c
 Contrast 2: RP (−) vs MBRP (+) 0.57 (0.32) 1.78 −0.06 (0.19) 0.94
 Age −0.06 (0.04) 0.95 −0.01 (0.02) 0.99
 Treatment history −0.04 (0.23) 0.96 −0.04 (0.14) 0.97
 SDS baseline 0.13 (0.12) 1.14 −0.03 (0.04) 0.97
 Treatment hours −0.04 (0.02) 0.96 0.02 (0.04) 1.02
 Treatment site, coded 0, 1 0.21 (0.41) 1.23 −0.89 (0.61) 0.41
12-mo Heavy drinking days
 Contrast 1: TAU (−) vs RP/MBRP (+) −0.04 (0.16) 0.97 0.17 (0.12) 1.19
 Contrast 2: RP (−) vs MBRP (+) 0.37 (0.39) 1.45 0.43 (0.11)c 1.51c
 Age 0.11 (0.04)c 1.11c −0.01 (0.02) 0.99
 Treatment history −0.37 (0.20) 0.69 0.05 (0.15) 1.05
 SDS baseline 0.31 (0.08)c 1.36c 0.03 (0.04) 1.03
 Treatment hours 0.02 (0.02) 1.02 −0.004 (0.04) 0.99
 Treatment site, coded 0, 1 1.13 (0.40)c 3.09c −0.45 (0.38) 0.64

Abbreviations: B, unstandardized regression coefficient; IRR, incidence rate ratio; MBRP, mindfulness-based relapse prevention; OR, odds ratio; RP, relapse prevention; SDS, Severity of Dependence Scale; TAU, treatment as usual.

a

Contrast 1 was coded with TAU as negative and RP/MBRP as positive; contrast 2 was coded with RP as negative and MBRP as positive.

b

The IRR can be interpreted as percentage increase (above 1.0) or decrease (below 1.0) in heavy drinking or drug use days for a 1-unit increase in the predictor (with other predictors in the model held constant). The OR can be interpreted as the increase (above 1.0) or decrease (below 1.0) in the odds of not using or not engaging in heavy drinking (with other predictors in the model held constant).

c

P < .05.