Background: The aim of this study was to conduct a cluster randomized control trial to assess the efficacy of screening and brief intervention (SBI) for conjoint alcohol and tobacco use among hospital out-patients.
Method: In all 620 hospital out-patients who screened positive for both tobacco and alcohol moderate risk in four hospitals were randomized into 2 control and 1 intervention condition using the hospital as a unit of randomization (2 intervention and 2 control hospitals) to 405 patients in the two control groups (tobacco only intervention, n=199, and alcohol only intervention, n=206) and 215 in the intervention group. The intervention or control consisted of three counselling sessions.
Results: Results of the interaction (Group × Time) effects using GEE indicated that there were statistically significant differences between the three study groups over the 6-month follow-up on the ASSIST tobacco score (Wald χ(2) = 8.43, P=0.004), and past week tobacco use abstinence (Wald χ(2)=7.34, P=0.007). Although there were no significant interaction effects on the other outcomes (Alcohol ASSIST score, low alcohol risk score, past week tobacco abstinence or low alcohol risk score, and past week tobacco abstinence and low alcohol risk score), the scores in all of the six outcome measures showed consistent improvements. For past week tobacco abstinence the tobacco only intervention was more effective than the alcohol only intervention and the integrated alcohol and tobacco intervention. For the outcome of low alcohol risk, the alcohol only intervention and the integrated alcohol and tobacco intervention was more effective than the tobacco only or alcohol only intervention.
Conclusions: The study found that for past week tobacco abstinence the tobacco only intervention was more effective than the alcohol only intervention and the polydrug use (alcohol and tobacco) integrated intervention.