Cannabis and traffic collision risk: findings from a case-crossover study of injured drivers presenting to emergency departments.

OBJECTIVES: This study examined whether acute cannabis use leads to an increased collision risk. METHODS: Participants were 860 drivers presenting to emergency departments in Toronto and Halifax, Canada, with an injury from a traffic collision, between April 2009 and July 2011. Cannabis and other drug use were identified either through blood sample or self-report. A case-crossover design was employed with two control conditions: a fixed condition measuring substance use during last time driving, and whether the driver typically uses cannabis prior to driving. Collision risk was assessed through conditional fixed-effects logistic regression models. RESULTS: Results revealed that 98 (11 %; 95 % CI: 9.0-13.1) drivers reported using cannabis prior to the collision. Regression results measuring exposure with blood and self-report data indicated that cannabis use alone was associated with a fourfold increased (OR 4.11; 95 % CI: 1.98-8.52) odds of a collision; a regression relying on self-report measures only found no significant association. CONCLUSIONS: Main findings confirmed that cannabis use increases collision risk and reinforces existing policy and educational efforts, in many high-income countries, aimed at reducing driving under the influence of cannabis.

Computer-based intervention in HIV clinical care setting improves antiretroviral adherence: the LifeWindows Project.

We evaluated the efficacy of LifeWindows, a theory-based, computer-administered antiretroviral (ARV) therapy adherence support intervention, delivered to HIV + patients at routine clinical care visits. 594 HIV + adults receiving HIV care at five clinics were randomized to intervention or control arms. Intervention vs. control impact in the intent-to-treat sample (including participants whose ARVs had been entirely discontinued, who infrequently attended care, or infrequently used LifeWindows) did not reach significance. Intervention impact in the On Protocol sample (328 intervention and control arm participants whose ARVs were not discontinued, who attended care and were exposed to LifeWindows regularly) was significant. On Protocol intervention vs. control participants achieved significantly higher levels of perfect 3-day ACTG-assessed adherence over time, with sensitivity analyses maintaining this effect down to 70% adherence. This study supports the utility of LifeWindows and illustrates that patients on ARVs who persist in care at clinical care sites can benefit from adherence promotion software.

Information-motivation-behavioral skills barriers associated with intentional versus unintentional ARV non-adherence behavior among HIV+ patients in clinical care.

Since the arrival of antiretroviral (ARV) therapy, HIV has become better characterized as a chronic disease rather than a terminal illness, depending in part on one's ability to maintain relatively high levels of adherence. Despite research concerning barriers and facilitators of ARV adherence behavior, relatively little is known about specific challenges faced by HIV-positive persons who report "taking a break" from their ARV medications. The present study employed the Information-Motivation-Behavioral Skills Model of ARV adherence as a framework for understanding adherence-related barriers that may differentiate between non-adherent patients who report "taking a break" versus those who do not report "taking a break" from their ARV medications. A sample of 327 HIV-positive patients who reported less than 100% adherence at study baseline provided data for this research. Participants who reported "taking a break" from their HIV medications without first talking to their healthcare provider were classified as intentionally non-adherent, while those who did not report "taking a break" without first talking with their healthcare provider were classified as unintentionally non-adherent. Analyses examined differences between intentionally versus unintentionally non-adherent patients with respect to demographic characteristics and responses to the adherence-related information, motivation, and behavioral skills questionnaire items. Few differences were observed among the groups on demographics, adherence-related information, or adherence-related motivation; however, significant differences were observed on about half of the adherence-related behavioral skills items. Implications for future research, as well as the design of specific intervention components to reduce intentionally non-adherent behavior, are discussed.