Marijuana Use and Health in Primary Care

Abstract

To The Editor: With the increased in prevalence of marijuana use in the past 20 years in the United States, and recent trends suggesting it may continue to rise,1 there is a great need for research that will improve our understanding and highlight the range of effects associated with marijuana use. Consequently, the article by Fuster et al.2 in your September issue was an interesting and timely piece. The authors found no significant association between frequency of current marijuana use and health care utilization and health among primary care patients identified by screening positive for use of any illicit drug. However, a few reservations remain. The study was a secondary analysis of data originally collected for a randomized trial. The large number of participants that were excluded as a result of ineligibility and refusal to participate make the study subject to selection bias. The authors reported that of the 270 subjects that were excluded due to ineligibility to the randomized trial and therefore their study, unwillingness/inability to return for visits was the reason for 77 % (209). It is possible that these excluded subjects were frequent users of marijuana, had poor health, and were more likely to have significant comorbidities that may have made them unable to return for visits. Also, another 428 subjects were excluded for refusal to participate. While the authors attempted to ascertain the homogeneity of this group to their study sample, based on age, gender and substance use, other variables that could potentially be associated with the study’s outcomes, including income, educational status, ethnicity, accessibility to care and depressive symptoms3 were not considered in their analysis. Also, the lack of appropriate comparison groups, which should include non-drug using individuals or limited drug users, in all sub-group analysis, including those with exclusive marijuana use, make drawing any substantive conclusion from the study problematic. Yet, in their discussion, the authors state that among exclusive marijuana users, cutting down use may have little measurable effect on health status or health utilization.2 Given that marijuana is perceived as having minimal health problems among users,4 and as the authors rightly state, there is a lack of research on its impact in health care utilization, more studies with convincing evidence are warranted.