An Exploratory Prospective Study of Marijuana Use and Mortality After AMI
An Exploratory Prospective Study of Marijuana Use and Mortality After AMI
Background:The relationship of marijuana use with coronary heart disease, including prognosis among patients with coronary heart disease, is uncertain.
Methods:We conducted an inception cohort study of 1913 adults hospitalized with myocardial infarction at 45 US hospitals between 1989 and 1994, with a median follow-up of 3.8 years. We ascertained total mortality according to self-reported marijuana use in the preceding year.
Results:A total of 52 patients reported marijuana use during the prior year, and 317 patients died during follow-up. Compared with nonuse, marijuana use less than weekly was associated with a hazard ratio of 2.5 (95% CI, 0.9-7.3). The corresponding hazard ratio for weekly use or more was 4.2 (95% CI, 1.2-14.3). The age- and sex-adjusted hazard ratios associated with any use were 1.9 (95% CI, 0.6-6.3) for cardiovascular mortality and 4.9 (95% CI, 1.6-14.7) for noncardiovascular mortality. In a comparison of 42 marijuana users and 42 other patients matched on propensity scores, there were 6 deaths among marijuana users and one among non-users (log-rank P = .06).
Conclusions:These preliminary results suggest possible hazards of marijuana for patients who survive acute myocardial infarction. Although marijuana use has not been associated with mortality in other populations, it may pose particular risk for susceptible individuals with coronary heart disease.
Marijuana use is not uncommon in the United States. A 2001-2002 national survey found that 4.1% of the adult population of the United States had used marijuana within the last year. Although younger adults were most likely to report marijuana use, such use among adults aged 45 to 64 years was almost 3-fold higher than it had been a decade earlier.
Few studies have documented the long-term outcomes of marijuana users. In one previous study of marijuana use and mortality in the general population, Sidney et al found no increased risk of mortality associated with marijuana use among Kaiser Permanente enrollees <50 years old, very similar to earlier findings among Swedish conscripts. However, marijuana use has cardiovascular effects that could pose particular risk for older adults and those with coronary heart disease, including a sizable increase in resting heart rate. Moreover, in a previous analysis of the Onset Study, the risk of triggering a myocardial infarction (MI) was elevated almost 5-fold within 1 hour after smoking marijuana, compared with periods of nonuse, consistent with case reports describing this phenomenon. However, Steffens et al recently found that orally administered tetrahydrocannabinol, a cannabinoid derivative, inhibits atherosclerosis progression in a mouse model, apparently through effects on lymphoid and myeloid cells. Marijuana use also has a wide variety of noncardiovascular effects, including potentially adverse respiratory, neurologic, and immunologic effects. The net balance of these apparently disparate effects of marijuana use on the most clinically vulnerable patients, such as those with established coronary heart disease, has not been studied.
An impediment to understanding the clinical consequences of marijuana use has been the stark dearth of studies that have collected information on exposure. To address this paucity of information, we explored the association of marijuana use assessed at the time of acute MI (AMI) with subsequent mortality among participants of the Onset Study. This multicenter, prospective cohort study included chart reviews and in-depth personal interviews with hospitalized patients with confirmed AMI.
Background:The relationship of marijuana use with coronary heart disease, including prognosis among patients with coronary heart disease, is uncertain.
Methods:We conducted an inception cohort study of 1913 adults hospitalized with myocardial infarction at 45 US hospitals between 1989 and 1994, with a median follow-up of 3.8 years. We ascertained total mortality according to self-reported marijuana use in the preceding year.
Results:A total of 52 patients reported marijuana use during the prior year, and 317 patients died during follow-up. Compared with nonuse, marijuana use less than weekly was associated with a hazard ratio of 2.5 (95% CI, 0.9-7.3). The corresponding hazard ratio for weekly use or more was 4.2 (95% CI, 1.2-14.3). The age- and sex-adjusted hazard ratios associated with any use were 1.9 (95% CI, 0.6-6.3) for cardiovascular mortality and 4.9 (95% CI, 1.6-14.7) for noncardiovascular mortality. In a comparison of 42 marijuana users and 42 other patients matched on propensity scores, there were 6 deaths among marijuana users and one among non-users (log-rank P = .06).
Conclusions:These preliminary results suggest possible hazards of marijuana for patients who survive acute myocardial infarction. Although marijuana use has not been associated with mortality in other populations, it may pose particular risk for susceptible individuals with coronary heart disease.
Marijuana use is not uncommon in the United States. A 2001-2002 national survey found that 4.1% of the adult population of the United States had used marijuana within the last year. Although younger adults were most likely to report marijuana use, such use among adults aged 45 to 64 years was almost 3-fold higher than it had been a decade earlier.
Few studies have documented the long-term outcomes of marijuana users. In one previous study of marijuana use and mortality in the general population, Sidney et al found no increased risk of mortality associated with marijuana use among Kaiser Permanente enrollees <50 years old, very similar to earlier findings among Swedish conscripts. However, marijuana use has cardiovascular effects that could pose particular risk for older adults and those with coronary heart disease, including a sizable increase in resting heart rate. Moreover, in a previous analysis of the Onset Study, the risk of triggering a myocardial infarction (MI) was elevated almost 5-fold within 1 hour after smoking marijuana, compared with periods of nonuse, consistent with case reports describing this phenomenon. However, Steffens et al recently found that orally administered tetrahydrocannabinol, a cannabinoid derivative, inhibits atherosclerosis progression in a mouse model, apparently through effects on lymphoid and myeloid cells. Marijuana use also has a wide variety of noncardiovascular effects, including potentially adverse respiratory, neurologic, and immunologic effects. The net balance of these apparently disparate effects of marijuana use on the most clinically vulnerable patients, such as those with established coronary heart disease, has not been studied.
An impediment to understanding the clinical consequences of marijuana use has been the stark dearth of studies that have collected information on exposure. To address this paucity of information, we explored the association of marijuana use assessed at the time of acute MI (AMI) with subsequent mortality among participants of the Onset Study. This multicenter, prospective cohort study included chart reviews and in-depth personal interviews with hospitalized patients with confirmed AMI.