This single center data demonstrates that methamphetamine abuse is seen in 4.5% of the patients with acute ischemic stroke at our medical center. The patients with methamphetamine use are significantly younger (54.5 ± 6.9 vs. 70 ± 12.4, p < 0.001) and more likely male (77% vs. 54%, p < 0.001). In addition, sensitivity analysis with propensity score-matched controls showed that methamphetamine abuse is associated with increased burdens of cSVD, independent of age, sex, comorbidities, acute hypertension, and stroke severity.
Previous studies showed that elevated blood pressure levels are associated with each of the MRI markers of cSVD [14–15]. Effective treatment of hypertension may reduce the rates of cSVD and stroke [13, 15]. In this retrospective study, there was no significant difference in blood pressures at admission or hospital discharge, blood pressure reduction during hospitalization, and the numbers of antihypertensives required to control hypertension between the Meth or Meth + group and propensity score-matched Non-Meth controls. It is possible that chronic hypertension from methamphetamine abuse plays an important role in the development of cSVD [13].
Advanced age and male sex were reported to be major risk factors for cSVD [16, 23–25]. In a recent study, cerebral SVD was seen in 18.9% of age group 70s as compared to 3% in age group 40s [23]. In a Chinese population-based study, advanced age was shown to be independently associated with the prevalence of cSVD [24]. In our study, we demonstrated that methamphetamine abuse increases the risk of cSVD in young stroke patients.
In a cohort study of homeless and unstably housed women (n = 30) from San Francisco community, 86% patients had a history of cocaine use and 54% patients had WMHs [25]. In our cohort, more patients in the Meth group had a history of cocaine abuse than the Non-Meth group (11.5% vs. 0.7%). The relatively low proportion of patients (11.5%) with concomitant cocaine use may be a confounding factor in our study.
Since cSVD increases the risk of cognitive impairment and vascular dementia, methamphetamine abuse in young adults may have more significant long-term public health concerns than stroke and other detrimental effects.
Our study has a few limitations. First, some patients were unable to provide history of drug use due to aphasia or severe neurological deficit. and was unable to provide history of drug abuse. Others tested positive but denied history of drug abuse. In addition, only 932 patients (71%) in the Non-Meth group had a UDS. The rate of methamphetamine abuse was highly likely underestimated. Second, there was no information regarding the route, frequency, and duration of methamphetamine abuse. Third, the sample size of this retrospective is relatively small. Therefore, additional studies are warranted to establish the temporal relationship between methamphetamine abuse and cSVD.
Of note, it was challenging to get accurate information on polysubstance abuse, particularly, in patients with neurological deficit. It may be also unethical to conduct randomized controlled studies on methamphetamine abuse. Well-designed prospective registry may be a good option to further investigate the effect of chronic methamphetamine use on cSVD.
In conclusion, our preliminary results demonstrates that methamphetamine abuse is common in young adults with acute ischemic stroke and increases the risk of cSVD. Given increased prevalence of methamphetamine abuse in young adults, additional studies are warranted to investigate the effects of chronic methamphetamine use on the pathogenesis of stroke, cSVD, and vascular dementia.