Mortality among people with regular or problematic use of amphetamines: a systematic review and meta-analysis.

Abstract

Amphetamines are the second most commonly used class of illicit drugs. We aimed to produce pooled estimates of mortality risks among people with regular or dependent use of amphetamines, with a focus upon all-cause mortality as well as specific causes of death. Systematic review and meta-analysis of cohorts of people with problematic use or dependence on amphetamines with data on all-cause or cause-specific mortality. Of 4240 papers, 30 were eligible, reporting on 25 cohorts that measured all-cause mortality, drug poisoning, suicide, accidental injuries, homicide and cardiovascular mortality. Cohorts (n = 35-74 139) were in North America, several Nordic countries and Asia Pacific. Titles/abstracts were independently screened by one reviewer and excluded those reviewed by a second reviewer. Full-text screening was by two reviewers with discrepancies resolved via a third reviewer. We extracted data on crude mortality rates (CMR) per 100 person-years (py), standardized mortality ratios (SMRs). We imputed SMRs where possible if not reported by study authors. We also calculated mortality relative risks. Data were pooled using random-effects models; potential reasons for heterogeneity were explored using subgroup analyses and meta-regressions. Twenty-three cohorts contributed data for the pooled all-cause CMR: 1.14 per 100 py [95% confidence interval (CI) = 0.92-1.42]. Pooled cause-specific mortality rates were: drug poisoning, 0.14 per 100 py (95% CI = 0.06-0.34); cardiovascular disease, 0.13 per 100 py (95% CI = 0.06-0.29); suicide, 0.20 per 100 py (95% CI = 0.07-0.55); accidental injury, 0.20 per 100 py (95% CI = 0.08-0.47) and homicide, 0.03 per 100 py (95% CI = 0.02-0.06). There was substantial heterogeneity for all pooled CMR estimates except homicide. The pooled all-cause SMR was 6.83 (95% CI = 5.27-8.84). Pooled cause-specific SMRS were: poisoning, 24.70 (95% CI = 16.67, 36.58); homicide, 11.90 (95% CI = 7.82-18.12); suicide, 12.20 (95% CI = 4.89-30.47); cardiovascular disease, 5.12 (95% CI = 3.74-7.00) and accidental injury, 5.12 (95% CI = 2.88-9.08). People with regular or dependent amphetamine use are at elevated risk of a range of causes of mortality compared with people without regular or dependent amphetamine use.