Mortality, morbidity, and predictors of death among amphetamine-type stimulant users - a longitudinal, nationwide register study.

Introduction: Use of amphetamine-type stimulants (ATS) contributes substantially to the global burden of disease. Large-scale follow-up studies of morbidity and mortality in ATS users are few. This study analysed morbidity, mortality, and potential predictors of all-cause mortality in a nationwide cohort of patients with ATS use disorder.

Methods: Data was acquired from national Swedish registers. All Swedish residents 18 years or older, with a registered ATS use diagnosis in 2013-2014 were included (N = 5,018) and followed until December 31, 2017. Comorbid diagnoses and causes of death were assessed and potential predictors of all-cause mortality were examined through Cox regression.

Results: Median age at inclusion was 36.6 years (interquartile range 27.4---48.1) and 70.5 % were men. The crude mortality rate was 24.6 per 1,000 person-years. The adjusted all-cause standardized mortality ratio was 12.4 (95 % CI [11.34-13.55]). The most common cause of death was overdose (28.9 %). Multiple drug use (hazard ratio 1.39, 95 % CI [1.14-1.70], p = 0.004), anxiety (hazard ratio 1.39, 95 % CI [1.11-1.72], p = 0.014), viral hepatitis (hazard ratio 1.85, 95 % CI [1.50-2.29], p = 0.004), and liver disease (hazard ratio 2.41, 95 % CI [1.55-3.74], p = 0.004) were predictors of all-cause mortality.

Conclusions: Multiple drug use, anxiety disorders, viral hepatitis and liver diseases were identified as risk factors for death. Our findings call for better screening, prevention, and treatment of somatic and psychiatric comorbidity among ATS users to reduce mortality.