Results of mortality cohort study of problem drug users in Poland.

Method: The study was conducted using longitudinal, retrospective method. All problem drug users attending residential treatment due to mental disorders related to drug use in the 2000-2014 period were enrolled. The observation period was 2000-2016. The vital status was checked using national electronic population register.

Results: Among 42 771 persons admitted to treatment with known vital status 5 489 persons died (12.8%). The mortality crude rate (CMR) was 15.8 deaths per 1000 person-years while standardized mortality ratio (SMR) – 3.4. The ratio is higher for males 4.6 than for females 2.1. Decreasing trend was noted in both CMR and SMR. CMR decreased from 48 per 1000 person-years in 2000 to 15 per 1000 person-years in 2016. The SMR went down from 85 in 2000 to 19 in 2016. The survival analyze shows that cumulative risk of deaths increases faster among cohorts earlier admitted to the treatment than cohorts later enrolled to the treatment. The results of Cox regression show that risk of deaths is higher for males, low educated people, homeless or staying alone, having basic income from sources other than permanent job, having F11 diagnoses at the moment of entry to cohort and finishing unsuccessfully that treatment episode. Risk of deaths is increasing with increasing age. The drug related deaths according to EMCDDA definition constitute only 5.3% of all deaths.

Conclusion: Low social and economic position is an important factor of mortality among problem drug users. Decreasing trend in mortality can be related to changes in drug use pattern and development in harm reduction measures.