Citation

Degenhardt L, Bucello C, Mathers B, Briegleb C, Ali H, Hickman M, McLaren J. Addiction 2011; 106(1): 32-51.

Copyright

(Copyright © 2011, John Wiley and Sons)

DOI

10.1111/j.1360-0443.2010.03140.x

PMID

unavailable

Abstract

Aims To review the literature on mortality among dependent or regular users of opioids across regions, according to specific causes, and related to a number of demographic and clinical variables.

Methods Multiple search strategies included searches of Medline, EMBASE and PsycINFO, consistent with the methodology recommended by the Meta‐analysis of Observational Studies in Epidemiology (MOOSE) group; grey literature searches; and contact of experts for any additional unpublished data from studies meeting inclusion criteria. Random‐effects meta‐analyses were conducted for crude mortality rates (CMRs) and standardized mortality ratios (SMRs), with stratified analyses where possible. Meta‐regressions examined potentially important sources of heterogeneity across studies.

Results Fifty‐eight prospective studies reported mortality rates from opioid‐dependent samples. Very high heterogeneity across studies was observed; pooled all‐cause CMR was 2.09 per 100 person‐years (PY; 95% CI; 1.93, 2.26), and the pooled SMR was 14.66 (95% CI: 12.82, 16.50). Males had higher CMRs and lower SMRs than females. Out‐of‐treatment periods had higher mortality risk than in‐treatment periods (pooled RR 2.38 (CI: 1.79, 3.17)). Causes of death varied across studies, but overdose was the most common cause. Multivariable regressions found the following predictors of mortality rates: country of origin; the proportion of sample injecting; the extent to which populations were recruited from an entire country (versus subnational); and year of publication.

Conclusions Mortality among opioid‐dependent users varies across countries and populations. Treatment is clearly protective against mortality even in non‐randomized observational studies. Study characteristics predict mortality levels; these should be taken into account in future studies.