Impaired physical health among methamphetamine users in comparison with the general population: the role of methamphetamine dependence and opioid use.

Aim: To examine the extent of physical health impairment among a community sample of methamphetamine users in comparison with the general population, and factors associated with impairment among this group.
Method: A cross-sectional survey of 309 regular methamphetamine users from Sydney. The Physical Component Scale of the Short Form 12 (SF-12) was used to measure impairment in physical health (score < 40). Age-matched general population data for the SF-12 were derived from the Australian National Survey of Mental Health and Well-Being.
Results: Participants had a higher prevalence of impaired physical health compared to the Australian general population (20% vs. 10%, p<0.05), but this effect occurred among only dependent methamphetamine users over 24 years of age (25 - 34 years, 23% vs. 10%; 35 - 44 years, 41% vs. 12%). Methamphetamine dependence remained significantly predictive of impaired physical health after adjusting for age and other confounding factors. Opioid pharmacotherapy was also related strongly to poor physical health, accounting for 63% of participants with physical impairment. Other factors associated with impaired physical health were being female, having less than 10 years of schooling, and having been diagnosed previously with an anxiety disorder (p<0.05).
Conclusion: Methamphetamine users are more likely to report impaired physical health than the general population, but this impairment is specific to older methamphetamine users who are dependent on the drug, particularly those who are enrolled in opioid pharmacotherapy.