Our findings showed that less than half of PWID in Iran received OST in the previous year and there was a significant disparity in OST uptake across cities. Being ever married, HIV positive, and having history of incarceration were positively associated with receiving OST, while using non-opioid drugs were negatively associated with receiving OST.
We showed that less than half of PWID in Iran used OST in the previous year. Based on WHO’s definition of high coverage of OST as 40% or more, Iran falls into the high coverage category[15]. However, extrapolating these results to the estimated number of PWID in Iran (200,000) indicate that still more than 100,000 PWID are not currently on OST[16]. Furthermore, there is a high level of disparity for OST uptake across cities. We showed that OST uptake varied from 0–75% in different cities. Interestingly, all cities with low OST coverage are among the less and under developed regions which disproportionally have higher rate of child mortality and lower number of rehabilitation centers and paramedics[17]. Therefore, to reach and maintain the high coverage goal in all regions of the country, allocation of resources regarding the degree of inequality in the distribution of OST services should be considered in future planning. In addition, addressing and removing the potential barriers to access and use of OST including financial barriers, lack of awareness and negative attitudes, worries about methadone’s side effects, and social stigma attached to receiving OST is a key to increase the coverage rate of OST uptake among Iranian PWID[8]. Comparing our results to other countries of region indicate that OST uptake in Iran is still higher than most neighborhood countries in the region. In 2017, only 7 countries out of all countries located in MENA region provided OST to PWID resulting in an overall assessment of approximately 6% of PWID in the MENA region being on OST[18].
Compared to 2011, the OST uptake in PWID slightly decreased in 2014. This trend is in opposite direction with increasing number of facilities (from 700 centers in 2007 to 3,373 centers in 2014) [19], that provide OST services to PWID. Due to emergence and increasing supply of synthetic non-opioid drugs including methamphetamines, more PWID have tendency to use these drugs[20]. On the other hand, the use of methamphetamine in PWID reduces the effectiveness of OST program and subsequently lower satisfaction of patients from OST[21]. These issues are problematic in a way that treatment of PWID who use synthetic drugs has turned into a challenging issue within the last years. For example, we found that compared to PWID who used only opioids within the last month, those who used only non-opioids and those who used opioids and non-opioids simultaneously were less likely to receive OST. This result is in line with the finding of study in Thailand[22]. OST is the primary treatment for opiates dependency and therefore, it may not be helpful for people who use non-opioids and is less effective in poly drug users. Therefore, PWID who mainly use stimulants or poly drug users wouldn't refer to OST centers or if they refer, they wouldn’t get the desired result. In Iran, there are only limited number of centers providing stimulants treatment. Preliminary studies indicate that integration of stimulant harm reduction services in to opioid HR programs at DICs could be an effective strategy in reducing some high risk behaviors of clients [23] So, policies toward establishment of such centers and providing stimulant treatments at DICs should be strengthen in future planning across the country.
Living with HIV was associated with increased likelihood of OST uptake, a finding which is consistent with study that conducted in Vancouver[24]. This may be partly due to the effect of post-test counselling which is freely available for all PWID who underwent HIV testing in Iran. Integration of HIV and substance use services cause to improve the HIV treatment and care continuum among PWID living with HIV[25, 26].
In our study, having history of incarceration positively associated with OST uptake. This may be due to establishment of harm reduction program inside Iran's' prisons. Similar to many parts of the world, people using drugs are overrepresented in prisons across Iran. More than 50% of all Iranian prisoners are being held on drug-related offenses and 70% of them use illicit drugs[27]. Since Iran experience two large outbreaks of HIV in prison inmates, the harm reduction program inside prisons initiated from 2001 and expanded quickly and reached to a high coverage up to now. Therefore, most of PWID who are being arrested would receive OST inside prisons. Previous studies showed that exposure of prisoners to OST inside prison increase the chance of receiving OST even after their release[18, 28]. So, the continuation and extension of current strategies of harm reduction inside prisons is highly recommended in Iran.
There are three key limitation to consider in the interpretation of the findings provided here including social desirability, limited causality, and potential recruitment biases. First, social desirability bias may result in over-reporting of OST uptake and under-reporting of stigmatized behaviors such as abuse of drugs and alcohol. Second, the study was cross-sectional and the observed associations with limited assessment of causality between the determinants of OST and OST uptake. Last, some of the participants were recruited from care facilities and so the selection bias may limit the generalizability of finding to the all PWID in Iran.