Prevalence of HIV infection among high-risk groups in Iran: a systematic review and meta-analysis

Introduction

Risky behaviors, such as substance abuse, alcohol consumption, high speed driving, attempting/committing suicide, and illegal sexual contacts are considered major health problems worldwide. Unfortunately, unhealthy and risky behaviors are increasing, causing a serious concern for community health and policymakers [1]. Among them, illegal injection drug use (IDU) and unsafe sex with infected partner or sex with multiple partners are two of the most common routes of transmission for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficieny virus (HIV) [2]. Nowadays, HIV infection is estimated to occur in 40 million chronic cases around the world [3]. But the prevalence of this disease differs in various sub-groups of population as compared with general population; for example, in a study conducted in Chennai, India, the prevalence of HIV among IDUs was 29.8% [4], whereas in Miami, Florida, the prevalence of HIV among sex workers was 22.4% [5]. Results on the review from 75 low-income and middle-income countries revealed that in 10 countries, the prevalence of HIV among prisoners was greater than 10% [6].
The estimated prevalence of HIV infection in the general population of Iran is < 0.2% [6], but in high-risk groups, the prevalence rate is much higher. In Tehran, capital of Iran, results of a study indicated that the prevalence of HIV among male injecting drug users was 23.5% [7]. Kazerooni et al. found that prevalence of HIV among FSWs in Shiraz was 4.7% [8]. Due to dreadful conditions of prisons, inmates are more susceptible to infectious diseases, as shown in a survey conducted on prisoners in Southern Khorasan [9]. There is growing number of studies about HIV infections among high-risk groups in different regions of Iran. However, many of these studies result in different or occasionally contradictory conclusions; therefore, the generalizability of any single study to all its sub-groups is limited. Considering the enormous number of drug users and increasing trend of extramarital sex among Iranian youth [10], the aim of this study was an attempt to provide comprehensive and reliable epidemiological characteristics of HIV infection among high-risk groups in Iran, to assist developing prevention strategies for policy makers, and to guide further research within this field.

Material and methods

Search strategy

A comprehensive literature search of international electronic bibliographic databases was performed, including PubMed, Scopus, EMBASE and Science Direct and National databases, with Magiran, Iranmedex, and SID from inception to November 20, 2016. In addition, to identify further relevant studies, hand searches were also performed. Key search terms included terminology for ‘‘Prostitute’’, ‘‘FSW’’ or ‘‘Sex Worker’’, ‘‘Intravenous Drug Users’’, ‘‘Drug Addicts’’, ‘‘IDU’’ or ‘‘Injection Drug Users’’, ‘‘Prisoner’’, ‘‘Jail’’, ‘‘Inmate’’ or ‘‘Prison’’, ‘‘HCV’’, ‘‘Human Immunodeficiency Virus’’ or ‘‘Blood-Borne Infection’’ and “Iran”. Studies restricted to those performed in 2000 and after, and all published studies in English and Persian languages conducted in Iran were considered for the study. The reason studies have been reviewed from 2000 onwards was that HIV is an emerging disease and serological studies on high-risk groups, such as prisoners, have been considered in recent years in Iran. We defined sex work as exchanging sex for money, drugs, or goods [2]. Also, IDUs were defined as people who inject narcotic substances into the body with a hollow needle and a syringe, which is pierced through the skin into the body, usually intravenously [11]. We only included articles that determined HIV infection in patients by laboratory criteria according to country guideline definitions [12]. Case reports, case series, letters to the editors, review articles, animal studies, and conference records were excluded from the study.

Data extraction and quality assessment

Two independent authors (SK and KM) reviewed the retrieved studies, and the following information was extracted: 1) name of the first author; 2) year of publication and location of study conduction; 3) total sample size; 4) reported prevalence of infection; 5) recruitment setting; 6) recruitment method; 7) age group; 8) high-risk group (IDUs, FSWs, or prisoners). Kappa statistics (95%) was used to identify the inter-authors reliability. The third author (EA) was considered as arbiter to resolve any disagreements. STROBE statement was applied to assess the quality of studies.

Statistical analysis

At first, the variance of each study was calculated through the variance of binomial distribution, given that the prevalence rate has a binomial distribution. Then, each study was given a weight, and was inversely proportional to the variance. The heterogeneity of results across the studies was checked using Cochran’s Q test (with p-value < 0.10), and it was quantified by I2 statistic. The I2 statistic greater than 50% was considered as significant heterogeneity across the studies. Tau-squared (t2 or Tau2) statistic and Egger’s linear regression test were used to investigate the between-study variance and to examine publication bias, respectively. For detecting source of heterogeneity, sub-groups analysis was conducted on the basis of infection type, high-risk group, and geographical regions. To examine the impact of moderator variables on prevalence rate, meta-regression analysis was used. In order to estimate a weighted-mean estimate of prevalence for mentioned infections across the included studies, prevalence estimates by each study were pooled using a random-effects meta-analysis model at a confidence level of 95%. All meta-analysis and meta-regression were performed with Stata software version 12 (StataCorp, College Station, TX, USA). PRISMA statement was utilized as a guide to enhance quality reporting of the review [13].

Results

The results of the literature search and the selection process are showed in Figure 1. A total of 1,113 potentially relevant articles were identified from the initial search. After removing duplicates, 587 articles remained and then, out of which 511 articles were excluded by screening titles and abstracts. Finally, 43 studies [8, 9, 12, 14-53] met eligibility criteria for meta-analysis, which involved 1,746 HIV-positive patients.

Study characteristics

Studies’ characteristics and results are displayed in Table 1 and Figure 2. These studies were published between 2000 and 2015. The sample size of included articles varied from 70 to 4,536, with a total of 21,450 cases with high-risk behavior, including FWS (3 studies), IDUs (25 studies), prisoners (8 studies), drug addicts (3 studies), and drug addict prisoners (3 studies). In five studies, the prevalence rate of HIV/AIDS among high-risk groups were 0%, and the highest prevalence was related to Amin-Zadeh et al. among IDUs in Tehran (30%) [52].

Evaluation of heterogeneity and meta-analysis

The results of Cochran’s Q test and I2 statistics suggested a significant heterogeneity among the included studies (Q = 2178.92, df = 42, p < 0.001, I2 = 98.07%). The pooled prevalence of HIV infection in high-risk groups was 0.06% (95% CI: 0.04-0.09%). In order to reduce the heterogeneity, we performed sub-group analysis based on geographical region (3 countrywide study were excluded) (Table 2). Accordingly, the prevalence of HIV among high-risk groups was ranged from 0 among drug addict prisoners in the North to 0.2 (95% CI: 0.018-0.22%) among drug addicts in the South parts of Iran.

Meta-regression

The results of meta-regression analysis are shown in Figure 3. The prevalence of HIV among IDUs was not related to the year of study, and mild increasing trend in this period was not significant (B = 0.44, p = 0.43). also, the prevalence of HIV among IDUs was not related to study sample size (p = 0.55).

Discussion

The present systematic review on HIV cross-sectional studies in Iran was conducted on 43 studies, including 25 studies on injection drug users (IDUs), 4 studies on female sex workers (FSWs), and 11 studies on prisoners. The estimated pooled HIV prevalence was 0.06% in these high-risk groups, ranging from 0.01% in prisoners, who use drugs, to 0.2% in IDUs. We found that only 4 studies have been conducted on female sex workers in Iran, reporting a prevalence of 0.02% in the South to 0.06% in the West of the country. Although female sex workers have long been understood to be a key affected population, the extent of their disproportionate risk for HIV infection had not yet been documented appropriately.
We found a great deal of heterogeneity in studies regarding HIV prevalence among FSWs. Such heterogeneity reflect various social, political, economic, and cultural factors within every country [54], yet an understanding of how these factors contribute to HIV acquisition; however, transmission risks has only recently been noticed. On the other hand, changes in macro-structural context and policies (such as sex work decriminalization) as well as features of FSWs’ work environment are urgently needed. Although the prevalence of HIV among FSWs in Iran are comparably low, responses for HIV epidemic, such as free condom campaigns, community empowerment, campaigns to address stigma, and structural policy support are highly recommended [55].
Our systematic review on the prevalence of HIV among IDUs in Iran yielded a pooled prevalence of 0.18. Injecting drug use is an important cause of HIV transmission. Globally, around 13 million people inject drugs, and 1.7 million of them are living with HIV [55]. On the other hand, HIV is an important contributor to the burden of drug use and has the potency to spread to a wider community through sexual transmissions [56]. There are a few effective interventions addressing HIV in IDUs, including provision of clean needles and syringes (typically through needle and syringe programs; NSPs) to avoid HIV transmission by sharing contaminated injecting equipment, and treatment of opioid dependence with opioid substitution therapy (OST), particularly methadone and buprenorphine, leading to a reduction of drug injection practices [57]. Opioid substitution therapy (OST) and the distribution of sterile needles/ syringes are fundamental and core components of HIV prevention efforts. However, for various IDUs populations, the coverage could be increased by delivering these interventions through several models, rather than relying on one delivery model. For instance, expansion of both pharmacy and NSP distribution of needles/ syringes, establishment of special clinics, and office-based delivery of OST are some of the combined responses. Condom provision, instead, could be off paramount importance since sexual transmission of HIV is also a risk for IDUs, and therefore interventions have a maximum effect when they are delivered in combination [58]. Given the challenges of further reducing HIV infection rates and developing an effective vaccine [30], it is critical to focus on behavioral prevention efforts that are based on the best available scientific evidence. Modification of HIV-risk behaviors requires high-risk populations to understand the mechanism of HIV transmission. Without such comprehension, HIV prevention attempts (especially provision of clean needles/ syringes) could be completely useless. Furthermore, provision of ART might also have a role in primary HIV prevention, specifically in IDU populations as well as for people with high-risk sexual encounters [58].
There are some limitations to generalize the results of this review to the whole country. Firstly, sampling of marginalized populations often were carried out using convenient schemes from various locations, including prisons, drug treatment centers, and harm reduction clinics. Secondly, lacking information from many parts of the country affects generalizability of the study at national level. Another limitation is that most studies have been carried out in high-risk areas and settings like prisons, hospitals, or behavioral counseling centers, where the clients have special profile of risky behaviors. In summary, studies on HIV prevalence in key populations (i.e., high-risk groups) are still lacking in Iran. More complete data is needed to improve the response to HIV epidemic. Moreover, concerted efforts must be launched to gather more reliable and wider information about the epidemic in every part of the country.

Conclusions

Our results indicate that prevalence of HIV infection among high-risk groups in Iran is low. The prevalence of HIV in high-risk groups in different parts of Iran has a different pattern. Due to significant prevalence of HIV in injecting drug users compared to other high-risk groups, there is a need to pay serious attention to this high-risk group and adopt preventive strategies.

Acknowledgement

Herewith, we would like to express our appreciation to Dr. Nedjat, Professor of Epidemiology from Tehran University of Medical Sciences for her technical support.

Conflict of interest

The authors declare no conflict of interest with respect to the research, authorship, and/or publication of this article.

References