This study indicated that the prevalence of HIV/HCV coinfection in our country is considerably low (0.9%). Although occult HCV infection is a concern in HIV-positive patients, HCV-RNA testing is recommended in case of unexplained transaminase elevation in those with a CD4+ < 200/mm³, when acute HCV is suspected, or among subjects with a high risk of acquiring HCV (
13). In our study, 223 patients with HIV/HCV coinfection had CD4+ < 200/mm³ and none had high ALT or suspicion of acute HCV infection. Therefore, we did not test HCV RNA in this group.
Depending on the mode of HIV transmission, the prevalence of HIV/HCV coinfection varies from one country to another (
14). As the main route of HCV spread is IDU, HIV/HCV coinfection rates are often more than 90% among patients with HIV/AIDS who are injection drug users. High HIV/HCV coinfection rates (around 70%) can be found in Eastern European countries (e.g. Belarus and Ukraine) and in Middle Eastern countries such as Iran where IDU is the main route of HIV transmission (
15-
17). Nevertheless, in Western Europe, for example in Barcelona, the prevalence of HCV coinfection among newly diagnosed HIV-positive patients had decreased from 24% between 2000-2002 to 10% in the years 2006-2008 as a result of needle exchange programs among injection drug users (
18). On the contrary, HCV coinfection among HIV-positive patients was as low as 3.39% in Northeast Brazil, which was associated with low IDU rate in HIV-positive patients (
19).
In Turkey, the first case of HIV/AIDS was reported in 1985. According to the survey conducted by the Turkish Ministry of Health, there were 6854 cases of HIV infection out of a population of 76.6 million people in Turkey between October 1985 and June 2013. In a recent study on the antiretroviral-naive Turkish patients with HIV-1, the transmission route was reported as sexual intercourse (heterosexual contact in 60% and homosexual contact in 38%) and IDU in just 2% (
20,
21). According to a study covering the whole country (TURKHEP Study), the HCV seroprevalence rate was 1% in Turkey (
22). Moreover, referring to a conducted meta-analysis in our country, while the HCV seroprevalence rate was 0.1% to 0.8% according to the geographic areas, the rates among blood donors, preoperative patients, sex workers, and hemodialysis patients were 0.3%, 0.6% to 1.3%, 2.2%, and 20.4%, respectively (
23). In another study by Karaca et al., the most common risk factors of HCV infection were history of surgery (98%), blood transfusion (39.7%), and dental procedure (27.5%). In addition, history of IDU (3.1%) and suspicious sexual intercourse (1.5%) were determined as minor risk factors (
24).
According to the aforementioned studies, heterosexual intercourse is the most frequenr route of HIV transmission in Turkey. Moreover, IDU is the least common risk factor in the transmission of both HIV and HCV. According to a study conducted in Turkey, the IDU prevalence rate had been 0.05% in general population (
25). In our study, only 9 patients (0.9%) had the history of IDU among all the cases while the rate was 44.4% (4:9) in patients with HIV/HCV coinfection; however, three were not Turkish citizens and the other three had resided out of Turkey. In addition to IDU, a history of residence in a foreign country was determined as a risk factor in terms of HIV/HCV coinfection in our patients.
Although rate of sexual transmission of HCV is known to be low in serodiscordant heterosexual couples, there has been a dramatic rise in the incidence of HCV among HIV-infected MSM in Europe, the United States, Australia, and Asia since 2000 (
26-
29). Increases in HCV seroconversion among HIV-positive MSM have been reported in association with unprotected anal intercourse, multiple sexual partners, rough sexual techniques, and coinfection with HIV and other sexually transmitted infections (
2,
14). In our study on the contrary, none of the coinfected patients had reported homosexual intercourse.
Previous studies have revealed at least six major genotypes and more than 70 subtypes of HCV (
30). HCV genotypes 1, 2, and 3 have a worldwide distribution, genotype 4 is prevalent in Africa and Middle East, genotype 5 and 6 are found in South Africa and Southeast Asia, respectively (
31). According to a multicenter study in Turkey during 2009, HCV genotype 1 was the predominant one (87.5%) in 834 patients (
32). Similarly, HCV genotype 1b was also predominant in our study (5:8, 62.5%). Nevertheless, two patients with genotype 3 had been infected in Germany and in China through IDU. The only patient with genotype 2a/2c was infected through IDU in Moldova.
The possible limitation of this study might be due to the low number of the patients with HIV/HCV coinfection; however, it was unavoidable since the total number of patients with HIV/AIDS coinfection is low in Turkey.
In conclusion, the prevalence rate of HCV among HIV-positive patients in our study was similar to the rate in Turkey. Furthermore, the prevalence level detected in our patients with HIV/HCV coinfection was the lowest ever reported rate in the literature. The extremely rare prevalence of HCV infection among HIV-positive population in our country might be a consequence of the small number of the injection drug users. Additionally, relatively low rate of MSM among our HIV-positive patients might have a role in low HIV/HCV coinfection prevalence. Although the prevalence of HCV coinfection is low among HIV-positive patients, HCV should also be screened in all patients with HIV/AIDS.