Introduction

HIV/AIDS remains one of the major global public health issues, although the burden of the epidemic varies considerably between countries and regions [1]. In Spain it is estimated that there are 150,000 people infected with HIV, representing an overall prevalence in the Spanish adult population of 4 per 1000 inhabitants [1]. In 2012, a delayed diagnosis was observed in 48 % of the new cases of HIV in our country. Of these new diagnosis, 35 % affected to people from other countries, and the spread in men who have sex with men (MSM) was the most frequent (51 % of the total new cases) [2]. Recently it has been shown that advanced disease and late presentation in new HIV diagnosis increased with age, male sex, infection through drug use or heterosexual contact, and being an immigrant, except western Europeans [3].

In the Autonomous Community of Madrid (ACM) 7.452 new diagnoses of HIV infection were reported in the period 2007–2013 [4], mainly in men (84.0 %), and almost half born outside of Spain (45.8 %). The incidence rate of diagnosis in 2012 was 33.8 per 100.000 in the foreign born population and 11.6 per 100.000 in the autochthonous population [4]. The main source of infection was unprotected sex, and delayed diagnosis was higher among immigrants [5].

There is experience in programs performing rapid tests in different settings, as sexually transmitted infections (STI) clinics [6–8], pharmacies [9, 10], and non-clinical settings [11–15], including mobile units, offering rapid testing in highly visible locations, what it appears to promote diagnosis in populations that do not actively seek testing in other venues [11]. Rapid tests are ideal for community settings in which clients may not have ongoing relationships with providers and may be unlikely to return for counseling [16]. It may also facilitate testing for many patients who do not perceive themselves at risk.

Certain populations are at higher risk of HIV infection and can also be more affected by delayed diagnosis. Different factors have been associated to this higher risk, like having suffered previous STI [13, 14], or the use of drugs before or during sexual intercourse [15, 17, 18]. Among MSM the role of serodiscordant relationships in newly acquiring infection is well-recognised [15, 19], and persistent unprotected anal intercourse with occasional partners is predictor of seroconversion [20]. The knowledge of the predictors of a reactive result in the assisted population can help guide preventive interventions.

Since December 2009 Public Health authorities in the ACM have been promoting the development of Services of Prevention and Early diagnosis of HIV, set in selected primary care centers. More details regarding the Services are provided elsewhere [21]. The primary objectives of these Services include: increasing knowledge of HIV serostatus among people who belong to groups disproportionately affected by HIV or those who are at a higher risk of contracting it, or those who may have more difficulties accessing health care.

The objectives of this study were to describe population with rapid-HIV test performed by the Services, analyze the test results in MSM, men who have sex exclusively with women (MSW) and women according to socio demographic and sexual history characteristics, and to identify factors associated to a reactive result for each of these three groups.

Methods

Descriptive cross-sectional study. Data from the consultations that took place in the Services of Prevention and Early diagnosis of HIV, between 29th April 2010 and 30st June 2014 (50 months) were analyzed. These Services were selectively set in seven primary care centers in Madrid, chosen due to their location in areas of new HIV diagnoses and a higher immigrant population. These centers had cultural mediators who target MSM and immigrants, and promote the effectiveness of counseling. Consultations could be carried out in 10 different languages. The Services were promoted through street level outreach work by cultural mediators, adverts, brochures, via the Red Cross´ telephone information service and by Non-Governmental Organizations. Access to the service was free. After a user requested an appointment a date was given for an interview, counseling and HIV testing when needed. The result is available within 20 min. Those with a reactive or indeterminate test were informed and referred for a confirmatory test and medical follow-up in the public health system. There were no restrictions to access, offering counseling and rapid-HIV testing, but children under 13 years old had to be accompanied by a responsible adult.

Patients were interviewed by the mediators, which completed an anonymous questionnaire with the following variables: sex, age, country of birth –grouped in big geographical regions-, level of education achieved and HIV test performed previously. Sexual history collected the following information: existence of steady and casual sexual partners and their sex, number of sexual partners in the last year, use of condoms (infrequent: in half of the sexual encounters or less, and frequent), serology of current sexual partner, sex worker, visits to sex workers, time from last risk practice (unprotected sexual intercourse, including accident with condom), history of STI, and sexual intercourse under the influence of drugs. The classification of the partners as steady or casual was established by the participants, following their personal and subjective criteria. In the case of steady partners it was implicit some stability and commitment to the affective relationship, regardless of its temporal duration, and casual partners would be those with whom sporadic sexual intercourses would take place. The categories for each variable are shown in Tables 1 and 2. After a risk assessment carried out by specially trained mediators (psychologist, social workers and social educators), a rapid-HIV test was performed by nurses from the center with the Determine™ HIV 1/2 Ag/Ab Combo rapid test, a fourth generation in vitro immunoassay of visual interpretation for the qualitative detection of HIV p24 antigen and antibodies to HIV 1 and HIV 2 in serum, plasma or whole blood. The result was communicated to the individual and recorded in the database.

Table 1 Sociodemographic characteristics of population tested (N = 6039) by the Services of Prevention and Early diagnosis of HIV (29 April 2010–30 June 2014) and proportion of rapid HIV test reactive result, according to sexual practice
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Table 2 Sexual history of population tested (N = 6039) by the Services of Prevention and Early diagnosis of HIV (29 April 2010 to 30 June 2014) and proportion of rapid HIV test reactive result, according to sexual practice
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Statistical Analysis

A descriptive analysis of the population with rapid-HIV test performed in the Services was performed, stratified into three groups: MSM, MSW and women. These three categories were constructed by combining the sex of the participants and the sex of their steady and/or casual partners. When a man had had sexual relations with another man was classified as MSM, and men who had no sexual relationships with other men were classified as MSW. The terms describe sexual behaviour, regardless of how men perceive their sexual identity.

The distribution of the study variables in these three groups were described and compared. To assess the differences between and within each group, we used the two-sided independent t test for continuous variables, and the Chi square statistic and z-test for comparison of proportions for categorical variables. The proportion of reactive results was calculated, total and by all the described variables. Crude Odds Ratios (OR) and 95 % confidence intervals (CI) are reported as measures of magnitude for the relationship between each independent variable and having a reactive result for HIV test. Factors which were significant in bivariate analysis (p < 0.05) were entered into a multivariable logistic model. The level of significance was set at 0.05 (two tails). Analyses were performed with SPSS 19.0 software.

Data confidentiality was maintained at all times. It was not possible to identify patients at individual levels, either in this paper or in the database. Verbal informed consent is required to perform HIV test, signing written consent is not mandatory according to the Spanish legislation.

Results

From 29 April 2010 to 30 June 2014, 6039 test were performed. Of these, 1678 (27.8 %) were in MSM, 2489 (41.2 %) were in MSW and 1872 (31.0 %) were in women (Table 1). The mean age was highest in MSW (34.8, SD 13.5, p < 0.001). By country of birth, 35.7 % of the tested were immigrant population. Latin America was the most represented region, followed by West Europe. The proportion of immigrants was significantly lower among MSM, 25.6 versus 38.2 % in MSW and 41.3 % in women (p < 0.05). The educational level was especially high among MSM (64.1 % had some college education, p < 0.05).

Overall around 55 % had a steady partner, being less frequent this situation among MSM (49.6 %, p < 0.01) (Table 2). Statistically significant differences were also found in casual sexual partners: 87.1 % of MSM had them, compared to 77.6 % of MSW and 66.5 % of women. The use of condom was less frequent in women: 24.9 % used it in less than half of the sexual encounters, compared to 14.3 % MSW and 7.9 % MSM. The group who more frequently had undergone previous HIV test was MSM (76.5 %). Regarding the serology of the partner, MSM were the ones with a higher percentage of HIV-positive partners (7.3 %). Sex worker condition was more common among women (4.0 %) and up to 26.3 % of MSW was clients of prostitution. Risk practices were more frequent in women (95.8 %) and they took place more recently (50.2 % in the previous 3 months). Antecedents of STI were more common among MSM, especially gonorrhea (9.8 %) and syphilis (7.4 %). Sexual intercourses under drug effects were more common among MSW (37.1 %), with a significantly higher consumption of alcohol among MSW (32.8 %) and cocaine in MSW and MSM compared to women (4.5 vs. 2.9 %).

The rapid-HIV test was reactive in 125 occasions and indeterminate in other 10, which is a positivity rate of 2.1 %. A reactive result was more common among MSM, with a 6.0 % of positivity, compared to 0.6 % in women and 0.5 % in MSW (Table 1).

Globally, a reactive result was more frequent in the group of 35–44 years (3.0 %), in immigrants (2.4 %), especially from Subsaharian Africa and Latin America among MSM (14.3 and 11.9 % respectively), from East Europe among MSW (1.6 %) and from Subsaharian Africa among women (6.3 %), and in MSM and women with lower level of studies (Table 1).

A reactive result was also more frequent among MSM without steady partner (6.6 %) and in MSM and women with no casual sexual partners (8.2 and 1.2 % respectively) (Table 2). The total frequency of rapid-HIV test reactive among those having more than ten sexual partners the previous year reached 6.4 % (9.6 % in MSM), among those using condom in less than half of the sexual encounters it was 2.3 % (9.8 % in MSM and 1.5 % in women), in those with a previous HIV test performed it was 2.6 % and when the sexual partner was HIV-positive it rose to 10.0 % (11.9 % in women). Positivity among sex workers was 8.8 % in MSM and 2.7 % in women, and 4.1 % among MSM clients of prostitution. When there was a risk practice in the last 3 months there was a 2.4 % of reactive result. For MSM and women who had suffered several STI the test was reactive in more than a quarter. Among MSM positivity was higher in those who had sexual intercourses with consumption of drugs.

In the bivariate analysis a reactive result in MSM was associated to foreign origin, and the antecedent of several STI, in MSW it was associated to seropositive sexual partner and heroine consumption, and in women to higher age, infrequent use of condom, seropositive sexual partner, being sex worker, and history of several STI (Table 3).

Table 3 Factors associated to reactive result in rapid-HIV test, bivariate analysis (logistic regression models)
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After the multivariate analysis in MSM the reactive test was independently associated to being immigrant (ORa 1.84, CI 95 % 1.21–2.80) and to antecedents of several STI (ORa 6.69, CI 95 % 2.32–19.32 compared to none). Among MSW the reactive test was associated to seropositivity of sexual partners (ORa 24.94, CI 95 % 3.25–191.25) and heroine consumption (ORa 18.89, CI 95 % 2.21–161.75). In women it was associated to infrequent use of condoms (ORa 4.45, CI 95 % 1.28–15.42), seropositivity of sexual partners (ORa 10.20, CI 95 % 2.16–48.22) and antecedents of several STI (ORa 107.02, CI 95 % 9.51–1204.68 compared to none).

Discussion

The implementation of the Services of Prevention and Early diagnosis of HIV integrated into primary care centers of the Public Health System, and especially aimed to vulnerable groups, is a pioneering intervention in our environment. According to our study, the Services were used by a high proportion of immigrants and MSM, two groups considered vulnerable to HIV. The highest reactive HIV test prevalence was found among MSM, immigrants (especially MSM), in those whose sexual partner was HIV-positive, sex workers, those who had had some STI, and those who had sexual intercourses under the effect of some drugs like poppers, heroin or cocaine.

Multiple strategies have been developed to implement alternative models for diagnosing HIV infections outside medical settings using rapid-HIV test, although with a wide range of detection rates [22]. When interventions for HIV detection were addressed at vulnerable populations, positive rates were high, reaching levels similar to that of our study in the case of centers for STI [6, 8, 12]. Between 2004 and 2006, a pilot project funded by the CDC targeted to racial/ethnic minority populations and others at high risk, and aimed to provide rapid HIV testing and referral to medical care via outreach work and in community settings, found a 1.4 % preliminary reactive HIV result [12]. In STI Units in Spain and USA the proportion of positive test reached higher values, ranging from 2.2 to 2.7 % [6, 8].

The rate of reactive result of rapid-HIV test in the Services was higher than that reached in other programs implemented in different settings. A pilot program implemented in pharmacies in our country in 2009–2010, in which rapid HIV test was offered to clients, had a rate of reactive results of 0.85 % (95 % CI 0.34–1.75) [10]. A similar experience was performed between 2009 and 2011 in community pharmacies of New York City, with a 0.3 % of seropositivity found [9]. In UK the last National Survey of Sexual Attitudes and Lifestyles, performed between 2010 and 2012 among general population aged 16–74 years, found an estimated prevalence for HIV of 0.1 % in women and 0.2 % in men, with a weighted prevalence of 2.8 % in MSM [23]. When using other settings, like mobile units, the rate of reactive results was close to 1 % when the mobile units were placed in central urban locations [13], but dropped to 0.24 % when they were located in university campuses in different cities in our country [14].

Regarding the cases with reactive result, the highest percentage of MSM is in line with the data described in our country [2, 3, 13, 14], and in the ACM [4, 5]. The odds ratio of having HIV in MSM compared to reference populations has been estimated in 19.3 (95 % CI 18.8–19.8) for low and middle-income countries [24] and epidemics in MSM are re-emerging in many high-income countries [25]. Data from the recent European MSM Internet Survey (EMIS) in Spain showed a high level of knowledge about HIV, diagnostic tests (up to 73.8 % had been tested for HIV) and mechanisms of transmission in this group [26]. However, sexual risk behaviors were present. Among those with casual partners in the last 12 months, the prevalence of unprotected anal intercourse with a partner of unknown or discordant HIV status was 29.4 % [26]. A study in Spain in 2006 identified as independent variables associated with unprotected anal intercourse among MSM: HIV-positivity (OR 1.77), the use of more than four drugs before sex, immigration, having had more than 20 sexual partners, meeting casual sex partners on the Internet and high levels of internalised homophobia [18]. Coordinated behavioural, medical, and structural interventions that incorporate efficacious strategies could substantially reduce the incidence of HIV infection in MSM [25].

Among immigrants also a higher proportion of reactive results were found, and immigration was a clear independent predictor of reactive HIV result in MSM assisted by the Services. Between 2004 and 2006 the study of an open hospital-based cohort of naïve HIV-infected subjects found almost one third of foreign-born patients, mainly from Latin America, with a high educative level, being more than one half MSM [27]. The analysis of new diagnoses of HIV infection reported in the ACM between 2005 and 2010 showed that unprotected sex was the main source of infection in immigrants, being in men from Latin America and Western Europe mainly among MSM [5]. Migrants are at high risk of HIV infection and its consequences, they have a higher frequency of delayed HIV diagnosis and are more vulnerable to the negative effects of HIV status disclosure [28].

Data on reactive results in users with and without casual and/or steady partners, and related to the number of sexual partners in the last 12 months could seem someway contradictory, but this is probably because steady and casual partners were not mutually exclusive categories, and both were related to the moment of the consultation, meanwhile the number of partners included the previous last year.

Seropositivity of sexual partner was independently associated to a reactive HIV result in MSW and women in our population, although information about condom use with these partners, viral load or antiretroviral treatment was not available. Serodiscordant primary relationships are increasingly recognized as a key context for the transmission of HIV globally [29]. Avoidance of unprotected intercourse and receipt of combined antiretroviral treatment by the infected partner in accordance with protocols are complementary measures to prevent HIV transmission [30]. However, some people who find out that they are HIV-positive may continue to have difficulties with changing their risk sexual and drug using behaviors [31], and even seropositivity has been identified as a predictor of unprotected intercourse in some studies [18, 32]. In a recent study of HIV-positive MSM in the UK the reasons for the high prevalence of sexual risk behaviours in HIV-positive MSM include the availability of highly active antiretroviral therapy, access to Internet, increased substance use, and the stigma or discrimination [33].

Higher prevalence of reactive test in people who had suffered previous STI has been described previously [13, 14]. Sexually transmitted diseases could increase the infectiousness of HIV-positive men and women and the susceptibility of HIV-negative individuals to HIV infection [34]. These clinical antecedents may also indicate a higher frequency of sexual risk practices.

In relation with drugs use, a higher risk of STI/HIV has been described associated to substance use, and attributable to unsafe sexual behaviors [17, 18]. Although this association has been clearly established in MSM [35, 36], those assisted by the Services had sexual intercourses under the drugs effect less frequently than in other studies [15, 18], with data even lower than MSW, and there was no association with the detection of reactive results. Only in the group of MSW there was an association with heroine consumption, probably linked to intravenous injection, but this could not be ascertained, since information about sharing injection drug material was collected as an antecedent of risk practice, but without temporal reference or vinculation to a drug. Moreover, the proportion of HIV-negative injection drug users who engage in dual HIV risk (both receptive syringe sharing and unprotected sex), can reach a 26.2 % [37].

This study has some remarkable strengths. To approach the Services to the target population, along with the task of mediators, including their ability to communicate with users in their native language, contributed to this high uptake. The size and diversity of the population assisted was important, including a wide representation of women and MSW.

Some limitations of our study need to be addressed. The results of multivariate analysis in MSW and women should be interpreted with caution given the low number of reactive test results in these groups. It was not possible to establish causal relationships between risk factors and the dependent variable because the study was cross-sectional. Due to the anonymity of the programme, the results of confirmatory tests and the immune status were not available. This prevented the evaluation of the rate of false positive results or the study of the diagnostic delay. Information about sharing injection drug material was collected in order to establish the presence of risk practices, but it was not possible to analyse this information separately due to its low prevalence (0.4 %). Self-reported information may be affected by recall bias or the desire to provide socially acceptable answers, though the climate of confidentiality and confidence could have contributed to reduce this bias.

Conclusions

The socio-culturally adapted Services of Prevention and Early diagnosis of HIV located in primary care centers managed to reach a high detection rate of HIV. The predictive factors of a reactive test result varied among the different groups analyzed. Preventive interventions must be adapted and targeted to high risk population.