In resource-rich countries, migrants have a higher risk of progressing to AIDS in the first year of HIV therapy

The difference is mainly driven by higher rates of TB among migrant populations

Improvements in treatment and care mean that rates of AIDS-defining illnesses and deaths have fallen substantially in Europe and North America. However, AIDS-related illness and mortality is still common in resource-limited countries. This is even the case among people who have recently started HIV therapy.

A large number of HIV infections in resource-rich countries involve migrants from resource-limited settings. Investigators from Europe, Canada and the United States wanted to see if rates of AIDS-related illnesses and death differed between migrant and non-migrant patients in the first 12 months after the initiation of antiretroviral treatment. They therefore analysed outcome data obtained from 12 cohort studies involving over 48,000 people who started HIV treatment between 1996 and 2009.

Just of over a quarter of participants (26%) were migrants, including 16% from sub-Saharan Africa, 6% from Latin America, 2% from North Africa/Middle East and 2% from Asia.

Compared to non-migrants, migrants were younger (median age 34 vs 38 years), more likely to be female (51 vs 22%) and to have been infected with HIV through heterosexual sex (76 vs 33%).

During the first year of HIV therapy, approximately 2300 participants (5%) developed an AIDS-defining illness. The overall incidence of such illnesses was  61 per 1000 person-years, but was significantly higher among migrant (70 per 1000 person-years) than non-migrant (58 per 1000 person-years) participants.

After taking into account other factors that can affect the risk of HIV disease progression, the authors found that migrants were 21% more likely to be diagnosed with AIDS compared to non-migrants (HR = 1.21; 95% CI, 1.08-1.40). A similar result was observed when analysis was limited to participants whose probable route of HIV infection was heterosexual intercourse (HR = 1.23; 95% CI, 1.08-1.40).

Mortality rates during the first year of HIV treatment were somewhat lower among migrants than non-migrants. However, the difference was largely explained by the older age of non-migrant patients (40 vs 30 years). Once this was taken into account, mortality rates were similar between the two groups.

The investigators also examined the risk of specific AIDS-defining illnesses according to migrant status.

They found that migrants were almost twice as likely as non-migrants to be diagnosed with TB (HR = 1.94; 95% CI, 1.53-2.46). Incidence of TB was especially high among people from sub-Saharan Africa (16 per 1000 person-years), North Africa/Middle East (16 per 1000 person-years) and Latin America (12 per 1000 person-years).

“Tuberculosis was the most common ADE [AIDS-defining event] among migrants during the first year of ART,” comment the authors.

They believe their results have important implications for patient care, highlighting the importance of screening for TB before the initiation of HIV therapy. They add that the results “also raise issues regarding the choice of initial regimen among migrants, given known interactions between anti-tuberculosis medications and protease inhibitors”.

Rates of several other AIDS-defining illnesses were also elevated among migrants. These included cryptococcosis, Kaposi’s sarcoma and candidiasis.

“In this large study of HIV-positive patients initiating ART in multiple sites…patients who had migrated from Africa, Latin America, or the Middle East tended to have higher rates of ADEs during the first year of ART,” conclude the investigators. “These findings could influence screening for specific ADEs prior to ART initiation in high-income countries.”