It may seem like common sense: People with HIV who live in rural areas of the United States are more likely to die than those who live in urban areas. New study results published in the May issue of AIDS Research and Human Retroviruses suggest this to be true, but did not find any major clinical factors to explain the disparity.

The study reviewed the medical files of 327 rural and 317 urban adult HIV-infected patients treated at one of four New England clinics associated with the Dartmouth-Hitchcock HIV program between 1995 and 2005. The study found that the death rate was 10.4% among rural dwellers, compared to 6.0% among urbanites. When adjusting for age, sex, black race and high-risk groups, rural patients were still twice as likely to die from HIV-related causes.

“What I found coming to Dartmouth, even though we had the same doctors taking care of rural and urban patients, was that more rural patients were dying,” said Timothy Lahey, MD, MMSc, the study’s lead researcher and professor of medicine at Dartmouth Medical School. “We aren’t delivering care to [rural patients] as well as we should.”

Similar to Dr. Lahey’s initial hypothesis, previous research evaluating higher death rates among rural HIV-positive patients has often pointed to issues like lack of regular access to HIV-experienced doctors and life-saving treatment. But once Dr. Lahey and his team studied the patients in rural New England, they found these variables to be insufficient in explaining the higher death rates.

In this study, all patients, regardless of their location, received care from the same team of doctors, thereby ruling out the possibility that the rural patients had less access to the same level of expert care as the urban patients. In addition, all of the patients received antiretroviral drug therapy, as well as necessary prophylaxis against AIDS-related opportunistic infections. In fact, HIV-positive people from rural locations (74%) were more likely to receive combination therapy than their urban counterparts (62%).

Nearly 42% of people in the rural group had private health insurance, compared to only 28.4% in the urban group. Almost 52% of urban patients were covered by public healthcare programs, like Medicaid or Medicare, as opposed to 39% of the rural group. Rural and urban patients had similar percentages of uninsured patients, 9.8% vs. 11.7% respectively.

Rates of intravenous drug use, male sex, and foreign birth were similar in both groups. The average CD4 count upon beginning treatment was similar in both groups (376 and 351 in the rural and urban groups respectively). As for the percentage of patients first presenting for HIV care with a CD4 count less than 200 – indicative of a delayed HIV diagnosis – the difference between the rural and urban patients was again insignificant (27.8% vs. 28.1% respectively).

With so many similarities between the two groups with respect to treatment and care, how did death rates end up being significantly higher among the rural HIV-positive patients? According to the study authors, clear-cut answers may be hard to come by. “The source of the increased mortality in rural patients with HIV infection isn’t clear, and is likely multifactorial,” they write.

One of the findings in the study was that rural-based injection drug users (IDU) and men who have sex with men (MSM) had poorer outcomes than their urban counterparts. In fact, IDUs were the only rural demographic group to have significantly higher death rates than their urban counterparts.

The authors describe mostly non-medical issues in rural areas that potentially affect health outcomes for people with HIV. Though the rural group received care from the same doctors and equally aggressive therapies as the urban group, Dr. Lahey ’s group suggests – but was unable to confirm using the available data – that the disease-free health of rural patients may have been compromised by the distances they needed to travel for various aspects of their care.  Such distances may have affected the frequency of their medical appointments, their ability to adhere to treatment, as well as access to vital social support services.

“What is different between these two groups is the social context,” explained Dr. Lahey. “If you’re more than ‘x’ amount of hours from treatment, or if your church or family isn’t supportive may be issues that contribute to how well someone responds to clinical treatment. The place that we’re going forward is the impact of stigma and local social support on HIV care.”