Brief incarceration increases risk of rebound in viral load for patients taking HIV therapy

Brief incarceration is associated with an increased risk of virological failure for injecting drug users taking HIV therapy, US investigators report in the October 1st edition of Clinical Infectious Diseases.

Spending between seven and 30 days behind bars increased the risk of HIV treatment failure sevenfold. However, longer periods of imprisonment were not associated with virological rebound.

“Pretrial detention centers are often described as hectic environments where over-crowding, insufficient communication with care providers, and unpredictable lengths of stay make delivery of health care challenging,” write the authors.

HIV disproportionately affects marginalised groups, and in the US rates of imprisonment are significantly higher among HIV-positive individuals than in the general population.

In any given year between a quarter and one-third of all HIV-positive individuals in the US pass through the justice system, spending time behind bars.

“By disrupting access to usual sources of care…incarceration may cause interruptions in treatment for HIV infection,” comment the investigators.

They therefore hypothesised that: “incarceration my be an important but overlooked cause of treatment failure for individuals receiving ART [antiretroviral therapy].”

To test this theory that looked at the viral load of 437 injecting drug users who received HIV treatment in Baltimore between 1998 and 2009. All suppressed their viral load to below 400 copies/ml. A series of analyses were performed to see if spending time behind bars increased the risk of viral load rebounding.

The patients were monitored every six months. At each visit they were asked if they had been incarcerated, and if so, whether the period of incarceration was between seven and 30 days or over 30 days.

Over a median of 6.6 years of follow-up, a total of 175 (40%) of individuals reported at least one period of incarceration and 26% of patients had multiple incidents of imprisonment.

Brief periods behind bars account for 19% of all reported incarcerations.

Overall, virological failure occurred in 26% of patients. A viral load above 400 copies/ml was present at 53% of follow-up visits when an incarceration had been reported, compared with 25% of visits when there had been no incarceration.

In the first set of statistical analysis both brief (OR = 6.6; 95% CI, 2.1-19.8) and longer (OR = 1.7; 95% CI, 1.0-3.0) periods of incarceration were associated with an increased risk of viral load rebounding to above 400 copies/ml.

The investigators then controlled for potentially confounding factors such as demographics, current patterns of drug and alcohol use, and HIV disease stage.

They found that brief incarceration remained significantly associated with an increased risk of treatment failure (OR = 7.7; 95% CI, 3.0-19.7). However, the relationship between longer periods of imprisonment and treatment failure ceased to be significant (OR = 1.4; 95% CI, 0.8-2.6).

Medical care for people in detention awaiting trial is often chaotic, note the investigators. In contrast, longer periods of imprisonment can facilitate the provision of good quality health care: “Many patients receive ART for the first time in prison, and treatment for comorbid psychiatric and substance use disorders in prison may facilitate better levels of ART adherence than some IDUs [injecting drug users] sustain in community settings.”

Restricting analysis to patients whose viral load rebounded above 1000 copies/ml also showed that shorter (OR = 4.1; 95% CI, 1.6-6.9), but not longer (OR = 1.7; 95% CI, 0.9-2.3) periods of incarceration increased the risk of virological failure.

Clinic attendance and use of HIV therapy was poorer for patients who had a recent experience of incarceration than those who did not spend time behind bars (27% vs. 47%).

Incarceration was also associated with higher rates of HIV risk behaviours, including sharing injecting equipment (p = 0.002) and the use of shooting galleries (p < 0.001).

“Loss of virologic control after incarceration may facilitate increased transmission of HIV,” comment the investigators, “future studies should evaluate the contribution of loss of virological control among recently incarcerated persons to community viral load estimates.”

The authors conclude: “our data show that incarceration is a strong marker of increased vulnerability to virologic failure for IDUs using ART…our study findings highlight that improved strategies to indentify and successfully link HIV-infected inmates to appropriate HIV care are urgently needed.”

Westergaard RP et al. Incarceration predicts virologic failure for HIV-infected injection drug users receiving antiretroviral therapy. Clin Infect Dis, 53: 725-31, 2011 (click here for the free full text article).