HIV-positive patients who aren't tested for HCV have an increased risk of death

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HIV-positive patients who are not screened for infection with hepatitis C virus have an increased risk of death, according to French research published in the September edition of the Journal of Viral Hepatitis. The investigators from Lyon found that only older age and a low CD4 cell count had a greater association with death. However the investigators do not think that suboptimal care was the reason why unscreened patients had a greater risk of death. They suggest that the poor health of unscreened patients at baseline made hepatitis C infection less of a priority for their doctors.

Treatment guidelines recommend that all HIV-positive individuals should be tested soon after diagnosis for infection with hepatitis C virus. The guidelines of the British HIV Association (BHIVA) further recommend that individuals with an ongoing risk of infection with hepatitis C should be regularly screened for the infection.

HIV-positive patients who are coinfected with hepatitis C have a poorer prognosis, but there are limited data regarding the characteristics and survival of patients who have not been screened for the infection.

Glossary

confounding

Confounding exists if the true association between one factor (Factor A) and an outcome is obscured because there is a second factor (Factor B) which is associated with both Factor A and the outcome. Confounding is often a problem in observational studies when the characteristics of people in one group differ from the characteristics of people in another group. When confounding factors are known they can be measured and controlled for (see ‘multivariable analysis’), but some confounding factors are likely to be unknown or unmeasured. This can lead to biased results. Confounding is not usually a problem in randomised controlled trials. 

multivariate analysis

An extension of multivariable analysis that is used to model two or more outcomes at the same time.

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

prognosis

The prospect of survival and/or recovery from a disease as anticipated from the usual course of that disease or indicated by the characteristics of the patient.

hazard ratio

Comparing one group with another, expresses differences in the risk of something happening. A hazard ratio above 1 means the risk is higher in the group of interest; a hazard ratio below 1 means the risk is lower. Similar to ‘relative risk’.

Investigators from Lyon therefore analysed data for 3,244 patients who received HIV care in the city between 1992 and 2005. The data were collected prospectively and entered onto the French Hospital Database on HIV.

At baseline, information on gender, age, presumed mode of HIV infection, AIDS at the time of HIV diagnosis, and CD4 cell count were collected. The investigators also gathered data on hepatitis C screening, the duration of follow-up, and the use of potent antiretroviral therapy.

A total of 14,631 person years of follow-up were available for the investigators’ analysis. The patients had a mean age of 37 years on enrolment, and mean CD4 cell count at baseline was 354 cells/mm3.

The hepatitis C infection status of 299 patients (9%) was unknown. The investigators found that these unscreened patients were less likely to have acquired HIV through either homosexual or heterosexual sex and to have an unknown mode of HIV infection (p = 0.041), to have a CD4 cell count below 50 cells/mm3 or an unknown baseline CD4 cell count (p = 0.009), to have a shorter mean duration of follow-up (40 months vs. 56 months, p

Significantly more unscreened patients than screened patients died during follow-up (17% vs. 11%, p

In multivariate analysis, the investigators found that, after controlling for possible confounding factors, being unscreened for hepatitis C infection remained a significant predictor of death (hazard ratio [HR] 2.48; 95% CI, 1.83 – 3.35, p 3 (HR 13.71; 95% CI, 9.63 – 19.50, p 3 (HR 5.62; 95% CI, 3.97 – 7.97, p

“We observed that the progression to death was higher for patients with unknown HCV status vs. the patients with known HCV status after adjusting of potentially confounding factors”, comment the predictors.

Although the investigators initially speculated that suboptimal care might be associated with lack of hepatitis C screening and poorer survival, they emphasise that there is good evidence to believe that this was not the case. They write “the missing data on HCV status do not seem to be associated with poor adherence or access to care because these individuals accessed highly active antiretroviral therapy more often...and the mean number of visits was higher in the group not screened for HCV.”

As unscreened patients often had AIDS or a low CD4 cell count at baseline, the investigators speculate that their advanced HIV disease meant that hepatitis C status was less of “a priority to their medical practitioners.” However, they emphasise that “guidelines clearly recommend that HIV-infected persons be screened for HCV infection with HCV antibody test[s].”

References

Benet T et al. Characteristics of survival of HIV-infected patients not screened for hepatitis C virus infection in a hospital based cohort. Journal of Viral Hepatitis 14: 730 – 735, 2007.