The contribution of health risk behaviours to excess mortality in American adults with chronic hepatitis C: A population cohort-study

ABSTRACT

BACKGROUND: In resource-rich countries, chronic hepatitis C (CHC) infection is associated with a sizeable excess mortality risk. The extent to which this is due to: (a) the biological sequelae of CHC infection, versus b) a high concomitant burden of health risk behaviours (HRBs), is unclear.

METHODS: We used data from the 1999-2010 US National-Health-and-Nutritional-Examination-Surveys (NHANES), which include detailed information on HRBs and CHC infection status. We calculated the prevalence of the five major HRBs – alcohol use; cigarette smoking, physical inactivity, unhealthy diet, and illicit drug use –according to CHC after adjusting for socio-demographic differences. Mortality status after survey interview was ascertained via linkage to the US National Death Index. To assess the contribution of HRBs to the excess mortality risk, we determined the all-cause mortality rate ratio (MRR) for individuals with CHC relative to individuals without, and then calculated the attenuation in this MRR following adjustment for HRBs.

RESULTS: This analysis included 27,468 adult participants of NHANES of which 363 tested positive for CHC. All HRBs were markedly more prevalent among individuals with CHC versus individuals without. CHC was associated with a 2.4-fold higher mortality rate after adjustment for socio-demographic factors (MRR:2.36;95%CI:1.60-3.49). Subsequent adjustment for all five HRBs attenuated this ratio by 50.7% to MRR:1.67(95%CI:1.14-2.44). Higher levels of attenuation (69.1%) were observed among individuals aged 45-70yrs, who form the target demographic for US birth cohort screening.

CONCLUSION: At least half the excess mortality risk for individuals with CHC in the US may be due to HRBs rather than CHC. The remedial response to hepatitis C must not neglect action on HRBs if it is to fully resolve the high mortality problem in this population. This article is protected by copyright. All rights reserved.

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