Hospitalisation for an alcohol-related cause among injecting drug users in Scotland: increased risk following diagnosis with hepatitis C infection.

BACKGROUND

The rate of hepatitis C (HCV) related liver disease progression is known to be strongly associated with alcohol consumption, yet there are very few data on alcohol use in injecting drug users (IDUs), who represent 90% of Scotland's HCV-diagnosed population. To investigate the extent of alcohol use in IDUs, we used hospitalisation with an alcohol-related diagnosis as an indicator for problematic consumption levels, and compared admission rates pre- and post-HCV diagnosis.

METHODS

Data for 41,062 current/former IDUs attending drug treatment/support services in Scotland from April 1995 to March 2006 were linked to the national hospital discharge database to retrieve alcohol-related episodes, and to the national HCV Diagnosis database to determine HCV-diagnosed status. Relative risks were estimated using Cox proportional hazards regression for recurrent events.

RESULTS

The proportion of IDUs with ≥1 alcohol-related admission following first attendance at drug services was greater among those diagnosed with HCV by the end of follow-up (16%) compared with those who were not (6%). For the 9145 IDUs who had been diagnosed with HCV by 31 March 2006, there was a 1.5-fold increased relative risk of an alcohol-related admission >30 days post-HCV diagnosis (95% CI: 1.2-1.7) compared with >30 days pre-HCV diagnosis, adjusted for sex, age, and deprivation.

CONCLUSIONS

IDUs diagnosed with HCV infection have an increased risk of subsequent hospital admission for an alcohol-related cause. Because of the synergistic effect of HCV infection and excessive alcohol intake on the development of cirrhosis, it is imperative that alcohol intake is addressed in the management of chronic HCV infection in this population.