Objectives: To determine the prevalence of hepatitis C virus (HCV) co-infection among HIV-infected veterans, assess the prevalence of comorbid conditions that may complicate or limit treatment options, and ascertain whether comorbid conditions were more common in co-infected veterans.
Design and methods: We used the Veterans Administration electronic medical records system to identify all veterans receiving care for HIV during fiscal years 1997-2002. Demographic data and diagnostic codes for HIV, HCV, and comorbid conditions were extracted. The validity of using diagnostic codes was assessed by calculating the agreement between chart extraction and electronic data on a separate sample of veterans. Factor analysis was used to identify the structure underlying the intercorrelation between comorbid conditions. Logistic regression was used to compare the prevalence of comorbid conditions and factors between HIV/HCV-co-infected and HIV-mono-infected veterans, adjusting for age and race.
Results: We identified 25,116 HIV-infected veterans in care, of whom 4489 (18%) were HCV co-infected. A validity assessment revealed moderate agreement between chart extraction and electronic data for each of the comorbid conditions assessed. HIV/HCV-co-infected veterans were significantly more likely to have each of the comorbid conditions, and to have significantly more comorbid conditions. Factor analysis revealed three dimensions of comorbidity: mental disorders, medical disorders, and alcohol-related complications. Veterans with co-infection were significantly more likely to have mental disorders and alcohol-related complications.
Conclusions: HIV/HCV-co-infected veterans had a higher prevalence of comorbid conditions that may complicate and limit treatment options for HIV and for HCV co-infection. Strategies to improve treatment options for co-infected patients with comorbidities must be developed.