Table 1 Candidate predictors used in the random forest algorithms

Questions related to mental health

Psychiatric institution or psychiatric hospital stay; Psychiatric diagnoses in chart reviews; Use of psychotropic medications (e.g., antidepressants, sedative hypnotics, atypical and typical anti-psychotics)

HR-QoL

EQ-5D-3L—standardized instrument

- Descriptive system (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression)

- Current health state with a visual analog scale – scores range between 0–100

Sociodemographic characteristics

Age; Gender; Race/ethnicity; Immigration status; Living situation; Shared accommodation details; Education; Employment; Monthly income; Source of income

Behavioral characteristics

Injection drug use (ever/P6M); Non-injection drug use (ever/P6M); Needle/equipment sharing behaviors (ever/P6M); Snort (ever/P6M); Sharing behaviors for snorting apparatus (ever/P6M); Marijuana use; Therapy for drug addiction; Alcohol use (ever/P6M); Alcohol abuse; Smoking (ever/P6M); Sexual orientation; number of sexual partners; Sex work; Incarceration (ever/P6M); Tattoos; Body piercing

Clinical characteristics

BMI category; HIV viral load; CD4 count; HCV RNA; HIV disease stage; AIDS defining illness; health services used in the past 6 months (walk-in clinic, emergency room, inpatient, general practitioner, HIV clinic and specialist); Previous interferon-based HCV treatment; current antiretroviral therapy; Hepatitis B diagnosis; sexually transmitted disease diagnosis; end-stage liver disease (cirrhosis, ascites, varices, portal hypertension, encephalopathy, hepatocellular carcinoma); APRI, a measure of liver fibrosis; cardiovascular disease; autoimmune disease; hypertension; thyroid disease; psoriasis; lipodystrophy; hypercholesterolemia