THE IMPACT OF CURRENT ILLICIT DRUG USE ON QUALITY OF LIFE IN HIV INFECTED AND AT RISK WOMEN: IMPLICATIONS FOR COMBINED HEALTH UTILITIES

Purpose: Health utility scores accounting for multiple comorbid conditions are required in order to assess interventions that address substance use disorders among patients with HIV and at risk for HIV infection. We assessed the impact of illicit drug use on health utilities for HIV infected and non-infected women using data from a U.S. cohort.

Methods: Cross-sectional analysis of data collected in the Women's Interagency Health Study (WIHS) of women with HIV (n=2508) and at high risk of HIV infection (n=889) at most recent study visit. SF-6D utility weights were derived from SF-12 items included in the MOS-HIV. Multivariate linear regression models were used to determine the effect on health utilities of current illicit drug use (heroin and/or cocaine), HIV status, and CD4 cell count (>200 cells/ul: non-advanced; ≤ 200 cells/ul: advanced) as a measure of HIV disease severity. Analyses controlled for HIV treatment, chronic hepatitis C, age, race/ethnicity, education, year (2006, n=1832; 1995-2005, n=1629), and subsequent death as indicator of late stage illness.

Results:   HIV-infected women with non-advanced HIV had similar mean health utility scores (0.74 (SD:0.14)) to HIV-uninfected women (0.76 (SD:0.13)). In multivariate analysis, illicit drug use and advanced HIV disease were independently associated with lower health utility scores  and there was a significant interaction between CD4 and illicit drug use; illicit drug use had a greater effect on health utility among women with non-advanced HIV (-0.056)   than women with advanced HIV (-0.011).

Impact on SF6D Score among HIV+ Women of illicit drug use and disease severity
	Estimate	p-value
Intercept	0.740
Heroin and/or cocaine use vs. no drug	-0.011	0.40
Non-advanced HIV vs advanced HIV	0.029	<0.01
Non-advanced HIV *Heroin and/or cocaine use	-0.045	0.01

Adjusted for age, ethnicity, education level, chronic hepatitis c, year of survey, and subsequent death

Conclusions:   Illicit drug use more substantially decreased health utility among women with with non-advanced HIV than among women with advanced disease.  In some illicit drug-using populations with chronic illness,  the effect of drug use on health utility may vary by the severity of the comorbid chronic disease.  Further research should explore the implications for cost-effectiveness of treating both conditions.