Medical disease and alcohol use among veterans with human immunodeficiency infection - A comparison of disease measurement strategies

Background: Many people with human immunodeficiency (HIV) infection drink alcohol. We asked whether level of exposure to alcohol is associated with medical disease in a linear,or nonlinear manner, whether the association depends upon the proximity of alcohol use, and whether it varies by source used to measure disease (chart review vs. ICD-9 Diagnostic Codes). Methods: The Veterans Aging 3 Site Cohort Study (VACS 3) enrolled 881 veterans, 86% of all HIV-positive patients seen, at 3 VA sites from June 23, 1999, to July 28, 2000. To maximize the sensitivity for alcohol exposure, alcohol use was measured combining data from patient self-report, chart review, and ICD-9 codes. We assigned the greatest exposure level reported from any source. Alcohol use within the past 12 months was considered current. Data on comorbid and AIDS-defining medical diseases were collected via chart review and ICD-9 diagnostic codes. The association of alcohol use (level and timing) and disease was modeled only for diseases demonstrating >= 10% prevalence. Linearity was compared with nonlinearity of association using nested multivariate models and the likelihood ratio test. All multivariate models were adjusted for age, CD4 cell count, viral load, intravenous drug use, exercise, and smoking. Results: Of 881 subjects enrolled, 866 (98%) had sufficient data for multivariate analyses, and 876 (99%) had sufficient data for comparison of chart review with ICD-9 Diagnostic Codes. Of the 866, 42 (5%) were lifetime abstainers; 247 (29%) were past drinkers; and 577 (671/6) were current users. Among the 824 reporting past or current alcohol use, 341 (41%) drank in moderation, 192 (23%) drank hazardously, and 291 (35%) carried a diagnosis of abuse or dependence. ICD-9 codes showed limited sensitivity, but overall agreement with chart review was good for 15 of 20 diseases (kappa > 0.4). The following diseases demonstrated a >= 10% prevalence with both measures (hepatitis C, hypertension, diabetes, obstructive lung disease, candidiasis, and bacterial pneumonia). All of these were associated with alcohol use (P < 0.05). Hepatitis C, hypertension, obstructive lung disease, candidiasis, and bacterial pneumonia demonstrated linear associations with level of alcohol use (P < 0.03). Past alcohol use increased the risk of hepatitis C and diabetes after adjustment for level of exposure (P < 0.01). With the exception of candidiasis, the associations between level and timing of alcohol use were similar when measured by ICD-9 codes or by chart review. Conclusions: Past and current use of alcohol is common among those with HIV infection. Estimates of disease risk associated with alcohol use based upon ICD-9 Diagnostic Codes appear similar to those based upon chart review. After adjustment for level of alcohol exposure, past use is associated with similar (or higher) prevalence of disease as among current drinkers. Finally, level of alcohol use is linearly associated with medical disease. We find no evidence of a "safe" level of consumption among those with HIV infection.