Methods
A cross-sectional sample using concurrent longitudinal studies of the natural history of HIV-1 infection among intravenous drug users (N=539) and homosexual men (N=932) was recruited in Baltimore, Md. Participants were administered a risk behavior interview and physical examination, and had hematologic tests evaluated in a similar calendar period.

Results
Both risk groups demonstrated an inverse relationship between frequency of symptoms and CD4 cell count. Fever, night sweats, and lymphadenopathy were not evaluated because pilot data suggested a confounding association with drug injection. Among those with mild to moderate immune suppression, intravenous drug users were significantly more likely than homosexual men to experience fatigue, weight loss, diarrhea, and shortness of breath; to have oral candidiasis, palpable spleen, and lower mean weight on physical examination; and abnormal hematocrit, platelets, and total lymphocyte counts. However, participants in either risk group with CD4 cell levels below 0.2 x10⁹/L experienced similar frequency of all clinical symptoms. Self-reported oral candidiasis increased fourfold with HIV infection and was as likely in both groups at all CD4 cell levels. Duration and recency of intravenous drug use was not significantly associated with the higher frequency of most clinical symptoms.

Conclusion
Social factors are an important consideration in evaluating the association between clinical symptoms and HIV immunosuppression. Except for oral candidiasis, there are limitations for the use of clinical symptoms as intermediate outcome measures for HIV infection among intravenous drug users.

(Arch Intern Med. 1993;153:1806-1812)