Recent evidence from observational studies and a clinical trial suggests that rates of comorbidities not related to HIV infection or AIDS among demographically similar HIV-uninfected individuals are higher than expected [1
]. This suggests that HAART may be effective in reducing the rate of comorbidities not related to HIV infection or AIDS in addition to reducing the rate of AIDS-defining illnesses. The Strategies for Management of Antiretroviral Therapy Study may have provided the best evidence of the efficacy of HAART in preventing non–AIDS-related comorbidities [1
], although it is not known how well the results from this trial can be generalized to clinical contexts in which structured interruption of therapy does not occur. Our results demonstrate that comorbidities not related to HIV infection or AIDS that result in hospitalization are relatively common in our clinical practice. The incidence rate of these comorbidities was highest when the CD4 cell count was low, and the incidence rate ratio was significantly higher among patients not using HAART who had a CD4 cell count <350 cells/mm3
than it was among the other patients; this indicated a protective effect associated with HAART use. The overall rate of non–AIDS-related comorbidities was lower among patients with a CD4 cell count >350 cells/mm3
than it was among patients with a CD4 cell count ≤350 cells/mm3
. There was also a higher relative risk associated with not using HAART, compared with using HAART, but the association was not statistically significant.
Other factors associated with a high incidence of comorbidities not related to HIV infection or AIDS were injection drug use, African-American race, and older age. Other researchers have revealed that injection drug use is associated with high AIDS-defining morbidity and mortality [1
], and older age is well-known to be associated with most of these non–AIDS-related comorbidities. In the United States, compared with non-Hispanic white race, African-American race has been found to be associated with a higher risk of renal, cardiovascular, pulmonary, and other disease [10
Although International Classification of Diseases, Ninth Revision, Clinical Modification coding was used to categorize diagnoses, we did not rely on coding alone; we also required the diagnoses to be consistent with the clinical diagnoses in the medical records. However, because our data were retrospective, we were limited to relying on the diagnoses of the care providers. Therefore, there is the possibility of some degree of misclassification. Unfortunately, our sample size was not sufficient to support analyses of individual diagnostic categories (e.g., cardiovascular conditions only). Another caveat is that the use of HAART could be a surrogate for better engagement in HIV care, making hospital admission less likely. For that reason, we restricted our analysis to a longitudinal follow-up period during which the patients were documented to have received care in our HIV clinic; thus, the bias may have been mitigated.
In summary, this analysis provides evidence from clinical practice that HAART use is associated with a decreased risk of comorbidities not related to HIV infection or AIDS among patients with a CD4 cell count <350 cells/mm3. HAART may have a protective effect on the occurrence of comorbidities not related to HIV infection or AIDS and may reduce the risk of AIDS-defining illness.