AIDS-Defining Opportunistic Illnesses in the U.S.

Although rare, such illnesses are still seen, particularly among patients presenting late and those on public insurance.

Opportunistic illnesses, including both infections (OIs) and malignancies, have become less common in the U.S. with the widespread use of prophylaxis and potent combination antiretroviral therapy (ART). However, they remain a leading cause of hospitalization and death, both in the U.S. and worldwide. A large U.S. cohort study sheds some light on these trends and related risk factors.

Investigators analyzed the incidence of OIs and opportunistic malignancies among 8070 patients who enrolled in the HOPS study between 1994 and 2007. Median age at study entry was 38, and median CD4 count was 298 cells/mm³. Most study participants were white (57%) and male (81%), and most reported male-to-male sexual activity (59%).

The incidence of opportunistic illnesses declined from 92.4 per 1000 person-years in 1994–1997 to 16.6 per 1000 person-years in 2003–2007, with the greatest decrease occurring immediately after ART was introduced. All the individual OIs, except for HIV encephalopathy and esophageal candidiasis, declined from 1994 through 2002; however, infection with Mycobacterium avium complex was the only OI that continued to decline through 2007. Risk factors associated with higher OI rates in the 2003–2007 period included public insurance, lower current CD4-cell count, and higher current viral load. Higher viral load (>5 log copies/mL vs. <3 log copies/mL) was also associated with opportunistic malignancies, but lower CD4-cell count was not.

Comment

The incidence of opportunistic illness has declined dramatically, thanks to the availability of prophylaxis and ART. Nevertheless, even among ART recipients in the most recent period assessed, a low CD4 count (<50 cells/mm³) was the strongest predictor of an incident OI, whereas a high viral load (>100,000 copies/mL) was the most important predictor of an opportunistic malignancy. One must not forget that opportunistic illnesses, while rare, continue to occur, particularly among patients presenting late and those on public insurance (a proxy for lower socioeconomic status). Although not new, the finding that a higher viral load is associated with opportunistic malignancies underscores the importance of maintaining virologic suppression while receiving ART.

Reviewing Author

Carlos del Rio, MD

Disclosures

Grant/Research SupportNIH/National Institute of Allergy and Infectious Diseases; NIH/National Institute on Drug Abuse

Editorial BoardsJAIDS: Journal of Acquired Immune Deficiency Syndromes; Vaccines

Leadership Positions in Professional SocietiesInternational Antiviral Society–USA (Board of Directors); Infectious Diseases Society of America (Past President)