Appendicitis more common in HAART patients than general population

Doctors should consider appendicitis as a potential diagnosis when HIV patients present with right lower quadrant pain, recommend researchers from the Kaiser Permanente group in California. They found a higher rate of appendicitis in HIV patients on HAART than in HIV-negative controls.

Appendicitis in people on HAART was studied among 5563 patients who received treatment through the Kaiser Permanente clinics in northern California; 42 events were identified. The event rate was compared with 23,000 individuals contributing 80,000 years of person follow up, with 59 cases identified. Amongst HIV-positive individuals on HAART the event rate was 3.2 cases per 1000 patient years, four times higher than the rate in the control group (0.8). Perforation of the appendix, which can lead to peritonitis, a life threatening condition, was somewhat more common in HIV-positive individuals, although the difference was not significant.

Some research groups have speculated that the raised rate of appendicitis may be an immune reconstitution illness, due to its inflammatory character, but the review found a similar degree of difference in event rates between HIV-positive persons and controls in the pre-HAART era. There were no differences within the HIV-positive group in terms of last CD4 cell count prior to appendicitis or CD4 percentage, although time on therapy and CD4 cell increase since commencing HAART were not analysed.

Another factor suggesting that appendicitis is not an immune reconstitution phenomenon was the delay between the initiation of HAART and the diagnosis of appendicitis; this averaged one year.