Appendicitis in HIV-infected Patients, Highly Active Antiretroviral Therapy
Appendicitis in HIV-infected Patients, Highly Active Antiretroviral Therapy
Background: Limited studies have suggested increased incidence rates and unusual clinical presentations of appendicitis among HIV-infected patients during the pre-highly active antiretroviral therapy (HAART) era. Data in the HAART era are sparse, and no study has evaluated potential HIV-related risk factors for the development of appendicitis.
Methods: We retrospectively studied 449 HIV-infected patients receiving care at a US Naval hospital involving 4750 person-years (PY) of follow-up. We also evaluated the rates of appendicitis among HIV-negative persons at our medical facility. We compared demographics, HIV-specific data, and HAART use in HIV-infected patients with and without appendicitis.
Results: Sixteen (3.6%) of 449 patients developed appendicitis after HIV seroconversion. The incidence rate was 337 cases/100 000 PY, more than fourfold higher than among HIV-negative persons. Eighty-eight per cent of cases among HIV-infected patients had an elevated white blood count at presentation, 39% were complicated, and 64% required hospitalization. HIV-infected patients with appendicitis compared with those who did not develop appendicitis were less likely to be receiving HAART (25 vs. 71%, P<0.001), had higher viral loads (3.5 vs. 1.7 log10 HIV-1 RNA copies/mL, P = 0.005), and were younger (median age of 30 vs. 41 years, P<0.002). In the multivariate model, receipt of HAART remained protective [odds ratio (OR) 0.21, P = 0.012] for appendicitis, while younger age was positively associated (OR 1.08, P = 0.048) with appendicitis.
Conclusion: Acute appendicitis occurs at higher incidence rates among HIV-infected patients compared with the general population. Our study demonstrates that the lack of HAART may be a risk factor for appendicitis among HIV-infected patients; further studies are needed.
Appendicitis was first reported in association with HIV in 1986; early reports focused on opportunistic causes of appendicitis including Kaposi's sarcoma and cytomegalovirus. Subsequently, other opportunistic agents were described to either cause or mimic acute appendicitis among HIV-infected patients, including Mycobacterium spp. (including Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium complex), cryptosporidiosis, and a variety of other unusual pathogens such as Strongyloides stercoralis, spirochetosis,Salmonella typhi, group A streptococcus and Streptococcus pneumoniae.
It was noted early in the HIV epidemic that HIV-infected patients may have a higher risk of appendicitis, even beyond the risks accounted for by opportunistic infections. Some speculated that the higher-than-usual occur-rence of appendicitis was related to the fact that the appendix is a target site for infection because it is predominantly supplied by terminal arteries. However, no investigation has been performed that examines the link between HIV-specific factors and the occurrence of appendicitis.
In addition to the reported higher rates of appendicitis among HIV-infected patients, some authors recognized that this patient population also had higher rates of complications (e.g. perforation) and perioperative mortality, which were predominantly attributed to the immunodeficient state. Of note, patients frequently had end-stage AIDS and were often unable to mount appropriate leucocyte or fever responses. More recent studies have suggested that appendicitis may now occur at earlier stages of HIV infection and that patients have similar presentations and outcomes to those of the general population.
Limited data are available since the advent of highly active antiretroviral therapy (HAART) to determine if appendicitis continues to occur at higher incidence rates among HIV-infected persons than in the general population. In addition, there is a lack of data regarding the impact of HIV-specific factors (e.g. CD4 cell count, HIV viral load and HAART) on its occurrence. One recent report suggested that appendicitis may be a type of immune reconstitution inflammatory syndrome (IRIS), suggesting that HAART may be a risk factor for appendicitis. We carried out an investigation in a large HIV clinic to determine the incidence rate and predictors for appendicitis among HIV-infected persons.
Abstract and Introduction
Abstract
Background: Limited studies have suggested increased incidence rates and unusual clinical presentations of appendicitis among HIV-infected patients during the pre-highly active antiretroviral therapy (HAART) era. Data in the HAART era are sparse, and no study has evaluated potential HIV-related risk factors for the development of appendicitis.
Methods: We retrospectively studied 449 HIV-infected patients receiving care at a US Naval hospital involving 4750 person-years (PY) of follow-up. We also evaluated the rates of appendicitis among HIV-negative persons at our medical facility. We compared demographics, HIV-specific data, and HAART use in HIV-infected patients with and without appendicitis.
Results: Sixteen (3.6%) of 449 patients developed appendicitis after HIV seroconversion. The incidence rate was 337 cases/100 000 PY, more than fourfold higher than among HIV-negative persons. Eighty-eight per cent of cases among HIV-infected patients had an elevated white blood count at presentation, 39% were complicated, and 64% required hospitalization. HIV-infected patients with appendicitis compared with those who did not develop appendicitis were less likely to be receiving HAART (25 vs. 71%, P<0.001), had higher viral loads (3.5 vs. 1.7 log10 HIV-1 RNA copies/mL, P = 0.005), and were younger (median age of 30 vs. 41 years, P<0.002). In the multivariate model, receipt of HAART remained protective [odds ratio (OR) 0.21, P = 0.012] for appendicitis, while younger age was positively associated (OR 1.08, P = 0.048) with appendicitis.
Conclusion: Acute appendicitis occurs at higher incidence rates among HIV-infected patients compared with the general population. Our study demonstrates that the lack of HAART may be a risk factor for appendicitis among HIV-infected patients; further studies are needed.
Introduction
Appendicitis was first reported in association with HIV in 1986; early reports focused on opportunistic causes of appendicitis including Kaposi's sarcoma and cytomegalovirus. Subsequently, other opportunistic agents were described to either cause or mimic acute appendicitis among HIV-infected patients, including Mycobacterium spp. (including Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium complex), cryptosporidiosis, and a variety of other unusual pathogens such as Strongyloides stercoralis, spirochetosis,Salmonella typhi, group A streptococcus and Streptococcus pneumoniae.
It was noted early in the HIV epidemic that HIV-infected patients may have a higher risk of appendicitis, even beyond the risks accounted for by opportunistic infections. Some speculated that the higher-than-usual occur-rence of appendicitis was related to the fact that the appendix is a target site for infection because it is predominantly supplied by terminal arteries. However, no investigation has been performed that examines the link between HIV-specific factors and the occurrence of appendicitis.
In addition to the reported higher rates of appendicitis among HIV-infected patients, some authors recognized that this patient population also had higher rates of complications (e.g. perforation) and perioperative mortality, which were predominantly attributed to the immunodeficient state. Of note, patients frequently had end-stage AIDS and were often unable to mount appropriate leucocyte or fever responses. More recent studies have suggested that appendicitis may now occur at earlier stages of HIV infection and that patients have similar presentations and outcomes to those of the general population.
Limited data are available since the advent of highly active antiretroviral therapy (HAART) to determine if appendicitis continues to occur at higher incidence rates among HIV-infected persons than in the general population. In addition, there is a lack of data regarding the impact of HIV-specific factors (e.g. CD4 cell count, HIV viral load and HAART) on its occurrence. One recent report suggested that appendicitis may be a type of immune reconstitution inflammatory syndrome (IRIS), suggesting that HAART may be a risk factor for appendicitis. We carried out an investigation in a large HIV clinic to determine the incidence rate and predictors for appendicitis among HIV-infected persons.
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