The Risk ofPneumocystis cariniiPneumonia among Men Infected with Human Immunodeficiency Virus Type 1

Abstract

We assessed the risk of pneumonia due to Pneumocystis carinii in 1665 participants in the Multicenter AIDS Cohort Study who were seropositive for human immunodeficiency virus type 1 (HIV-1) but did not have the acquired immunodeficiency syndrome (AIDS) and were not receiving prophylaxis against P. carinii. During 48 months of follow-up, 168 participants (10.1 percent) had a first episode of P. carinii pneumonia. The risk was greatly increased in participants with CD4+ cell counts at base line of 200 per cubic millimeter or less (relative risk, 4.9; 95 percent confidence interval, 3.1 to 8.0). Although most participants (60.7 percent) described no HIV-1-related symptoms at the clinic visit at which a CD4+ cell count of 200 per cubic millimeter or less was first noted, this finding during follow-up was also associated with an increased risk of P. carinii pneumonia. The development of thrush or fever significantly and independently increased the risk of P. carinii pneumonia in these patients (adjusted relative risks, 1.86 and 2.15 for thrush and fever, respectively). Most participants with CD4+ cell counts above 200 per cubic millimeter who had P. carinii pneumonia within six months were symptomatic. We conclude that P. carinii pneumonia is unlikely to develop in HIV-1-infected patients unless their CD4+ cells are depleted to 200 per cubic millimeter or below or the patients are symptomatic, and therefore that prophylaxis should be reserved for such patients.

Once-Weekly Administration of Dapsone/Pyrimethamine vs. Aerosolized Pentamidine as Combined Prophylaxis for Pneumocystis carinii Pneumonia and Toxoplasmic Encephalitis in Human Immunodeficiency Virus-Infected Patients

“…This score, for selecting patients with a high risk for PCP [2,19], was determined according to the following clinical and laboratory criteria: 5 points were assigned for a peripheral blood CD4 lymphocyte count of <200/AL or AIDS (except Kaposi's sarcoma); 3 points for symptomatic HIV infection without AIDS; and 2 points for Kaposi's sarcoma, a CD4 lymphocyte count of 200-500/AL, or positivity for HIV p24 antigen in serum. Previous PCP, previous prophylaxis with aerosolized pentamidine, and simultaneous antiretroviral treatment were allowed in the study protocol.…”

The use of readily available biomarkers to predict CD4 cell counts in HIV-infected individuals

“…Patients with depleted CD4 cell counts less than 200 cells/mm 3 are more likely to develop Pneumocystis jiroveci pneumonia (PJP) amongst various other opportunistic infections. 21 The Centres for Disease Control and Prevention (CDC) advocates primary prophylaxis with co-trimoxazole for adults whose CD4 cell count is less than 200 cells/mm 3 . 22 The majority of patients with CD4 counts of < 200 cells/mm 3 who were treated with PJP had a mortality of between 20% and 40%; this is further increased to 60% in PJP patients who are intubated (Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents.…”

Pneumocystis Pneumonia Associated with Human Immunodeficiency Virus

“…In the ASD study the CD4 count among persons developing PCP while receiving cART was low (median=29 cells/µL), and was lower among those not taking cART (median=13 cells/µL) [11]. The prospective pan-European EuroSIDA study reported that the median CD4 count was 30 cells/µL among persons developing PCP while receiving cART, and was similar among those not receiving cART who got PCP [8]. Patients without improvement in their CD4 count after starting cART remain at risk for PCP.…”

“…During the early years of the AIDS epidemic, PCP accounted for two thirds of AIDS-defining illness in patients in the United States, and an estimated 75% of HIV-infected patients developed PCP during their lifetime [6] [7]; rates of PCP were as high as 20 per 100 person-years among those with CD4 cell counts <200 cells/µL [7] [8].…”