Nonadherence to Primary Prophylaxis against Pneumocystis jirovecii Pneumonia James D. Heffelfinger1*, Andrew C. Voetsch1, Glenn V. Nakamura1, Patrick S. Sullivan2, A. D. McNaghten1, Laurence Huang3 1 Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America, 2 Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America, 3 HIV/AIDS Division and Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California, United States of America Abstract Background: Despite the effectiveness of prophylaxis, Pneumocystis jirovecii pneumonia (PCP) continues to be the most common serious opportunistic infection among HIV-infected persons. We describe factors associated with nonadherence to primary PCP prophylaxis. Methodology/Principal Findings: We used 2000–2004 data from the Supplement to HIV/AIDS Surveillance (SHAS) project, a cross-sectional interview project of HIV-infected persons $18 years conducted in 18 states. We limited the analysis to persons who denied having prior PCP, reported having a current prescription to prevent PCP, and answered the question ‘‘In the past 30 days, how often were you able to take the PCP medication(s) exactly the way your doctor told you to take them?’’ We used multivariable logistic regression to describe factors associated with nonadherence. Of 1,666 subjects prescribed PCP prophylaxis, 305 (18.3%) were nonadherent. Persons were more likely to be nonadherent if they reported using marijuana (adjusted odds ratio [aOR] = 1.6, 95% confidence interval [CI] = 1.1–2.4), non-injection drugs other than marijuana (aOR = 1.5, 95% CI = 1.0–2.1), or injection drugs (aOR = 2.3, 95% CI = 1.3–4.1) in the past year; their mental health was ‘‘not good’’ for $1 day during the past month (aOR = 1.6, 95% CI = 1.2–2.2); their most recent CD4 count was ,200 cells/mL (aOR = 1.6, 95% CI = 1.1–2.2); or taking ART usually (aOR = 9.6, 95% CI = 6.7–13.7) or sometimes/rarely/never (aOR = 18.4, 95% CI = 11.1–30.4), compared with always, as prescribed. Conclusion/Significance: Providers should inquire about and promote strategies to improve adherence to PCP prophylaxis, particularly among persons who use illicit drugs, have mental health issues, and who are not compliant with ART to reduce the occurrence of PCP. Citation: Heffelfinger JD, Voetsch AC, Nakamura GV, Sullivan PS, McNaghten AD, et al. (2009) Nonadherence to Primary Prophylaxis against Pneumocystis jirovecii Pneumonia. PLoS ONE 4(3): e5002. doi:10.1371/journal.pone.0005002 Editor: Ben Marais, University of Stellenbosch, South Africa Received November 26, 2008; Accepted March 1, 2009; Published March 25, 2009 This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. Funding: LH was partly funded by the National Institutes of Health (NIH) K24 087713. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: izh7@cdc.gov Introduction Pneumocystis jirovecii pneumonia (PCP) continues to be the most common serious opportunistic infection occurring among persons with HIV infection in the United States despite effective prophylactic therapy [1]. During the 1980s, PCP was the AIDS- defining illness for approximately two-thirds of patients, and it was estimated that 75% of HIV-infected persons would develop PCP in their lifetime [2,3]. Trimethoprim-sulfamethoxazole (TMP- SMX) was shown to be effective in preventing PCP in persons with AIDS in the late 1980s [4], and the proportion of cases in which PCP was an AIDS-defining illness decreased appreciably as prescription of TMP-SMX to prevent PCP became the standard of care [5,6]. The widespread use of antiretroviral therapy (ART) in the late 1990s led to a further decline in the incidence of PCP [3]. Current Centers for Disease Control and Prevention (CDC) guidelines recommend the initiation of primary PCP prophylaxis for persons with CD4 cell counts less than 200 cells/mL or a history of oropharyngeal candidiasis, and discontinuation of prophylaxis for persons who have responded to ART with an increase in CD4 cell counts to more than 200 cells/mL for greater than 3 months [7]. Although prophylaxis against PCP is effective, the benefits can only be realized if HIV-positive persons access healthcare, providers appropriately prescribe prophylaxis to persons at risk for PCP, and patients adhere to prescribed PCP prophylaxis. In an analysis of PCP cases diagnosed during 1999–2001, 44% of cases occurred among persons not receiving care, 10% occurred among persons in care who met criteria for prophylaxis but were not prescribed prophylaxis, and 41% occurred among persons prescribed prophylaxis but who were either not adherent to treatment or who developed PCP despite appropriate use [3]. The U.S. Healthy People 2010 goal is for 95% of eligible persons to receive PCP prophylaxis [8]. The proportion of eligible persons prescribed PCP prophylaxis in a large U.S. cohort of HIV-positive persons was 80% [9], whereas in another study, the proportion of providers who adhered with guidelines for prescribing PCP prophylaxis in federally funded HIV treatment facilities ranged PLoS ONE | www.plosone.org 1 March 2009 | Volume 4 | Issue 3 | e5002