An undetectable polymerase chain reaction signal in routine HIV plasma viral load monitoring is associated with better virological outcomes in patients receiving highly active antiretroviral therapy* P Pugliese, 1 C Delpierre, 2 L Cuzin, 3 I Poizot-Martin, 4,5 D Rey, 6 K Saune, 7 J Cottalorda, 8 D Bettinger, 9 C Delaugerre 10,11 and B Hoen 12,13 for the Dat AIDS Study Group 1 Department of Infectious Diseases, Hôpital de l’Archet, Nice, France, 2 Inserm UMR1027, Université de Toulouse III, Toulouse, France, 3 Department of Infectious Diseases, Hôpital Purpan, Toulouse, France, 4 Inserm U912 (SESSTIM), Université d’Aix Marseille, Marseille, France, 5 Department of Clinical Immunology and Hematology, APHM Sainte-Marguerite, Marseille, France, 6 HIV Care Centre, Hôpitaux Universitaires, Strasbourg, France, 7 Laboratory of Virology, Hôpital Purpan, Toulouse, France, 8 Laboratory of Virology, Hôpital de l’Archet, Nice, France, 9 Laboratory of Virology, CHRU de Besançon, Besançon, France, 10 Inserm U941, Université Paris Diderot, Paris, France, 11 Laboratory of Virology, Hôpital Saint-Louis, APHP, Paris, France, 12 Université de Franche-Comté, UMR CNRS 6249 Chrono-environnement, Besançon, France and 13 Department of Infectious Diseases, CHRU de Besançon, Besançon, France Objectives The aim of the study was to assess whether patients with undetectable viraemia [a negative polymerase chain reaction result (PCR neg )] and those with plasma viral load (PVL) < 40 HIV-1 RNA copies/mL but a detectable (positive) PCR signal (PCR pos ) had different outcomes in terms of the development of blips and virological failure (VF). Methods A multicentre observational database analysis was carried out. Data for patients whose highly active antiretroviral therapy (HAART) regime had been unchanged for 6 months by 1 January 2008, whose first two PVL measurements of 2008 were < 40 copies/mL and who had at least five PVL measurements between 1 January 2008 and 31 December 2010 were extracted from a multicentre observational database of 4928 patients receiving HAART. PVL assays used during this period had a detection threshold of 20 or 40 copies/mL. Undetectable PVL at baseline (BLPCR neg ) was defined as PCR neg at the first two PVL determinations of 2008. Multivariable Cox regression analysis was performed to investigate factors associated with the occurrence of blips and VF, defined as two consecutive PVL measurements > 40 copies/mL. Results Of the 1957 patients included in the study (mean age 47 years; median antiretroviral exposure 10.3 years), 1312 had BLPCR neg . Outcome events included 322 blips and 139 VFs, with incidence rates being significantly lower in patients with BLPCR neg than in those with BLPCR pos [13.0% vs. 23.4% (P < 0.0001) and 5.1% vs. 11.2% (P < 0.0001), respectively]. In multivariable analysis, BLPCR neg was associated with a reduced risk of blips [hazard ratio (HR) 0.58; 95% confidence interval (CI) 0.47–0.73; P < 0.0001] and VF (HR 0.44; 95% CI 0.31–0.62; P < 0.0001). Correspondence: Dr Bruno Hoen, Service de Maladies Infectieuses et Tropicales, CHU de Besançon, Hôpital Saint-Jacques, 25030 Besançon Cedex, France. Tel: 33 381 218 533; fax: 33 381 218 772; e-mail: bruno.hoen@univ-fcomte.fr *This work was presented in part at the 19th Conference on Retroviruses and Opportunistic Infections, Seattle, WA, 5–8 March 2012 (poster L-134). See Appendix. DOI: 10.1111/hiv.12041 © 2013 British HIV Association HIV Medicine (2013) SHORT COMMUNICATION 1