Development and validation of decision rules to guide frequency of monitoring CD4 cell count in HIV-1 infection before starting antiretroviral therapy

• Published in: PloS one 2011-04, Vol.6 (4), p.e18578
• Main Authors: Buclin, Thierry, Telenti, Amalio, Perera, Rafael, Csajka, Chantal, Furrer, Hansjakob, Aronson, Jeffrey K, Glasziou, Paul P
• Format: Article
• Language: English
• Subjects: Acquired immune deficiency syndrome; AIDS; Antiretroviral agents; Antiretroviral drugs; Antiretroviral therapy; Antiretroviral Therapy, Highly Active; Biomarkers; Care and treatment; CD4 antigen; CD4 Lymphocyte Count - methods; Cohort analysis; Cohort Studies; Computer simulation; Decision Making; Drug therapy; Ethnicity; Evidence-based medicine; Health aspects; Health Planning Guidelines; Highly active antiretroviral therapy; HIV; HIV infections; HIV Infections - drug therapy; HIV Infections - immunology; HIV Infections - virology; HIV patients; HIV-1 - immunology; Hospitals; Human immunodeficiency virus; Humans; Infections; Literature reviews; Medicine; Monitoring; Nomograms; Patients; Primary care; Random variables; Reproducibility of Results; Sensitivity and Specificity; Shot; Studies; Therapy; Thresholds; Toxicology; Trajectory analysis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0018578

Although CD4 cell count monitoring is used to decide when to start antiretroviral therapy in patients with HIV-1 infection, there are no evidence-based recommendations regarding its optimal frequency. It is common practice to monitor every 3 to 6 months, often coupled with viral load monitoring. We developed rules to guide frequency of CD4 cell count monitoring in HIV infection before starting antiretroviral therapy, which we validated retrospectively in patients from the Swiss HIV Cohort Study. We built up two prediction rules ("Snap-shot rule" for a single sample and "Track-shot rule" for multiple determinations) based on a systematic review of published longitudinal analyses of CD4 cell count trajectories. We applied the rules in 2608 untreated patients to classify their 18 061 CD4 counts as either justifiable or superfluous, according to their prior ≥5% or 650 for a threshold of 200, >900 for 350, or >1150 for 500×10(6)/L, respectively. When CD4 counts fall below these limits, increased monitoring frequency becomes advisable. These rules offer guidance for efficient CD4 monitoring, particularly in resource-limited settings.