Name an important variable to monitor in patients on HAART therapy.

Monitoring CD4 count is crucial for patients on Highly Active Antiretroviral Therapy (HAART) because it serves as a key marker of immune system function in individuals living with Human Immunodeficiency Virus (HIV). The CD4 count assesses the level of CD4 T lymphocytes, which are essential immune cells that help the body fight infections.

In the context of HAART, an increase in CD4 count indicates a positive response to therapy, reflecting improved immune function and a reduced risk of opportunistic infections. Conversely, a declining CD4 count can signify treatment failure or progression of the infection, prompting a reevaluation of the therapy regimen. Regular monitoring of CD4 counts helps guide clinical decisions regarding the need for prophylactic treatments or adjustments in antiviral therapy to maintain effective management of HIV.

While hepatic enzymes, blood pressure, and heart rate are also important to monitor in patients for various reasons, they do not specifically signal the effectiveness of HAART as directly as CD4 counts do.