This means that when comparing two individuals with the same baseline characteristics (i.e. sex, route of HIV infection, nadir CD4+ cell count, specialist care duration (years), ART duration (years), previous use of AZT and ‘D’ drugs, and ART adherence (based on the presence or absence of viral rebound following complete suppression), the 5 years older individual had a 28% higher chance of developing chronic pain. Here, CD4 is linked to HIV infectious disease.