PTH and parathyroid hyperplasia: Across the included studies in Table 4, consistent signals emerge: PTH dysregulation in PLWHIV arises from immune activation and antiretroviral effects with TDF often linked to higher PTH despite normal calcium and 25(OH)D; histopathology reports describe parathyroid hyperplasia, and physiological work indicates reduced parathyroid reserve with CD4 cell loss [Table 4].