Glucose reabsorption has been recently shown to be linked to that of sodium. When sodium reabsorption is enhanced, so is glucose reabsorption; when sodium reabsorption is depressed, so is that of glucose. Glucose reabsorption, like that of sodium, is also tied to the glomerular filtration rate (GFR), increasing when the GFR increases and falling when the GFR falls (glomerular tubular balance). Thus, no maximal rate of tubular reabsorption exists for glucose, at least in the classical sense. Those altered states of homeostasis accompanied by hyperglycemia and volume contraction (the major stimulus to increased renal reabsorption of sodium) will also be accompanied by increased glucose reabsorption that will both accentuate and perpetuate the hyperglycemia.
Kurtzman NA, Pillay VKG. Renal Reabsorption of Glucose in Health and Disease. Arch Intern Med. 1973;131(6):901-904. doi:10.1001/archinte.1973.00320120141010