Quantification of insulin-mediated glucose disposal in HIV-infected individuals: comparison of patients treated and untreated with protease inhibitors.

To describe the distribution of insulin sensitivity and glucose tolerance in HIV-infected patients, the authors measured insulin-mediated glucose disposal (IMGD) in 51 subjects (24 protease inhibitor (PI)-treated subjects and 27 non-PI-treated subjects). IMGD was determined by measuring the steady-state plasma glucose (SSPG) concentration during the last 30 minutes of a 180-minute intravenous infusion of octreotide, glucose, and insulin. In addition, oral glucose tolerance testing was performed. SSPG concentrations varied six-fold in both groups, and the mean values +/- SEM did not differ between PI-treated and non-PI-treated groups (8.7 +/- 0.9 vs. 8.0 +/- 0.7 mmol/L, respectively). The mean fasting plasma glucose concentration +/- SEM was higher in the PI-treated subjects than in the non-PI-treated subjects (5.44 +/- 0.11 vs. 5.05 +/- 0.11 mmol/L, respectively; p =.01), whereas fasting plasma insulin concentrations did not differ. PI-treated patients also had significantly higher plasma glucose (p =.001) and insulin (p =.03) responses to the oral glucose challenge. However, whereas the incremental plasma glucose response during the first 30 minutes was significantly higher in PI-treated patients, the incremental insulin response in the two groups was identical. In conclusion, insulin sensitivity varies widely in HIV-infected patients irrespective of PI treatment, and the adverse effect of PIs on insulin sensitivity is likely to be of modest magnitude. Finally, PI treatment may have an inhibitory effect on insulin secretion.