In Reply: Dr Lin and colleagues suggest that group differences in baseline insulin resistance as quantified by HOMA-IR may be driving the findings of our trial. Of the participants, 18% were taking insulin at baseline, which greatly affects the measurement of fasting plasma insulin. As such, it is of little value to calculate HOMA-IR using the baseline insulin data. The prevalence of insulin use was similar across the control, resistance, aerobic, and combination groups (17%, 12%, 21%, and 22%, respectively). When participants using insulin were removed from the analysis, baseline fasting insulin was similar across treatment groups (mean, 16.4 μIU/mL; 95% confidence interval [95% CI], 12.7-20.0 μIU/mL, in the control group; mean, 18.1 μIU/mL; 95% CI, 15.4-20.8 μIU/mL, in the resistance exercise group; mean, 15.8 μIU/mL; 95% CI, 12.9-18.6 μIU/mL, in the aerobic exercise group; and mean, 16.3 μIU/mL; 95% CI, 13.5-19.0 μIU/mL, in the combination exercise group; P = .65) as was baseline HOMA-IR value (mean, 6.5; 95% CI, 5.1-8.0, in the control group; mean, 6.9; 95% CI, 5.9-8.0, in the resistance exercise group; mean, 5.4; 95% CI, 4.3-6.6, in the aerobic exercise group; and mean, 5.9; 95% CI, 4.8-7.0, in the combination exercise group; P = .23). Thus, we do not think that different baseline levels of insulin resistance account for our findings of the combination of aerobic and resistance training being superior in lowering HbA1c than either modality alone.
Church TS. Aerobic and Resistance Training for Patients With Type 2 Diabetes—Reply. JAMA. 2011;305(9):891-892. doi:10.1001/jama.2011.227