In Reply Dr Lederle states that Figure 3 showed no significant reduction in retinopathy for the subgroup with a baseline systolic blood pressure of less than 140 mm Hg. However, because the test for interaction by baseline blood pressure was not significant, it is inappropriate to take the subgroup results as stand-alone results. The overall estimate is the best estimate of an effect across subgroups.1 Thus, an appropriate interpretation of Figure 3 is that blood pressure lowering was associated with a 13% (95% CI, 1%-24%) reduction in retinopathy, regardless of whether the baseline systolic blood pressure was above or below 140 mm Hg.
Emdin CA, Rahimi K, Patel A. Lowering Blood Pressure in Patients With Diabetes—Reply. JAMA. 2015;313(21):2183-2184. doi:10.1001/jama.2015.4265