Amlodipine Vs. hydrochlorothiazide: is there any disparity in its antihypertensive effect or not?

We have read the article "Comparison of effects between calcium channel blocker and diuretics in combination with angiotensin II receptor blocker on 24-h central blood pressure and vascular hemodynamic parameters in hypertensive patients: study design for a multicenter, double-blinded, active controlled, phase 4, randomized trial" by GC Oh., et al. and found it quite interesting to learn the testing of effectiveness between amlodipine and hydrochlorothiazide in combination with losartan. After 4 weeks of therapy, non-responders were exposed for dose titration of losartan/amlodipine 100/5 mg daily or losartan/hydrochlorothiazide 100/25 mg daily. However, authors didn't increase in the amlodipine dose from 5 to 10 mg from randomization. However, as per literature both drugs are non-significant in their blood pressure lowering effect. The clarification on above point will further allay the efficacy concerns of clinicians and result in wider usage of future published data.