Inferences Beyond a Study Design’s Grasp

During the past 6 years, the technique of renal sympathetic denervation has been proposed as a treatment for drug-resistant hypertension, and several studies have been published that claimed to provide supportive evidence of its efficacy. There is no question that resistant hypertension is a major medical concern: hypertension has been authoritatively designated as the greatest threat to the global burden of disease, and approximately 8% of hypertensive individuals have resistant hypertension. However, the first studies reporting the efficacy of renal sympathetic denervation were not methodologically capable of supporting such claims. Subsequently, in March 2014, the most appropriately designed clinical trial failed to provide supportive evidence of the intervention’s efficacy. This Commentary presents a cautionary case study to exemplify the need for optimal methodologic rigor in all experimental clinical research and highlights the pitfalls should claims from less than optimally rigorous studies be afforded more weight than is scientifically appropriate.