At least this story was better than the Toronto Star story, which led, “In what’s being described as a potential public health miracle….” and better than some recent Star Tribune stories on renal denervation.
But the flaws we point out are not difficult to address.
There are more than 7 million Americans who have hypertension that is resistant to drug therapy. That resistance may be the result of inadequate drug dosing, incorrect drug combination, poor compliance and adherence or underlying physiology. A new approach for patients with truly resistant hypertension is clearly needed. Renal denervation is not new or novel. A new device that reduces the risks of the original procedure may bring the approach to many more patients if it truly works, is durable and is not associated with kidney damage. While preliminary studies appear to be promising, the true test of multiyear durability has yet to be demonstrated.
No discussion of costs. This approach is not going to be cheap.
The story adequately reports what the researchers reported about decline in systolic blood pressure.
It’s not sufficient to simply act as stenographer when study authors say “the procedure is safe as well as effective.” In fact, a careful review of the actual journal paper contradicts the safety statement. One subject in the crossover group suffered a renal artery dissection (tear) during placement of the guide catheter that required urgent repair. Not important enough to report?
And it certainly isn’t adequate to quote from a news release that “participants’ kidneys were not damaged or functionally impaired. We also found no ill effects on long-term health from the procedure.” Would most blood pressure experts consider 6-12 months as “long-term health”?
Can a procedure be proclaimed “safe” in the hands of one experienced team? What might the learning curve be for this approach?
These are not merely academic questions when a researcher – and a story – proclaim a tiny study as proof of safety.
There was no critical analysis of the evidence that was reported – no discussion of the limitations of drawing conclusions from the experience of one team reporting on 35-82 patients (depending on whom you count in this study).
No discussion of the issue that lowering blood pressure is a surrogate for reducing cardiovascular risk. So letting the researcher get away with saying the procedure is “safe and effective” is incomplete and misleading and lacking necessary context.
The study design is not well described in the story. There were actually 190 entered into the study with 106 actually randomized. Importantly, 36 of the enrolled subjects were removed from the study during a period when their compliance to medication was closely observed, pointing to the importance of compliance and adherence. 52 subjects were assigned to have the procedure performed while 54 acted as a control group for the first 6 months of the study. They then went on to have the procedure performed. Importantly, only 35/54 actually went on to the second part of the study and received the procedure. 9/54 were ineligible for the procedure at 6 months because their blood pressure dropped below 160mm Hg systolic. And finally, the story really did not focus on the fact that all the subjects continued on drug therapy despite the qualifier by Dr. Singh. The headline of the story should have been “Treating Kidneys with Radio Waves and Drugs May Ease Tough to Control Hypertension.”
No overt disease mongering at play here.
Medtronic funding was disclosed.
There was an independent expert who provided some needed balance – although that expert was not quoted about any real critical analysis of the evidence.
Nonetheless, enough to get a satisfactory score.
The independent expert quoted provided important reminders about “so many things that go into getting blood pressure under control” – lifestyle, medications, adherence, etc.
The story explained that the procedure is used in other countries but not yet approved in the US.
However suggesting it is used in other countries doesn’t really provide the reader with enough information. Here is what the UK’s National Institute for Health and Clinical Excellence (IPG418 Percutaneous transluminal radiofrequency sympathetic denervation of the renal artery for resistant hypertension: guidance ) had to say about the approach:
“Current evidence on percutaneous transluminal radiofrequency sympathetic denervation of the renal artery for resistant hypertension is from limited numbers of patients, but there is evidence of efficacy in the short and medium term. There is inadequate evidence on efficacy in the long term; this is particularly important for a procedure aimed at treating resistant hypertension. The limited evidence suggests a low incidence of serious periprocedural complications, but there is inadequate evidence on long-term safety. Therefore this procedure should only be used with special arrangements for clinical governance, consent, and audit or research.”
These evidence-based questions will have some impact on availability – whether in other countries or in the US. And the story should have dug a bit deeper.
The story didn’t reference any of the other of a growing list of other approaches to resistant hypertension. See some of our recent blog posts on this issue:
The story did pull a researcher quote from a journal news release, but there’s no evidence that it relied solely or largely on a news release.