Tuesday, December 10, 2013

Top Nephrology Stories of 2013 NEPHRON-D: The End of the Combination Treatment Era

This is a guest post. I don't think I have ever done this before but we are trying to get as many voices to weigh in on the Top Nephrology Stories of the Year as possible and I knew that I wanted Ed El Sayed (@iApothecary) to be part of this. If you don't follow him, you should, he is one of the sharpest medical minds on Twitter. When I invited him he said he had no place publish, so I offered a temporary home on PBFluids. Hey Ed, start a Tumblr, they're free!

Here are his words on the top nephrology story of the year:

Diabetic nephropathy is the leading cause of Chronic Kidney Disease (CKD) and End Stage Renal Disease (ESRD) in the US. It has long been postulated that combination pharmacotherapy with

Angiotensin Converting Enzyme Inhibitors (ACEi) and Angiotensin Receptor Blockers (ARBs) could slow the progression of nephropathy, and have a positive impact on the prognosis, morbidity, and mortality of patients with diabetic kidney disease. This hypothesis arose from the unfortunate fact that neither ACEi nor ARBs working alone are able to fully block the renin angiotensin aldosterone system (RAAS).

Design of Combination Angiotensin Converting Enzyme Inhibitor Angiotensin Receptor Blocker for Treatment of Diabetic Nephropathy (NEPHRON-D) was a large multi-center, prospective, and parallel trial that was terminated early due to serious side effects. In this study, 1,648 patients (average age of 64 years) with type 2 diabetes, albuminuria, and stage 3 or 4 CKD were recruited. All patients were started on losartan 100 mg and then randomized to receive either Lisinopril 10-40 mg daily or placebo..

As mentioned above, this well designed and well powered trial was terminated early due to a significantly higher rate of adverse events with combination therapy. Investigators reported that the incidence of hyperkalemia was higher with ACEi and ARBs compared to ARBs and placebo (6.3 vs 2.6 events per 100-persons-years with P = 0.001). Acute Kidney Injury (AKI) was also higher with combination therapy (12.2 vs 6.7 events per 100 person-years with P = 0.001).

With 2.2 years of follow up investigators reported no significant difference in the study’s primary end point of progression of renal disease or death (152 vs 132 with P = 0.3).

The ONTARGET and ALTITUDE studies were the two previous attempts to show renal or cardiovascular benefits from combination RAAS blockade (ACEi + ARBs in ONTARGET; ACEi + Renin Inhibitor in ALTITUDE). ONTARGET involved patients with an increased risk for cardiovascular disease but predominantly normal albumin excretion levels, while ALTITUDE involved patients with kidney disease and diabetes who were not necessarily proteinuric. Neither showed any benefit and had increased adverse events with combination therapy.

Experts now have three solid trials that clearly convey one message: Combination pharmacotherapy with ACEi and ARBs in patients with DM induced nephropathy and CKD does not provide any additional benefit and may, in fact, increase the incidence of harm.

It is worthy to note that NEPHRON-D is a perfect example of a “negative” trial that has a huge impact on the strategies used by clinicians in treating their patients; emphasizing the importance of publishing both negative and positive outcome trials.

Update from Twitter:

I set the onset of combo therapy at the publication of COOPERATE because it was a landmark study at the time. It was regularly brought out as justification for the use of dual therapy, because it's end-point was doubling of serum creatinine or ESRD, not just a change in proteinuria. According to the Cardiobrief pos,t that Dr. Sparks referenced, combo therapy was already in wide use at the time of publication but I think COOPERATE was the study that made its use acceptable to EBM purists.
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