Thursday, December 25, 2014
Top nephrology-related stories of 2014
I also want to make a last minute honorable mention:
The new US Kidney Allocation System- This had been in the works for several years and was implemented on December 4th of this year. Some of the highlights of the new system are; 1. credit is given for time on dialysis prior to listing 2. patients with blood type B will be able to receive a blood type A2 kidney and highly sensitized patients will receive points to allow for more of a change for transplant. 3. an attempt to match kidneys based on "longevitiy". 4. increased sharing across the country. These changes are supposed to level the field so kidney transplants are allocated equitably across socioeconomic lines. It also attempts to find ways to offer more kidneys to patients that are highly sensitized while pair a kidney with the right donor. How this plays out across the US will be the true test.
Below are links to the last 4 years of the top nephrology stories polls
And now for the top 10 of 2014 and the 5th straight year of top nephrology stories on RFN...
10. POSEIDON Trial showing fluid administration guided by LV end diastolic pressure reduced contrast-induced AKI (6%)- Coming in at number 10 this year was an interesting study reported in the Lancet. This was also covered during NephJC journal club as well. POSEIDON was a single center study with ~400 patients with high risk for contrast-induced AKI undergoing coronary angiography. Patients were randomized to either control (0.9% NS 1hr before and 4hr after cardiac cath) or the intervention arm (the same 1hr pre NS dose but gave NS post cath based on LVEDP). The strategy was to maximize fluid administration while minimizing volume overload in order to prevent AKI. The patients in the intervention ended up getting more fluids and thus a reduction in AKI from ~16% to ~7%. How can these results be translated to other settings (such as CT scan with contrast)? Measures of LVEDP are more difficult to obtain when you are not performing a heart cath. My take away from this study is that patients at high risk for AKI need significant volume expansion and the more you can safely give the better. Strategies to minimize fluid overload will be needed to mitigate the risk of volume overload .
9. Gestational HTN or preeclampsia was more common in kidney donors (6%)- This was an interesting study reported in the NEJM in November. This group utilized a retrospective cohort of 85 healthy women in Ontario, Canada who underwent kidney donation who later became pregnant. These women were compared in a 1:6 ratio with 510 healthy non-donors in the general population who became pregnant. They reported that gestational hypertension or preeclampsia were more common in the donor population compared to healthy controls (11% versus 5%). This finding comes on the heals of several reports linking kidney donation to small by statistically significant increase in ESRD. Paul has a nice review on RFN. The caveat to each of these studies is that they are retrospective case-control studies. While kidney donation might confer some risk, the benefit conferred to the recipient in terms of quantity and quality of life are substantial.
8. Patiromer OPAL-HK trial for hyperkalemia (7%)- It is likely that patiromer and ZS-9 will be in a death match for potassium binding supremacy. The OPAL-HK trial (reported in NEJM) studied 243 patients with mild (av 5.3 mmol/l) and moderate-to-severe (av 5.7 mmol/l) hyperkalemia to treatment with patiromer (a nonabsorbed polymer that binds potassium in exchange for calcium). The study showed remarkable efficacy in lowering potassium in both groups. During the randomized withdrawal phase the majority of patients assigned to placebo had recurrent hyperkalemia. Safety signals include mild to moderate constipation. It will be interesting to see how this drug will stack up against ZS-9. Having 2 drugs in the fight could equal a win in the pricing war. We will see.
7. IgA Nephropathy GWAS implicates genes involved in helminth immune response (7%)- This was the surprise of the year in my opinion. This was a genome wide association study (GWAS) in IgA Nephrology and was reported in Nature Genetics. This group performed GWAS on ~2,700 patients with biopsy proven IgA Nephropathy and ~3,900 controls of European and Chinese ancestry. They found 6 new associations, 4 in ITGAM-ITGAX, VAV3 and CARD9 and 2 new independent signals at HLA-DQB1 and DEFA. "Most loci were either directly associated with risk of inflammatory bowel disease or maintenance of the intestinal epithelial barrier and response to mucosal pathogens. The risk alleles were highly suggestive of helminth diversity adaptation". So it appears that yet another kidney disease could be linked to infectious pathogens (see APOL1 and Trypanosoma brucei rhodesiense).
6. HALT-PKD Trials of low BP target and ACEi/ARB combo (10%)- The much awaited dual release of the HALT-PKD trials were presented and simultaneously reported in NEJM at kidney week this year. HALT-PKD consisted of 2 trials: the first study was termed "early" in which patients had preserved renal function and the other termed "late" in which patients had a decline in renal function. They both tested dual ACEi/ARB blockade and the "early" study had an additional focus on blood pressure reduction. 120/70 to 130/80mmHg (Standard BP) and the low blood-pressure target group was quite low at 95/60 to 110/75 mm Hg (Low BP). Both the "early" and "late" trial dual ACEi/ARB combo groups had no additional benefit over monotherapy. However the "low BP" arm of the "early" study had benefits in LVH, kidney size and urinary albumin excretion at the expense of dizziness and light-headedness. However, this did not confer eGFR benefit. How these results would translate into clinical benefit is uncertain. It is clear that combo ACEi/ARB therapy is done in this patient population as it is for diabetic kidney disease (see Nephron-D). Will it be feasible to push blood pressure this low in patients with PKD. Without changes in eGFR or another solid end-point my guess is no.
5. Anti-Phospholipase A2 receptor assay licensed for commercial testing (13%)- Another exciting development in the field was the news that the anti-phospholipase A2 receptor assay gained clearance for commercial use by the FDA. This test has the potential to really help guide therapy in patients with membranous nephropathy. A recent paper in CJASN and covered in CJASNeJC discusses the potential application of this assay in membranous. Much is still to be learned about how the measurement of anti-PLA2R will affect treatment but this could be a much needed non invasive insight into the disease process. 2015 will surely be filled with more research into the topic. Some questions that remain to be answered. 1. Would you re-initiate immunosuppression if titers increase in absence of worsening proteinuria or worsening renal function in a patient with biopsy proven membranous? 2. Could this test bypass invasive biopsy in select patients? 3. How often should you measure titers? 4. Could anti-PLAR2 offer another index to gauge prognosis and potentially lengthen or intensify therapy?
4. ZS-9 trials for hyperkalemia (14%)- Coming in a number 4 is ZS-9. Another "potassium buster" drug for hyperkalemia. The company ZS Pharma reported the results of 2 trials, the HARMONIZE trial in JAMA and a phase 3 trial in NEJM. Both these studies showed efficient potassium lowering versus placebo and rebound once the drug is discontinued. NephJC hosted a lively twitter discussion about the HARMONIZE trial. Concerns for how ZS-9 will be tolerated long term and why it was compared to placebo and not kayexalate or diet. Also, in the high dose group more patients had peripheral edema. ZS-9 has the potential to really change the landscape of hyperkalemia treatment, but long term safety data is needed. The other positive from all of the hyperkalemia trials is that the medical community is finally actually starting to study this.
3. SYMPLICITY-3 trial for renal denervation in resistant HTN (19%)- Probably the biggest disappointment of the year was the SYMPLICITY-3 trial. An introduction isn't even needed as the results have been widely publicized and critiqued. You can read a summary from NOD Kidney Konnection. The SYMPLICITY-3 trial was performed in response to the FDA who requested a sham procedure group be used as a control against renal denervation in patients with resistant hypertension. The results have reverberated across the medical community. Both the sham and denervation groups had impressive drops in blood pressure by ~15 mm Hg. This was the problem. What went wrong? Was it ineffective denervation? Was it a powerful placebo effect? Was it the Hawthorne effect? Bottom line is this trial didn't achieve a significant benefit in renal denervation. Questions remain as to the effectiveness of the actual denervation technique. Will industry put money back into this technology after the results of SYMPLICITY-3? We will see.
2. JNC8 Hypertension Guidelines published in JAMA (22%)- Coming in at number 2 and the winner of NephMadness 2014 is JNC-8. This was an honorable mention in 2013 as it was published online after the end of the year poll. These guidelines were much anticipated and sometimes referred to has JNC-late. JNC-8 attempted to answer questions using randomized controlled data while carefully adjudicating the available evidence. JNC-8 is far narrower in scope than JNC-7 and was not a “how to” document. JNC-8 explicitly states places where we do not have evidence for and what we really need to know. Lastly, the document simplifies the blood pressure goals. Some have expressed concern about raising the systolic blood pressure target in patients over 60 (without DM or CKD) from 140 to 150 mm Hg. For a review of the major changes with JNC-8 see the NephMadness champion post.
1. Perivascular Gli1+ progenitors contribute to myofibroblast pool leading to fibrosis in multiple organs including kidney (57%)- Coming in at number 1 this year is an interesting report from Cell Stem Cell. I'll have to add an asterix to this win though. It appears the stem cell community really got the word out to vote for this one. It is still deserving of a top story of the year as it paves a new paradigm in the pathogenesis of fibrosis. In a real tour de force Kramann et al not only define this process in kidney fibrosis but also look at lung, liver and heart fibrosis. They utilized lineage tracing to show that tissue-resident (not circulating) Gli1+ cells (pericytes) proliferate after kidney, lung, liver, or heart injury to generate myofibroblasts. This has been a hot topic and covered in detail in this years NephMadness. Next, they genetically ablated these cells and induced organ injury in various mouse models. They showed that kidney and heart fibrosis was substantially less compared to controls. These are exciting studies that have the potential to open new therapeutic targets for chronic kidney disease and other chronic disease such as cirrhosis, lung fibrosis and heart failure. This could be a candidate for the next basic science NephJC discussion. An exciting development and it will be fun to watch where this goes.
Another busy and exciting year in the world of nephrology in 2014. Thanks to all of the contributors and readers for keeping the site fun, interesting and educational.
Thanks for supporting RFN and happy holidays. Can't wait to see what 2015 has in store!