Week 47 – VA NEPHRON-D

“Combined Angiotensin Inhibition for the Treatment of Diabetic Nephropathy”

by the Veterans Affairs Nephropathy in Diabetes (VA NEPHRON-D) Investigators

N Engl J Med. 2013 Nov 14;369(20):1892-903. [free full text]

Inhibition of the renin-angiotensin-aldosterone system (RAAS) decreases the progression of proteinuric kidney disease, such as diabetic nephropathy. Prior studies have demonstrated that the greater the proteinuria is reduced by RAAS inhibition, the slower the further loss of GFR. Therefore, it had been hypothesized that combination RAAS inhibition with both an ACEi and an ARB in diabetic kidney disease would reduce the rate of renal decline and incidence of ESRD. The investigators of the VA NEPHRON-D trial hypothesized that “the benefit in slowing the progression of kidney disease would outweigh the risks of hyperkalemia and AKI associated with more intensive blockade of the RAAS.”

Population: US veterans with T2DM, eGFR 30.0-89.9 ml/min, and urinary albumin/Cr ratio ≥ 300

Notable exclusion criteria: nondiabetic kidney disease, K > 5.5, current treatment with sodium polystyrene sulfonate (Kayexalate)

Intervention: losartan 100mg PO daily and lisinopril 10mg, uptitrated q2 weeks to 20mg and then 40mg, respectively, as tolerated (meaning no hyperkalemia or Cr rise > 30%)

Comparison: losartan 100mg PO daily and placebo, uptitrated q2 weeks as tolerated

(Note: prior to randomization, there was a run-in period with uptitration to target dose of losartan to ensure hyperkalemia did not develop prior to initiating the study drug.)

Outcome:
Primary – time to first occurrence of composite endpoint of decline in eGFR (≥ 30 ml/min if baseline eGFR ≥60 ml/min, or relative decrease of ≥ 50% if baseline eGFR < 60 ml/min), ESRD, or death

Secondary, selected:

  • first occurrence of decline in eGFR or ESRD
  • ESRD
  • cardiovascular events (MI, stroke, or hospitalization for CHF)
  • all-cause mortality
  • hyperkalemia (> 6, or requiring ED visit/hospitalization/dialysis)
  • AKI


Results
:
724 patients were randomized to each treatment arm. Baseline characteristics were similar among the two groups. The trial was stopped early after the data and safety monitoring committee found increased rates of serious adverse events, hyperkalemia, and AKI in the combination-therapy group. Median follow-up at time of study closure was 2.2 years.

132 patients in the combination-therapy group (18.2%) and 152 patients in the monotherapy group (21.0%) met the primary composite endpoint of decline in eGFR, ESRD, or death (p = 0.30).

Decline in eGFR or progression to ESRD occurred in 77 (10.6%) of the combination-therapy group and 101 (14.0%) of the monotherapy group (p = 0.10). There were also no significant group differences in the individual rates of ESRD, all-cause mortality, or MI/stroke/CHF.

AKI events occurred 190 times in 130 patients in the combination-therapy group (12.2 events per 100 person-years). In comparison, there were only 105 AKI events in 80 patients in the monotherapy group (6.7 events per 100 person-years) [HR 1.7, 95% CI 1.3-2.2, p < 0.001]. Hyperkalemia occurred in 72 (9.9%) of the combination-therapy patients versus 32 (4.4%) of the monotherapy patients (p < 0.001).

Implication/Discussion:
Among patients with T2DM, CKD, and proteinuria, combination therapy with an ARB and ACEi did not reduce the progression of kidney disease or mortality relative to an ARB alone; in fact, combination therapy increased the risks of AKI and hyperkalemia.

This was a well-designed, double-blind, randomized, controlled trial with definitive results. Its results align with those of its contemporary studies ONTARGET (2008, combination ARB and ACEi vs. monotherapy) and ALTITUDE (2012, ARB or ACEi plus the direct renin inhibitor aliskiren vs. ARB or ACEi monotherapy), which demonstrated no benefit and increased adverse event rates with combination therapy.

Although dual RAAS blockade reduces proteinuria in diabetic nephropathy greater than monotherapy, it is not recommended currently due to a lack of benefit and increased adverse events.

Further Reading/References:
1. VA NEPHRON-D @ Wiki Journal Club
2. ONTARGET @ Wiki Journal Club
3. ALTITUDE @ PubMed

Summary by Duncan F. Moore, MD

Week 46 – Transfusion Strategies for Upper GI Bleeding

“Transfusion Strategies for Acute Upper Gastrointestinal Bleeding”

N Engl J Med. 2013 Jan 3;368(1):11-21. [free full text]

A restrictive transfusion strategy of 7 gm/dL was established following the previously discussed 1999 TRICC trial. Notably, both TRICC and its derivative study TRISS excluded patients who had an active bleed. In 2013, Villanueva et al. performed a study to establish whether there was benefit to a restrictive transfusion strategy in patients with acute upper GI bleeding.

Population: adults with hematemesis (or bloody nasogastric aspirate), melena, or both; selected consecutively at a single-center in Spain

Notable exclusion criteria: a clinical Rockall score* of 0 with a hemoglobin level higher than 12g/dL, massive exsanguinating bleeding, lower GIB, patient refusal of blood transfusion, ACS, stroke/TIA, transfusion within 90 days, recent trauma or surgery

*The Rockall score is a system to assess risk for further bleeding or death on a scale from 0-11. Higher scores (3-11) indicate higher risk. Of the 648 patients excluded, the most common reason for exclusion (n = 329) was low risk of bleeding.

Intervention: restrictive transfusion strategy (transfusion threshold Hgb = 7.0 gm/dL) [n = 444]

Comparison: liberal transfusion strategy (transfusion threshold Hgb = 9.0 gm/dL) [n = 445]

During randomization, patients were stratified by presence or absence of cirrhosis.

As part of the study design, all patients underwent emergent EGD within 6 hours and received relevant hemostatic intervention depending on the cause of bleeding.

Outcome:
Primary outcome: 45-day mortality

Secondary outcomes, selected:

  • Incidence of further bleeding associated with hemodynamic instability or hemoglobin drop > 2 gm/dL in 6 hours
  • Incidence and number of RBC transfusions
  • Other products and fluids transfused
  • Hgb level at nadir, discharge, and 45 days

Subgroup analyses: Patients were stratified by presence of cirrhosis and corresponding Child-Pugh class, variceal bleeding, and peptic ulcer bleeding. An additional subgroup analysis was performed to evaluate changes in hepatic venous pressure gradient between the two strategies.


Results
:
The primary outcome of 45-day mortality was lower in the restrictive strategy (5% vs. 9%; HR 0.55, 95% CI 0.33-0.92; p = 0.02; NNT = 24.8). In subgroup analysis, this finding remained consistent for patients who had Child-Pugh class A or B but was not statistically significant among patients who had Class C. Further stratification for variceal bleeding and peptic ulcer disease did not make a difference in mortality.

Secondary outcomes:
Rates of further bleeding events and RBC transfusion, as well as number of products transfused, were lower in the restrictive strategy. Subgroup analysis demonstrated that rates of re-bleeding were lower in Child-Pugh class A and B but not in C. As expected, the restrictive strategy also resulted in the lowest hemoglobin levels at 24 hours. Hemoglobin levels among patients in the restrictive strategy were lower at discharge but were not significantly different from the liberal strategy at 45 days. There was no group difference in amount of non-RBC blood products or colloid/crystalloid transfused. Patients in the restrictive strategy experienced fewer adverse events, particularly transfusion reactions such as transfusion-associated circulatory overload and cardiac complications. Patients in the liberal-transfusion group had significant post-transfusion increases in mean hepatic venous pressure gradient following transfusion. Such increases were not seen in the restrictive-strategy patients.


Implication/Discussion
:
In patients with acute upper GI bleeds, a restrictive strategy with a transfusion threshold 7 gm/dL reduces 45-day mortality, the rate and frequency of transfusions, and the rate of adverse reactions, relative to a liberal strategy with a transfusion threshold of 9 gm/dL.

In their discussion, the authors hypothesize that the “harmful effects of transfusion may be related to an impairment of hemostasis. Transfusion may counteract the splanchnic vascoconstrictive response caused by hypovolemia, inducing an increase in splanchnic blood flow and pressure that may impair the formation of clots. Transfusion may also induce abnormalities in coagulation properties.”

Subgroup analysis suggests that the benefit of the restrictive strategy is less pronounced in patients with more severe hepatic dysfunction. These findings align with prior studies in transfusion thresholds for critically ill patients. However, the authors note that the results conflict with studies in other clinical circumstances, specifically in the pediatric ICU and in hip surgery for high-risk patients.

There are several limitations to this study. First, its exclusion criteria limit its generalizability. Excluding patients with massive exsanguination is understandable given lack of clinical equipoise; however, this choice allows too much discretion with respect to the definition of a massive bleed. (Note that those excluded due to exsanguination comprised only 39 of 648.) Lack of blinding was a second limitation. Potential bias was mitigated by well-defined transfusion protocols. Additionally, there a higher incidence of transfusion-protocol violations in the restrictive group, which probably biased results toward the null. Overall, deviations from the protocol occurred in fewer than 10% of cases.


Further Reading/References
:
1. Transfusion Strategies for Acute Upper GI Bleeding @ Wiki Journal Club
2. 2 Minute Medicine
3. TRISS @ Wiki Journal Club

Summary by Gordon Pelegrin, MD

Week 45 – Look AHEAD

“Cardiovascular Effects of Intensive Lifestyle Intervention in Type 2 Diabetes”

by the Look AHEAD (Action for Health in Diabetes) Research Group

N Engl J Med. 2013 Jul 11;369(2):145-54. [free full text]

NIH treatment guidelines recommend weight loss in patients with T2DM and overweight or obesity. Such weight loss is associated with improvements in glycemic control, hypertension, and quality of life. While retrospective cohort studies and a prospective trial of bariatric surgery in T2DM suggested that weight loss was associated with reduction in rates of cardiovascular events and mortality, no prospective trial has demonstrated such benefits from non-surgical weight loss. The Look AHEAD study was designed to determine if aggressive lifestyle intervention for weight loss in T2DM could provide benefits in hard cardiovascular outcomes.

Population: patients with T2DM, age 45-75, and BMI 25+ (27+ if on insulin), A1c < 11%, SBP < 160 mmHg, DBP < 100 mmHg, and the ability to complete a maximal exercise test

Intervention: an “intensive lifestyle intervention” with goal weight loss ≥ 7.0%, implemented via weekly group and individual counseling (decreasing in frequency over course of study). Specific recommended interventions: caloric restriction to 1200-1800 kcal/day, use of meal-replacement products, ≥ 175 min/wk of moderate-intensity exercise

Comparison: “diabetes support and education” comprised of three group meetings per year focused on diet, exercise, and social support (yearly meetings starting year 5)
Outcome:
Primary – composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for angina.

Of note, hospitalization for angina was not a pre-specified component of the primary outcome. It was added 2 years into the trial after event rates of the other cardiovascular components were lower than expected.

Secondary

  • composite of death from cardiovascular causes, nonfatal MI, nonfatal stroke (the original primary outcome)
  • composite of death (all-cause), nonfatal MI, nonfatal stroke, hospitalization for angina
  • composite of death (all-cause), nonfatal MI, stroke, hospitalization for angina, CABG, PCI, hospitalization for heart failure, or peripheral vascular disease

Results:
2570 patients were randomized to the intensive lifestyle intervention (ILI) group, and 2575 were randomized to the diabetes support and education (DSE) group. Baseline characteristics were similar in both groups. Mean BMI was 36.0, and 14% of patients had a history of cardiovascular disease.

At one year, mean weight loss from baseline was 8.6% in the ILI group and 0.7% in the DSE group (p < 0.001); however, weight loss at the end of the study was 6.0% in the ILI group and 3.5% in the DSE group (p < 0.001). The average group difference in A1c was 0.22% lower in the ILI group (p < 0.001) although A1c values were slightly higher than baseline in both groups at the end of the study (see Figure 1D for the time course).

The trial was terminated prematurely after interim analysis revealed that the likelihood of a significant positive primary result was approximately 1%. Median follow up was 9.6 years at the time of termination.

There was no group difference in rates of the primary composite cardiovascular endpoint. The endpoint occurred in 403 patients in the ILI group and 418 patients in the DSE group (1.83 and 1.92 events per 100 person-years, respectively; HR 0.95, 95% CI 0.83-1.09, p = 0.51).

There were no group differences in rates of the secondary composite outcomes.

Implication/Discussion:
Among patients with T2DM and overweight or obesity, an intensive lifestyle intervention for weight loss was not associated with improved cardiovascular outcomes, when compared to a control group-based diabetes support and education intervention.

Overall, this trial was a notable failure. Despite the trial’s adequate power and its authors shifting the goalposts at 2 years into the study, the intervention did not demonstrate “hard” cardiovascular benefits. Furthermore, generalizability of this study is limited by its exclusion of patients who could not complete a maximal-fitness test at baseline. With respect to diet, this trial did not address diet composition, only caloric restriction and increased physical activity.

The authors suggest that “a sustained weight loss of more than that achieved in the intervention group may be required to reduce the risk of cardiovascular disease,” and thus the trial failed to return a positive result.

Weight loss in patients with T2DM and overweight or obesity remains a Class A recommendation by the American Diabetes Association. The ADA also notes that weight loss may be achieved at 2 years with a “Mediterranean” diet. The 2013 PREDIMED study demonstrated that such a diet reduces the risk of ASCVD in high-risk patients.

Further Reading/References:
1. Look AHEAD @ Wiki Journal Club
2. American Diabetes Association. “Executive Summary: Standards of Medical Care in Diabetes – 2013.”
3. PREDIMED @ Wiki Journal Club

Summary by Duncan F. Moore, MD

Week 44 – Early TIPS in Cirrhosis with Variceal Bleeding

“Early Use of TIPS in Patients with Cirrhosis and Variceal Bleeding”

N Engl J Med. 2010 Jun 24;362(25):2370-9. [free full text]

Variceal bleeding is a major cause of morbidity and mortality in decompensated cirrhosis. The standard of care for an acute variceal bleed includes a combination of vasoactive drugs, prophylactic antibiotics, and endoscopic techniques (e.g. banding). Transjugular intrahepatic portosystemic shunt (TIPS) can be used to treat refractory bleeding. This 2010 trial sought to determine the utility of early TIPS during the initial bleed in high-risk patients, when compared to standard therapy.

Population: cirrhotic patients with acute esophageal variceal bleeding, either Child-Pugh class C with score 10-13 or class B (score 7-9) with active bleeding at diagnostic endoscopy

Notable exclusion criteria: Child-Pugh score > 13, age > 75, HCC that did not meet transplantation criteria, bleeding gastric varices, total portal vein thrombosis, prior TIPS

All patients received endoscopic band ligation (EBL) or endoscopic injection sclerotherapy (EIS) at the time of diagnostic endoscopy. All patients also received vasoactive drugs (terlipressin, somatostatin, or octreotide).

Intervention: TIPS performed within 72 hours after diagnostic endoscopy

Comparison: 1) treatment with vasoactive drugs with transition to nonselective beta blocker when patients free of bleeding followed by 2) addition of isosorbide mononitrate to maximum tolerated dose, and 3) a second session of EBL at 7-14 days after the initial session (repeated q10-14 days until variceal eradication was achieved)

Outcome:
Primary – composite of failure to control acute bleeding or failure to prevent “clinically significant” variceal bleeding (requiring hospital admission or transfusion) at 1 year after enrollment

Secondary, selected

  • mortality at 1 year
  • failure to control acute bleeding
  • early rebleeding (at 5 days and 6 weeks)
  • rate of development of hepatic encephalopathy (HE)
  • ICU days, time in hospital

 

Results:
359 patients were screened for inclusion, but ultimately only 63 were randomized. Baseline characteristics were similar among the two groups except that the early TIPS group had a higher rate of patients with previous hepatic encephalopathy. Among early TIPS patients, the mean portal pressure dropped from 20.2±7 mmHg to 6.2±3 mmHg.

The primary composite endpoint of failure to control acute bleeding or rebleeding within 1 year occurred in 14 of 31 (45%) patients in the pharmacotherapy-EBL group and in only 1 of 32 (3%) of the early TIPS group (p = 0.001). The 1-year actuarial probability of remaining free of the primary outcome was 97% in the early TIPS group vs. 50% in the pharmacotherapy-EBL group (ARR 47 percentage points, 95% CI 25-69 percentage points, NNT 2.1).

Regarding mortality, at one year, 12 of 31 (39%) patients in the pharmacotherapy-EBL group had died, while only 4 of 32 (13%) in the early TIPS group had died (p = 0.001, NNT = 4.0).

Regarding HE: the 1-year actuarial probability of HE was 28% in the early TIPS group vs. 40% in the pharmacotherapy-EBL group (p = 0.13). Most of the episodes of HE occurred during the index bleed. Following discharge from index hospitalization, the 1-year risk of additional HE episodes was 10% in the pharmacotherapy-EBL group and 19% in the early TIPS group (p = 0.80).

There were no group differences in 1-year actuarial probability of new or worsening ascites.

There were no group differences in length of ICU stay or hospitalization duration.

Implication/Discussion:
Early TIPS in acute esophageal variceal bleeding, when compared to standard pharmacotherapy and endoscopic band ligation, improved control of index bleeding, reduced recurrent variceal bleeding at 1 year, and reduced all-cause mortality.

Prior studies had demonstrated that TIPS reduced the rebleeding rate but increased the rate of hepatic encephalopathy without improving survival. As such, TIPS had only been recommended as a rescue therapy. Obviously, this study presents compelling data that challenges these paradigms.

The authors note that in “patients with Child-Pugh class C or in class B with active variceal bleeding, failure to initially control the bleeding or early rebleeding contributes to further deterioration in liver function, which in turn worsens the prognosis and may preclude the use of rescue TIPS.”

Authors at UpToDate note that, given the totality of evidence to date, the benefit of early TIPS in preventing rebleeding “is offset by its failure to consistently improve survival and increasing morbidity due to the development of liver failure and encephalopathy.” Today, TIPS remains primarily a salvage therapy for use in cases of recurrent bleeding despite standard pharmacotherapy and EBL. There may be a subset of patients in whom early TIPS is the ideal strategy, but further trials will be required to identify this subset.


Further Reading/References
:
1. Wiki Journal Club
2. 2 Minute Medicine
3. UpToDate, “Prevention of recurrent variceal hemorrhage in patients with cirrhosis”

Summary by Duncan F. Moore, MD