Week 18 – Rivers Trial

“Early Goal-Directed Therapy in the Treatment of Severe Sepsis and Septic Shock”

N Engl J Med. 2001 Nov 8;345(19):1368-77. [free full text]

Sepsis is common and, in its more severe manifestations, confers a high mortality risk. Fundamentally, sepsis is a global mismatch between oxygen demand and delivery. Around the time of this seminal study by Rivers et al., there was increasing recognition of the concept of the “golden hour” in sepsis management – “where definitive recognition and treatment provide maximal benefit in terms of outcome” (1368). Rivers and his team created a “bundle” of early sepsis interventions that targeted preload, afterload, and contractility, dubbed early goal-directed therapy (EGDT). They evaluated this bundle’s effect on mortality and end-organ dysfunction.

The “Rivers trial” randomized adults presenting to a single US academic center ED with ≥ 2 SIRS criteria and either SBP ≤ 90 after a crystalloid challenge of 20-30ml/kg over 30min or lactate > 4mmol/L to either treatment with the EGDT bundle or to the standard of care.

Intervention: early goal-directed therapy (EGDT)

      • Received a central venous catheter with continuous central venous O2 saturation (ScvO2) measurement
      • Treated according to EGDT protocol (see Figure 2, or below) in ED for at least six hours
        • 500ml bolus of crystalloid q30min to achieve CVP 8-12mm
        • Vasopressors to achieve MAP ≥ 65
        • Vasodilators to achieve MAP ≤ 90
        • If ScvO2 < 70%, transfuse RBCs to achieve Hct ≥ 30
        • If, after CVP, MAP, and Hct were optimized as above and ScvO2 remained < 70%, dobutamine was added and uptitrated to achieve ScvO2 ≥ 70 or until max dose 20 μg/kg/min
          • dobutamine was de-escalated if MAP < 65 or HR > 120
        • Patients in whom hemodynamics could not be optimized were intubated and sedated, in order to decrease oxygen consumption
      • Patients were transferred to inpatient ICU bed as soon as able, and upon transfer ScvO2 measurement was discontinued
      • Inpatient team was blinded to treatment group assignment

The primary outcome was in-hospital mortality. Secondary endpoints included: resuscitation end points, organ-dysfunction scores, coagulation-related variables, administered treatments, and consumption of healthcare resources.

130 patients were randomized to EGDT, and 133 to standard therapy. There were no differences in baseline characteristics. There was no group difference in the prevalence of antibiotics given within the first 6 hours. Standard-therapy patients spent 6.3 ± 3.2 hours in the ED, whereas EGDT patients spent 8.0 ± 2.1 (p < 0.001).

In-hospital mortality was 46.5% in the standard-therapy group, and 30.5% in the EGDT group (p = 0.009, NNT 6.25). 28-day and 60-day mortalities were also improved in the EGDT group. See Table 3.

During the initial six hours of resuscitation, there was no significant group difference in mean heart rate or CVP. MAP was higher in the EGDT group (p < 0.001), but all patients in both groups reached a MAP ≥ 65. ScvO2 ≥ 70% was met by 60.2% of standard-therapy patients and 94.9% of EGDT patients (p < 0.001). A combination endpoint of achievement of CVP, MAP, and UOP (≥ 0.5cc/kg/hr) goals was met by 86.1% of standard-therapy patients and 99.2% of EGDT patients (p < 0.001). Standard-therapy patients had lower ScvO2 and greater base deficit, while lactate and pH values were similar in both groups.

During the period of 7 to 72 hours, the organ-dysfunction scores of APACHE II, SAPS II, and MODS were higher in the standard-therapy group (see Table 2). The prothrombin time, fibrin-split products concentration, and d-dimer concentrations were higher in the standard-therapy group, while PTT, fibrinogen concentration, and platelet counts were similar.

During the initial six hours, EGDT patients received significantly more fluids, pRBCs, and inotropic support than standard-therapy patients. Rates of vasopressor use and mechanical ventilation were similar. During the period of 7 to 72 hours, standard-therapy patients received more fluids, pRBCs, and vasopressors than the EGDT group, and they were more likely to be intubated and to have pulmonary-artery catheterization. Rates of inotrope use were similar. Overall, during the first 72 hrs, standard-therapy patients were more likely to receive vasopressors, be intubated, and undergo pulmonary-artery catheterization. EGDT patients were more likely to receive pRBC transfusion. There was no group difference in total volume of fluid administration or inotrope use. Regarding utilization, there were no group differences in mean duration of vasopressor therapy, mechanical ventilation, or length of stay. Among patients who survived to discharge, standard-therapy patients spent longer in the hospital than EGDT patients (18.4 ± 15.0 vs. 14.6 ± 14.5 days, respectively, p = 0.04).

In conclusion, early goal-directed therapy reduced in-hospital mortality in patients presenting to the ED with severe sepsis or septic shock when compared with usual care. In their discussion, the authors note that “when early therapy is not comprehensive, the progression to severe disease may be well under way at the time of admission to the intensive care unit” (1376).

The Rivers trial has been cited over 11,000 times. It has been widely discussed and dissected for decades. Most importantly, it helped catalyze a then-ongoing paradigm shift of what “usual care” in sepsis is. As noted by our own Drs. Sonti and Vinayak and in their Georgetown Critical Care Top 40: “Though we do not use the ‘Rivers protocol’ as written, concepts (timely resuscitation) have certainly infiltrated our ‘standard of care’ approach.” The Rivers trial evaluated the effect of a bundle (multiple interventions). It was a relatively complex protocol, and it has been recognized that the transfusion of blood to Hgb > 10 may have caused significant harm. In aggregate, the most critical elements of the modern initial resuscitation in sepsis are early administration of antibiotics (notably not protocolized by Rivers) within the first hour and the aggressive administration of IV fluids (now usually 30cc/kg of crystalloid within the first 3 hours of presentation).

More recently, there have been three large RCTs of EGDT versus usual care and/or protocols that used some of the EGDT targets: ProCESS (2014, USA), ARISE (2014, Australia), and ProMISe (2015, UK). In general terms, EGDT provided no mortality benefit compared to usual care. Prospectively, the authors of these three trials planned a meta-analysis – the 2017 PRISM study – which concluded that “EGDT did not result in better outcomes than usual care and was associated with higher hospitalization costs across a broad range of patient and hospital characteristics.” Despite patients in the Rivers trial being sicker than those of ProCESS/ARISE/ProMISe, it was not found in the subgroup analysis of PRISM that EGDT was more beneficial in sicker patients. Overall, the PRISM authors noted that “it remains possible that general advances in the provision of care for sepsis and septic shock, to the benefit of all patients, explain part or all of the difference in findings between the trial by Rivers et al. and the more recent trials.”

Further Reading/References:
1. Rivers trial @ Wiki Journal Club
2. Rivers trial @ 2 Minute Medicine
3. “Early Goal Directed Therapy in Septic Shock” @ Life in The Fast Lane
4. Georgetown Critical Care Top 40
5. “A randomized trial of protocol-based care for early septic shock” (ProCESS). NEJM 2014.
6. “Goal-directed resuscitation for patients with early septic shock” (ARISE). NEJM 2014.
7. “Trial of early, goal-directed resuscitation for septic shock” (ProMISe). NEJM 2015.
8. “Early, Goal-Directed Therapy for Septic Shock – A Patient-level Meta-Analysis” PRISM. NEJM 2017.
9. “Hour-1 Bundle,” Surviving Sepsis Campaign
10. UpToDate, “Evaluation and management of suspected sepsis and septic shock in adults”

Summary by Duncan F. Moore, MD

Image Credit: by Clinical_Cases, CC BY-SA 2.5 , via Wikimedia Commons

Week 17 – CURB-65

“Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study”

Thorax. 2003 May;58(5):377-82. [free full text]

Community-acquired pneumonia (CAP) is frequently encountered by the admitting medicine team. Ideally, the patient’s severity at presentation and risk for further decompensation should determine the appropriate setting for further care, whether as an outpatient, on an inpatient ward, or in the ICU. At the time of this 2003 study, the predominant decision aid was the 20-variable Pneumonia Severity Index. The authors of this study sought to develop a simpler decision aid for determining the appropriate level of care at presentation.

The study examined the 30-day mortality rates of adults admitted for CAP via the ED at three non-US academic medical centers (data from three previous CAP cohort studies). 80% of the dataset was analyzed as a derivation cohort – meaning it was used to identify statistically significant, clinically relevant prognostic factors that allowed for mortality risk stratification. The resulting model was applied to the remaining 20% of the dataset (the validation cohort) in order to assess the accuracy of its predictive ability.

The following variables were integrated into the final model (CURB-65):

      1. Confusion
      2. Urea > 19mg/dL (7 mmol/L)
      3. Respiratory rate ≥ 30 breaths/min
      4. low Blood pressure (systolic BP < 90 mmHg or diastolic BP < 60 mmHg)
      5. age ≥ 65

1068 patients were analyzed. 821 (77%) were in the derivation cohort. 86% of patients received IV antibiotics, 5% were admitted to the ICU, and 4% were intubated. 30-day mortality was 9%. 9 of 11 clinical features examined in univariate analysis were statistically significant (see Table 2).

Ultimately, using the above-described CURB-65 model, in which 1 point is assigned for each clinical characteristic, patients with a CURB-65 score of 0 or 1 had 1.5% mortality, patients with a score of 2 had 9.2% mortality, and patients with a score of 3 or more had 22% mortality. Similar values were demonstrated in the validation cohort. Table 5 summarizes the sensitivity, specificity, PPVs, and NPVs of each CURB-65 score for 30-day mortality in both cohorts. As we would expect from a good predictive model, the sensitivity starts out very high and decreases with increasing score, while the specificity starts out very low and increases with increasing score. For the clinical application of their model, the authors selected the cut points of 1, 2, and 3 (see Figure 2).

In conclusion, CURB-65 is a simple 5-variable decision aid that is helpful in the initial stratification of mortality risk in patients with CAP.

The wide range of specificities and sensitivities at different values of the CURB-65 score makes it a robust tool for risk stratification. The authors felt that patients with a score of 0-1 were “likely suitable for home treatment,” patients with a score of 2 should have “hospital-supervised treatment,” and patients with score of  ≥ 3 had “severe pneumonia” and should be admitted (with consideration of ICU admission if score of 4 or 5).

Following the publication of the CURB-65 Score, the creator of the Pneumonia Severity Index (PSI) published a prospective cohort study of CAP that examined the discriminatory power (area under the receiver operating characteristic curve) of the PSI vs. CURB-65. His study found that the PSI “has a higher discriminatory power for short-term mortality, defines a greater proportion of patients at low risk, and is slightly more accurate in identifying patients at low risk” than the CURB-65 score.

Expert opinion at UpToDate prefers the PSI over the CURB-65 score based on its more robust base of confirmatory evidence. Of note, the author of the PSI is one of the authors of the relevant UpToDate article. In an important contrast from the CURB-65 authors, these experts suggest that patients with a CURB-65 score of 0 be managed as outpatients, while patients with a score of 1 and above “should generally be admitted.”

Further Reading/References:
1. Original publication of the PSI, NEJM (1997)
2. PSI vs. CURB-65 (2005)
3. CURB-65 @ Wiki Journal Club
4. CURB-65 @ 2 Minute Medicine
5. UpToDate, “CAP in adults: assessing severity and determining the appropriate level of care”

Summary by Duncan F. Moore, MD

Week 16 – National Lung Screening Trial (NLST)

“Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening”

by the National Lung Cancer Screening Trial (NLST) Research Team

N Engl J Med. 2011 Aug 4;365(5):395-409 [free full text]

Despite a reduction in smoking rates in the United States, lung cancer remains the number one cause of cancer death in the United States as well as worldwide. Earlier studies of plain chest radiography for lung cancer screening demonstrated no benefit, and in 2002 the National Lung Screening Trial (NLST) was undertaken to determine whether then recent advances in CT technology could lead to an effective lung cancer screening method.

The study enrolled adults age 55-74 with 30+ pack-years of smoking (if former smokers, they must have quit within the past 15 years). Patients were randomized to either the intervention of three annual screenings for lung cancer with low-dose CT or to the comparator/control group to receive three annual screenings for lung cancer with PA chest radiograph. The primary outcome was mortality from lung cancer. Notable secondary outcomes were all-cause mortality and the incidence of lung cancer.

53,454 patients were randomized, and both groups had similar baseline characteristics. The low-dose CT group sustained 247 deaths from lung cancer per 100,000 person-years, whereas the radiography group sustained 309 deaths per 100,000 person-years. A relative reduction in rate of death by 20.0% was seen in the CT group (95% CI 6.8 – 26.7%, p = 0.004). The number needed to screen with CT to prevent one lung cancer death was 320. There were 1877 deaths from any cause in the CT group and 2000 deaths in the radiography group, so CT screening demonstrated a risk reduction of death from any cause of 6.7% (95% CI 1.2% – 13.6%, p = 0.02). Incidence of lung cancer in the CT group was 645 per 100,000 person-years and 941 per 100,000 person-years in the radiography group (RR 1.13, 95% CI 1.03 – 1.23).

Lung cancer screening with low-dose CT scan in high-risk patients provides a significant mortality benefit. This trial was stopped early because the mortality benefit was so high. The benefit was driven by the reduction in deaths attributed to lung cancer, and when deaths from lung cancer were excluded from the overall mortality analysis, there was no significant difference among the two arms. Largely on the basis of this study, the 2013 USPSTF guidelines for lung cancer screening recommend annual low-dose CT scan in patients who meet NLST inclusion criteria. However, it must be noted that, even in the “ideal” circumstances of this trial performed at experienced centers, 96% of abnormal CT screening results in this trial were actually false positives. Of all positive results, 11% led to invasive studies.

Per UpToDate, since NSLT, there have been several European low-dose CT screening trials published. However, all but one (NELSON) appear to be underpowered to demonstrate a possible mortality reduction. Meta-analysis of all such RCTs could allow for further refinement in risk stratification, frequency of screening, and management of positive screening findings.

No randomized trial has ever demonstrated a mortality benefit of plain chest radiography for lung cancer screening. The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial tested this modality vs. “community care,” and because the PLCO trial was ongoing at the time of creation of the NSLT, the NSLT authors trial decided to compare their intervention (CT) to plain chest radiography in case the results of plain chest radiography in PLCO were positive. Ultimately, they were not.

Further Reading:
1. USPSTF Guidelines for Lung Cancer Screening (2013)
2. NLST @ ClinicalTrials.gov
3. NLST @ Wiki Journal Club
4. NLST @ 2 Minute Medicine
5. UpToDate, “Screening for lung cancer”

Summary by Duncan F. Moore, MD

Image Credit: Yale Rosen, CC BY-SA 2.0, via Wikimedia Commons

Week 15 – COPERNICUS

“Effect of carvedilol on survival in severe chronic heart failure”

by the Carvedilol Prospective Randomized Cumulative Survival (COPERNICUS) Study Group

N Engl J Med. 2001 May 31;344(22):1651-8. [free full text]

We are all familiar with the role of beta-blockers in the management of heart failure with reduced ejection fraction. In the late 1990s, a growing body of excellent RCTs demonstrated that metoprolol succinate, bisoprolol, and carvedilol improved morbidity and mortality in patients with mild to moderate HFrEF. However, the only trial of beta-blockade (with bucindolol) in patients with severe HFrEF failed to demonstrate a mortality benefit. In 2001, the COPERNICUS trial further elucidated the mortality benefit of carvedilol in patients with severe HFrEF.

The study enrolled patients with severe CHF (NYHA class III-IV symptoms and LVEF < 25%) despite “appropriate conventional therapy” and randomized them to treatment with carvedilol with protocolized uptitration (in addition to pt’s usual meds) or placebo with protocolized uptitration (in addition to pt’s usual meds). The major outcomes measured were all-cause mortality and the combined risk of death or hospitalization for any cause.

2289 patients were randomized before the trial was stopped early due to higher than expected survival benefit in the carvedilol arm. Mean follow-up was 10.4 months. Regarding mortality, 190 (16.8%) of placebo patients died, while only 130 (11.2%) of carvedilol patients died (p = 0.0014) (NNT = 17.9). Regarding mortality or hospitalization, 507 (44.7%) of placebo patients died or were hospitalized, but only 425 (36.8%) of carvedilol patients died or were hospitalized (NNT = 12.6). Both outcomes were found to be of similar directions and magnitudes in subgroup analyses (age, sex, LVEF < 20% or >20%, ischemic vs. non-ischemic CHF, study site location, and no CHF hospitalization within year preceding randomization).

Implication/Discussion:
In severe HFrEF, carvedilol significantly reduces mortality and hospitalization risk.

This was a straightforward, well-designed, double-blind RCT with a compelling conclusion. In addition, the dropout rate was higher in the placebo arm than the carvedilol arm! Despite longstanding clinician fears that beta-blockade would be ineffective or even harmful in patients with already advanced (but compensated) HFrEF, this trial definitively established the role for beta-blockade in such patients.

Per the 2013 ACCF/AHA guidelines, “use of one of the three beta blockers proven to reduce mortality (e.g. bisoprolol, carvedilol, and sustained-release metoprolol succinate) is recommended for all patients with current or prior symptoms of HFrEF, unless contraindicated.”

Please note that there are two COPERNICUS trials. This is the first reported study (NEJM 2001) which reports only the mortality and mortality + hospitalization results, again in the context of a highly anticipated trial that was terminated early due to mortality benefit. A year later, the full results were published in Circulation, which described findings such as a decreased number of hospitalizations, fewer total hospitalization days, fewer days hospitalized for CHF, improved subjective scores, and fewer serious adverse events (e.g. sudden death, cardiogenic shock, VT) in the carvedilol arm.

Further Reading/References:
1. 2013 ACCF/AHA Guideline for the Management of Heart Failure
2. 2017 ACC/AHA/HFSA Focused Update of the 2013 ACCF/AHA Guideline for the Management of Heart Failure
3. COPERNICUS, 2002 Circulation version
4. Wiki Journal Club (describes 2001 NEJM, cites 2002 Circulation)
5. 2 Minute Medicine (describes and cites 2002 Circulation)

Summary by Duncan F. Moore, MD

Week 14 – IDNT

“Renoprotective Effect of the Angiotensin-Receptor Antagonist Irbesartan in Patients with Nephropathy Due to Type 2 Diabetes”

aka the Irbesartan Diabetic Nephropathy Trial (IDNT)

N Engl J Med. 2001 Sep 20;345(12):851-60. [free full text]

Diabetes mellitus is the most common cause of ESRD in the US. In 1993, a landmark study in NEJM demonstrated that captopril (vs. placebo) slowed the deterioration in renal function in patients with T1DM. However, prior to this 2002 study, no study had addressed definitively whether a similar improvement in renal outcomes could be achieved with RAAS blockade in patients with T2DM. Irbesartan (Avapro) is an angiotensin II receptor blocker that was first approved in 1997 for the treatment of hypertension. Its marketer, Bristol-Meyers Squibb, sponsored this trial in hopes of broadening the market for its relatively new drug.

This trial randomized patients with T2DM, hypertension, and nephropathy (per proteinuria and elevated Cr) to treatment with either irbesartan, amlodipine, or placebo. The drug in each arm was titrated to achieve a target SBP ≤ 135, and all patients were allowed non-ACEi/non-ARB/non-CCB drugs as needed. The primary outcome was a composite of the doubling of serum Cr, onset of ESRD, or all-cause mortality. Secondary outcomes included individual components of the primary outcome and a composite cardiovascular outcome.

1715 patients were randomized. The mean blood pressure after the baseline visit was 140/77 in the irbesartan group, 141/77 in the amlodipine group, and 144/80 in the placebo group (p = 0.001 for pairwise comparisons of MAP between irbesartan or amlodipine and placebo). Regarding the primary composite renal endpoint, the unadjusted relative risk was 0.80 (95% CI 0.66-0.97, p = 0.02) for irbesartan vs. placebo, 1.04 (95% CI 0.86-1.25, p = 0.69) for amlodipine vs. placebo, and 0.77 (0.63-0.93, p = 0.006) for irbesartan vs. amlodipine. The groups also differed with respect to individual components of the primary outcome. The unadjusted relative risk of creatinine doubling was 33% lower among irbesartan patients than among placebo patients (p = 0.003) and was 37% lower than among amlodipine patients (p < 0.001). The relative risks of ESRD and all-cause mortality did not differ significantly among the groups. There were no significant group differences with respect to the composite cardiovascular outcome. Importantly, a sensitivity analysis was performed which demonstrated that the conclusions of the primary analysis were not impacted significantly by adjustment for mean arterial pressure achieved during follow-up.

In summary, irbesartan treatment in T2DM resulted in superior renal outcomes when compared to both placebo and amlodipine. This beneficial effect was independent of blood pressure lowering. This was a well-designed, double-blind, randomized, controlled trial. However, it was industry-sponsored, and in retrospect, its choice of study drug seems quaint. The direct conclusion of this trial is that irbesartan is renoprotective in T2DM. In the discussion of IDNT, the authors hypothesize that “the mechanism of renoprotection by agents that block the action of angiotensin II may be complex, involving hemodynamic factors that lower the intraglomerular pressure, the beneficial effects of diminished proteinuria, and decreased collagen formation that may be related to decreased stimulation of transforming growth factor beta by angiotensin II.” In September 2002, on the basis of this trial, the FDA broadened the official indication of irbesartan to include the treatment of type 2 diabetic nephropathy. This trial was published concurrently in NEJM with the RENAAL trial [https://www.wikijournalclub.org/wiki/RENAAL]. RENAAL was a similar trial of losartan vs. placebo in T2DM and demonstrated a similar reduction in the doubling of serum creatinine as well as a 28% reduction in progression to ESRD. In conjunction with the original 1993 ACEi in T1DM study, these two 2002 ARB in T2DM studies led to the overall notion of a renoprotective class effect of ACEis/ARBs in diabetes. Enalapril and lisinopril’s patents expired in 2000 and 2002, respectively. Shortly afterward, generic, once-daily ACE inhibitors entered the US market. Ultimately, such drugs ended up commandeering much of the diabetic-nephropathy-in-T2DM market share for which irbesartan’s owners had hoped.

Further Reading/References:
1. “The effect of angiotensin-converting-enzyme inhibition on diabetic nephropathy. The Collaborative Study Group.” NEJM 1993.
2. CSG Captopril Trial @ Wiki Journal Club
3. IDNT @ Wiki Journal Club
4. IDNT @ 2 Minute Medicine
5. US Food and Drug Administration, New Drug Application #020757
6. RENAAL @ Wiki Journal Club
7. RENAAL @ 2 Minute Medicine

Summary by Duncan F. Moore, MD

Image Credit: Skirtick, CC BY-SA 4.0, via Wikimedia Commons