Week 15 – TRICC

“A Multicenter, Randomized, Controlled Clinical Trial of Transfusion Requirements in Critical Care”

N Engl J Med. 1999 Feb 11; 340(6): 409-417. [free full text]

Although intuitively a hemoglobin closer to normal physiologic concentration seems like it would be beneficial, the vast majority of the time in inpatient settings we use a hemoglobin concentration of >7g/dL as our threshold for transfusion in anemia. Historically, higher hemoglobin cutoffs were used, often aiming to keep Hgb >10g/dL. In 1999, the landmark TRICC trial was published showing no mortality benefit in the liberal transfusion strategy and even harm in certain subgroup analysis.

Population:

Inclusion: critically ill patients expected to be in ICU > 24h, Hgb ≤ 9g/dL within 72hr of ICU admission, and clinically euvolemic after fluid resuscitation

Exclusion criteria: age < 16, inability to receive blood products, active bleed, chronic anemia, pregnancy, brain death, consideration of withdrawal of care, and admission after routine cardiac procedure.

Intervention: liberal strategy (transfuse to Hgb goal 10-12g/dL, N=420)

Comparison: restrictive strategy (transfuse to Hgb goal 7-9g/dL, N=418)

Primary outcome: 30-day all-cause mortality

Secondary outcomes: 60-day all-cause mortality, mortality during hospital stay (ICU plus step-down), multiple-organ dysfunction score, change in organ dysfunction from baseline

Subgroup analyses: patients with APACHE II score ≤ 20 (i.e. less-ill patients), patients younger than 55, cardiac disease, severe infection/septic shock, and trauma

Results:
The primary outcome of 30-day mortality was similar between the two groups (18.7% vs. 23.3%, p = 0.11). Secondary outcomes of mortality rates during hospitalization were lower in the restrictive strategy (22.2% vs. 28.1%, p = 0.05). 60-day all-cause mortality trended towards lower in the restrictive strategy although did not reach statistical significance (22.7% vs. 26.5 %, p = 0.23). Between the two groups there was no significant difference in multiple-organ dysfunction score or change in organ dysfunction from baseline.

Subgroup analysis was most notable for finding statistically significant benefits for the restrictive strategy in the patients with APACHE II score ≤ 20 and patients younger than 55. In these patients, a restrictive strategy showed decrease in 30-day mortality and a lower multiple-organ dysfunction score. In the subgroups of primary disease process (i.e. cardiac disease, severe infection/septic shock, and trauma) there was no significant difference.

Complications in the ICU were monitored, and there was a significant increase in cardiac events (primarily pulmonary edema) in the liberal strategy compared to the restrictive strategy.

Discussion/Implication:
TRICC showed no difference in 30-day mortality between a restrictive and liberal transfusion strategy. Secondary outcomes were notable for a decrease in inpatient mortality with the restrictive strategy. Furthermore, subgroup analysis showed benefit in various metrics for a restrictive transfusion strategy when adjusting for younger and less-ill patients. This evidence laid the groundwork for our current standard of transfusing to hemoglobin >7g/dL. A restrictive strategy has also been supported by more recent studies. In 2014 the Transfusion Thresholds in Septic Shock (TRISS) study showed no change in 90-day mortality with a restrictive strategy. Additionally, in 2013 the Transfusion Strategy for Acute Upper Gastrointestinal Bleeding study showed reduced 40-day mortality in the restrictive strategy. However, it excluded patients who had massive exsanguination or low rebleeding risk, thus making it difficult to generalize to our patient population. Currently, the Surviving Sepsis Campaign endorses only transfusing RBCs when Hgb <7g/dL unless there are extenuating circumstances such as MI, severe hypoxemia, or active hemorrhage.

References and Further reading:
1. TRISS @ Wiki Journal Club, full text, Georgetown Critical Care Top 40 pages 14-15
2. Transfusion strategy for acute upper gastrointestinal bleeding @ Wiki Journal Club, full text
3. “Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2016”
4. Wiki Journal Club

Summary by Gordon Pelegrin, MD

Week 14 – ARDSNet aka ARMA

“Ventilation with Lower Tidal Volumes as Compared with Traditional Tidal Volumes for Acute Lung Injury and the Acute Respiratory Distress Syndrome”

by the Acute Respiratory Distress Syndrome Network (ARDSNet)

N Engl J Med. 2000 May 4;342(18):1301-8. [free full text]

Acute respiratory distress syndrome (ARDS) is an inflammatory and highly morbid lung injury found in many critically ill patients. In the 1990s, it was hypothesized that overdistention of aerated lung volumes and elevated airway pressures might contribute to the severity of ARDS, and indeed some work in animal models supported this theory. Prior to the ARDSNet study, four randomized trials had been conducted investigating the possible protective effect of ventilation with lower tidal volumes, but their results were conflicting.

Population: patients with ARDS diagnosed within < 36 hrs
Intervention: initial tidal volume 6 ml/kg predicted body weight, downtitrated as necessary to maintain plateau pressure ≤ 30 cm of water
Comparison: initial tidal volume 12 ml/kg predicted body weight, downtitrated as necessary to maintain plateau pressure ≤ 50 cm of water

Outcomes:

primary
1) in-hospital mortality
2) ventilator-free days within the first 28 days

secondary
1) number of days without organ failure
2) occurrence of barotrauma
3) reduction in IL-6 concentration from day 0 to day 3

 

Results:
861 patients were randomized before the trial was stopped early due to the increased mortality in the control arm noted during interim analysis. In-hospital mortality was 31.0% in the lower tidal volume group and 39.8% in the traditional tidal volume group (p = 0.007, NNT = 11.4). Ventilator free days were 12±11 in the lower tidal volume group vs. 10±11 in the traditional group (n = 0.007). The lower tidal volume group had more days without organ failure (15±11 vs. 12±11, p = 0.006). There was no difference in rates of barotrauma among the two groups. IL-6 concentration decrease between days 0 and 3 was greater in the low tidal volume group (p < 0.001), and IL-6 concentration at day 3 was lower in the low tidal volume group (p = 0.002).

Implication/Discussion:
Low tidal volume ventilation decreases mortality in ARDS relative to “traditional” tidal volumes.

The authors felt that this study confirmed the results of prior animal models and conclusively answered the question of whether or not low tidal volume ventilation provided a mortality benefit. In fact, in the years following, low tidal volume ventilation became the standard of care, and a robust body of literature followed this study to further delineate a “lung protective strategy.”

Critics of the study noted that at the time of the study the standard of care/“traditional” tidal volume in ARDS was less than the 12 ml/kg used in the comparison arm. (Non-enrolled patients at the participating centers were receiving a mean tidal volume of 10.3 ml/kg.) Thus not only was the trial making a comparison to a faulty control, but it was also potentially harming patients in the control arm. Here is an excellent summary of the ethical issues and debate regarding this specific issue and regarding control arms of RCTs in general.

Corresponding practice point from Dr. Sonti and Dr. Vinayak and their Georgetown Critical Care Top 40: “Low tidal volume ventilation is the standard of care in patients with ARDS (P/F < 300). Use ≤ 6 ml/kg predicted body weight, follow plateau pressures, and be cautious of mixed modes in which you set a tidal volume but the ventilator can adjust and choose a larger one.”

PulmCCM is an excellent blog, and they have a nice page reviewing this topic and summarizing some of the research and guidelines that have followed.

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. PulmCCM “Mechanical Ventilation in ARDS: Research Update”
4. Georgetown Critical Care Top 40, page 6

Summary by Duncan F. Moore, MD

Week 13 – 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.

Population: adults admitted for CAP via the ED at three non-US academic medical centers

Intervention/Comparison: none

Outcome: 30-day mortality

Additional details about methodology: This study analyzed the aggregate 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

Results:
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).


Implication/Discussion
:
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 author 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. Wiki Journal Club
4. 2 Minute Medicine
5. UpToDate, “CAP in adults: assessing severity and determining the appropriate level of care”

Summary by Duncan F. Moore, MD

Week 12 – Early Palliative Care in NSCLC

“Early Palliative Care for Patients with Metastatic Non-Small-Cell Lung Cancer”

N Engl J Med. 2010 Aug 19;363(8):733-42 [free full text]

Ideally, palliative care improves a patient’s quality of life while facilitating appropriate usage of healthcare resources. However, initiating palliative care late in a disease course or in the inpatient setting may limit these beneficial effects. This 2010 study by Temel et al. sought to demonstrate benefits of early integrated palliative care on patient-reported quality of life outcomes and resource utilization.

Population: outpatients with metastatic NSCLC diagnosed < 8 weeks ago and ECOG performance status 0-2

Intervention: “early palliative care” – met with palliative MD/ARNP within 3 weeks of enrollment and at least monthly afterward

Comparison: standard oncologic care

Outcome:

Primary – change in Trial Outcome Index (TOI) from baseline to 12 weeks

TOI = sum of the lung-cancer, physical well-being, and functional well-being subscales of the Functional Assessment of Cancer Therapy­–Lung (FACT-L) scale (scale range 0-84, higher score = better function)

Secondary

  • change in FACT-L score at 12 weeks (scale range 0-136)
  • change in lung-cancer subscale of FACT-L at 12 weeks (scale range 0-28)
  • “aggressive care,” meaning one of the following: chemo within 14 days before death, lack of hospice care, or admission to hospice ≤ 3 days before death
  • documentation of resuscitation preference in outpatient records
  • prevalence of depression at 12 weeks per HADS and PHQ-9
  • median survival

Results:
151 patients were randomized. There were no significant difference in baseline characteristics among the two groups. Palliative-care patients (n=77) had a mean TOI increase of 2.3 points, versus a 2.3-point decrease in the standard-care group (n=73) (p=0.04).

Secondary outcomes:

  • ∆ FACT-L score at 12 weeks: +4.2± 13.8 in the palliative group vs. -0.4 ±13.8 in the standard group (p=0.09 for difference between the two groups)
  • ∆ lung-cancer subscale at 12 weeks: +0.8±3.6 in palliative vs. +0.3±4.0 in standard (p=0.50)
  • aggressive end-of-life care was received in 33% of palliative patients vs. 53% of standard patients (p=0.05)
  • resuscitation preferences were documented in 53% of palliative patients vs. 28% of standard patients (p=0.05)
  • depression at 12 weeks per PHQ-9 was 4% in palliative patients vs. 17% in standard patients (p = 0.04)
  • median survival was 11.6 months in the palliative group versus 8.9 months in the standard group (p=0.02). (See Figure 3 on page 741 for the Kaplan-Meier curve.)

Implication/Discussion:
Early palliative care in patients with metastatic non-small cell lung cancer improved quality of life and mood, decreased aggressive end-of-life care, and improved survival.

This is a landmark study, both for its quantification of the quality-of-life (QoL) benefits of palliative intervention and for its seemingly counterintuitive finding that early palliative care actually improved survival.

The authors hypothesized that the demonstrated QoL and mood improvements may have led to the increased survival, as prior studies had associated lower QoL and depressed mood with decreased survival. However, I find more compelling their hypotheses that “the integration of palliative care with standard oncologic care may facilitate the optimal and appropriate administration of anticancer therapy, especially during the final months of life” and earlier referral to a hospice program may result in “better management of symptoms, leading to stabilization of [the patient’s] condition and prolonged survival.”

In practice, this study and those that followed have further spurred the integration of palliative care into many standard outpatient oncology workflows, including features such as co-located palliative care teams and palliative-focused checklists/algorithms for primary oncology providers.

Limitations of this study: 1) a complex subjective primary endpoint, 2) non-blinded, 3) single-center, minimally diverse patient population.

Further Reading/References:
1. ClinicalTrials.gov
2. Wiki Journal Club
3. Profile of first author Dr. Temel
4. UpToDate, “Benefits, services, and models of subspecialty palliative care”

Summary by Duncan F. Moore, MD

Week 11 – CAST

“Mortality and Morbidity in Patients Receiving Encainide, Flecainide, or Placebo”

The Cardiac Arrhythmia Suppression Trial (CAST) [free full text]

N Engl J Med. 1991 Mar 21;324(12):781-8.

Ventricular arrhythmias are common following MI, and studies have demonstrated that PVCs and other arrhythmias such as non-sustained ventricular tachycardia (NSVT) are independent risk factors for cardiac mortality following MI. As such, by the late 1980s, many patients with PVCs post-MI were treated with antiarrhythmic drugs in an attempt to reduce mortality. The 1991 CAST trial sought to prove what predecessor trials had failed to prove – that suppression of such rhythms post-MI would improve survival.

Population:     

·       post-MI patients with ≥ 6 asymptomatic PVCs per hour and no runs of VT ≥ 15 beats, LVEF < 55% if within 90 days of MI, or LVEF < 40% if greater than 90 days since MI

o   patients were further selected by an open-label titration period in which patients were assigned to treatment with encainide, flecainide, or moricizine

o   “responders” had at least 80% suppression of PVCs and 90% suppression of runs of VT

Intervention: continuation of antiarrhythmic drug assigned during titration period

Comparison: transition from titration antiarrhythmic drug to placebo

Outcome:

Primary – death or cardiac arrest with resuscitation “either of which was due to arrhythmia”

Secondary
1. all-cause mortality or cardiac arrest
2. cardiac death or cardiac arrest due to any cardiac cause
3. VT ≥ 15 or more beats at rate ≥ 120 bpm
4. syncope
5. permanent pacemaker implantation
6. recurrent MI
7. CHF
8. angina pectoris
9. coronary artery revascularization

Results:
The trial was terminated early due to increased mortality in the encainide and flecainide treatment groups. 1498 patients were randomized following successful titration during the open-label period, and they were reported in this paper. The results of the moricizine arm were reported later in a different paper (CAST-II).

RR of death or cardiac arrest due to arrhythmia was 2.64 (95% CI 1.60–4.36). The number needed to harm was 28.2. See Figure 1 on page 783 for a striking Kaplan-Meier curve.

RR of death or cardiac arrest due to all causes was 2.38 (95% CI 1.59–3.57). The number needed to harm was 20.6. See Figure 2 on page 784 for the relevant Kaplan-Meier curve.

Regarding the other secondary outcomes, cardiac death/arrest due to any cardiac cause was similarly elevated in the treatment group, and there were no significant differences in non-lethal endpoints among the treatment and placebo arms.

Implication/Discussion:
Treatment of asymptomatic ventricular arrhythmias with encainide and flecainide in patients with LV dysfunction following MI results in increased mortality.

This study is a classic example of how a treatment that is thought to make intuitive sense based on observational data (i.e. PVCs and NSVT are associated with cardiac death post-MI, thus reducing these arrhythmias will reduce death) can be easily and definitively disproven with a placebo-controlled trial with hard endpoints (e.g. death). Correlation does not equal causation.

Modern expert opinion at UpToDate notes no role for suppression of asymptomatic PVCs or NSVT in the peri-infarct period. Indeed such suppression may increase mortality. As noted on Wiki Journal Club, modern ACC/AHA guidelines “do not comment on the use of antiarrhythmic medications in ACS care.”

Further Reading:
1. CAST-I Trial at ClinicalTrials.gov
2. CAST-II trial publication, NEJM (1992)
3. Wiki Journal Club
4. 2 Minute Medicine
5. UpToDate “Clinical features and treatment of ventricular arrhythmias during acute myocardial infarction”

Summary by Duncan F. Moore, MD

Week 10 – MELD

“A Model to Predict Survival in Patients With End-Stage Liver Disease”

Hepatology. 2001 Feb;33(2):464-70. [free full text]

Prior to the adoption of the Model for End-Stage Liver Disease (MELD) score for the allocation of liver transplants, determination of medical urgency was dependent on the Child-Pugh score. The Child-Pugh score was limited by the inclusion of two subjective variables (severity of ascites and severity of encephalopathy), limited discriminatory ability, and a ceiling effect of laboratory abnormalities. Stakeholders sought an objective, continuous, generalizable index that more accurately and reliably represented disease severity. The MELD score had originally been developed in 2000 to estimate the survival of patients undergoing TIPS. The authors of this 2001 study hypothesized that the MELD score would accurately estimate short-term survival in a wide range of severities and etiologies of liver dysfunction and thus serve as a suitable replacement measure for the Child-Pugh score in the determination of medical urgency in transplant allocation.

This study reported a series of retrospective validation cohorts for the use of MELD in prediction of mortality in advanced liver disease.

Methods:

Populations:

  1. cirrhotic inpatients, Mayo Clinic, 1994-1999, n = 282 (see exclusion criteria)
  2. ambulatory patients with noncholestatic cirrhosis, newly-diagnosed, single-center in Italy, 1981-1984, n = 491 consecutive patients
  3. ambulatory patients with primary biliary cirrhosis, Mayo Clinic, 1973-1984, n = 326 (92 lacked all necessary variables for calculation of MELD)
  4. cirrhotic patients, Mayo Clinic, 1984-1988, n = 1179 patients with sufficient follow-up (≥ 3 months) and laboratory data

Index MELD score was calculated for each patient. Death during follow-up was assessed by chart review.

MELD score = 3.8*ln([bilirubin]) + 11.2*ln(INR) + 9.6*ln([Cr])+6.4*(etiology: 0 if cholestatic or alcoholic, 1 otherwise)

Primary study outcome was the concordance c-statistic between MELD score and 3-month survival. The c-statistic is equivalent to the area under receiver operating characteristic (AUROC). Per the authors, “a c-statistic between 0.8 and 0.9 indicates excellent diagnostic accuracy and a c-statistic greater than 0.7 is generally considered as a useful test.” (See page 455 for further explanation.)

There was no reliable comparison statistic (e.g. c-statistic of MELD vs. Child-Pugh in all groups).

Results:

Primary:

  • hospitalized Mayo patients (late 1990s): c-statistic for prediction of 3-month survival = 0.87 (95% CI 0.82-0.92)
  • ambulatory, non-cholestatic Italian patients: c-statistic for 3-month survival = 0.80 (95% CI 0.69-0.90)
  • ambulatory PBC patients at Mayo: c-statistic for 3-month survival = 0.87 (95% CI 0.83-0.99)
  • cirrhotic patients at Mayo (1980s): c-statistic for 3-month survival = 0.78 (95% CI 0.74-0.81)

Secondary:

  • There was minimal improvement in the c-statistics for 3-month survival with the individual addition of SBP, variceal bleed, ascites, and encephalopathy to the MELD score (see Table 4, highest increase in c-statistic was 0.03).
  • When the etiology of liver disease was excluded from the MELD score, there was minimal change in the c-statistics (see Table 5, all paired CIs overlap).
  • C-statistics for 1-week mortality ranged from 0.80 to 0.95.

Implication/Discussion:
The MELD score is an excellent predictor of short-term mortality in patients with end-stage liver disease of diverse etiology and severity.

Despite the retrospective nature of this study, this study represented a significant improvement upon the Child-Pugh score in determining medical urgency in patients who require liver transplant.

In 2002, the United Network for Organ Sharing (UNOS) adopted a modified version of the MELD score for the prioritization of deceased-donor liver transplants in cirrhosis.

Concurrent with the 2001 publication of this study, Wiesner et al. performed a prospective validation of the use of MELD in the allocation of liver transplantation. When published in 2003, it demonstrated that MELD score accurately predicted 3-month mortality among patients with chronic liver disease on the waitlist.

The MELD score has also been validated in other conditions such as alcoholic hepatitis, hepatorenal syndrome, and acute liver failure (see UpToDate).

Subsequent additions to the MELD score have come out over the years. In 2006, the MELD Exception Guidelines offered extra points for severe comorbidities (e.g HCC, hepatopulmonary syndrome). In January 2016, the MELDNa score was adopted and is now used for liver transplant prioritization.

References and Further Reading:
1. “A model to predict poor survival in patients undergoing transjugular intrahepatic portosystemic shunts” (2000)
2. MDCalc “MELD Score”
3. Wiesner et al. “Model for end-stage liver disease (MELD) and allocation of donor livers” (2003)
4. Freeman Jr. et al. “MELD exception guidelines” (2006) 
5. 2 Minute Medicine
6. UpToDate “Model for End-stage Liver Disease (MELD)”

Summary by Duncan F. Moore, MD

Week 9 – Bicarbonate supplementation in CKD

“Bicarbonate Supplementation Slows Progression of CKD and Improves Nutritional Status”

J Am Soc Nephrol. 2009 Sep;20(9):2075-84. [free full text]

Metabolic acidosis is a common complication of advanced CKD. Some animal models of CKD have suggested that worsening metabolic acidosis is associated with worsening proteinuria, tubulointerstitial fibrosis, and acceleration of decline of renal function. Short-term human studies have demonstrated that bicarbonate administration reduces protein catabolism and that metabolic acidosis is an independent risk factor for acceleration of decline of renal function. However, until the 2009 study by de Brito-Ashurst et al., there were no long-term studies demonstrating the beneficial effects of oral bicarbonate administration on CKD progression and nutritional status.

Population: CKD patients with CrCl 15-30ml/min and plasma bicarbonate 16-20 mEq/L

Intervention: sodium bicarbonate 600mg PO TID with protocolized uptitration to achieve plasma HCO3 ≥ 23 mEq/L, for 2 years

Comparison: routine care

Outcomes:
primary:
1) decline in CrCl at 2 years
2) “rapid progression of renal failure” (defined as decline of CrCl > 3 ml/min per year)
3) development of ESRD requiring dialysis

secondary:
1) change in dietary protein intake
2) change in normalized protein nitrogen appearance (nPNA)
3) change in serum albumin
4) change in mid-arm muscle circumference

Results:
134 patients were randomized, and baseline characteristics were similar among the two groups. Serum bicarbonate levels increased significantly in the treatment arm (see Figure 2). At two years, CrCl decline was 1.88 ml/min in the treatment group vs. 5.93 ml/min in the control group (p<0.01); rapid progression of renal failure was noted in 9% of intervention group vs. 45% of the control group (RR 0.15, 95% CI 0.06–0.40, p<0.0001, NNT = 2.8); and ESRD developed in 6.5% of the intervention group vs. 33% of the control group (RR 0.13, 95% CI 0.04–0.40, p<0.001; NNT = 3.8). Regarding nutritional status: dietary protein intake increased in the treatment group relative to the control group (p<0.007), normalized protein nitrogen appearance decreased in the treatment group and increased in the control group (p<0.002), serum albumin increased in the treatment group but was unchanged in the control group, and mean mid-arm muscle circumference increased by 1.5 cm in the intervention group vs. no change in the control group (p<0.03).

Implication/Discussion:
Oral bicarbonate supplementation in CKD patients with metabolic acidosis reduces the rate of CrCl decline and progression to ESRD and improves nutritional status.

Primarily on the basis of this study, the KDIGO 2012 guidelines for the management of CKD recommend oral bicarbonate supplementation to maintain serum bicarbonate within the normal range (23-29 mEq/L).

This is a remarkably cheap and effective intervention. Importantly, the rates of adverse events, particularly worsening hypertension and increasing edema, were unchanged among the two groups. Of note, sodium bicarbonate induces much less volume expansion than a comparable sodium load of sodium chloride.

In their discussion, the authors suggest that their results support the hypothesis of Nath et al. (1985) that “compensatory changes [in the setting of metabolic acidosis] such as increased ammonia production and the resultant complement cascade activation in remnant tubules in the declining renal mass [are] injurious to the tubulointerstitium.”

The hypercatabolic state of advanced CKD appears to be mitigated by bicarbonate supplementation. The authors note that “an optimum nutritional status has positive implications on the clinical outcomes of dialysis patients, whereas [protein-energy wasting] is associated with increased morbidity and mortality.”

Limitations to this trial include its open label, no placebo design. Also, the applicable population is limited by study exclusion criteria of morbid obesity, overt CHF, and uncontrolled HTN.

Further Reading:
1. Nath et al. “Pathophysiology of chronic tubulo-interstitial disease in rats: Interactions of dietary acid load, ammonia, and complement component-C3” (1985)
2. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (see page 89)
3. UpToDate

Summary by Duncan F. Moore, MD

Week 8 – CORTICUS

“Hydrocortisone Therapy for Patients with Septic Shock”

N Engl J Med. 2008 Jan 10;358(2):111-24. [free full text]

Steroid therapy in septic shock has been a hotly debated topic since the 1980s. The Annane trial in 2002 suggested that there was a mortality benefit to early steroid therapy and so for almost a decade this became standard of care. In 2008 the CORTICUS trial was performed suggesting otherwise.

Population:
– inclusion criteria: ICU patients with septic shock onset with past 72 hrs (defined as SBP < 90 despite fluids or need for vasopressors, and hypoperfusion or organ dysfunction from sepsis)
– exclusion criteria: “underlying disease with a poor prognosis,” life expectancy < 24hrs, immunosuppression, recent corticosteroid use

Intervention: hydrocortisone 50mg IV q6h x5 days with taper

Comparison: placebo injections q6h x5 days plus taper

Outcome:

Primary: 28 day mortality among patients who did not have a response to ACTH stim test (cortisol rise < 9mcg/dL)

Secondary:
– 28 day mortality in patients who had a positive response to ACTH stim test
– 28 day mortality in all patients
– reversal of shock (defined as SBP ≥ 90 for at least 24hrs without vasopressors) in all patients
– time to reversal of shock in all patients

Results:
In ACTH non-responders (N=233): intervention vs. control 28 day mortality was 39.2% vs. 36.1% (p=0.69)

In ACTH responders (N=254): intervention vs. control 28 day mortality was 28.8% vs. 28.7% (p=1.00); reversal of shock 84.7%% vs. 76.5% (p=0.13)

Among all patients:
– intervention vs. control 28 day mortality was 34.3% vs. 31.5% (p=0.51)
– reversal of shock 79.7% vs. 74.2% (p=0.18)
– duration of time to reversal of shock was significantly shorter among patients receiving hydrocortisone (per Kaplan-Meier analysis, p<0.001; see Figure 2), median time to reversal 3.3 days vs. 5.8 days (95% CI 5.2 – 6.9)

Discussion:
The CORTICUS trial demonstrated no mortality benefit of steroid therapy in septic shock, regardless of a patient’s response to ACTH. Despite the lack of mortality benefit, it demonstrated an earlier resolution of shock with steroids. This lack of mortality benefit sharply contrasted with the previous Annane study. Several reasons have been posited for this including poor powering of the CORTICUS study (it did not reach the desired N=800), CORTICUS inclusion starting within 72 hrs of septic shock vs. Annane starting within 8 hrs, and Annane patients generally being sicker (including their inclusion criterion of mechanical ventilation). Subsequent meta-analyses disagree about the mortality benefit of steroids, but meta-regression analyses suggest benefit among the sickest patients. All studies agree about the improvement in shock reversal. The 2016 Surviving Sepsis Campaign guidelines recommend IV hydrocortisone in septic shock in patients who continue to be hemodynamically unstable despite adequate fluid resuscitation and vasopressor therapy.

Per Drs. Sonti and Vinayak of the GUH MICU (excerpted from their excellent Georgetown Critical Care Top 40): “Practically, we use steroids when reaching for a second pressor or if there is multiorgan system dysfunction. Our liver patients may have deficient cortisol production due to inadequate precursor lipid production; use of corticosteroids in these patients represents physiologic replacement rather than adjunct supplement.”

References / Further Reading
:
1. Wiki Journal Club
2. 2 Minute Medicine
3. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock (2016), section “Corticosteroids”
4. Annane trial (2002) [free full text]
5. Georgetown Critical Care Top 40 [iTunes / iBooks link]
6. UpToDate,“Glucocorticoid therapy in septic shock”

Summary by Gordon Pelegrin, MD

Week 7 – FUO

“Fever of Unexplained Origin: Report on 100 Cases”

Medicine (Baltimore). 1961 Feb;40:1-30. [free full text]

In our modern usage, fever of unknown origin (FUO) refers to a persistent unexplained fever despite an adequate medical workup. The most commonly used criteria for this diagnosis stem from the 1961 series by Petersdorf and Beeson.

This study analyzed a prospective cohort of patients evaluated at Yale’s hospital for FUO between 1952 and 1957. Their FUO criteria: 1) illness of more than three week’s duration, 2) fever higher than 101º F on several occasions, 3) diagnosis uncertain after one week of study in hospital. After 126 cases had been noted, retrospective investigation was undertaken to determine the ultimate etiologies of the fevers. The authors winnowed this group to 100 cases based on availability of follow up data and the exclusion of cases that “represented combinations of such common entities as urinary tract infection and thrombophlebitis.”

Results:
126 cases were reviewed as noted above, and ultimately 100 were selected for analysis. In 93 cases “a reasonably certain diagnosis was eventually possible.” 6 of the 7 undiagnosed patients ultimately made a full recovery. Underlying etiology (see table 1 on page 3): infectious 36% (including TB in 11%), neoplastic diseases 19%, collagen disease (e.g. SLE) 13%, pulmonary embolism 3%, benign non-specific pericarditis 2%, sarcoidosis 2%, hypersensitivity reaction 4%, cranial arteritis 2%, periodic disease 5%, miscellaneous disease 4%, factitious fever 3%, no diagnosis made 7%.

Implication/Discussion:
Clearly, diagnostic modalities have improved markedly since this 1961 study. However, the core etiologies of infection, malignancy, and connective tissue disease / non-infectious inflammatory disease remain most prominent, while the percentage of patients with no ultimate diagnosis has been increasing (for example, see PMIDs 9413425, 12742800, and 17220753). Modifications to the 1961 criteria have been proposed (e.g. 1 week duration of hospital stay not required if certain diagnostic measures have been performed) and implemented in recent FUO trials. One modern definition of FUO: fever ≥ 38.3º C, lasting at least 2-3 weeks, with no identified cause after three days of hospital evaluation or three outpatient visits.

Per UpToDate, the following minimum diagnostic workup is recommended in suspected FUO: blood cultures, ESR or CRP, LDH, HIV, RF, heterophile antibody test, CK, ANA, TB testing, SPEP, CT of abdomen and chest.

Further Reading:
1. “Fever of unknown origin (FUO). I A. prospective multicenter study of 167 patients with FUO, using fixed epidemiologic entry criteria. The Netherlands FUO Study Group.” Medicine (Baltimore). 1997 Nov;76(6):392-400.
2. “From prolonged febrile illness to fever of unknown origin: the challenge continues.” Arch Intern Med. 2003 May 12;163(9):1033-41.
3. “A prospective multicenter study on fever of unknown origin: the yield of a structured diagnostic protocol.” Medicine (Baltimore). 2007 Jan;86(1):26-38.
4. UpToDate, “Approach to the Adult with Fever of Unknown Origin”
5. “Robert Petersdorf, 80, Major Force in U.S. Medicine, Dies” The New York Times, 2006

Summary by Duncan F. Moore, MD

Week 6 – COURAGE

“Optimal Medical Therapy with or without PCI for Stable Coronary Disease”

by the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) Trial Research Group

N Engl J Med. 2007 Apr 12;356(15):1503-16 [free full text]

The optimal medical management of stable coronary artery disease has been well-described. However, prior to the 2007 COURAGE trial, the role of percutaneous coronary intervention (PCI) in the initial management of stable coronary artery disease was unclear. It was known that PCI improved angina symptoms and short-term exercise performance in stable disease, but its mortality benefit and reduction of future myocardial infarction and ACS were unknown.

Population: US and Canadian patients with stable coronary artery disease
(See paper for inclusion/exclusion criteria. Disease had to be sufficiently and objectively severe, but not too severe, and symptoms could not be sustained at the highest CCS grade.)
Intervention: optimal medical management and PCI
(Optimal medical management included antiplatelet, anti-anginal, ACEi/ARB, and cholesterol-lowering therapy.)
Comparison: optimal medical management alone
Outcome:
1º: composite of all-cause mortality and non-fatal MI
2º: composite of all-cause mortality, non-fatal MI, and stroke, and hospitalization for unstable angina

Results:
2287 patients were randomized. Both groups had similar baseline characteristics with the exception of a higher prevalence of proximal LAD disease in the medical-therapy group. Median duration of follow-up was 4.6 years in both groups. Death or non-fatal MI occurred in 18.4% of the PCI group and in 17.8% of the medical-therapy group (p=0.62). Death, non-fatal MI, or stroke occurred in 20.0% of the PCI group and 19.5% of the medical-therapy group (p=0.62). Hospitalization for ACS occurred in 12.4% of the PCI group and 11.8% of the medical-therapy group (p=0.56). Revascularization during follow-up was performed in 21.1% of the PCI group but in 32.6% of the medical-therapy group (HR 0.60, 95% CI 0.51–0.71, p<0.001). Finally, 66% of PCI patients were free of angina at 1 year follow-up compared with 58% of medical-therapy patients (p<0.001); rates were 72% and 67% at 3 years (p=0.02) and 72% and 74% at five years (not significant).

Implication/Discussion:
In the initial management of stable coronary artery disease, PCI in addition to optimal medical management provided no mortality benefit over optimal medical management alone.

However, initial management with PCI did provide a time-limited improvement in angina symptoms.

As the authors of COURAGE nicely summarize on page 1512, the atherosclerotic plaques of ACS and stable CAD are different. Vulnerable, ACS-prone plaques have thin caps and spread outward along the wall of the coronary artery, as opposed to the plaques of stable CAD which have thick fibrous caps and are associated with inward-directed remodeling that narrows the artery lumen (and thus cause reliable angina symptoms and luminal narrowing on coronary angiography).

Notable limitations in this study: 1) the population was largely male, white, and 42% came from VA hospitals, thus limiting generalizability of the study; 2) drug-eluting stents were not clinically available until the last 6 months of the study, so most stents placed were bare metal.

Later meta-analyses were weakly suggestive of an association of PCI with improved all-cause mortality. It is thought that there may be a subset of patients with stable CAD who achieve a mortality benefit from PCI. Per UpToDate, there are ongoing RCTs investigating this possibility.

It is important to note that all of the above discussions assume that the patient does not have specific coronary artery anatomy in which initial CABG would provide a mortality benefit (e.g. left main disease, multi-vessel disease with decreased LVEF). Finally, PCI should be considered in patients whose physical activity is limited by angina symptoms despite optimal medical therapy.

Further Reading:
1. Wiki Journal Club
2. 2 Minute Medicine
3. Canadian Cardiovascular Society grading of angina pectoris
4. https://www.uptodate.com/contents/stable-ischemic-heart-disease-indications-for-revascularization

Summary by Duncan F. Moore, MD