Recent Research

Swallowing screens after acute stroke, cardiac complications in CAP, and more.

Review finds four swallowing screens effective after acute stroke

Four swallowing screening protocols were found to be effective after acute stroke, according to a recent review.

Researchers from the University of Washington in Seattle performed a systematic review to determine how many existing swallowing screening protocols could be considered reliable, valid and feasible. The authors first searched MEDLINE for English-language studies published through Aug. 12, 2011. Supplemental searches included CINAHL, EMBASE and the Cochrane Library; reference lists of relevant papers and guidelines; and manual searches of journals' tables of contents. Protocols were determined to meet the authors' basic quality criteria if they:

  • defined screening as preliminary assessment by a health care worker of whether oral intake appeared safe for a patient at a particular moment in time;
  • did not require special training or skills in dysphagia;
  • included reliability data;
  • specified a gold standard of dysphagia or aspiration;
  • included a detailed enough description to allow duplication; and
  • evaluated patients with acute stroke.

The study results were published in the March Stroke.

The authors identified 35 swallowing screening protocols but determined that only four met their basic quality criteria: The Barnes Jewish Hospital Stroke Dysphagia Screen, the Modified Mann Assessment of Swallowing Ability, the Emergency Physician Swallowing Screening, and the Toronto Bedside Swallowing Screening Test. All of these had sensitivities of at least 87% and negative predictive values of at least 91% compared to the gold standard of a formal swallowing evaluation. However, the Emergency Physician Screen and the Modified Mann Assessment of Swallowing Ability were based on small sample sizes and had been “self-characterized” as preliminary. Of the remaining two protocols, the Barnes Jewish Hospital Stroke Dysphagia Screen was the most thoroughly validated, and, unlike the Toronto Bedside Swallowing Test, it is not copyrighted.

The authors acknowledged that their search may have missed or excluded relevant articles, but they concluded that the number of robust published swallowing screening protocols is limited. They also noted that performing a high-quality study of a swallowing screening protocol is difficult because it is hard to train all clinicians to perform such screening. In addition, screening and the gold standard test may be performed at different times, yielding different results. The authors wrote that their study did not look at how the swallowing protocols affected outcomes, including pneumonia, length of stay, and morbidity and mortality. They called for future studies to examine the cost-effectiveness of swallowing screening in patients with acute stroke, the risks of false-positive results, and the availability of effective interventions in patients identified as high risk via a screening protocol. “Only through such efforts will the use of swallowing screens in patients after acute stroke be established as evidence-based,” the authors concluded.

Cardiac complications are common in community-acquired pneumonia, study finds

Cardiac complications are frequently seen in patients with community-acquired pneumonia (CAP) and may increase short-term mortality, according to a recent study.

Researchers analyzed data from the prospective Pneumonia Patient Outcomes Team (PORT) cohort study, which involved patients who presented with CAP at one of five medical centers in Pittsburgh, Boston, and Halifax, Nova Scotia from October 1991 to March 1994. Patients included in the PORT study had to have given informed consent and had to be at least 18 years of age, have radiographic evidence of pneumonia within 24 hours of presentation, and have at least one acute symptom that suggested pneumonia. The study's main outcome measures were type, timing and frequency of incident cardiac complications; risk factors; and the association of all of the preceding with short-term mortality. The study results were published in the Feb. 14 Circulation.

Overall, the study followed 1,343 inpatients and 944 outpatients with CAP for 30 days after their presentation. Three hundred fifty-eight inpatients (26.7%) and 20 outpatients (2.1%) developed incident cardiac complications, defined as new or worsening heart failure or arrhythmias or myocardial infarction. Most events were diagnosed in the first week after presentation, and more than half were diagnosed in the first 24 hours. Of note, 84% of patients with cardiac complications had sepsis at presentation. After adjustment for pneumonia severity index score at baseline, incident cardiac complications were significantly associated with a higher risk for death at 30 days (odds ratio [OR], 1.6). Patients were more likely to be diagnosed with a cardiac complication if they had the following characteristics, each of which was statistically significant:

  • older age (OR, 1.03),
  • nursing home residence (OR, 1.8),
  • history of heart failure (OR, 4.3),
  • history of cardiac arrhythmia (OR, 1.8),
  • previous diagnosis of coronary artery disease (OR, 1.5),
  • arterial hypertension (OR, 1.5),
  • respiratory rate of 30 breaths/min or higher (OR, 1.6),
  • blood pH less than 7.35 (OR, 3.2),
  • blood urea nitrogen level of 30 mg/dL or greater (OR, 1.5),
  • serum sodium level less than 130 mmol/L (OR, 1.8),
  • hematocrit less than 30% (OR, 2.0),
  • pleural effusion on chest X-ray at presentation (OR, 1.6) or
  • inpatient care (OR, 4.8).

The authors acknowledged that some of the patients in their study may have been misclassified as having incident heart failure, that diagnosis of myocardial infarction may have been underestimated, and that information on antibiotic therapy was not available. They also noted that management of chronic conditions and cardiac events has improved since the PORT study was conducted and that therefore some of these incident events would have been prevented with current standards of care.

However, they concluded that patients with CAP—especially older patients, those who live in nursing homes, and those with preexisting cardiovascular disease or more severe pneumonia—are at risk for incident cardiac complications and that such complications can increase short-term mortality rates. They called for increased efforts to prevent pneumonia in high-risk patients via influenza and pneumococcal vaccination, as well as further studies to determine which drugs can best prevent cardiac complications in patients with CAP.

Analyses differ on whether dabigatran raises MI risk

Two recent analyses compared rates of myocardial infarction (MI) in patients taking dabigatran or warfarin and came to differing results.

Initial reports from the RE-LY trial had indicated that in patients with atrial fibrillation, dabigatran could be associated with an elevated rate of MI, although a post-publication reanalysis authorized by the FDA concluded that the difference was not significant. In an article published in the Feb. 7 Circulation, researchers used data from RE-LY to specifically compare rates of MI, unstable angina, cardiac arrest and cardiac death between patients taking dabigatran and those on warfarin. Of the 18,113 patients in the study, MI occurred in 98 patients on 110 mg of dabigatran, 97 patients on 150 mg of dabigatran, and 75 patients on warfarin. This worked out to annual event rates of 0.82%, 0.81% and 0.64%, a nonsignificant difference (P≥0.09 for comparison between dabigatran and warfarin).

The analysis also compared the drugs on the composite of adverse events (MI, unstable angina, cardiac arrest, cardiac death), and found annual rates of 3.16% with 110 mg of dabigatran, 3.33% for 150 mg of dabigatran and 3.41% for warfarin, also a nonsignificant difference. When the outcome was expanded to include strokes, systemic embolism, pulmonary embolism, major bleeding and all-cause death (which were the pre-specified “net clinical benefit” events included in the RE-LY trial), annual rates were 7.34% for 110 mg of dabigatran, 7.11% for 150 mg of dabigatran and 7.91% for warfarin. The difference between the 150 mg dose and warfarin was statistically significant (P=0.03). The researchers also divided patients by presence or absence of history of coronary artery disease or MI, and they found no difference in the relative effects of the drugs.

Based on the results, the authors concluded that dabigatran was associated with a nonsignificant increase in MI compared to warfarin, but no increase in other myocardial ischemic events. However, they cautioned that the outcomes included in this analysis were not prespecified and that the RE-LY trial was not powered to detect a difference in rates of MI between the various treatments. Still, given that dabigatran was associated with lower rates of the combined outcomes measured by the RE-LY trial, any possible increase in MI is likely to be outweighed by the other benefits of the drug, the authors concluded.

However, a meta-analysis published in the March 12 Archives of Internal Medicine concluded that dabigatran was associated with a significantly higher risk of MI and acute coronary syndrome (ACS). This analysis combined data from the RE-LY trial with six other trials comparing dabigatran with warfarin, enoxaparin, or placebo for stroke prophylaxis in atrial fibrillation, ACS, acute venous thromboembolism, and short-term prophylaxis of deep venous thrombosis. Overall, patients on dabigatran had significantly more cases of MI or ACS than those taking any of the other drugs (dabigatran, 237 events in 20,000 patients [1.19%] vs. control, 83 events in 10,514 patients [0.79%]; odds ratio, 1.33; P=0.03). The authors noted that the mechanism behind this association is unknown. They speculated, “Dabigatran might not directly increase the risk of MI, but it may lack the beneficial effects that warfarin and aspirin have in MI prevention.” Similar to the conclusion of the Circulation analysis, the researchers noted that the stroke prevention effects of dabigatran make it beneficial overall for patients with atrial fibrillation. However, they called for further investigation of the drug's possible cardiac risks.

Preoperative aspirin use associated with better outcomes in cardiac surgery patients, study finds

Aspirin therapy before cardiac surgery is associated with better outcomes, including lower 30-day mortality, according to a recent study.

Researchers performed an observational cohort study to determine whether using aspirin before cardiac surgery helped protect against complications and death. Consecutive patients at two tertiary hospitals who were undergoing coronary artery bypass grafting and/or valve surgery or other cardiac surgery were eligible for the study, unless they were receiving anticoagulants, adenosine diphosphate receptor inhibitors, glycoprotein IIb/IIIa inhibitors, or antiplatelets preoperatively, or their preoperative aspirin use was not known. Preoperative use of aspirin was defined as aspirin use in the five days before surgery. The study's main outcomes were 30-day all-cause mortality, postoperative renal failure or dialysis, and a composite outcome of major adverse cardiocerebral events, including permanent or transient stroke, coma, perioperative myocardial infarction, heart bloc and cardiac arrest. Readmission and ICU stay were also examined. The study results were published in the February Annals of Surgery.

Overall, 2,868 patients were eligible for the study. Of these, 1,923 were using aspirin before surgery and 945 were not. Most patients (88.4%) were having CABG and/or valve surgery. Patients in the preoperative aspirin group were more likely to have comorbidities, such as hypertension, diabetes, peripheral arterial disease, previous myocardial infarction, angina, and cerebrovascular disease. They were also more likely to be older and more likely to be men. The authors found that preoperative aspirin use significantly reduced mortality risk at 30 days compared with no aspirin before surgery (3.5% vs. 6.5%; odds ratio, 0.611; P=0.031). Patients in the aspirin group also had lower rates of postoperative renal failure (3.7% vs. 7.1%; odds ratio, 0.384; P<0.001), dialysis (1.9% vs. 3.6%; odds ratio, 0.441; P<0.001), and the composite outcome (8.7% vs. 10.8%; odds ratio, 0.662; P=0.011), as well as shorter ICU stays (mean, 107.2 hours vs. 136.1 hours; P<0.001). Rates of readmission to the hospital did not differ significantly between groups (14.5% vs. 12.8%; P=0.944).

The authors acknowledged that their study was limited because of its observational design and because they had no details on aspirin dose or duration, among other factors. However, they concluded that their study showed a significant association between use of aspirin before cardiac surgery and decreased risk for major cardiocerebral complications, ICU stay, renal failure and 30-day mortality, although aspirin did not appear to affect readmission rates. “Overall, the outcome benefits provided by preoperative aspirin therapy may override its possible risk of excess bleeding in patients undergoing cardiac surgery,” they wrote. “Nonetheless, further studies are certainly needed to examine this potential side effect carefully.”

Optimal potassium level after MI differs from guidelines, study finds

Post-myocardial infarction inpatients with blood potassium levels between 3.5 and 4.5 mEq/L had a lower mortality risk than those with levels higher or lower than this range, a recent study found.

Current guidelines recommend maintaining serum potassium levels between 4.0 and 5.0 mEq/L in acute myocardial infarction (AMI) patients, but most studies on which the guidelines are based occurred before the routine use of beta-blockers, reperfusion therapy and early invasive management for eligible patients, the study authors noted. Those previous studies also focused on ventricular arrhythmias, not mortality, they said.

For their retrospective cohort study, the researchers examined data from 38,689 patients with AMI confirmed by biomarkers, who were admitted to 67 U.S. hospitals from 2000 through 2008. All patients had serum potassium measured in the hospital and were categorized by mean level after admission as <3.0, 3.0 to <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, 5.0 to <5.5 or ≥5.5 mEq/L.

Researchers found a U-shaped relationship between mean post-admission potassium level and in-hospital morality. Nearly 7% of study patients (n=2,679, or 6.9%) died during hospitalization. Compared with the reference group (3.5 to <4.0 mEq/L; mortality rate, 4.8%), the group with levels of 4.0 to <4.5 mEq/L had similar mortality (5.0%). Patients with levels of 4.5 to <5.0 mEq/L had double the mortality rate (10%), and mortality was even higher for those at 5.0 mEq/L or higher.

Mortality rates were also higher for patients with potassium levels <3.5 mEq/L. However, rates of ventricular arrhythmias or cardiac arrest were higher (compared to the reference group) only for those with the lowest and highest average potassium levels (i.e, <3.0 mEq/L and ≥5.0 mEq/L). The study was published in the Jan. 11 Journal of the American Medical Association.

The findings “challenge current clinical practice guidelines” and suggest the optimal range of potassium levels in AMI patients is between 3.5 and 4.5 mEq/L, while levels greater than 4.5 mEq/L “should probably be avoided,” the authors wrote. Editorialists largely agreed, saying potassium repletion for levels lower than 3.5 mEq/L “remains reasonable,” while repletion for levels between 3.5 mEq/L and 4.0 mEq/L doesn't seem justified—and neither does targeting levels above 4.5 mEq/L.

Hospital stays involving C. diff leveled off between 2008 and 2009

Hospital stays involving Clostridium difficile infections leveled off between 2008 and 2009 after rising 300% between 1993 and 2008, the Agency for Healthcare Research and Quality (AHRQ) reported in January.

There were 336,600 hospitalizations (about 1% of all hospital stays) involving C. diff in 2009, with nearly one-third of these cases having C. diff as the principal diagnosis. By contrast, 349,000 hospital stays involved C. diff in 2008, and 86,000 hospital stays involved the infection in 1993.

Dehydration and electrolyte disorders were the most common conditions associated with C. diff infection (CDI) stays; they were seen in 81.2% of stays. Other common, associated conditions were septicemia (26.7%), renal failure (23.6%), septic shock (8.0%) and prolonged ileus (4.7%). Septic shock was eight times more common in secondary diagnosis CDI stays than in principal diagnosis stays (11.3% vs. 1.4%). Patients with CDI hospitalizations were more severely ill than hospitalized patients in general, with 9.1% of stays ending in death compared with less than 2% of other inpatients.

Patients with CDI spent an average of 13 days in the hospital, more than eight days longer than the average hospital stay for other inpatients. CDI patients were nearly 20 years older than other inpatients, and were more likely to be covered by Medicare, be female, live in the Northeast, and have an income greater than $50,000 per year, the AHRQ brief said.

Care improves for MI patients with COPD, but gaps in treatment remain

Care has improved for patients with chronic obstructive pulmonary disease (COPD) who are hospitalized for acute myocardial infarction (MI), but they are still less likely to receive certain therapies than acute MI patients without COPD, according to a recent study.

Researchers used data from the Worcester Heart Attack Study to determine differences in clinical characteristics, outcomes and treatment in patients with and without COPD who were hospitalized for acute MI at medical centers in Worcester, Mass., from 1997 to 2007. Demographics, length of stay, symptoms at presentation, medical history, characteristics of acute MI, laboratory measurements, discharge status and complications were all examined, and use of therapies including cardiac medications, cardiac catheterization, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) was determined. A patient was considered to have COPD if his or her medical record described clinical or radiographic evidence of the disorder. Researchers looked for differences in demographics, clinical characteristics, and treatments received in patients with COPD versus those without. The association of COPD with mortality and complication rates was also determined. The study results were published online Dec. 29 by Chest.

Overall, 17% of the 6,290 patients hospitalized for acute MI during the study period also had COPD. More than half (56%) of all patients were men, and the average age was 71 years. Patients with acute MI who also had COPD were less likely to receive interventional procedures during their initial hospitalization and were also less likely to receive beta-blockers or lipid-lowering therapy.

Risk for death was higher during hospitalization and 30 days after discharge for patients with COPD than for those without (13.5% vs. 10.1% and 18.7% vs. 13.2%, respectively), and outcomes for patients with COPD did not improve over the study period. The authors found that COPD continued to have a negative effect on in-hospital and 30-day mortality rates (odds ratios, 1.25 and 1.31, respectively) after adjustment for multiple variables. However, they also found that use of evidence-based therapies increased in all patients with acute MI over the study period, especially use of beta-blockers and cardiac catheterization in those who also had COPD.

The authors acknowledged that their study did not include information on pulmonary function testing and so could not confirm COPD diagnoses or determine disease severity. However, they concluded that although use of guideline-recommended therapy improved in all acute MI patients and in patients with both acute MI and COPD from 1997 to 2007, differences in treatment persisted and the outcomes of patients with AMI and underlying COPD did not improve.

“The older age, higher number of comorbidities, and overlap between the respiratory and cardiac symptoms in patients with [acute] MI and COPD have important implications for management of these complex patients,” the authors wrote. “Physicians may consider patients with COPD at high risk for complications and they may be hesitant to recommend cardiac catheterization and PCI although these patients may equally benefit from the receipt of these more aggressive, but evidence-based interventions.”

The authors called for increased education for specialists and general internists to help improve assessment and management of cardiovascular risk at the time of COPD diagnosis. Clinicians should not “focus on the pulmonary disease in isolation,” they wrote. “Careful consideration is necessary to treat established cardiovascular risk factors and optimize cardiac therapies in patients with COPD.”

Prophylaxis after discharge doesn't reduce VTE rates in high-risk patients

Venous thromboembolism (VTE) prophylaxis in high-risk medical service patients didn't reduce rates of symptomatic VTE in the 90 days after hospital discharge, a study found.

Researchers identified a case group of 461 consecutive hospitalized medical service patients with a discharge VTE risk score of three or more points (score based on eight common, weighted risk factors). The patients had been prescribed parenteral pharmacological VTE prophylaxis with low-molecular-weight heparin or unfractionated heparin (UFH), which was ordered to continue after discharge.

The case group was matched to a control group of 922 patients who got prophylaxis in the hospital, but didn't continue with it after discharge. Researchers followed up after 90 days, with the primary endpoint being incidence of symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) confirmed by imaging. Study results were published in the December 2011 American Journal of Medicine.

Symptomatic VTE at 90 days occurred in 5% of patients who received prophylaxis after discharge and 4.3% of patients who didn't (P=0.58). More patients in the former group had died at 90 days compared to the latter group (56.8% vs. 68.4%, P<0.001); malignancy was the most common cause of death in all patients. Major bleeding occurred more often in patients who received prophylaxis after discharge (3.9% vs. 1.9%, P=0.03); the duration of hospitalization was also longer in this group (9.1 days vs. 5.7 days, P<0.001). The prophylaxis-after-discharge group had more comorbidities of nonpulmonary infection, recent hospitalization, and brain cancers; while the other group had more leukemia. Those who received prophylaxis after discharge were most commonly prescribed enoxaparin (67.5%), then UFH (31.2%) and fondaparinux (0.9%).

Poorer outcomes in the extended prophylaxis group may reflect more acutely ill patients in this group, as suggested by longer lengths of stay and a higher incidence of all-cause mortality, the authors said. “Extended prophylaxis may be a proxy for patients who are particularly ill and destined for a high rate of adverse outcomes after hospital discharge,” they wrote. Regardless, the results do not support prescribing prophylaxis after discharge, though more research is needed to see if specific types of patients might benefit, they said.