American College of Physicians: Internal Medicine — Doctors for Adults ®

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ACP InternistWeekly



In the News for the Week of July 10, 2012




Highlights

Insulin injections, infusion pumps offer similar glucose control

Continuous insulin provides comparable glycemic control to injections, while continuous glucose monitoring is slightly superior to self-monitoring, a meta-analysis concluded. More...

MRSA rates in the U.S. appear to be decreasing, study indicates

Rates of methicillin-resistant Staphylococcus aureus (MRSA) appear to be decreasing in the U.S., according to a new study. More...


Test yourself

MKSAP Quiz: sudden onset of vertigo

This week's quiz asks readers to evaluate a 79-year-old man who presents to the emergency department with vertigo that began suddenly about 1 hour before, associated with severe nausea and vomiting. More...


Nephrology

Combination of creatinine and cystatin C more accurate than either alone for GFR

Combining creatinine and cystatin C measurements provided a more accurate estimation of glomerular filtration rate (GFR) than using either measurement alone, a new study found. More...


Geriatrics

Postoperative delirium associated with long-term cognitive impairment

Delirium after cardiac surgery occurred in nearly half of elderly patients and was associated with lower cognitive function postoperatively, a new study found. More...


Preventive care

Zoster vaccination didn't cause infection in patients on biologics

The herpes zoster vaccine reduced the incidence of herpes zoster infection in patients with immune-mediated disease, a new study found. More...


From the College

Upcoming immunization webinar on communicating risk-benefit of vaccination

ACP will host a webinar on communicating the risks and benefits of vaccination to patients on July 18 at noon as part of the ACP immunization webinar series. More...

New high-value, cost-conscious care curriculum available for internal medicine residents

ACP and the Alliance for Academic Internal Medicine (AAIM) have developed and released a curriculum for training internal medicine residents to practice high-value, cost-conscious care. More...


Cartoon caption contest

Put words in our mouth

ACP InternistWeekly wants readers to create captions for our new cartoon and help choose the winner. Pen the winning caption and win a $50 gift certificate good toward any ACP product, program or service. More...


Physician editor: Philip Masters, MD, FACP



Highlights


.
Insulin injections, infusion pumps offer similar glucose control

Continuous insulin provides comparable glycemic control to injections, while continuous glucose monitoring is slightly superior to self-monitoring, a meta-analysis concluded.

Researchers conducted a meta-analysis of 33 randomized controlled trials in children or adults with type 1 or 2 diabetes. Results of the study, funded by the Agency for Healthcare Research and Quality, were published online July 10 by Annals of Internal Medicine.

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In adults with type 1 diabetes, hemoglobin A1c (HbA1c) decreased more with continuous subcutaneous insulin infusion (CSII) than with multiple daily injections (MDIs), but study authors noted that results were heavily influenced by one study where participants had higher HbA1c values at enrollment. This allowed for greater HbA1c lowering compared with other studies where participants were closer to the target at enrollment. Glycemic control and hypoglycemia were similar for the two methods for patients with type 2 disease.

The researchers noted, "In comparison with MDI, CSII yielded better satisfaction with diabetes treatment in children with type 1 diabetes, and better diabetes-specific QOL [quality of life] in adults with type 1 diabetes, but the strength of evidence on QOL effects was low. The evidence was insufficient to draw definitive conclusions about other non-glycemic outcomes."

Compared with self-monitoring of blood glucose (SMBG), real-time continuous glucose monitoring (rt-CGM) was associated with lower HbA1c values (between-arm difference of change, −0.26%; 95% CI, −0.33% to −0.19%), without any difference in severe hypoglycemia. The difference in HbA1c was statistically significant but smaller than the 0.5% difference researchers defined as clinically meaningful.

Patients with type 1 diabetes who used a sensor-augmented insulin pump had a statistically and clinically significant greater reduction in HbA1c than those using MDI/SMBG (between-arm difference in HbA1c reduction, −0.68%; 95% CI, −0.81% to −0.54%). The evidence was insufficient to draw definitive conclusions about pumps' effects on severe hypoglycemia or quality of life, the authors said.

They concluded, "From a patient-focused perspective, CSII yielded better satisfaction with diabetes treatment in children with type 1 diabetes, and better diabetes-specific QOL in adults with type 1 diabetes. These data suggest that the approach to intensive insulin therapy can be individualized to patient preference that will maximize their treatment satisfaction and QOL, as both MDI and rapid-acting analog-based CSII have similar effectiveness for glycemic control."


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MRSA rates in the U.S. appear to be decreasing, study indicates

Rates of methicillin-resistant Staphylococcus aureus (MRSA) appear to be decreasing in the U.S., according to a new study.

Researchers used data from U.S. Department of Defense beneficiaries to examine incidence and trends of community- and hospital-onset S. aureus bacteremia and skin and soft-tissue infections (SSTIs), including the proportion due to MRSA. Beneficiaries included active duty members, retirees, guards and reservists, and their immediate family. S. aureus blood, wound or abscess cultures were classified as community- or hospital-onset infections and as methicillin-susceptible S. aureus or MRSA. Main outcome measures were unadjusted incidence rates per 100,000 person-years, proportion of infections due to MRSA, and annual trends. The study results appeared in the July 4 Journal of the American Medical Association.

The Department of Defense databases included 62,326 positive blood cultures and 181,317 positive wound or abscess cultures from 2005 through 2010. Among these, 12% of blood cultures and 62% of wound or abscess cultures yielded S. aureus isolates. Over 56 million person-years (47 million in nonactive duty and 9 million in active duty), 2,643 blood cultures and 80,281 wound or abscess cultures tested positive for S. aureus. Annual incidence rates were 3.6 to 6.0 per 100,000 person-years for S. aureus bacteremia and 122.7 to 168.9 per 100,000 person-years for SSTIs due to S. aureus. From 2005 to 2010, a decrease was seen in annual incidence rates of community-onset MRSA bacteremia (1.7 per 100,000 person-years vs. 1.2 per 100,000 person-years, respectively; P=0.005 for trend) and hospital-onset MRSA bacteremia (0.7 per 100,000 person-years vs. 0.4 per 100,000 person-years, respectively; P=0.005 for trend). Community-onset SSTIs due to MRSA reached a peak of 62% in 2006 but decreased each year thereafter to 52% in 2010 (P<0.001 for trend).

The authors noted that no pre-2005 data were available and that they were therefore unable to determine trends in S. aureus bacteremia and SSTIs before community-acquired MRSA emerged. Data on race, ethnicity and clinical outcomes were also unavailable, among other limitations. However, the authors concluded that while S. aureus bacteremia and SSTIs continue to place a substantial burden on the U.S. military health system, rates of community-onset MRSA and methicillin-susceptible S. aureus bacteremia and hospital-onset MRSA bacteremia decreased from 2005 to 2010, along with the proportion of community-onset SSTIs due to MRSA.

"These observations, taken together with results from others showing decreases in the rates of health care-associated infections from MRSA, suggest that broad shifts in the epidemiology of S. aureus infections may be occurring," the authors wrote. "Additional studies are needed to assess whether these trends will continue, which prevention methods are most effective, and to what degree other factors may be contributing."



Test yourself


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MKSAP Quiz: sudden onset of vertigo

A 79-year-old man is evaluated in the emergency department for vertigo that began suddenly about 1 hour ago, associated with severe nausea and vomiting. He noticed that he could not seem to sit up straight and could not walk without assistance. The patient denies confusion, motor weakness, hearing loss, dysarthria, diplopia, fever, or paresthesias. Medical history is remarkable for hypertension, hyperlipidemia, and type 2 diabetes mellitus. Current medications are lisinopril, atorvastatin, low-dose aspirin, insulin glargine, metformin and atenolol. There are no allergies.

mksap.jpg

Vital signs are normal. The patient demonstrates unsteadiness on finger-to-nose testing in the right upper extremity and is unable to walk more than a few steps or stand without assistance. Motor strength and reflexes are normal. Visual acuity and visual fields are normal. An otoscopic examination and cursory evaluation of hearing are normal. Cardiopulmonary examination is normal.

A complete blood count, liver chemistry studies, and renal function studies are normal. Plasma glucose level is 168 mg/dL (9.32 mmol/L). An electrocardiogram is normal except for evidence of an old inferior myocardial infarction, unchanged from an electrocardiogram 1 year ago.

Which of the following is the most appropriate management option for this patient?

A) Admit for telemetry
B) Brain MRI
C) Intravenous methylprednisolone
D) Oral meclizine

Click here or scroll to the bottom of the page for the answer and critique.


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Nephrology


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Combination of creatinine and cystatin C more accurate than either alone for GFR

Combining creatinine and cystatin C measurements provided a more accurate estimation of glomerular filtration rate (GFR) than using either measurement alone, a new study found.

Researchers used data from more than 5,000 participants in 13 studies to develop estimating equations for GFR using cystatin C alone and in combination with creatinine. They then used more than 1,000 participants in five studies in which GFR had been measured to validate the equations. Results were published in the July 5 New England Journal of Medicine.

In the validation cohort, the combined cystatin C-creatinine equation showed similar bias to the equations using only one marker, and it was more precise and accurate than either of them. The median difference between measured and estimated GFR was 3.9 mL/min/1.73 m2 with the combined equation compared to 3.7 mL/min/1.73 m2 with creatinine alone and 3.4 mL/min/1.73 m2 with cystatin C alone. Using the combined equation, only 8.5% of estimates were more than 30% off the measured value, compared to 12.8% and 14.5% with creatinine and cystatin C, respectively.

The combined equation performed better than either of the single-marker ones, study authors concluded. One advantage of cystatin C as a measure is that it is less subject to variation due to age, sex and race, and in fact doesn't require race for its calculation, the authors noted. The combined equation was also more accurate in patients with a body mass index less than 20 kg/m2, a difficult-to-measure subgroup.

However, the results do not suggest that cystatin C should replace creatinine as a marker in clinical practice, according to the authors. Routine use of it could increase laboratory costs, so it may be most useful as a confirmatory test for diagnosis of chronic kidney disease, they said. An accompanying editorial suggested that clinicians also keep in mind the value of presence or absence of albuminuria for diagnosis and staging of kidney disease. The editorialist suggested use of the cystatin C measurement to diagnose patients who have no albumin in the urine and an estimated GFR close to 60 mL/min/1.73 m2 according to creatinine measurement.



Geriatrics


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Postoperative delirium associated with long-term cognitive impairment

Delirium after cardiac surgery occurred in nearly half of elderly patients and was associated with lower cognitive function postoperatively, a new study found.

Researchers enrolled 225 patients 60 years of age or older who were planning to undergo coronary artery bypass grafting or valve replacement at two academic medical centers and one Veterans Administration hospital. Patients were assessed with the Mini-Mental State Examination (MMSE) preoperatively; daily during hospitalization beginning on postoperative day 2; and at one, six and 12 months after surgery.

Results appeared in the July 5 New England Journal of Medicine.

Postoperative delirium developed in 103 patients (46%), with delirium lasting one to two days in 65% and three or more days in 35%. Those who developed postoperative delirium were more likely to be older, less educated, female, and nonwhite and to have a history of stroke or transient ischemic attack, a higher average score on the Charlson comorbidity index, and a lower level of preoperative cognitive function.

Among all patients, there was a significant decline in cognitive function—4.6 points on the MMSE—from baseline to postoperative day 2 (P<0.001), followed by average increases of 1 point on the MMSE each day on days 3 to 5 (P<0.001). Improvement slowed considerably from day 6 to day 183, and then stabilized from day 184 to day 365. A higher percentage of patients with delirium than those without delirium had not returned to their preoperative baseline level at six months (40% vs. 24%, P=0.01), but the difference was not significant at 12 months (31% vs. 20%, P=0.055).

"In patients with postoperative delirium, cognitive screening at hospital discharge may identify high-risk patients who require close monitoring after discharge or tailored transitional care in order to enhance functional and clinical outcomes," the authors noted.



Preventive care


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Zoster vaccination didn't cause infection in patients on biologics

The herpes zoster vaccine reduced the incidence of herpes zoster infection in patients with immune-mediated disease, a new study found.

The vaccine is currently contraindicated in patients taking anti-tumor necrosis factor (TNF) therapies or other biologic drugs, due to concerns that it could increase the risk of infection. To investigate this assumption, researchers conducted a retrospective cohort study of more than 400,000 Medicare beneficiaries 60 and over who had been diagnosed with rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis or inflammatory bowel disease.

Between 2006 and 2009, 4% of the cohort patients received the zoster vaccine. Researchers followed the patients for an average of two years, but also focused specifically on the first 42 days after vaccination. During that initial period, the incidence of zoster infection was 7.8 per 1,000 patient-years (95% CI, 3.7 to 16.5 per 1,000 patient-years). In patients who weren't vaccinated, the overall zoster incidence rate was 11.6 per 1,000 patient-years (95% CI, 11.4 to 11.9 per 1,000 patient-years). About 600 of the vaccinated patients were taking biologics within 42 days of vaccination; none of them were found to develop zoster or varicella in that time. Overall, the researchers calculated a 39% reduced risk of zoster infection associated with vaccination over the two years (hazard ratio, 0.61; 95% CI, 0.52 to 0.71).

The study authors concluded that vaccination of patients with immune-mediated diseases may not be associated with any increased risk of zoster infection shortly after vaccination, and that a significant reduction in long-term risk of zoster infection from vaccination is also possible. They cautioned that the study was limited by the number of subjects and wide confidence intervals, so the finding of no infections in vaccinated patients' first 42 days should not be taken to mean that no risk is present.

Still, the results call into question the current contraindication against using the zoster vaccine in patients on biologics. The authors called for a randomized, controlled trial of these patients to further establish the safety and efficacy of zoster vaccination for them. The study was published in the July 4 Journal of the American Medical Association.



From the College


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Upcoming immunization webinar on communicating risk-benefit of vaccination

ACP will host a webinar on communicating the risks and benefits of vaccination to patients on July 18 at noon as part of the ACP immunization webinar series.

Participants will learn how to help their patients navigate the relationship between public health and individual benefits and risks, as well as receive practical guidance on how and why vaccines are important in patients' day-to-day lives. Marie Brown, MD, FACP, governor for ACP's Illinois Northern region, of Rush University Medical Center, will be the speaker. More information is available online.


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New high-value, cost-conscious care curriculum available for internal medicine residents

ACP and the Alliance for Academic Internal Medicine (AAIM) have developed and released a curriculum for training internal medicine residents to practice high-value, cost-conscious care. The curriculum focuses on helping residents understand the potential benefits, harms and costs of medical interventions and enabling them to avoid overuse and misuse of tests and treatments that do not improve outcomes and may cause harm.

The curriculum is available for free download on a publicly accessible website. It is designed to engage residents and faculty in small group activities organized around actual patient cases that require careful analysis of the benefits, harms, and costs of intervention and the use of evidence-based, shared decision making. The flexible curriculum consists of 10 one-hour interactive sessions that can be incorporated into the existing conference structure of a program. More information on ACP's High Value, Cost-Conscious Care Initiative is online.



Cartoon caption contest


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Put words in our mouth

ACP InternistWeekly wants readers to create captions for this cartoon and help choose the winner. Pen the winning caption and win a $50 gift certificate good toward any ACP product, program or service.

acpi-20120710-cartoon.jpg

E‑mail all entries to acpinternist@acponline.org. ACP staff will choose finalists and post them online for an online vote by readers. The winner will appear in an upcoming edition.


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MKSAP Answer and Critique



The correct answer is B) Brain MRI. This item is available to MKSAP 15 subscribers as item 46 in the General Internal Medicine section. MKSAP 16 will release Part A on July 31. More information is available online.

This patient with severe vertigo has symptoms concerning for a cerebellar infarction. In addition, he has several risk factors for stroke, including diabetes mellitus, hypertension, hyperlipidemia, and age. The finding of ataxia involving the right upper extremity further suggests a focal cerebellar lesion. He should undergo immediate MRI of the brain.

The patient had a normal cardiac examination and an unchanged electrocardiogram. Although the patient has a history of cardiac disease, further cardiac testing and monitoring for arrhythmias is not a priority in the absence of symptoms or electrocardiographic changes and is unlikely to uncover an etiology for acute vertigo.

Constant, severe vertigo that is not self-limited and may be associated with nausea and vomiting is characteristic of both posterior circulation cerebrovascular disease and vestibular neuronitis. Vestibular neuronitis is often difficult to differentiate from posterior circulation cerebral ischemia. The disorders are differentiated by characteristic examination findings on the Dix-Hallpike maneuver, the presence of associated neurologic findings in stroke, general preservation of auditory function in stroke, and neuroimaging studies. If this patient were able to tolerate a Dix-Hallpike maneuver, nonfatiguing vertical nystagmus with no latent period would have supported a central cause of vertigo, such as stroke, rather than a peripheral cause, such as vestibular neuronitis. However, truncal ataxia and limb ataxia are more characteristic of a cerebellar infarction than vestibular neuronitis. Therefore, treatment for vestibular neuronitis with methylprednisolone is not indicated.

Treatment with meclizine may help the patient's vertigo symptoms; however, he needs a brain MRI to rule out stroke.

Key Point

  • Patients with risk factors for stroke who present with acute vertigo should undergo brain MRI.

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Test yourself

A 38-year-old man is evaluated for a mass in his right neck that he first noticed 2 weeks ago while shaving. The patient also reports experiencing a pressure sensation when swallowing solid foods for the past year and daily diarrhea for the past 2 months. His personal medical history is unremarkable. His younger brother has nephrolithiasis, and his father died of a hypertensive crisis and cardiac arrest at age 62 years while undergoing anesthesia induction to repair a hip fracture. Following a physical exam, lab studies, and a chest radiograph, what is the most likely diagnosis?

Find the answer

MKSAP 16 Holiday Special: Save 10%

MKSAP 16 Holiday Special:  Save 10%

Use MKSAP 16 to earn MOC points, prepare for ABIM exams and assess your clinical knowledge. For a limited time save 10% when you use priority code MKPROMO! Order now.

Maintenance of Certification:

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Maintenance of Certification: What if I Still Don't Know Where to Start?

Because the rules are complex and may apply differently depending on when you last certified, ACP has developed a MOC Navigator. This FREE tool can help you understand the impact of MOC, review requirements, guide you in selecting ways to meet the requirements, show you how to enroll, and more. Start navigating now.