2 Minute Medicine Rewind June 1 – June 7, 2015

Follow-up of Glycemic Control and Cardiovascular Outcomes in Type 2 Diabetes

There has been lack of adequate long-term follow up in the large randomized control trials of glucose control in type 2 diabetes mellitus. In this era of modern combination glycemic therapy, the long term benefits and risks of tight vs. liberal glucose control is still unknown. In this study the authors report cardiovascular outcomes after an additional 5 years of observational follow-up (for a median of 9.8 years) of the Veterans Affairs Diabetes Trial, a multicenter randomized controlled trial of intensive (stepwise plan from 1 evening injection of insulin, alone or with glipizide, to multiple daily injections) versus standard glucose control (1 insulin injection every morning) in US military veterans. In the original trial they found that intensive glucose lowering did not significantly reduce the rate of major cardiovascular events. After a median of 9.8 years follow-up, the intensive-therapy group had a significantly lower risk of time to first major cardiovascular event compared to the standard therapy group (hazard ratio, 0.83; 95% CI: 0.70 to 0.99; p = 0.04), with an absolute reduction in risk of 8.6 major cardiovascular events per 1000 person-years, but did not have reduced cardiovascular mortality (hazard ratio, 0.88; 95% CI: 0.64 to 1.20; p = 0.42). These results demonstrate that patients on intensive glucose control have 8.6 fewer major cardiovascular events per 1000 person-years than those assigned to standard therapy, but no improvement in the rate of overall survival.

Preoperative testing before low-risk surgical procedures

Given the present fiscal restraint on health care spending there are growing concerns regarding the utilization of low-value health care services. The 2007 American College of Cardiology/American Heart Association guidelines included a recommendation to avoid routinely performing preoperative testing (including chest radiography, echocardiography and cardiac stress tests) for patients undergoing low-risk surgery (including endoscopy, ophthalmologic surgery, knee arthroscopy, and hernia repair). In this retrospective cohort study, investigators compared utilization rates of preoperative tests before hospital-based low-risk surgical procedures at the jurisdictional, regional and institutional level from 2008 to 2013. In addition they looked at temporal trends of preoperative testing over a 5-year period. They found that ECG and chest radiography were performed before 31.0% (95% CI 30.9%–31.1%) and 10.8% (95% CI 10.8%– 10.8%) of procedures, respectively, whereas the rates of preoperative echocardiography and stress testing were 2.9% (95% CI 2.9%–2.9%) and 2.1% (95% CI 2.1%–2.1%), respectively, with wide ranges between institutions. Receipt of preoperative ECG and radiography were associated with older age, preoperative anesthesia consultation and preoperative medical consultation. These results show that despite guideline recommendations to limit testing before low-risk surgical procedures, preoperative ECG and chest radiography were still performed frequently.

Marked Regional Variation in Acute Stroke Treatment Among Medicare Beneficiaries

Treatment of acute ischemic stroke includes thrombolysis with intravenous tissue-type plasminogen activator (tPA) and acute intra-arterial treatment (IAT). Little is known, however, about regional variations in the use of thrombolysis for acute stroke. In this retrospective cross-sectional study of all fee-for-service Medicare patients from 2007 to 2010, the authors determined regional variation in thrombolysis treatment and investigated the extent to which regional variation is accounted for by patient demographics, regional factors, and elements of stroke systems of care. Over the study period the authors found that 3.7% of ischemic stroke admissions received intravenous tPA and 0.5% received IAT. The unadjusted proportion of patients with ischemic stroke who received thrombolysis varied from 9.3% in the highest treatment quintile compared with 0% in the lowest treatment quintile. Demographic and stroke system factors were weakly associated with treatment rates and region accounted for 7% to 8% of the variation. The results demonstrate that there is substantial regional variation in thrombolysis treatment, and high-performing treatment regions should be further studied to identify opportunities to improve thrombolysis rates in other treatment regions.

Adverse Events After Routine Immunization of Extremely Low-Birth-Weight Infants

The immunization of extremely low-birth weight (ELBW; birth weight <1000g) infants has been associated with adverse events, including fever and adverse cardiorespiratory events, such as apnea and bradycardia in the immediate postimmunization period. These events can mimic the clinical presentation of sepsis and can lead to additional workup including blood and urine cultures and exposure to empirical antibiotic therapy. In this multicenter retrospective cohort study the authors used a large NICU database of infants born at 28 weeks gestation or less from 2007 to 2012 to investigate the incidence of sepsis evaluations and adverse cardiorespiratory events after immunization between the ages of 53 days and 110 days in ELBW infants.The results show that sepsis evaluations increased from 5.4 per 1000 patient-days in the preimmunization period to 19.3 per 1000 patient-days in the postimmunization period (adjusted rate ratio [ARR], 3.7; 95% CI, 3.2-4.4). The need for increased respiratory support increased from 6.6 per 1000 patient-days in the preimmunization period to 14.0 per 1000 patient-days in the postimmunization period (ARR, 2.1; 95% CI, 1.9-2.5), and intubation increased from 2.0 per 1000 patient-days to 3.6 per 1000 patient-days (ARR, 1.7; 95% CI, 1.3-2.2). In addition, the postimmunization incidence of adverse events was similar across immunization types, including combination vaccines when compared with single-dose vaccines. Given that ELBW infants in the NICU had an increased incidence of sepsis evaluations and increased respiratory support and intubation after routine immunization, the authors suggest not using combination vaccines in these infants.

Utility analysis of management strategies for suspected subarachnoid haemorrhage in patients with thunderclap headache with negative CT result

The standard of care for a clinical suspicion of a subarachnoid hemorrhage (SAH) is a non-contrast CT followed by a lumbar puncture (LP) if the initial CT is negative for acute blood. In recent years a CT angiography (CTA) has become a rapid, easily available, less invasive and highly reliable means to detect aneurysms rather than bleeds. In this study the authors aimed to determine the most effective strategy for further work-up in patients with thunderclap headache and negative CT results using a Monte Carlo simulation. They used a decision tree to assess three different strategies following a negative initial non-contrast CT: no follow-up, LP follow-up and CTA follow-up.The decision tree analysis showed CT with LP follow-up to be the most effective strategy with the highest expected utility of 0.79926 quality-adjusted life-year (QALY) compared with 0.79875 QALY for no follow-up and 0.79869 QALY for CTA follow-up. Monte Carlo simulation showed LP was the best strategy in 86.4% of all iterations. In addition, the sensitivity analysis showed that CT without follow-up is the best strategy only when the sensitivity of CT is very high (99.6%) or the pre-test probability of SAH in a patient with thunderclap headache with negative initial CT is low (1.6%). Therefore LP should be the preferred follow-up test unless the pre-test probability of SAH is low (<1.6%) or the sensitivity of initial non-contrast CT for blood is high (>99.6%).

Image: CC/Wiki/Heilman

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