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29-07-2012 | Article

Global medical news in review: July 22-28, 2012

MedWire News: A roundup of select stories of interest to US physicians from the Merck Medicus Medical News wire.

Gout a risk marker for MI

Gout is a significant and independent risk factor for the development of myocardial infarction (MI), even in younger patients and those with no other cardiovascular (CV) risk factors, researchers report in Rheumatology.

During a 9-year follow-up period, in a study of 704,503 patients aged 20 years or older, the incidence of MI among patients with gout was 2.20 per 1000 person-years, compared with 0.60 events per 1000 person-years in the comparator group.

Shue-Fen Luo (Chang Gung Memorial Hospital, Guishan Township, Taiwan) and colleagues also report that patients with gout were more likely to have diabetes, hypertension, and coronary heart disease at baseline than those without.

After adjustment for age, gender, and CV and metabolic syndrome risk factors, the hazard ratio (HR) for the association of gout with MI was 1.23. Further analysis confirmed this significantly increased risk occurred in all age groups and in patients with no CV risk factors for both overall MI (HR=1.84) and nonfatal MI (HR=1.80). In the patients with gout, the overall risk for MI was slightly higher in men than in women.

The risk for fatal MI was similar between those with and those without gout. However, the investigators' analysis did not include mortality not attributable to the first MI event or MI-related deaths that occurred prior to hospitalization.

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Pop a pill for one-stop prevention

Results of the first trial to administer a polypill on the basis of age alone has shown the largest reductions in blood pressure (BP) and cholesterol levels of any polypill trial to date, report David Wald (Queen Mary University of London, UK) and team.

In their study, the polypill, which consisted of amlodipine 2.5 mg, losartan 25 mg, hydrochlorothiazide 12.5 mg, and simvastatin 40 mg, was administered to 84 participants aged a mean of 59 years and reduced mean systolic BP by 17.9 mmHg and diastolic BP by 9.8 mmHg compared with placebo.

In addition, low-density lipoprotein (LDL) cholesterol was reduced by 1.4 mmol/L, as reported in PLoS One.

Of note, aspirin was not included in the pill. The authors say this was because "the risk of bleeding in people without existing cardiovascular disease might be unacceptable in relation to the expected benefit."

Further analysis revealed that the BP and LDL cholesterol reductions observed in the current study were close to those expected from meta-analyses of randomized trials of the individual classes of polypill components, at 12%, 11%, and 39% observed for systolic BP, diastolic BP, and LDL cholesterol, respectively.

At the end of the trial, 24 of the participants reported one or more side effects while on the polypill, including cough, muscle ache/pain, ankle swelling, flushing, rash, or tongue or lip swelling. However, none of these participants considered their symptoms troublesome enough to stop treatment.

The authors say that based on the quantitative relationship of LDL cholesterol and BP with ischemic heart disease and stroke risk, and given the composition of the polypill they used, the predicted effect in reducing ischemic heart disease events is 72% and in reducing stroke is 64%.

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ADHD in childhood associated with comorbid disorders in teens

Attention deficit/hyperactivity disorder (ADHD) in childhood is associated with an increased risk for a broad range of comorbid psychiatric disorders in adolescence, report researchers Slavica Katusic (Mayo Clinic, Rochester, Minnesota) and team.

The findings come from a retrospective study of 5718 children born between 1976 and 1982 who were followed up until the age of 19 years as part of the Rochester Epidemiology Project.

In total, 343 children who were diagnosed with ADHD during the study period were compared with 712 age- and gender-matched children without ADHD (controls) for the development of psychiatric disorders.

The researchers found that 62% of children with ADHD had developed one or more comorbid psychiatric disorders by the age of 19 years. By contrast, just 19% of controls had developed a psychiatric condition by this age.

Compared with controls, children with ADHD were significantly more likely to develop conduct/oppositional defiant disorder (HR=9.54), tic disorders (HR=6.53), personality disorders (HR=5.80), eating disorders (HR=5.68), substance-related disorders (HR=4.03), adjustment disorders (HR=3.88), mood disorders (HR=3.67), and anxiety disorders (HR=2.94).

Overall, children with ADHD were 10.6 times more likely to develop coexisting internalizing and externalizing disorders, 10.0 times more likely to develop externalizing-only disorders, and 4.1 times more likely to develop internalizing-only disorders compared with controls.

Writing in the Journal of Child Psychology and Psychiatry, Katusic et al conclude: "Clinicians should be aware that children and adolescents with ADHD are at significant risk for a wide range of psychiatric disorders."

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Elderly at high AMI risk in 2 weeks after knee or hip replacement

Older patients are at a significantly increased risk for acute myocardial infarction (AMI) in the 2 weeks following total hip- or knee-replacement surgery, research shows.

"The association was strongest in patients 80 years or older, whereas we could not detect a significantly increased risk in patients younger than 60 years," report Arief Lalmohamed (Utrecht University, the Netherlands) and colleagues in the Archives of Internal Medicine.

By contrast, the risk for AMI declined after the first fortnight in patients undergoing total knee-replacement surgery, but remained significantly elevated for 6 weeks in patients who had hip-replacement surgery.

Previous studies have shown that cardiac risk is elevated in the perioperative period.In the setting of hip- and knee-replacement surgery, epidemiologic studies have reported 90-day AMI rates as high as 1.8%. Most of these adverse events occur in the first week.

Using data from the Danish national registries, the current study included 95,227 individuals who underwent total hip- or knee-replacement surgery between 1998 and 2007.

The 2-week risk for AMI was 25 times greater in patients who had undergone hip-replacement surgery than in healthy controls (HR=25.5).

The risk for AMI in the 2 weeks following knee-replacement surgery was even higher, at more than 30 times greater in knee replacement patients than in age- and gender-matched controls (HR=30.9).

In weeks 2‑6 postsurgery, the increased risk for AMI in patients undergoing knee-replacement was no longer statistically significant. However, patients undergoing total hip-replacement surgery still had a fivefold greater risk for AMI compared with control patients (HR=5.05).

In addition, a previous AMI was associated with a twofold higher risk for a new AMI in the 6 weeks following surgery.

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Oxygen balance critical after brain injury

Both hyperoxia and hypoxia early after hospital admission are associated with poor outcomes and mortality in patients with traumatic brain injury, report researchers in the Archives of Surgery.

In an invited critique, H Gill Cryer (University of California at Los Angeles Medical Center, USA) suggests that doctors tend to give patients high oxygen supplementation to prevent hypoxia and its known detrimental effects.

This seemed evident in the current study, which included 1547 patients with severe brain injury, defined as a head Abbreviated Injury Score of 3 or more. Megan Brenner (University of Maryland School of Medicine, Baltimore, USA) and team report that 43% of the patients were hyperoxic during the first 24 hours of hospitalization, with average partial pressure of oxygen in the blood (PaO2) values exceeding 200 mmHg. By contrast, just 7% were hypoxic, with average levels below 100 mmHg.

The mortality rates were 31% and 38% in the hyperoxic and hypoxic groups, respectively, compared with 25% among patients with PaO2 values of 100‑200 mmHg. These associations persisted after accounting for confounders, with hyperoxia increasing mortality risk 1.5-fold and hypoxia raising it 2.2-fold, relative to normoxia.

Also, hyperoxic patients had a significant 1.52-fold increase in risk for poor short-term outcomes, defined as a discharge Glasgow Coma Scale score of 3‑8, relative to patients with normal PaO2 levels, while hypoxic patients had a 1.66-fold increased risk.

There were no significant differences in most outcomes when comparing hyperoxic and hypoxic patients. Hyperoxic patients had longer stays in the intensive care unit and in hospital, but this was explained by a larger proportion of hypoxic patients who died doing so within 7 days of admission, at 90%, compared with 76% of hyperoxic and 74% of normoxic patients.

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By Neil Osterweil, MedWire Reporter