Wednesday 3 September 2008

BIT'S & BOB'S



Cary G Dean.



1.
Flu Shot Doesn’t Reduce Deaths


The widely-held perception that the influenza vaccination reduces overall mortality risk in the elderly does not withstand careful scrutiny, according to researchers in Alberta.

The vaccine does confer protection against specific strains of influenza, but its overall benefit appears to have been exaggerated by a number of observational studies that found a very large reduction in all-cause mortality among elderly patients who had been vaccinated.


The results will appear in the first issue for September of the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society.

The study included more than 700 matched elderly subjects, half of whom had taken the vaccine and half of whom had not.

After controlling for a wealth of variables that were largely not considered or simply not available in previous studies that reported the mortality benefit, the researchers concluded that any such benefit "if present at all, was very small and statistically non-significant and may simply be a healthy-user artifact that they were unable to identify."


"While such a reduction in all-cause mortality would have been impressive, these mortality benefits are likely implausible".

"Previous studies were likely measuring a benefit not directly attributable to the vaccine itself, but something specific to the individuals who were vaccinated-a healthy-user benefit or frailty bias," said Dean T. Eurich,Ph.D. clinical epidemiologist and assistant professor at the School of Public Health at the University of Alberta.

"Over the last two decades in the United Sates, even while vaccination rates among the elderly have increased from 15 to 65 percent, there has been no commensurate decrease in hospital admissions or all-cause mortality."

"Further, only about 10 percent of winter-time deaths in the United States are attributable to influenza, thus to suggest that the vaccine can reduce 50 percent of deaths from all causes is implausible in our opinion."


The finding has broad implications:

* For patients:
People with chronic respiratory diseases such as chronic obstructive pulmonary disease, immuno-compromised patients, healthcare workers, family members or friends who take care of elderly patients and others with greater exposure or susceptibility to the influenza virus should still be vaccinated.

"But you also need to take care of yourself."

'Everyone can reduce their risk by taking simple precautions," says Dr. Majumdar.

"Wash your hands, avoid sick kids and hospitals during flu season, consider antiviral agents for prophylaxis and tell your doctor as soon as you feel unwell because there is still a chance to decrease symptoms and prevent hospitalization if you get sick- because flu vaccine is not as effective as people have been thinking it is."


* For vaccine developers:
Previously reported mortality reductions are clearly inflated and erroneous-this may have stifled efforts at developing newer and better vaccines especially for use in the elderly.


* For policy makers:
Efforts directed at "improving quality of care" are better directed at where the evidence is, such as hand-washing."


Finally, Dr. Majumder said, the findings are a reminder to researchers that "the healthy-user effect is everywhere you don't want it to be."

2.
Treadmill Retrains Body and Brain of Stroke Victims


People who walk on a treadmill even years after stroke damage can significantly improve their health and mobility, changes that reflect actual "rewiring" of their brains, according to research spearheaded at Johns Hopkins.

"This is great news for stroke survivors because results clearly demonstrate that long-term stroke damage is not immutable and that with exercise it's never too late for the brain and body to recover," says Daniel Hanley, M.D., professor of neurology at the Johns Hopkins University School of Medicine.

The study's results, published in Stroke: Journal of the American Heart Association, suggest that patients' brains may retain the capacity to rewire through a treadmill exercise program months or years after conventional physical therapy has ended.

The research was conducted by scientists at Johns Hopkins, the University of Maryland, and the Department of Veterans Affairs Maryland VA Medical Center at their Geriatric Research, Education, and Clinical Center (GRECC).

Researchers at the GRECC, led by Richard F. Macko, M.D., and Andrew P. Goldberg, M.D., have developed treadmill therapy for stroke patients over the past decade.

Investigators at all three institutions combined efforts to recruit 71 patients who had a stroke at least six months earlier, with an average time lapse of nearly four years.

At the study's onset, half of the subjects could walk without assistance, while the rest used a cane, a walker or a wheelchair.


All of the subjects, separated into two random groups regardless of disability, were tested for mobility and aerobic capacity (also known as VO2 peak), a measure of cardiac fitness.

Thirty-two patients drawn equally from both groups underwent functional magnetic resonance imaging (fMRI) to assess brain activity linked to moving their legs in a walking motion.


One group then participated in an exercise program that principally involved walking on a treadmill three times a week for up to 40 minutes, assisted by a supporting sling and tether if needed.

Physical therapists assigned to each subject increased the intensity of the workouts over time by increasing the treadmills' speed and incline, though the workouts never taxed the patients beyond a moderate level of 60 percent VO2 peak.


With the second group of patients, therapists assisted the patients in performing stretching exercises for the same period of time.

After six months, patients were again tested for walking speed and VO2 peak, and the same group who had undergone fMRI was rescanned.

Walking speed for the treadmill group increased 51 percent compared to about 11 percent faster for those in the stretching group.

Ground walking speed among the treadmill exercisers increased 19 percent, compared to about 8 percent for the stretchers.

The treadmill exercisers also were significantly more fit at study completion, with VO2 peak increasing by about 18 percent.

VO2 peak decreased slightly in the stretching group.


Hoping to find evidence that improved brain activity was responsible for the results, the investigators analyzed the brain scans and found markedly increased metabolic activity in brainstem areas associated with walking among all the treadmill exercisers.

Brain scans of patients in the stretching group showed no such changes.


"This suggests that the brain is responsible for the improvement we saw in patients' walking ability.

It seems to be recruiting other regions to take on the job of areas damaged by stroke," says Andreas Luft, M.D., a visiting researcher who worked with all three institutions who conducted this study.

Luft is currently a stroke attending physician and professor of neurorehabilitation at the University of Zurich in Switzerland.


Those patients with the most improvement in walking showed the strongest change in brain activity, though the researchers don't yet know whether these brain changes were caused by more walking or whether participants walked better because brain activity in these key areas increased.

This question will be the focus of a future study.


"Many stroke survivors believe there's nothing to be gained from further rehabilitation, but our results suggest that health and functional benefits from walking on a treadmill can occur even decades out from stroke," says Macko, professor of neurology at the University of Maryland School of Medicine, noting that one of the patients in the study had significant improvement 20 years after a stroke.

"We believe exercise gives individuals a way to fight back against stroke disabilities."


3.
Happiness and Satisfaction May Lead to Health


It's the opposite of a vicious cycle:

Healthy people might be happier, and a new study shows that people who are happy and satisfied with their lives might be healthier.


Moreover, the benefit comes with a quick turnaround time, with greater happiness possibly boosting health in as little as three years.

"Everything else being equal, if you are happy and satisfied with your life now, you are more likely to be healthy in the future.

Importantly, our results are independent of several factors that impact on health, such as smoking, physical activity, alcohol consumption and age,” said lead author Mohammad Siahpush, Ph.D.


Siahpush is a professor of health promotion at the University of Nebraska Medical Center in Omaha.

The study appears in the September/October issue of the American Journal of Health Promotion.


The researchers looked at data from two waves of an Australian survey conducted in 2001 and 2004.

Nearly 10,000 adults responded to items about health indicators including the presence of long-term, limiting health conditions and physical health.

They used the question, "During the past four weeks, have you been a happy person?" to assess happiness.

They determined satisfaction with life by asking:

"All things considered, how satisfied are you with your life?"


"We found strong evidence that both happiness and life satisfaction have an effect on our indicators of health," Siahpush said.

Happiness and life satisfaction at the baseline survey were both associated with (1) excellent, good or very good health; (2) the absence of long-term, limiting health concerns and (3) higher levels of physical health three years later.

In addition, the results suggested that improving happiness or life satisfaction might also result in better future health.

"There are indications that as you become happier and more satisfied with your life, you tend to become healthier as well," Siahpush said.

4.
Antipsychotic Drugs Double Stroke Risk


People taking antipsychotic drugs are nearly twice as likely to have a stroke compared to those not on the treatment, British researchers reported on Friday.

The risk is even higher -- about 3.5 times -- for men and women with dementia, which means doctors should only prescribe such medicine to these patients as a last resort, the researchers said.

Previously, stroke risk associated with older antipsychotic drugs was unclear but the study published in the British Medical Journal showed both old and new treatments carry increased risk.

"The risks associated with antipsychotic use in patients with dementia generally outweigh the potential benefits, and in this patient group, use of antipsychotic drugs should be avoided whenever possible," Ian Douglas and colleagues at the London School of Hygiene and Tropical Medicine wrote."

The researchers looked at the medical records of nearly 7,000 men and women and recorded the incidence of stroke among those who at some point had taken antipsychotic drugs.

They found that they were 1.7 times more likely to have a stroke and that the risk was much higher if people had dementia.

The most common older treatments included a drug class called phenothiazine and the generic medicines haloperidol and benperidol.

The most widely used newer drug in the study was Johnson & Johnson's Risperdal, known generically as risperidone, the researchers said.


Other newer drugs in the study included Eli Lilly and Co's Zyprexa, or olanzapine, Sanofi-Aventis' Solian, or amisulpride and AstraZeneca Plc's Seroquel, known generically as quetiapine.

The researchers did not look at why people with dementia are at greater risk but one possibility may be that vascular causes of certain types of dementia may be involved, said Douglas, an epidemiologist.

"We don't know why this extra risk associated with antipsychotics is even greater in people with dementia," he said in a telephone interview

5.
Some Diabetes Drugs Carry Big Heart Risks


A class of oral drugs used to treat type 2 diabetes may make heart failure worse, according to an editorial published online in Heart Wednesday by two Wake Forest University School of Medicine faculty members.

"We strongly recommend restrictions in the use of thiazolidinediones (the class of drugs) and question the rationale for leaving rosiglitazone on the market," write Sonal Singh, M.D., M.P.H., assistant professor of internal medicine, and Curt D. Furberg, M.D., Ph.D., professor of public health sciences.

Rosiglitazone and pioglitazone are the two major thiazolidinediones.


In the editorial Singh and Furberg say, "At this time, justification for use of thiazolidinediones is very weak to non-existent."

Oral drugs are given to control diabetes by lowering blood sugar.

But diabetics also experience elevated rates of high blood pressure and high levels of cholesterol and triglyceride, which "further compound their already increased risk of developing ischemic heart disease," Singh and Furberg say.

Heart disease and high blood pressure "represent conditions that are major precursors of congestive heart failure."


About 22 percent of diabetics have heart disease.

Among elderly patients with diabetes, more than half will develop congestive heart failure over a 10-year period, the editorial says.


Singh and Furberg reported in The Journal of the American Medical Association in 2007 after an analysis of four long-term trials that use of rosiglitazone was associated both with increased heart attacks and a doubling of heart failure.

They said that results from three large randomized clinical trials published this past June all failed to demonstrate that intensive control of blood sugar reduces mortality or events from cardiovascular disease in patients with type 2 diabetes.

The three trials were ACCORD, ADVANCE, and the Veterans Affairs Diabetes study.

In ACCORD, the patients who received intensive treatment to control blood sugar actually had more cardiovascular disease mortality than patients receiving standard treatment.


In ADVANCE, intensive control of blood sugar produced no benefit; there was no effect on cardiovascular events or deaths from cardiovascular causes compared to standard oral diabetes agents.

In the VA Diabetes trial, when intensive blood sugar control produced levels of blood sugar that were too low and led to loss of consciousness, that was a strong predictor of future cardiovascular events.

"The unfavorable findings from the three trials have not been fully realized by the medical community," Singh and Furberg say.

Singh said in an interview, "Safer, cheaper and more effective treatment alternatives are available that do not carry these negative cardiovascular risks in patients with diabetes.

The rationale for the use of the thiazolidinediones is unclear.”



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