|
|
|
September
2001
Lyme
Disease Update
Can antibiotics catch Lyme disease before it develops? Do antibiotics
alleviate the lingering symptoms after the infection is cured? Two recent
studies published in The New England Journal of Medicine shed
light on these two controversial questions.
In the first study, conducted in Westchester County, New York, an area
with high rates of Lyme disease, researchers gave a single dose of either
an antibiotic or a placebo to patients who were bitten by deer ticks
in the previous 72 hours.
The researchers found the antibiotic doxycycline prevented the disease
form developing. However, only 3.2% of the untreated patients developed
the characteristic bull's eye rash around the tick bite. This suggests
the risk of Lyme disease is low even in Westchester County. The study
also found the infection was more likely to develop from bites by ticks
in the nymph stage, and if the tick was attached for 72 hours or more.
This study suggests preventive treatment is only worthwhile in areas
with a particularly high incidence of the disease or if you are bitten
by a nymphal deer tick that has been attached for three days or more.
You should save the tick in a jar of alcohol so it may be identified
to help you and your physician make that decision.
In the second study, researchers
investigated whether prolonged treatment with antibiotics reduces the
fatigue, muscle and joint pain, and mood or memory disturbances that
some people experience even after the infection has cleared. But the
study was discontinued early when preliminary results showed prolonged
antibiotic treatment was no more effective than a placebo at improving
the persistent symptoms.
If you are experiencing post-Lyme disease symptoms, long-term use of
antibiotics is unlikely to help. But there is hope your condition will
improve —
the study found symptoms improved in 36% of the untreated patients.
September 2001 Update
Back
to Top
Smoking
Cessation and Congestive Heart Failure
Quitting smoking greatly reduces your risk of death from congestive heart
failure within two years.
Despite a lack of evidence, physicians have long advised patients with
congestive heart failure to quit smoking to improve their chances of
survival. Now, a recent study provides the necessary proof.
Researchers in Canada investigated the rates of death, hospitalization
for heart failure, and heart attack in smokers, ex-smokers of less than
2 years, ex-smokers of more than 2 years, and non-smokers. All the participants
in the study had congestive heart failure in the form of left ventricular
dysfunction — failure of the left ventricle of the heart to properly
pump oxygen-rich blood to the body.
The study found current smoking was associated with a substantial increase
in the risk of death, rate of hospitalization, and heart attack. Patients
who had quit smoking or never smoked had a 30% lower risk of dying during
the time of the study (41 months). Moreover, ex-smokers had the same
mortality rate as non-smokers.
These results suggest people who quit smoking lower their risk of recurrent
congestive heart failure within two years. The research also showed the
benefit from quitting smoking was just as great as the benefit from taking
drugs for heart failure.
September 2001 Update
Back
to Top
Diet
and Exercise Dramatically Delay Type 2 Diabetes
Americans at high risk for type 2 diabetes can sharply lower their chances
of getting the disease with diet and exercise, according to the results
of a major clinical trial. The same study also found the oral diabetes
drug metformin (Glucophage) reduces diabetes risk, though less dramatically.
The findings came from the Diabetes Prevention Program (DPP), a major
clinical trial comparing diet and exercise to metformin in 3,234 people
with impaired glucose tolerance, a condition that often precedes diabetes.
Smaller studies in China and Finland had previously shown diet and exercise
can delay type 2 diabetes in at-risk people. But the DPP, conducted at
27 centers nationwide, is the first major trial to show diet and exercise
can effectively delay diabetes in a diverse American population of overweight
people with impaired glucose tolerance (IGT). IGT is a condition in which
blood glucose levels are higher than normal but not yet diabetic.
Of the 3,234 participants enrolled in the DPP, 45 percent are from groups
that suffer disproportionately from type 2 diabetes: African Americans,
Hispanic Americans, Asian Americans and Pacific Islanders, and American
Indians. The trial also recruited others known to be at higher risk for
type 2 diabetes, including people age 60 and older, women with a history
of gestational diabetes, and people with a first-degree relative with
type 2 diabetes.
Participants ranged from age 25 to 85, with an average age of 51. All
had impaired glucose tolerance as measured by an oral glucose tolerance
test, and all were overweight, with an average body mass index (BMI)
of 34. They were randomly assigned to one of the following groups: intensive
lifestyle changes with the aim of reducing weight by 7 percent through
a low-fat diet and exercising for 150 minutes a week; treatment with
the drug metformin (850 mg twice a day), approved in 1995 to treat type
2 diabetes; and a standard group taking placebo pills in place of metformin.The
latter two groups also received information on diet and exercise.
During an average follow up of about 3 years, about 29 percent of the
group receiving standard treatment developed diabetes. In contrast, 14
percent of the diet and exercise, and 22 percent of the metformin arms
developed diabetes. Volunteers in the diet and exercise arm achieved
the study goal, on average a 7 percent — or 15-pound — weight
loss, in the first year and generally sustained a 5 percent total loss
for the study's duration. Participants in the lifestyle intervention
arm received training in diet, exercise (most chose walking), and behavior
modification skills.
In all, participants in the random intensive lifestyle intervention reduced
their risk of type 2 diabetes by 58 percent, and those who received metformin
reduced their risk of getting type 2 diabetes by 31 percent.
September 2001 Update
Back
to Top
Flu
Vaccine and Recurrent Heart Attack Risk
Late each fall, the call goes out to remind people to get their flu vaccinations.
Most healthy people equate the flu with a week of being miserable. However
for the elderly or people with chronic illnesses, the complications of
influenza, such as pneumonia, can be life threatening. Good enough reason
to get the shot, but now research suggests the vaccination may also lower
heart attack risk.
The study, conducted by researchers at the University of Texas-Houston,
questioned whether getting a flu shot could reduce the risk of a second
heart attack in people with coronary artery disease. Scientists have
been studying a potential link between cardiovascular disease and infection,
and some of their work suggests upper respiratory infections, such as
the flu, might be a risk factor for heart attack.
The investigators evaluated 218 individuals with previous heart attacks
who were seen in the university's cardiology outpatient clinic during
the 1997-98 flu season. Of the patients who met the study criteria, 109
experienced a heart attack during the study period. These volunteers
were matched with 109 controls with coronary artery disease, but had
not experienced a second heart attack during the same period.
Of those who had had new myocardial infarctions, the rate of flu vaccination
during the current season was 47%, versus 71% among those who did not
have new heart attacks. After adjusting for differences between these
groups, the researchers found the risk of heart attack was reduced by
two-thirds among patients who had gotten a flu shot that season. This
study showed no evidence that use of multivitamins or physical exercise
changed risk for recurrent heart attack.
No one knows how flu vaccination might reduce a person's risk of heart
attack. Perhaps exposure to the flu might cause atherosclerotic plaques
to become less stable or the stress of this illness might dangerously
increase the heart's workload for people with cardiovascular disease.
Other theories include an increased tendency for blood clots during the
flu or that the flu may contribute to poor blood vessel function. Whatever
the cause and effect, people with coronary artery disease (and who are
not allergic to the vaccine) should strongly consider getting a flu shot
this season.
September 2001 Update
Back
to Top
More
Encouraging Data on Alcohol and the Heart
Having a drink or two
per day lowers your risk heart disease and stroke. Little surprise
then that two new studies report people who drink alcohol also
have lower risk of developing heart failure and better outcomes
if they have heart attacks. The studies were reported in a recent
issue of the Journal of the American Medical Association.
The first study involved 1913 adults who were admitted to 45
different U.S. hospitals between August 1989 and September
1994 for heart attacks. The researchers, who were based at
Harvard Medical School and Harvard School of Public Health,
interviewed the patients an average of 4 days after their heart
attacks, inquiring about a range of issues including their
alcohol consumption.
About half (47%) reported they didn't drink alcohol during
the year before their heart attacks. Another 36% said they
drank fewer than 7 drinks per week. The remainder (17%) said
they had 7 or more drinks per week. Those who drank the most
were younger, and more likely to be male, current or former
cigarette smokers, and have physically active life styles.
Survival rates were lowest for those who did not drink at all
before their heart attacks and best for those who drank 7 or
more drinks per week. For every 100 people, 6.3 of the abstainers
died each year, compared with 3.4 of those who drink 1-6 drinks
per week and 2.4 of those drank 7 or more drinks.
Heart failure
The second study was based on 2,235 elderly people (average
age 74 years) who participated in a long-term epidemiological
survey in New Haven, CT. None of the subjects had heart failure
at the time of enrollment in the study in 1982. And the researchers
excluded heavy drinkers (those drinking more than four drinks
per day).
Half of the subjects reported no alcohol consumption in the
month before enrollment, while 40% reported consumption of
1-20 ounces (up to 1 or 1.5 drinks per day), and 10% reported
drinking 21 to 70 ounces (about 1.5 to 4 drinks per day).
During the next 14 years, 281 people developed heart failure,
including 28 fatalities. The rates of heart failure for every
1000 people per year were 16.1 for abstainers; 12.2 for those
who drank 1-1.5 drinks per day; and 9.2 for those who drank
more heavily. Statistical analyses that adjusted for other
differences among these groups concluded that light drinking
reduced one's risk for heart failure by 19%, and moderate or
heavy drinking reduced the risk by 53%.
Because moderate drinking
can easily progress to problem drinking, no experts feel comfortable
in encouraging nondrinkers to take up alcohol for medical reasons.
However, researchers are debating whether some people who have given
up alcohol might be encouraged to resume it. Future research may also
define certain subgroups who can benefit most from alcohol, perhaps
by raising their HDL cholesterol.
September 2001 Update
Back
to Top
Lung
Volume Reduction Surgery Poses High Risk for Certain Patients
Patient eligibility for lung volume reduction surgery (LVRS), a procedure
for treating emphysema, has been modified because of early findings
from the National Emphysema Treatment Trial (NETT).
NETT, a five-year randomized study, is comparing the safety and effectiveness
of LVRS with medical treatments, such as medications and exercise rehabilitation,
in patients with advanced emphysema. The study has already found emphysema
patients who have severe lung obstruction with either limited ability
to exchange gas when breathing or damage that's evenly distributed
throughout their lungs receive little benefit, and are at an unacceptable
high risk of death from the surgery.
LRVS is believed by some to improve the ability to move air in and
out of the lungs by surgically removing up to 30 percent of the diseased
lung
— targeting the most damaged regions — with the expectation
the remaining lung will have better air exchange. However, high-risk
patients who survived the surgery were found to have only slightly
improved functional outcomes and quality-of-life scores six months
later.
As a result, NETT is no longer enrolling patients who have a forced
expiratory volume (FEV) in one second that's less than 20 percent of
their predicted value, plus one of the following characteristics: severe
loss of lung surface area or homogeneous (evenly distributed) damage
to the lung caused by the disease.
September 2001 Update
Back
to Top |
