People with diabetes and severe obesity who had bariatric surgery
were 40 percent less likely to have a heart attack or stroke within 5
years than those who had usual medical care for their diabetes,
according to a new study published today in JAMA.
During the same period, those who had surgery were also more than
one-third less likely to develop heart disease — and two-thirds less
likely to die from any cause. This research was done at four systems in
the Health Care Systems Research Network: Kaiser Permanente in
Washington, Northern California and Southern California, and
HealthPartners Institute in Minnesota.
Senior author Steve Sidney, MD
“Our study’s large size contributed to its precision and allows us to
have confidence in the results that we reported,” said research
scientist and senior author Stephen Sidney, MD,
director of research clinics at the Kaiser Permanente Division of
Research in Northern California. “Another strength is the long follow-up
and comprehensive information from our health care systems, which
provide integrated care and coverage.”
The findings matter because about 30 million — more than 9 percent of
adult Americans — have type 2 diabetes, according to the American
Diabetes Association. With time, the disease tends to worsen, raising
the risks of diseases of the large blood vessels (heart attack, stroke
and heart disease) and of death. About 1 in 3 people with type 2
diabetes have a body mass index (BMI) of at least 35 kg/m2,
and according to National Institutes of Health guidelines, the disease
plus that degree of obesity makes them eligible for bariatric surgery.
Bariatric surgery includes different operations that help people lose
weight by making changes to their digestive system.
“For most people with diabetes and severe obesity, lifestyle changes
and medication may not be successful at significantly lowering those
risks,” said internist and corresponding author David Arterburn, MD,
MPH, a senior investigator at Kaiser Permanente Washington Health
Research Institute. “We’re excited about our results, which suggest that
bariatric surgery may reduce new cases of heart attack and stroke — and
risk of death from all causes.”
Members of the same research team had shown that diabetes goes into
long-term remission (for an average of 7 years) for about half of people
who undergo gastric bypass, one of the most common bariatric
procedures. Last month in the Annals of Internal Medicine,
these researchers also reported that people with diabetes who undergo
bariatric surgery have half the risk of small-blood-vessel diseases of
the feet, hands, kidneys and eyes within the first 5 years after
surgery, compared to usual medical care for diabetes.
The new study, “Association between bariatric surgery and
macrovascular disease outcomes in patients with type 2 diabetes and
severe obesity,” included 5,054 Kaiser Permanente and 247 HealthPartners
patients with diabetes and severe obesity who received bariatric
surgery. It also included a matched control group of nearly 15,000
patients who had similar characteristics but received usual medical care
for their weight and diabetes instead of bariatric surgery.
Bariatric surgeon and first author David P. Fisher, MD, noted that
the study is observational, not a randomized clinical trial, so it
cannot definitively prove that bariatric surgery caused the decrease in
the rates of heart attack, stroke, heart disease and death.
“Ideally, randomized clinical trials would confirm — or refute — our
findings,” said Fisher, who was the inter-regional chair of Kaiser
Permanente Bariatric Surgery before his recent retirement. “But such
trials are expensive and difficult to conduct, and they probably
couldn’t be done with enough patients to assess these relatively rare
“Our results add to the evidence that should inform conversations
between people with diabetes and severe obesity and their health care
providers about the potential benefits and risks of weight-loss
surgery,” Dr. Arterburn said. “We hope this helps them make more
informed decisions about their care.”
A National Institutes of Diabetes and Digestive and Kidney Diseases
award funded this study. Co-author Emily B. Schroeder, MD, PhD, at the
Institute for Health Research at Kaiser Permanente in Colorado, in
Denver, and coauthor Patrick J. O’Connor, MD, MPH, at HealthPartners
Institute, in Minneapolis, were also supported in part by NIH awards.
Additional coauthors are Sebastien Haneuse, PhD, Harvard T.H. Chan
School of Public Health Andy Bogart, MS, RAND; Karen J. Coleman, PhD,
Department of Research and Evaluation, Kaiser Permanente Southern
California; Rebecca O’Brien, MD, Division of Research, Kaiser Permanente
Northern California; and Eric Johnson, MS, Mary Kay Theis, MA, MS, and
Jane Anau, Kaiser Permanente Washington Health Research Institute.
Diabetes is an active area of research at Kaiser Permanente, with
more than 840 articles published since 2007. An overview of this
research can be found here.