(CBS News)-- This past week, there was good news and bad news about diabetes in the U.S.
CBS News Chief Medical Correspondent Dr. Jon LaPook credits the variety of medications available for the improvement in numbers.
"We're getting better in diagnosing; there are improvement medicines to lower blood sugar, better insulin, better oral medications," LaPook said on "CBS This Morning: Saturday." "There's also statins to lower cholesterol and blood pressure medications."
But the bad news is that the number of people in the U.S. who have diabetes has increased, due to the obesity epidemic, LaPook said.
The number of people who are confirmed to have diabetes has increased from 6 percent to 10 percent over the past 20 years, according to the journal Annals of Internal Medicine.
In 2010, approximately 21 million American adults aged 20 or older have diabetes, and 79 million Americans have pre-diabetes.
"We're doing well in treatment, but this is a preventable illness," said Dr. LaPook. "We do particularly badly in non-Hispanic blacks and Mexican Americans. So that's an area we really have to focus our attention on.
Also this week, a new study published in the journal BMJ Quality and Safety says 1 in 20 U.S. adults are misdiagnosed by their doctors every year -- that's 12 million people nationwide.
One-half of those errors are potentially harmful.
"These are really alarming numbers when you look at it. When you think about the hundreds and millions of outpatient visits that happen every year, these numbers suggest in about five percent of those visits patients are actually misdiagnosed," said CBS News contributor Dr. Holly Phillips on "CBS This Morning."
When asked why misdiagnosis is so common among outpatients, Dr. Philips noted several factors.
"Some of it has to do with the doctor's fault -- misinterpreting lab results, giving incorrect medications. Some of it has to do with the patient -- they might give incomplete or incorrect medical histories," she said. "But a lot of it has to do with how medicine happens today. Basically, visits are very short. Everyone is crunched for time ... and that's where I think mistakes happen."
Dr. LaPook advises patients to be aggressive with their doctor to make sure they have all the information they need, such as family medical history and knowing what medications they are taking.
"Help your doctor to help you," he said.
Emmitt and Owen Ezell were born conjoined. They shared a liver and some of their intestines, until separation surgery in August. They were taken to a rehab center this past week.
"They're doing so well," their mother, Jenni Ezell, told CBS News. "Look at how beautiful they are." She says they're sitting up on their own and "flirt with all the girls that come in."
Doctors say the twins are no longer being fed intravenously but continue to be fed through tubes in their abdomens. And instead of being hooked to breathing machines, they now need only the assistance of a trachea tube.
"I think we can say, 'Alright, this is finally... this is normal.' Even if it's normal with the boys and they've got feeding tubes and trachs, but they're home," said father Dave Ezell. "That's going to be normal. That's going to be fantastic."
Two studies out this week highlight the long term dangers of concussions in teen athletes.
Canadian researchers say teens who suffer traumatic brain injuries during sports have a much higher risk of suicide attempts. Teen who suffer a traumatic brain injury are more likely to have emotional and behavioral issues leading them to do things like damage property, take a car without permission, sell marijuana, run away from home or fight at school, according to scientific journal PLOS ONE.
Another study this week said that many teens don't get enough down-time in the off-season. In the study, researchers looked at football players right at the end of their season, many of whom had signs of traumatic brain injuries. They then looked at them during their off-season, when they weren't playing as vigorously; many of the athletes still hadn't healed and the injuries were still there.
Dr. Philips said the off-season needs to be a true off-season where players are not playing or practicing.
"The body has this incredible ability to heal itself if you let it," she said.