An estimated 160,000 lives are lost each year from avoidable medical errors in hospitals.

Safety statistics are improving. The number of avoidable hospital deaths in 2016 was far higher, a total of 205,000.

There are steps consumers can take to make sure their hospitals are safe.

There's yet another task health-care consumers need to add to their to-do lists: Check hospital safety ratings.

The Leapfrog Group last week released its annual hospital safety grades -- and the results are both alarming and useful. Leapfrog, a nonprofit that represents employers and other purchasers of health care, surveyed about 2,600 general, acute care hospitals in the U.S. and assigned each a letter grade from A through F. The organization, which represents big employers and other health-care purchasers, also contracted with the Johns Hopkins Armstrong Institute for Patient Safety and Quality to further analyze the data.

The result? Patients at D and F-graded hospitals are at a 92% greater risk of dying from safety problems, such as mistakes, infections and falls, compared to hospitals that received an A grade. Hospitals that received a C or B also had significantly higher numbers of avoidable deaths — 88% and 35% respectively.

Overall, the Institute found that an estimated 160,000 lives are lost annually from avoidable medical errors. That's an astounding number but, it is a significant improvement over the 205,000 avoidable deaths the Institute calculated in 2016. "Hopefully the letter grades serve as a motivator for hospitals to improve their safety records," said Erica Mobley, director of operations for Leapfrog.

Mobley strongly suggests consumers keep track of the safety records of hospitals they may be admitted to or are in their area. "Consumers don't always realize that in many cases they have a choice of hospitals," Mobley said.

Doctors often have privileges at several area hospitals and in a non-dire emergency, patients can often direct ambulance drivers to a specific facility, she explained. "Safety should be an important part of making a hospital decision," Mobley added.

But like all types of data-driven rankings, understanding and interpreting hospital safety scores can be complicated. Here's what you need to know.

Behind the letter grades

Leapfrog used data from the Centers for Medicare & Medicaid Services and its own annual survey to grade more than half of the estimated acute care hospitals in the U.S. Leapfrog does not grade veterans, military, specialty or surgical hospitals. You can check for a specific hospital's grade on Leapfrog's website.

The Leapfrog survey asks for information and simulations concerning safety, and also other general information such as data on maternity services. All of the data and the letter grade is open to consumers on the website.

But some hospitals decline to fill out the survey, which can take as much as 40 to 80 hours to complete. Or they may only fill out part of it. In those cases, data that Leapfrog can find independently from CMS and often from the American Hospital Association survey (the results of which are not disclosed to the public) is reweighted and used to calculate the grade. Whether or not a hospital cooperated with the survey is noted next to its grade.

Compare with other rankings

It's a good idea to check other rankings for hospitals in your area. CMS issues star ratings (from one to five, five being the best) to most hospitals, which consumers can access through its hospital compare tool. And the U.S. News and World Report annual hospital ranking is another popular resources.

Used all together, the combination of rankings can give patients a broad look at the quality of specific hospitals. But don't be surprised if you end up having to decipher large discrepancies in the grades.

That's because of the different ways hospitals are evaluated. CMS's stars, for example, are based on general quality control measures and performance data the agency collects, including inpatient and outpatient treatments. Because this is a broader measure than the Leapfrog safety grades, the same hospital can have very different results in each.

The same goes for the U.S. News and World Report annual hospital ranking. This rates hospitals based on specialties, procedures and care for specific conditions. If your hospital makes the list, that's great. But also look closely at the other published data in the survey, including information under the heading "patient experience", which includes feedback on safety and communication.

What to do when your hospital earns a bad grade

Many times patients simply have no choice but to go to a C-grade hospital or worse. You may live in one of the many rural communities with few hospital choices. Or, your doctor may insist on a particular facility. (Many hospitals have state-of-the-art equipment and treatments, but still lack excellence when it comes to routine safety.) And, of course, in a dire emergency getting care as quickly as possible is the main priority.

When that happens, Mobley suggests the following:

Get an advocate . Have a friend or family member check on you frequently. If you're in the hospital, you're simply not at your best. An advocate can help keep an eye out for basic safety precautions better than you will be able to.

. Have a friend or family member check on you frequently. If you're in the hospital, you're simply not at your best. An advocate can help keep an eye out for basic safety precautions better than you will be able to. Speak up. Whether it's you or your advocate, "the importance of speaking up cannot be overstated," said Mobley. If anything seems different or unusual, ask about it. Yesterday you got pink pills but today they are yellow? Ask. There may be a perfectly good explanation, but it never hurts to find out.

Whether it's you or your advocate, "the importance of speaking up cannot be overstated," said Mobley. If anything seems different or unusual, ask about it. Yesterday you got pink pills but today they are yellow? Ask. There may be a perfectly good explanation, but it never hurts to find out. Ask everyone to wash their hands . If a nurse, doctor or other practitioner or staffer comes into your room to treat you and doesn't wash their hands, ask them to do so. This is the easiest way to prevent infection.

. If a nurse, doctor or other practitioner or staffer comes into your room to treat you and doesn't wash their hands, ask them to do so. This is the easiest way to prevent infection. Bring a list of your medicines. Errors involving medicines, including the wrong dosage, getting another patient's drugs or receiving medicines that interact with drugs and supplements you are already taking are some of the most common hospital safety errors, according to Leapfrog data. Always bring a list of the medicines you take with you to the hospital and make sure it is entered into your chart. Look for hospitals that use a computerized order entry -- a system that allows practitioners to enter medicines into to the pharmacies database to detect potential errors and allergies -- and bar coding systems that can wrist bands and medications to make sure they match.

Errors involving medicines, including the wrong dosage, getting another patient's drugs or receiving medicines that interact with drugs and supplements you are already taking are some of the most common hospital safety errors, according to Leapfrog data. Always bring a list of the medicines you take with you to the hospital and make sure it is entered into your chart. Look for hospitals that use a computerized order entry -- a system that allows practitioners to enter medicines into to the pharmacies database to detect potential errors and allergies -- and bar coding systems that can wrist bands and medications to make sure they match. Avoid falls. People at high risk of falls, recovering from hip surgery, for instance, need to be diligent. Always call a nurse or aid to help get in and out of bed after surgery. Make sure no visitor chairs or extra items are cluttering the path to the bathroom.

These precautions work for every hospital patient, Mobley said. "Even if you're in an A hospital, keeping an eye on these basics is really important."