Star ratings for medical apps can be misleading. Here’s the best way to determine which ones are right for you.

Earlier this year, the Pew Research Center reported that 95 percent of Americans now own a mobile phone, and 77 percent own smartphones.

That number is up from 35 percent the last time similar data was gathered in 2011.

It’s an indicator that we are becoming more dependent on the technology that connects and informs us. Every day, new software is being created to help with a variety of everyday tasks — including managing our health — at the touch of a screen.

Mention a problem, and someone around you is bound to proclaim, “There’s an app for that.” The first quarter of 2018 found 3.8 million apps available to Android users, and 2 million apps up for grabs in Apple’s App Store.

Over 325,000 of those apps, across both types of devices, are medical apps.

Some may be surprised to learn that a number of these apps are even considered medical devices. However, the growing number of them can make selecting a useful app confusing, and if you’re letting an app’s high rating influence your downloading decisions, chances are you’re not selecting the app that’s best for you.

In fact, five-star ratings don’t mean a medical app or devise even works.

In a new report following up on a previous 2016 study, researchers at Johns Hopkins University found additional evidence that high ratings don’t reflect the validity of a medical app.

The researchers analyzed over 250 user reviews of an app that once claimed to turn an iPhone into a blood pressure monitor.

The app, called Instant Blood Pressure, was proven to be inaccurate and removed from the market in July 2015. But despite warnings to users to not rely on the app for medical monitoring, the app continued to be popular up to the point it was removed from the app store.

The researchers concluded that consumers treated app purchases in the same way they might treat online shopping, relying on user reviews to guide them to the app that might best meet their needs.

But when it comes to medical apps, user reviews don’t stand up to clinical trials or U.S. Food & Drug Administration (FDA) approval.

In testing, the Instant Blood Pressure app was found to produce inaccurate, non-elevated results, four out of five times. Nevertheless, in the app store it maintained a four-star rating, with 42 percent of the reviewers commenting on just how accurate the app was.

Some of those reviewers even claimed to be medical professionals, giving the app their seal of approval.

“We’ve done research that’s found patients like being told their blood pressure is lower than expected. So, the higher ratings may have actually been driven by inaccurate data,” said study author Dr. Timothy Plante, an assistant professor of medicine at the Larner College of Medicine at the University of Vermont. “With the example of the blood pressure app, you can’t check blood pressure unless you have a blood pressure cuff. But a lot of folks will download an app and just assume it works.”

He added, “We know there is empowerment in managing one’s own blood pressure, but when patients are titrating their blood pressure medication and managing it based on bad data, that’s a big problem.”

In short, yes. However, the full answer is a bit more complicated.

First, you need to understand what counts as a medical app. If you have a step counter, a period tracker, or a fitness app on your phone — you’re using a medical app. But these types of apps don’t carry as much risk as those that promise to replace actual medical devices.

Healthline spoke with Jill Sakowski, a mom with epilepsy who uses an app to track her seizures.

“I can push a button when I feel a seizure coming on and then I know how long it lasted. My guesses are always way off, so it’s very helpful,” she said.

She also uses the app to indicate what type of seizure she had, what her warning signs were, her specific symptoms, and other information her neurologist finds helpful in making his recommendations.

For Sakowski, the app does help her manage a serious condition, and Plante acknowledges the potential benefits of many medical apps.

However, the problem, as he sees it, is how unregulated they are — making it difficult for consumers to know which apps are actually safe to use and rely on.

In fact, Sakowski says she only discovered the app she currently uses to help manage her seizures through trial and error, trying several others before finding one she felt worked for her.

“There are only a handful of FDA-approved medical apps,” Plante said. “Of the mobile health apps that exist, a lot are very low risk, more like a pad of paper for writing your blood pressure or medication reminders on.”

He says it’s the “high-risk” apps that concern him most — those apps that claim to be equivalent to FDA-regulated devices such as blood pressure cuffs, stethoscopes, or heart monitors.

“I’d like to say ask your doctor if you should use an app or not, but this isn’t something they’re teaching in medical school,” Plante said. “And I think even in the medical profession, there are people who are well-meaning and want to keep up with the technology, but who don’t necessarily understand the limitations.”

Outside of low-risk apps such as fitness or medicine trackers, Plante advises only using FDA-approved apps.

As of this writing, the FDA has approved more than 100 medical apps, and they’ve stepped up their approval process substantially in the last two years.

But many app creators don’t even realize their apps may potentially require approval. And the risks are low for those who don’t want to bother jumping through those hoops. Often, if an app is shown to be inaccurate, it simply gets taken down.

“It’s the wild west with app stores,” Plante said. “It doesn’t take much to get a smartphone app onto the app store. And it also doesn’t take much to make an app store listing seem high-quality.”

So, buyer beware and proceed with caution. Any medical app you download should be heavily scrutinized. At present, there simply aren’t enough regulations in place to accurately determine the validity of most higher-risk medical apps — and those five-star ratings most likely aren’t a good indicator either.