A monitor on Colette Morris' forearm has reversed her struggle with diabetes. Its constant data feed to her mobile phone teaches her about the foods and stresses that throw her blood sugar out of whack.

The technology isn't for everyone. Four of Morris' siblings have type 2 diabetes, and some dislike sensors attached to their arms and false alarms when blood sugar blips.

Old-school finger-stick tests work fine for them, and they still maintain safe A1C blood sugar levels, said the 68-year-old from Minneapolis. "If you're doing all that and your A1Cs are OK, maybe you don't need to know, hour by hour" all of this information.

Trouble is, nobody really knows whether the high-tech monitoring makes a difference. Continuous glucose monitors have exploded on the market — with Richfield-based Best Buy selling them through a partnership with an online clinic that prescribes them. But there is little data to prove value from the investment of $300 or more for the transmitter, and $100 per month for disposable sensors.

Enter HealthPartners. The Bloomington-based health care system launched one of the nation's first real-world clinical trials to see whether monitors provide superior health outcomes to older and cheaper finger-prick blood tests.

The head-to-head study of more than 300 Minnesotans taking insulin for type 2 diabetes was ongoing earlier this year, but just received funding to double in size.

The quality of glucose monitors has evolved, with most pairing quarter-sized arm sensors that transmit blood sugar readings to mobile devices. The key question is whether a continuous stream of blood sugar data helps people manage diabetes and prevent complications better than the point-in-time data gained from placing a drop of blood manually on a test strip.

By whatever means, blood sugar monitoring is crucial — helping people with diabetes avoid too much blood sugar (hyperglycemia) or too little (hypoglycemia). Immediate consequences include car wrecks if people are driving when their levels swoon, but long-term impacts include kidney problems and other disabilities.

Solving the economic question could prove vital. Type 2 diabetes has become a $5 billion problem for Minnesota when tallying medical costs and lost worker productivity from the disease. More than 10% of Minnesota adults were told by doctors that they have diabetes in 2022, double the proportion two decades ago, according to federal survey data.

"Using glucose data to alter lifestyle management to improve diabetes is a big deal," said Dr. Thomas Martens, a leader of the study and medical director of HealthPartners Institute's International Diabetes Center in St. Louis Park. "If one or the other of these technologies helps to do that better, it's a big deal."

"Financial toxicity" has become a problem, according to a University of Michigan study, which found that half of Americans struggle to afford their diabetes care.

Costs have skyrocketed for insulin, the medication that regulates blood sugar levels, prompting Minnesota lawmakers in 2020 to create a discount option. Their effort was named after Alec Smith, a 26-year-old Minneapolis restaurant manager who died while rationing his insulin. But medication is only one component of diabetes management, Martens said.

"All of that adds up to a lot of financial burden," he said.

Morris is eager to see the results of the study, funded privately by the Patient-Centered Outcomes Research Institute in Washington, D.C. She is a consultant for the study, guiding HealthPartners' scientists on how to communicate with participants.

Eighteen years with diabetes has made Morris something of an expert on living with the disease. It forced her to give up rice, pizza and the sourdough bread she used to make from scratch. But she said she learned even more after she switched to a continuous monitor about how stress, heat and other foods influence her blood sugar.

She has calibrated the device to avoid false readings and alarms, but sometimes she still needs to do a finger-prick test to be safe and then react if her blood sugar is low.

"In almost every coat pocket, I have Swedish Fish," she said. "That brings up my blood sugar, and I like them!"

Correction: Previous versions of this story misstated the role of insulin medication in managing type 2 diabetes.