Taxes are due April 17, and while many Americans dread the coming deadline, filing could be a saving grace for others. That's because many people use their refunds to pay for key medical expenses they had otherwise been putting off.

The JPMorgan Chase Institute analyzed the out-of-pocket spending habits of 1.2 million Americans who received a refund in 2016 and found a "dramatic link between health care spending and tax refunds."

Those who filed earliest and received their refund in February put 64 percent of their spending response toward paying for deferred care. A smaller but still startling 55 percent of those who filed in the following months did the same.

In both groups, almost all of the remaining spending went to paying bills with service-providers, with a small fraction going toward drugs or other medical supplies that could be stockpiled, according to the data.

In the week after receiving a refund, the overall level of health care spending was 60 percent higher than in a typical week over the 100 days before. Out-of-pocket spending on debit cards increased 83 percent with no offsetting change to credit-card spending, "suggesting the cash infusion provided by the tax refund was a major factor driving changes in health-care spending behavior," the report notes.

And 62 percent of spending was paid in-person at health-care providers, which "means cash-flow dynamics influenced not just when consumers paid for health care but also when they received it."