UnitedHealth Group boosted earnings guidance for the second time this year after a strong performance in the second quarter, even as it expects costs related to COVID-19 to continue in the coming months.

Earnings were off by roughly one-third compared with the year-ago quarter, when the Minnetonka-based health care giant posted huge profits amid an unprecedented shutdown of non-emergency health care due to the pandemic. The company operates UnitedHealthcare, the nation's largest health insurer, so premium revenue collected at the time far exceeded health care expenses.

Over the past year, health insurance earnings have moderated as patients have returned to the health care system. The quarter reflected those trends, with stronger financial results at the company's OptumCare business, which operates outpatient clinics, surgery centers and urgent care facilities.

"The second quarter saw overall care activity continuing to trend toward baseline or normalized levels," said John Rex, UnitedHealth Group's chief financial officer, during a call with investors Thursday. "We were gratified to see care activity for these populations begin to progress over the course of the quarter as vaccination rates advanced."

With quarterly profit and revenue beating expectations, UnitedHealth Group upped financial guidance for the year while touting growth prospects.

"The strengthening of our sales pipeline is a key opportunity as we emerge from the COVID market pause," UnitedHealth Group Chief Executive Andrew Witty said. "I have great confidence that we're emerging from the last 18 months of disruption with an unprecedented set of opportunities to help improve the health system for all of those we can serve."

UnitedHealth Group cautioned, however, that the pandemic is expected to weigh on financial results for the remainder of the year due to health care deferred in 2020, the cost of COVID-19 testing and treatment this year and broader economic factors. The company anticipates the bulk of pandemic expenses will hit during the second half of the year.

Executives have been watching for signs that deferred care will result in sicker patients who require more costly services when they return to hospitals and clinics.

"We haven't observed that yet, but it's still probably a little bit early to say," Rex said. "Among the things we look at, we look at new cancer diagnoses, new cardiac diagnoses — those are still running below baseline levels that we'd expect."

When one stock analyst asked if some of the deferred care actually wasn't needed by patients, Witty replied that the company will look closely at the issue over the next six to 12 months. There are some "tantalizing signals," Witty said, when looking at depressed utilization of emergency rooms across the country.

During the pandemic, people avoided hospitals and many may have tried urgent care centers or online telemedicine for the first time to avoid a trip to the emergency room.

"A lot of people don't expect [emergency department] utilization to come back," Witty said. "So, whether it's unnecessary, whether or not the pandemic has disturbed people's allegiance to certain types of sites of care, and people are a little bit more open minded about where to go, all of that I think is in play."

In June, UnitedHealthcare announced a new policy to stop paying for non-emergency care provided in ERs. The company subsequently delayed implementation following an outcry by physicians.

UnitedHealth Group is Minnesota's largest company by revenue and employs about 330,000 people worldwide. The company also runs a health services business called Optum, which includes a pharmacy benefits management business, health care consulting and a unit for direct patient care.

OptumHealth, the division that includes OptumCare health care facilities, posted second quarter earnings from operations of nearly $1.13 billion, up about 34% from $841 million in the year-ago period.

About 250,000 patients during the quarter underwent outpatient surgeries at Optum-owned centers, generating 20% more revenue than during the second quarter of 2019, said Dirk McMahon, chief operating officer at UnitedHealth Group. OptumCare has more than 1,600 clinics and is rapidly expanding virtual offerings, he said.

Optum plans to hire about 10,000 clinicians this year, Witty said.

For the three-month period ending June 30, UnitedHealth posted a profit of $4.37 billion on $71.32 billion of revenue, down about 34% from the year-ago quarter's earnings of $6.64 billion on $62.14 billion of revenue.

After adjusting for one-time factors, earnings per share of $4.70 easily beat the $4.46 expected by analysts surveyed by Refinitiv.

At the end of June, the company was providing health insurance coverage to more than 44 million people in the U.S., up by about 135,000 people compared with March 31.

UnitedHealth Group now expects full-year adjusted earnings of $18.30 to $18.80 per share, up from the previous range of $18.10 to $18.60 per share.

UnitedHealth Group shares closed Thursday at $420.05, up 1.3%.