CNA Financial Corp. reported a profit of $273 million in the fourth quarter of 2019, compared with an $84 million loss in the year-earlier period that the company attributed to high catastrophe losses and low investment earnings.

The fourth-quarter 2019 results continued “strong underwriting performance” and increasing premium rates, Dino Robusto, CNA’s chairman and chief executive officer, said during an earnings call Monday. “Now it is fair to point out that I had categorized the 2018 fourth-quarter results as an outlier. … An improvement in the subsequent quarters proved that out.”

Revenue grew 3% to $1.91 billion in the most-recent quarter, compared with fourth-quarter 2018, with nearly two-thirds of the revenue growth attributed to net investment income, according to the company’s financial supplement.

“Strong underlying performance in both commercial and specialty, combined with improved international performance, drove the strong results,” Mr. Robusto said.

In the insurer’s property/casualty segment, net written premiums improved 5% to $1.75 billion in the quarter compared with fourth-quarter 2018. The combined ratio jumped nearly 10 points, from 105.4% in fourth-quarter 2018 to 95.6% in the same quarter 2019. This reflected a substantial decrease in catastrophe losses, from $146 million in fourth-quarter 2018 to $51 million in the same quarter of 2019, as well as an increase in net investment income.

In specialty, net written premiums in the quarter grew 3% to $705 million, compared with the same quarter in 2018, and the combined ratio improved 3 points to 88.2%. Commercial also saw improvement, with net written premiums growing 8% to $779 million in fourth-quarter 2019, driven by strong retention, new business and favorable rates, according to the company.

For all of 2019, CNA reported net income of $1 billion, up from $813 million in 2018.

In its aging services book, the company has continued to introduce large deductibles on medical malpractice coverage, Mr. Robusto said, which had a positive impact on frequency trends. CNA has also seen a flattening in attorney involvement in aging services claims for the past several years, he said.

Unlike many insurers that have been affected by social inflation, CNA has not seen any significant change in attorney involvement in claims in any of its lines of business, Mr. Robusto said on the analyst call.

“We’ve actually seen slightly lower levels of attorney involvement in primary auto,” he said. Although the insurer has seen a slight uptick in attorney involvement in primary general liability, overall across all lines “it hasn’t really changed,” he said.