Aetna Inc., which has agreed to be bought by CVS Health Corp., reported a higher-than-expected quarterly profit on Tuesday, partly due to higher premium yields in the health insurer's commercial and government businesses.

U.S. drugstore operator CVS agreed in December to acquire Aetna for $69 billion, seeking to tackle soaring healthcare spending through lower-cost medical services in pharmacies.

The CVS-Aetna deal will combine one of the nation's largest pharmacy benefits managers (PBMs) and pharmacy operators with one of its oldest health insurers, whose national business ranges from employer healthcare to government plans.

Aetna, which expects the deal with CVS to close in the second half of 2018, said the U.S. tax reform will increase gross 2018 adjusted earnings by about $800 million.

Net income attributable to Aetna rose to $244 million, or 74 cents per share, in the fourth quarter ended Dec. 31, from $139 million, or 39 cents per share, a year earlier.

Excluding items, the company earned $1.25 per share, beating analysts' average estimate of $1.20, according to Thomson Reuters I/B/E/S.

Total revenue fell nearly 6 percent to $14.85 billion, but inched ahead of analysts' estimate of $14.83 billion.