Health insurers have had to deal with higher-than-expected medical costs in 2008, but next year looks like it could be equally challenging for HMOs, albeit for an entirely different reason.

Yesterday, UnitedHealth Group (NYSE:UNH) was the first of the health insurers to release third-quarter earnings. The company moved up its release by five days, presumably to prove that it isn't in the same class as AIG (NYSE:AIG). While it accomplished that goal -- it's had capital gains of $58 million year to date -- its premonitions for next year were far from stellar.

The company is looking for earnings between $2.90 and $3.15 per share next year, compared to the $2.80 to $3.00 that analysts are expecting in 2008. That's not a whole lot of confidence that it can grow its business, and in fact, enrollment of members into its UnitedHealth care business is expected to be down year over year in the first quarter of next year.

The problem, of course, is the jobs numbers. As employers cut back on the number of employees, they also cut back on the number of people insured. Not a good sign for UnitedHealth and the rest of the health insurers.

The good news for investors is that the health insurers are priced like they're not expecting any growth.

Company 

Market Cap (in billions)

Trailing P/E Ratio

CAPS Rating (out of 5)

UnitedHealth Group

$26.4

7.3

*****

Aetna (NYSE:AET)

$14.4

8.4

***

Coventry Health Care (NYSE:CVH)

$3.9

7.3

*****

Humana (NYSE:HUM)

$6.0

7.3

***

WellPoint (NYSE:WLP)

$20.4

7.3

****

Data courtesy of Capital IQ and Motley Fool Caps. Trailing P/E based on earnings through the second quarter of 2008.

Long-term investors should be salivating at these prices. Yes, the stocks aren't likely to jump anytime soon, but the growth will eventually come back. Dollar-cost average into these stocks, and the long-term fortunes should be yours.

WellPoint and UnitedHealth are Motley Fool Inside Value recommendations. UnitedHealth and Coventry Health Care are Motley Fool Stock Advisor picks. No matter what kind of companies float your boat, we've got a newsletter for you.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool owns shares of UnitedHealth. The Fool has a disclosure policy.