Citing continued increases in health-care costs, Wellmark Blue Cross and Blue Shield is seeking a 10.8 percent premium increase for the majority of its individual policyholders in Iowa next spring.

If Wellmark’s request is approved by the Iowa Insurance Division, approximately 46,000 Iowa policyholders under age 65 will see an increase in their base premium rate of 10.8 percent, effective April 1. Approximately 3,000 Basic and Standard policyholders will receive an increase of 11.3 percent, and about 2,500 2500 Blue Transitions policyholders will receive a 15 percent premium hike.

The increases do not apply to policyholders with Medicare products, the company said in a press release.

In March, Wellmark received approval to increase individual premiums by an average of 18 percent; that increase went into effect on May 1. That increased was delayed a month while an independent review was conducted at the request of Gov. Chet Culver. Insurance companies in Iowa must obtain approval state approval for individual policy increases, but not for group health plans.

Among the factors driving up expected costs are chronic conditions such as obesity and diabetes, as well as increases in joint replacement surgeries for people at younger ages.

The cost of drugs to treat chronic conditions such as high blood pressure and diabetes has increased significantly.

Wellmark said the portion of policyholders’ premium dollars used to pay administrative expenses will decrease during the 2011 rating period, reflecting operational efficiencies the company has achieved in the last year. This includes an estimated 18 percent per square foot savings in operational costs in Wellmark’s new Des Moines headquarters when compared with remaining in the four buildings Wellmark occupied in 2010, the company said.

The insurer said that last year it spent 94 cents out of each dollar on health-care services, which exceeded the minimum 80 percent that will be mandated beginning Jan. 1 under federal health-care reform.