By Elise Viebeck - 05/02/14 06:00 AM EDT
ObamaCare enrollment beat the administration's projections in the majority of states with competitive Senate races, according to an analysis by The Hill.
Seven states exceeded expectations by the end of the special enrollment period in mid-April, including six with Senate seats currently held by Democrats.
The trend bodes well for Democratic candidates hoping to neutralize healthcare attacks and avoid politically perilous rate hikes on the exchanges.
While many factors contribute to insurance prices, higher enrollments will help stabilize the marketplaces as they enter their second year.
The analysis used enrollment data reported Thursday by the administration and compared it to projections made by federal health officials in September of last year.
The projections appeared in an internal Department of Health and Human Services (HHS) memo dated Sept. 5 that has been widely circulated.
Nearly every state experienced a dramatic surge of sign-ups in March and April that boosted its total number.
In Louisiana, which beat its target by 8 percent, more than half of enrollments took place in the last six weeks.
New Hampshire and North Carolina had the best results of the 11 states, achieving 211 and 187 percent of their enrollment goals.
Sens. Jeanne Shaheen (D-N.H.) and Kay Hagan (D-N.C.) are both considered vulnerable this cycle.
Michigan, Colorado, Montana and Georgia also beat expectations.
Responding to the numbers, the Democratic Senatorial Campaign Committee said Republicans should not count on ObamaCare as a winning issue for November.
"Regardless of projections, the Republican position of repeal is becoming more problematic for GOP candidates by the day," said DSCC spokesman Justin Barasky in a statement.
"Each of these races will come down to a clear choice between Democrats who are fighting for their states and Republicans who are beholden to the irresponsible Koch brothers agenda that helps billionaires and hurts the middle class."
Insurers are working to calculate 2015 premiums by comparing this year's enrollment data to what they anticipated in setting current rates.
While increases will vary by carrier, states with higher enrollments from young and healthy people are generally less likely to see dramatic price hikes.
Most of the 11 states achieved enrollments of people ages 18 to 34 that were near or exceeded the national share of 28 percent.
While falling short of the 40 percent seen as ideal, this share does not spell doom for premiums, according to healthcare experts.
Not all states achieved success, the analysis found.
Kentucky came in last with 37 percent based on an enrollment goal of 220,000, raising questions about how stable its premiums will be next year.
An administration official called the conclusion unfair, arguing the target represented a combination of projected exchange and Medicaid enrollments.
A spokeswoman for the Kentucky exchange did not immediately respond to a request for clarification.
Nonetheless, any significant spikes could create problems for Alison Lundergan Grimes, the Democrat challenging Senate Minority Leader Mitch McConnell (R-Ky.).
Alaska, Iowa and Arkansas performed better but still did not reach their goals. Democrats are hoping to keep seats in all three states.
The White House pointed to strong Medicaid enrollment in states like Arkansas and Kentucky, which Democrats believe will benefit their candidates politically.
But Brook Hougesen, a spokeswoman with the National Republican Senatorial Committee, disputed the numbers generally by questioning how many people have paid their first premium.
"If the Obama administration has great numbers of those who have paid, why aren't they releasing them?" Hougesen said in a statement.
"It's becoming clear that Democrats like Mary Landrieu, Kay Hagan and the Obama White House continue to make one misleading claim after another and voters are left paying the price."