麻豆传媒

While out-of-pocket caps on insulin indeed cut down on costs for commercially insured patients in the U.S., the policies didn't do much to increase insulin use, claims data showed.

After such policies were implemented in eight such states, insulin users under age 65 had a 17.4% (95% CI -23.9 to -10.9) relative reduction in costs compared with users in control states, a difference that translated to an average $11.46 (95% CI -15.96 to -6.96) reduction in monthly costs.

But there was no difference in mean 30-day insulin equivalent fills per month before to after implementation when compared with control states, reported researchers led by Laura Garabedian, PhD, MPH, of Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston, in .

The drop in insulin costs with state-wide insulin caps was largely driven by reductions for enrollees with health savings accounts (HSAs) that require high insulin out-of-pocket payments, according to the study. This group had a 43.4% relative drop in monthly costs marked by an average $61.58 monthly saving. On the other hand, nonaccount plan members -- people with no HSA or health reimbursement arrangements (HRAs) -- didn't have any significant out-of-pocket savings.

"Our findings suggest that the proposed national $35 insulin cap for commercially insured persons would reduce OOP [out-of-pocket] costs by a large degree for HSA plan members but have little effect on OOP costs for nonaccount plan members, who comprise the vast majority of the commercial market," the researchers noted. They added that "even a national policy that successfully reduces patient-facing insulin OOP costs might be unlikely to contain long-term insulin price inflation, which is ultimately passed on to health plan members through premium increases."

On the lack of change in average 30-day insulin fills per month, this held true regardless of plan type and when looking separately at states with $25 to $30 out-of-pocket caps and states with a $100 cap.

Because of this, the researchers said that "other policies might be needed to improve access to affordable insulin among commercially insured patients with diabetes who have cost-related underuse."

" evaluated the effect on insulin use of Medicare's $35 insulin OOP cap that was implemented in 2023," they pointed out. "In contrast to our overall findings, this study found that insulin use gradually increased among Medicare beneficiaries."

This likely happened for a few reasons, Garabedian told 麻豆传媒. One was that insulin use was already adequate in the current study's population, which mainly focused on commercially insured members in largely higher-income areas of the U.S.

"We did see an increase in insulin use among lower-income members with diabetes in HSA plans in states with more generous caps (i.e., $25-30)," she highlighted. For these patients in states with the most generous caps, there was an average increase of 53.2 (95% CI 24.8-81.7) fills per 1,000 lower-income HSA members, a relative increase of 31.2%.

"Other reasons for our finding that the state insulin cap policies didn't impact insulin use, overall, could be that the caps weren't generous enough to increase use, or that patients and their doctors weren't aware of the caps," she added. "I think people are more aware of these state policies now -- the time period of our study was before the implementation of the Medicare $35 insulin cap and the 2023 and 2024 State of the Union Addresses, in which President Biden called for a $35 insulin cap for the commercially insured."

She added that her group also only looked at the impact of the state insulin caps over the first 9 months of the policies. "It is possible that insulin use would have increased over a longer follow-up period," she said. Other study limitations included an overrepresentation of states with a larger enrollment in the health insurer studied, and the possibility that "caps might have shifted insulin use toward higher-cost and potentially safer and more convenient products," such as , the author stated.

The primary analysis included 79,794 members under age 65 with diabetes who were continuously enrolled in the same plan type -- HSA, HRA, or a nonaccount plan. They had the same fully insured or self-insured status for 1 year before and at least 1 month after the states' implementation of the insulin out-of-pocket cap.

Member-level claims data were pulled from Optum's deidentified Clinformatics Data Mart Database, which included enrollment information and all medical and pharmacy claims. Garabedian's group analyzed data from eight states that enacted insulin out-of-pocket cap policies in January 2021. This included three states with caps of $25 to $30 (New Mexico, Maine, Utah); one with a $50 cap (Virginia); and four with $100 caps (Washington, New York, Illinois, and Delaware). They were compared with 17 "control" states that had no out-of-pocket caps during the study period.

"We used a controlled pre-post design (difference-in-differences) to estimate changes in outcomes before versus after implementation of insulin OOP caps in the intervention states versus the control states," the researchers explained.

As expected, people in the three states with the most generous caps had greater average savings in monthly costs ($27.82). Those with HSA plans in these states had an average $64.11 monthly cost savings. For those in states with $100 caps, there was an average $8.81 in savings, with HSA plan members in these states saving an average $58.66 a month.

"Clinicians and population health managers should be aware of their state's insulin OOP cost caps and should facilitate appropriate therapy among patients with cost-related insulin underuse," Garabedian concluded.

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