With a Senate vote on the GOP’s tax reform bill expected to come before the end of the week, advocacy groups are urging lawmakers to reject the legislation for its potentially “drastic” effect on Medicare and Medicaid.

The tax plan, which was passed by the House of Representatives earlier this month, has garnered criticism from healthcare provider groups for provisions they say could hurt seniors, such as its elimination of the medical expense deduction.

In a post published Tuesday, Barbara Gay, vice president of public policy communications for LeadingAge, said the group’s primary concern is the bill’s potential toll on the federal budget, which could in turn jeopardize Medicare, Medicaid and other programs vital to seniors.

“With a massive revenue loss widening an already large budget gap, it is completely foreseeable that enactment of H.R. 1 would lead to calls for huge cutbacks in federal spending on programs serving elders,” Gay wrote. “We have already seen budget proposals calling for hundreds of billions of dollars in Medicare and Medicaid cuts.”

While the bill making its way through the Senate differs slightly from the one that passed the House, Gay warned that both contain provisions that are “problematic for our field and also would enormously expand the federal budget deficit,” such as eliminating deductions and tax exemptions.

LeadingAge joined dozens of other aging and healthcare-focused groups on Monday in a letter to Senate leaders urging them to “start over” on the reform bill and create legislation that wouldn’t slash healthcare access for older adults or people with disabilities.

The groups, which included the American Geriatrics Society, the Center for Medicare Advocacy and the National Consumer Voice for Quality Long-Term Care, also expressed concerns that the deficit created by the bill could trigger Medicare and Medicaid cuts. In addition, the letter described the group’s dismay over the “rushed and partisan process” of the legislation.

“Historically, the Senate has worked through a bipartisan, transparent process that included public hearings, open comment periods on discussion drafts, multi-stakeholder meetings, and more,” the letter reads. “Any changes to the tax code should be thoughtful and deliberative.”