A new study examines the potentially fatal impacts of Medicaid cuts in the new Republican-backed spending bill.

WASHINGTON—Senate Republicans detailed major revisions of the House’s giant tax-and-spending bill, offering more permanent business tax breaks, deeper cuts to Medicaid, slower phaseouts for clean-energy tax credits and a much lower cap on the state and local tax deduction.

Proposed Medicaid cuts in the House Republicans’ sprawling domestic policy bill could cause an estimated 7.6 million Americans to lose health insurance.