We get a rebate of Medicare premiums paid as part of my retirement package. How do we report the $900 received?

Late in the year we are eligible to apply for up to $900 reimbursement on our Medicare premiums from the company my husband retired from.  This is a provision of the IBM Medical plan. It is referred to as "Special Health Assistance Provision Reimbursement."(SHAP)  Do we report this as income or medical expense reimbursement?