Chronic Disease Management Act of 2018 This bill amends the Internal Revenue Code, with respect to health savings accounts (HSAs), to allow the high deductible health plans required for an HSA to provide care for chronic conditions with no deductible. The bill covers care and prescription medicines related to the treatment of medically complex chronic conditions which: (1) are substantially disabling or life threatening, (2) have a high risk of hospitalization or other significant adverse health outcomes, and (3) require specialized delivery systems across domains of care.