 In either case, the HMO takes a greater level of involvement in the patient's care, assigning a case manager to the patient or a group of patients to ensure that no two providers provide overlapping care, and to ensure that the patient is receiving appropriate treatment, so that the condition does not worsen beyond what can be helped.Although businesses pursued the HMO model for its alleged cost containment benefits, some research indicates that private HMO plans don't achieve any significant cost savings over non-HMO plans.Although out-of-pocket costs are reduced for consumers, controlling for other factors, the plans don't affect total expenditures and payments by insurers.