The war against Polypharmacy: A New Cost-Effective Geriatric-Palliative Approach for Improving Drug Therapy in Disabled Elderly People
A study from 2007 showed that:

•The death rate dropped: 21% of the test subjects died vs 45% of the control group
•The annual rate of hospital referrals dropped: 11.8% of the study group died vs. 30% of the controls
•There were significant cost savings from withdrawing the unneeded medications

For more in-depth discussion of the study: