Chronic Disease Research Group Study Shows Daily Home Hemodialysis Therapy with the NxStage Medical, Inc.'s System One(TM) is Associated with Lower Risk of Mortality and Higher Survival Estimates Compared to Conventional Thrice-Weekly Dialysis

LAWRENCE, Mass., April 28, 2011 /PRNewswire/ -- NxStage Medical, Inc. (Nasdaq: NXTM), a leading manufacturer of innovative dialysis products, today commented on study results presented by the Chronic Disease Research Group (CDRG) showing daily home hemodialysis with the NxStage System One is associated with reduced mortality and higher survival estimates for patients when compared with conventional thrice-weekly therapy. The retrospective cohort study examines the mortality and three-year survival rates of 1,873 daily home hemodialysis (DHHD) patients using the NxStage System One between 2005 and 2007, to a matched cohort of 9,365 in-center hemodialysis patients from the United States Renal Data System (USRDS) database. CDRG is a nonprofit division of the Minneapolis Medical Research Foundation committed to investigating chronic illness to improve public health, including leveraging USRDS data to conduct studies.

The study, "Relative Mortality in Daily Home and Matched, Thrice-Weekly In-Center Hemodialysis Patients," conducted by CDRG was presented at this week's National Kidney Foundation 2011 Spring Clinical Meeting in Las Vegas.

"This is the first study of its kind to carefully match the daily home hemodialysis patient population with comparable in-center dialysis patients based on variables such as comorbidity and severity of disease, determining the impact on mortality," said Dr. Allan Collins, professor of medicine, University of Minnesota, and director, Chronic Disease Research Group. "Results show a reduction in mortality for daily home hemodialysis patients consistent with recently published National Institutes of Health data on frequent home dialysis versus in-center therapy, though additional studies are needed to assess patient hospitalization risk and type of hospitalization."

Researchers compared daily home hemodialysis patient data with the USRDS registry, including those patients who either had Medicare as the primary payer for greater than three months before DHHD initiation or began renal replacement therapy less than six months before initiation. Unique to this study is the detailed matching process the researchers developed based on an ordered set of covariates that could impact mortality. These covariates included age, hospital days during preceding three months, epoetin alfa dose during preceding three months, body mass index, transplant waiting list status, congestive heart failure, renal replacement therapy duration, race, cancer, primary End Stage Renal Disease (ESRD) cause, stroke, peripheral vascular disease, other cardiac disease, diabetes, ischemic heart disease, gender and dual eligibility for Medicare and Medicaid.

"We commend Dr. Collins and the CDRG for conducting the largest, broadest, most rigorously analyzed study of survival in the daily home hemodialysis population to date," said Jeffrey H. Burbank, Chief Executive Officer, NxStage Medical Inc. "This study reaffirms our belief that the clinical evidence overwhelmingly supports the significant benefits of more frequent dialysis with the System One at home. We look forward to continue to work with policy makers to ensure patient access to this life-changing therapy."

About NxStage Medical

NxStage Medical, Inc. (Nasdaq: NXTM) is a medical device company, headquartered in Lawrence, Massachusetts, USA, that develops, manufactures and markets innovative systems for the treatment of end-stage renal disease, or ESRD, and acute kidney failure. NxStage is leading the development of the home hemodialysis market in the US with the only portable hemodialysis machine, the System One, cleared for home use by the FDA. For more information on NxStage and its products, please visit the company's website at http://www.nxstage.com/.

Forward-Looking Statements

This release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this release that are not clearly historical in nature are forward-looking, and the words "anticipate," "believe," "expect," "estimate," "plan," and similar expressions are generally intended to identify forward-looking statements. All forward-looking statements involve risks, uncertainties and contingencies, many of which are beyond NxStage's control, which may cause actual results, performance, or achievements to differ materially from anticipated results, performance or achievements including factors that are discussed in NxStage's Annual Report on Form 10-K for the year ended December 31, 2010 filed with the SEC. NxStage is under no obligation to (and expressly disclaims any such obligation to) update or alter its forward-looking statements, whether as a result of new information, future events or otherwise.

CONTACT: Kristin Sheppard, 1-978-332-5923, ksheppard@nxstage.com

SOURCE NxStage Medical, Inc.