Hip Replacements

Research in the Journal of the American Medical Association reviews trends in hip replacements, an increasingly common and expensive procedure.  (JAMA Article) About 280,000 hip replacements are performed annually, at a cost of more than $12 billion.  The procedure has been around for many years and presumably outcomes have improved over time, but there is not a lot of research to support this hypothesis.  Since the procedure is often used on older Americans, the researchers looked at experience with hip replacement in the Medicare program from the years 1991 through 2008.

The primary outcomes being evaluated were mortality, length of stay, place of discharge, and all cause readmission.  There were almost 1.5 million primary hip replacements and 350,000 revision procedures paid for by Medicare in the study’s time period.  The average age of the recipient increased slightly, from 74.1 years old in 1991 to 75.1 in 2008, but the number with diabetes and obesity increased dramatically.  The average length of stay declined significantly, from 9.1 days to 3.7, which is consistent both with the DRG payment incentives and the general belief that getting patients out of the hospital as soon as possible in best for their overall outcomes.  Mortality in the hospital declined from .5% to .2%, also consistent with the lower LOS.  And overall mortality at 30 and 90 days after discharge also decreased, indicating better outcomes.

The number of patients discharged to home, however, decreased from 68% to 48%, with most of the difference showing up in discharges to skilled nursing facilities.  Readmissions after 30 days increased from 5.9% to 8.5%, after an intermediate decline.  A similar result occurred for 90 day readmissions, with both trends likely reflecting use of the procedure on sicker patients over time.  While mortality is good, it appears possible that DRG incentives have lead to pushing patients out quicker, with more use of SNFs and more readmissions.  The total economic impact of these events was not delineated by the researchers.  Bundled payments may result in more careful discharge timing and planning.