Shorter Hospital Stay After Hip Replacement Surgery

Researchers Say Shorter Hospital Stay Could Be Behind Increase in Hospital Readmission Rates After Hip Replacement

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April 19, 2011 -- The average length of a hospital stay for hip replacement surgery has decreased significantly in recent years, new research indicates. But the rate of readmissions for complications or referrals to skilled care facilities has increased.

Researchers say the two findings are not likely coincidental. They say the readmissions and increased need for specialized care may be related to the shorter stay in hospitals after hip replacement.

Scientists examined data on 1.5 million Medicare Part A beneficiaries who underwent primary total hip replacement between 1991 and 2008, and also 348,596 people who underwent revision total hip replacements (replacement of an artificial hip joint).

The average age for hip replacement patients rose from 74.1 in the 1991-1992 period to 75.1 in 2007-2008, and obesity prevalence rose in the same period from 2.2% to 7.6%.

Revisions for Hip Replacements

For revision total hip replacement, the average age rose from 75.8 years to 77.3 years. Obesity prevalence went up from 1.4% in the early period to 4.7% in the most recent one.

Also, researchers say the average length of stay in a hospital for primary hip replacement patients decreased from 9.1 days in 1991-1992 to 3.7 days in 2007-2008.

Risk-adjusted 30-day mortality over the study period decreased from 0.7% to 0.3%. And 90-day mortality fell from 1.3% to 0.7%, according to the study.

Researchers also say that the proportion of primary total hip replacement patients who were discharged to their homes decreased from 68% in 1991-1992 to 48.2% in 2007-2008, while the proportion of patients sent to skilled or intermediate care facilities increased from 17.8% to 34.3%.

The readmission rate for all causes in 30 days decreased from 5.9% in 1991-1992 to 4.6% in 2001-2002, but then increased to 8.5% in 2007-2008.

“For revision total hip arthroplasty [replacement], similar trends were observed in hospital [length of stay], in-hospital mortality, discharge disposition, and hospital readmission rates,” the scientists write.

Hip Replacement Becoming More Common

The authors write that total hip replacement is considered a safe and effective therapy for people with advanced degenerative joint disease, but that there “has been a dramatic increase in performance of this procedure both in the United States and abroad.”


And though it has been assumed that increasing experience with total hip replacement procedures has resulted in improvements in patient outcomes, data to support this belief is limited, the authors say.

Study author Peter Cram, MD, MBA, of the University of Iowa, and colleagues suggest that statistics may indicate that reducing length of stay in hospitals after hip replacements might increase readmission rates and discharge of patients to non-home settings.

They also write that despite increasing patient complexity, unadjusted and adjusted mortality rates for primary total hip replacement procedures showed substantial improvement over time.

But the unadjusted revision total hip replacement mortality rate increased modestly, though this was “largely explained by increasing patient complexity,” the study says.

Shorter Hospital Stays: Implications

The finding of a “marked decrease” in hospital length of stay after hip replacement surgery may have policy implications, the authors write, adding that hospitals may be motivated to reduce length of stay for payment reasons.

“We found that the reduction in hospital [length of stay] in both primary and revision total hip [replacement] patients was accompanied by a significant increase in the proportion of patients discharged to post-acute care facilities” such as nursing homes and rehabilitation centers “and a significant reduction in the proportion of patients discharged directly home.”

Readmission rates have increased markedly in recent years, suggesting, among other things, that “perpetual reductions” in hospital lengths of stay seem to be occurring.

The study is published in the April 20 issue of the Journal of the American Medical Association.

WebMD Health News Reviewed by Laura J. Martin, MD on April 19, 2011



News release, University of Iowa.

Cram, P. Journal of the American Medical Association, April 20, 2011; vol 305: pp 1560-1567.

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