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Hospitals Could Be Unfairly Penalized for Joint Replacement Readmissions

PROVIDENCE, RI — If joint replacement patients end up being readmitted in 90 days, your hospital could face federal penalties.

That is not an unlikely occurrence, emphasizes a new study published recently in Arthritis Care & Research, because as many as one in 12 of the million Americans undergoing total knee or hip replacements annually return during that time period.

Concerned about the high rates, the Centers for Medicare & Medicaid Services (CMS) launched the Comprehensive Care for Joint Replacement (CJR) program in April last year, which includes penalties. The problem, according to the Brown University-led research, is the lack of any index for measuring that risk.

Lead author Amit Kumar, a postdoctoral research associate at the Brown University School of Public Health, and colleagues tested the three best candidate risk adjustment indices — including one developed by CMS — but found that none were useful in predicting readmissions among patients who underwent joint replacement to address osteoarthritis.

"In the absence of that risk adjustment, when sick patients have worse outcomes, hospitals will be penalized," Kumar explained. "If we could find an index that was working for this population, we could recommend that — but, unfortunately, none of them are working very well."

For the study, Medicare data was analyzed for every beneficiary who survived for 90 days after a total knee or total hip replacement performed because of osteoarthritis between January 2009 and September 2011. With the final study group exceeding 600,000 patients, results indicate that 46.3% of patients were discharged home, 40.9% went to skilled nursing facilities, and 12.7% percent stayed in inpatient rehabilitation.

Also tested were the three industry-leading indices for predicting mortality and healthcare utilization: the Charlson Comorbidity Index, the Elixhauser Comorbidity Index, and CMS's Hierarchical Condition Category.

The researchers sought to determine whether any of the three indices made a meaningful difference in predicting where patients would be discharged and whether they'd return to the hospital within 30, 60, or 90 days.

Yet, their evaluation showed that none of the indices significantly improved upon a "base model" of simply accounting for a mix of demographic and medical factors.

The study also identified the health conditions most frequently associated with hospital readmission after joint replacement surgery were diabetes, pulmonary disease, arrhythmia, and heart disease.

Kumar suggested that CMS begin tracking functional status of patients who undergo joint replacements and use the data in a new index that will help hospitals assess which patients are at greatest risk of readmission, as well as allow CMS assess which hospitals are treating riskier patients.