Hip replacement surgery – cost versus benefits

Total hip replacement surgery is an expensive business and, according to the findings of a study recently presented at the 2013 Meeting of theAmerican Academy of Orthopaedic Surgeons, costs over $6,000 more in Medicare expenses in the seven years after the procedure than other treatments for osteoarthritis-related hip pain. For patients who undergo surgery, however, there appears to be reduced mortality and reduced risk of heart complications and depression during that period.

The findings were based on a random sample of the Medicare population taken between 1997 and 2009 and looked at the nearly 24,000 patients diagnosed with hip osteoarthritis who had a minimum of one year’s follow-up and seven years of claims data; just over 10,500 had had total hip replacement surgery, while the rest had not.

In summary, the findings showed:

• After adjustment for age, race, sex and other relevant factors, for those who underwent surgery the risk of death at seven years after the procedure was half that for those who did not have surgery. This represents a hazard ratio (HR) of 0.52. The HR after just one year stood at 0.26.
• After one year, there was no significant difference in heart failure rates between the two groups, but it became significantly lower for the surgery group after seven years. The risk of depression follows the same pattern.
• The risk of diabetes was lower after one, three and five years for those having surgery, but statistically significant only at one year.
• The risk of artheriosclerosis and ischemic heart disease was higher after one year for the surgical group but at seven years the difference was insignificant.

According to the lead investigator in the study Dr. Scott Lovald, a biomedical engineer at Philadelphia-based scientific consultants Exponent, the study focussed only on known complications of osteoarthritis; nor did it explore indices for pain and function.

Dr. Lovald and his team established that Medicare costs for the surgery group totalled $89, 154 against $82,788 for the non-surgery group. He says that while the cost of surgery in financial terms might be higher than other treatments, in human terms it appears to be well worth the additional expense. He attributed the lower mortality and better health enjoyed by patients after hip replacement surgery to reduced pain levels and greater capacity for physical activity.

A separate study based on the same Medicare data examined the risk of revision surgery within one year of the initial procedure was presented at the same meeting.

According to Dr. Kevin Bozic of the University of California, the study found that the most significant independent factor influencing the need for revision was depression at the time of the operation. For patients suffering depression the risk was 3.53% against 1.86% for those who were not. Elaborating on the findings, Dr. Bozic said that depressed patients felt pain differently. He added that the data only recognised patients who had been diagnosed with depression, but not if they were receiving treatment.

The study also found that patients suffering from congestive heart failure at the time of surgery also ran a greater risk of requiring revision surgery. Other conditions increasing the risk of further surgery included coexisting rheumatologic disease, urinary tract infection, renal disease and psychoses. Identifying modifiable factors that could affect surgical complications, says Dr. Bozic, will have practical implications.

Medicare has since begun reporting outcomes for hip and knee replacement surgery, with details of complications and readmission rates being included.