by Elizabeth Hofheinz, M.P.H., M.Ed.
Noting that disparities in total hip arthroplasty (THA) utilization have worsened in recent years, a team of researchers from the Johns Hopkins University in Baltimore, Maryland set out to do the first-ever study on the role of composite, community-level geographic socioeconomic disadvantage.
The study, which involved population-based data from five-digit ZIP codes in Maryland from July 1, 2012 to March 31, 2019, sought to determine whether geographic socioeconomic disadvantage is associated with decreased THA rates in Medicare-aged patients, and if these associations persist after adjusting for differences in gender, race, ethnicity, and proximity to hospitals performing THA. 
All inpatient and outpatient primary THAs performed in individuals 65 years of age or older at acute-care hospitals in Maryland were included in the study. The research, “Is Geographic Socioeconomic Disadvantage Associated with the Rate of THA in Medicare-aged Patients?” appears in the September 14, 2020 edition of Clinical Orthopaedics and Related Research.
Co-author Casey J. Humbyrd, M.D., M.B.E. told OSN, “A major part of my prior research has focused on the potential for new payment models to further limit access for underrepresented minority and lower socioeconomic status individuals. At Johns Hopkins, we are privileged to care for an extremely diverse patient population, both in terms of demographics and socioeconomics. And even though we work to provide superlative care to all individuals, we were concerned that not all individuals were getting access to healthcare.”
“For example, many patients live in communities with less access to transportation, lower quality housing, increased unemployment, lower education levels, and reduced financial means. Limited health care access could certainly include access to important but ultimately elective orthopaedic procedures, including total joint replacement. While much is known about disparities in joint replacement surgery based on individual-level factors, we wondered whether the geographic community one lives in influences their access to orthopaedic care. And we were especially interested to evaluate access for an all Medicare population, that is, where all patients have the same insurance.”
Co-author Rafa Rahman M.P.H. commented to OSN, “We found that geographic areas with worse socioeconomic disadvantage have significantly lower rates of total hip arthroplasty (THA) among the Medicare-age population. These differences persisted even after correcting for potential confounders, including area distributions of gender, race, and ethnicity, as well as distance to the nearest hospital performing THA. To be specific, the adjusted rate of THA in the least disadvantaged quartile of ZIP-codes was 414 per 100,000 Medicare-aged individuals. The rate was 63 per 100,000 lower in the second-least disadvantaged quartile, 136 per 100,000 lower in the second-most disadvantaged quartile, and 183 per 100,000 lower in the most disadvantaged. This brings the adjusted rate in the most disadvantaged ZIP-codes to almost half that of the least disadvantaged. So, in layman’s terms, those patients with the greatest disadvantage had half the number of hip replacements of the most advantaged patients.”
Dr. Humbyrd: “Orthopaedic surgeons should understand that community-level disadvantage may be an important underlying driver of THA disparities, rather than individual-level demographics or isolated socioeconomic variables alone. This is an important finding given that prior research and initiatives to reduce orthopaedic disparities have focused largely on demographic groups such as race and gender. We demonstrate that the neighborhood one lives in may have a large role in their ability to receive THA.”
“We hope that our work will inform and encourage efforts to reduce disparities and provide more equitable orthopaedic care. Potential solutions include geographically targeting resources such as increased access to orthopaedic surgeons. We also recommend education for non-surgeons in these areas on when surgical referral is appropriate, as well as education for patients from these communities on the risks and benefits of joint replacement surgery.”