Researchers from the Mayo Clinic (Rochester) found an increase in obesity, psychological and other medical comorbidities in patients undergoing a total hip replacement, otherwise known as total hip arthroplasty (THA). The study entitled: “Increasing obesity and comorbidity in patients undergoing primary total hip arthroplasty in the U.S.: A 13-year study of time trends” presents data from Mayo Clinical Registry’s patients examined between 1993 to 2005, and was published in BMC Musculoskeletal Disorders on December 17, 2014.

THA surgery is used after failure of conventional therapy to replace the damaged hip joint with an artificial joint made of metal and very hard plastic, meant to significantly improve hip function. THA is the second most common joint replacement surgery in the U.S.: 478,000 primary THA procedures were performed in 2009, with the number of interventions rapidly increasing both in younger and aged patients.

Using the Mayo Clinic Total Joint Registry, researchers assessed data from 6,168 patients (50-80 years, 52% of women) who submitted to THA between 1993 and 2005. The study aimed to examine the time trend in body max index (BMI), medical and psychiatric comorbidities in patients undergoing THA by analyzing the periods 1993 to 1995 and 2002 to 2005.

Comparison of the two periods showed an increase in excessive BMI (2.3% vs. 6.3%), depression (4.1% vs. 9.8%) and anxiety (3.4% vs. 5.7%) diagnosed cases, although in the cases of anxiety and depression the increasing incidence might indicate either a true increase in its incidence in this patient population or improved efficacy in diagnostics.

Other medical comorbidities were assessed with the Deyo-Charlson index, a score that analyzes the presence of 17 comorbidities (including cardiac, pulmonary, renal, hepatic disease, diabetes, cancer, hemiplegia etc.), also resulting in a 21% increase. In contrast, arthritis was reduced by 65% to 75% in patients submitted to THA.

The results are similar to previous studies described for other national U.S. cohorts, thereby indicating that this trend may be extended to the rest of the country. Overall, the collected information indicates a change in patients’ characteristics undergoing THA over time, which may be relevant to study THA outcomes.