In a sample consisting of all patients in the FY 1999 who were 50 years of age or older and carried the diagnosis of OA, there were no statistically significant gender differences in the odds of undergoing TKA or THA within the 2-year study period.
Our finding is in contrast to previous population analyses that did not consider the gender differences in OA prevalence or the population at risk for the treatment when examining gender variations in TJA utilization rates.8–13
Our results also differ from those by the Canadian investigators,7
who found gender differences in TJA utilization rates. The Canadian study, however, was a population-based study in a different country with a different health care system. For example, long waiting times for elective TJA are common in publicly funded universal health care systems such as Canada's,15
and it is not clear how such access issues impact gender utilization of the treatment. Furthermore, the Canadian study evaluated socio-economically diverse, community-dwelling patients whose preferences and access to care may differ. In fact, baseline income comparisons between men and women in that study showed women to have significantly lower yearly income than men. This is particularly important in light of the evidence that lower income, regardless of insurance status, is associated with lower THA utilization rates.16
Compared with the sample in the Canadian study, our study sample of VA patients appears to be of a more socio-economically similar background.17
Understanding the existence of gender differences in the utilization of TJA is important. Because of its high prevalence and associated functional disability, knee/hip OA is a major health burden in the elderly, and women may bear this burden more so than men.1
There is currently no cure for OA, but TJA provides an effective treatment option for those patients who have exhausted medical management of their disease. Although our study did not demonstrate gender differences in the rates of TJA utilization, underutilization by both genders has been reported.7
Additionally, there is evidence that women may delay accessing this treatment even when it is needed. For example, women have worse pain and functional status than men at the time of THA.18
Patients with worse functional status prior to TJA do not achieve as good a functional result postoperatively as those with a better preoperative functional status.19
Therefore, on top of overall underutilization of THA, women's health status may be additionally compromised because of a delay in timing of the procedure. Women may be under a different set of social pressures, such as care-giving roles, that could influence their access and treatment decisions regarding elective procedures such as joint arthroplasty.20
Our study has several limitations. First, the study examined a VA sample, a patient population that is predominately male and, commonly, of low socioeconomic status. Therefore, our results may not be generalizable to the larger U.S. population. Second, we had no information on disease severity. While TJA rates between the genders were similar in this study, it is possible that more women may have severe disease compared with men and that a higher TJA utilization rate in women compared with men would be more clinically appropriate. Third, although our denominator for rate calculations is more specific with regard to OA diagnosis compared with other similar studies, it included patients with OA in any joint. The lack of information of disease severity and of the specific joint involved limited our ability to evaluate the appropriateness of hip/knee joint arthroplasty utilization in the sample. Fourth, we did not fully examine VA outsourcing. Veterans 65 years of age or older who have access to non-VA care through Medicare may have accessed non-VA hospitals for TJA. If one gender preferentially accessed non-VA hospitals, this could have potentially influenced our ORs comparing TJA utilization rates between the genders.
In summary, we examined a sample of VA patients, 50 years of age or older with or without the diagnosis of OA regarding total knee/hip arthroplasty utilization. We found that when disease prevalence is considered, there are no statistically significant gender differences. However, given previous studies that have shown significant gender differences in the use of medical procedures, further investigation using more clinically informative data is warranted.