Surgical quality among Medicare beneficiaries undergoing outpatient urological surgery

Abstract

Purpose: The cost efficiency gains achieved from moving procedures to ambulatory surgery centers and offices may be mitigated if the quality of surgical care at these facilities is not comparable to that at the hospital. Motivated by this, we assessed short-term morbidity and mortality for patients by location of care.

Materials and methods: Using a national sample of Medicare claims (1998 to 2006), we identified elderly beneficiaries who underwent one of 22 common outpatient urological procedures. After determining the facility type where each procedure was performed, we measured 30-day mortality, unexpected admissions and postoperative complications. Finally, we fit multivariable logistic regression models to evaluate the association between occurrence of an adverse event and the ambulatory setting where surgical care was delivered.

Results: During the study period, there was a substantial increase in the frequency of nonhospital based outpatient surgery. Compared to ambulatory surgery centers and offices, hospitals treated more women (p <0.001). Those patients also tended to be less healthy (p <0.001). While patients experienced fewer postoperative complications following surgery at an ambulatory surgery center, procedures performed outside the hospital were associated with a higher likelihood of a same day admission (ambulatory surgery centers OR 6.96, 95% CI 4.44-10.90 and offices OR 3.64, 95% CI 2.48-5.36). However, notably with case mix adjustment the probability of any adverse event was exceedingly low across all ambulatory settings.

Conclusions: These data indicate that small but measurable variation in surgical quality exists by location of care delivery.

Figure 1

Distribution of selected urologic procedures across ambulatory surgery settings over the study period. Abbreviations: ASC, ambulatory surgery center; HOPD, hospital outpatient department. Note: In the bar chart, black, grey, and white shading indicate the HOPD, ASC, and office, respectively.

Figure 2

Predicted probability of an adverse event following surgery, stratified by ambulatory setting. Abbreviations: ASC, ambulatory surgery center; HOPD, hospital outpatient department. Note: In the bar chart, black, grey, and white shading indicate the HOPD, ASC, and office, respectively. Models adjusted for case mix (i.e., patient age, gender, race, comorbid status, area of residence) and calendar year.