Our findings highlight a national trend toward increased use of lower-intensity ambulatory settings for several common outpatient urologic procedures. Outcomes varied significantly by location of care with ASCs outperforming hospitals on one dimension of surgical quality—a difference likely related to favorable patient selection. While hospital-based surgery was associated with a lower rate of same-day admission, it is important to note that the probability of any adverse event was exceedingly low, regardless of location of care.
To date, much of the literature on ambulatory surgical care in nonhospital-based facilities has focused on the issue of physician ownership and overuse.14, 15
Little empirical work has assessed the relationship between surgical quality and the setting for ambulatory surgery. Our results are concordant with prior research, showing ASCs and hospitals to have similar risk-adjusted postoperative mortality.5
However, unlike Vila and colleagues,16
we found death rates at ASCs and the office to be both low and comparable. This finding may relate, in part, to increased state-level regulation of office-based surgery.17
We also observed more frequent same-day admissions following outpatient surgery in ASCs versus hospitals. This observation contrasts with that from a previous Medicare analysis.18
It may be a reflection of the limited organizational resources at ASCs. For instance, a cautious urologist could exercise clinical judgment and admit a less healthy patient following an ASC-based surgery because the hospital would be better equipped to handle problems if they occurred. Alternatively, it may reflect decreased staffing hours at ASCs or efficiency priorities, whereby urologists at these facilities have a lower threshold to admit patients in order to maximize throughput rather than holding on to them in the post-anesthesia care unit.
Our study has several limitations that merit further discussion. First, there is clear selection bias in our study population. While we attempted to adjust for differences in case mixes between hospitals, ASCs, and the office, it is entirely possible that urologists recommend certain settings based on information that is not readily available in billing claims. Second, we used HCPCS codes to identify procedures of interest. Medical coding, which is intended for billing and reimbursement, may not accurately reflect how complex a surgery was. To the extent that significant heterogeneity in procedure complexity exists within a given procedure code, this could also account for quality differences across locations of care. Third, we used Medicare claims exclusively for our analysis, and our findings may not be generalizable to nonelderly Americans.
Limitations notwithstanding, our study has both clinical and policy implications. From a clinical perspective, these data highlight the need to consider a patient’s age and level of comorbidity when planning an outpatient procedure. As expected, we observed that older patients and those with more comorbid illnesses had higher odds of an adverse event. Being able to identify subgroups of patients at risk for an adverse event following ambulatory surgery will allow for more effective targeting of care delivery. From a policy perspective, large payers, like Medicare, may use our data to inform their payment systems for providers. For instance, they might consider directing patients to certain nonhospital-based facilities given the comparable quality that they provide.