Ambulatory-Based Bladder Outlet Procedures Offer Significant Cost Savings and Comparable 30-Day Outcomes Relative to Inpatient Procedures

Introduction

With an aging population, the prevalence and economic burden of benign prostatic hyperplasia (BPH) are increasing. ¹ Cost pressures and newer minimally invasive outlet procedures have led to a migration away from the traditional inpatient care setting toward ambulatory surgical centers for bladder outlet obstruction (BOO) procedure. ² However, there is limited literature evaluating the impact that this transition in care setting has had on perioperative costs and outcomes after BOO procedure. Literature to date has largely consisted of prospective studies comparing the effectiveness of various surgical techniques (e.g., transurethral resection of the prostate [TURP] vs photo/laser therapy) or retrospective case series describing the feasibility of ambulatory procedure, ³ with little attention given to associated costs or comparison of care settings.

Elucidating the factors influencing the cost of BOO procedure is a necessary first step in developing higher quality pathways of care for BPH patients, which will grow in importance as value-based purchasing practices are applied to an ever-growing number of health care services. ⁴ However, it remains unclear which patient- and provider-level characteristics influence the index setting of operation (inpatient or outpatient), and whether perioperative outcomes and costs differ between inpatient and outpatient cohorts. Using all-payer claims data, we sought to identify factors associated with index surgical care setting and its impact on risk-adjusted perioperative outcomes and costs after elective surgical therapy for BPH. We hypothesize that ambulatory-based BOO procedure is associated with significant cost savings and comparable 30-day revisit rates relatively to procedures conducted in the inpatient setting.

Methods

Patient selection

The cohort selection process is given in Figure 1. All patients undergoing an index TURP (Current Procedural Terminology [CPT] codes 52601 and 52630; International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] code 60.29), photo/laser therapy (CPT code 52648; ICD-9-CM code 60.21), or thermotherapy (CPT codes 53850 and 53852; ICD-9-CM codes 60.96 and 60.97) were included, yielding 3182 revisits among 15,283 unique individuals. As BOO procedure performed in the inpatient setting represents a more costly alternative to ambulatory procedure, index surgical care setting was dichotomized into either inpatient (n = 5470) or ambulatory (n = 8902). For the purpose of our cost and 30-day revisit analyses, ambulatory procedures were further categorized into those requiring an admission (n = 3234) vs not requiring an admission (n = 5668). Index BOO procedures were defined as the first operation performed on an individual over a 365-day period. Of note, patients undergoing a repeat TURP within 90 days of their index procedure (CPT code 52620) were excluded from our analysis.

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FIG. 1.

Consort diagram depicting cohort selection process.

Results

Univariate differences between individuals treated in the inpatient vs outpatient settings are given in Table 1. A total of 14,372 individuals underwent an outlet procedure during the study period, of which 61.9% (n = 8902) were performed in the ambulatory setting. Among ambulatory procedures, 36.3% (n = 3234) resulted in an admission ranging in length from 1 to 3 days. In multivariate logistic regression analysis, negative predictors of undergoing operation in the ambulatory care setting included a CCI score ≥2 (odds ratio [OR] = 0.45, confidence interval [CI] = 0.38–0.53, p < 0.001), Medicaid insurance (OR = 0.48, CI = 0.3–0.75, p < 0.001), and Black race (OR = 0.75, CI = 0.59–0.96, p = 0.02) (Table 2).

Index care setting and 30-day acute care costs

Adjusted mean index surgical costs were significantly lower among patients undergoing operation within the ambulatory compared with inpatient setting ($5777.64 vs $7926.71, p < 0.001). Adjusted mean 30-day acute care costs were also significantly lower among patients undergoing index procedure within the ambulatory compared with inpatient setting ($5212.27 vs $6212.12, p < 0.001). Differences in index ($6134.84 vs $7926.71, p < 0.001) and 30-day ($4066.35 vs $6212.12, p < 0.001) costs persisted even after accounting for ambulatory procedures requiring admission (Fig. 2).

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FIG. 2.

Unadjusted cost figures by index care setting. Following risk adjustment, patients undergoing operation in the ambulatory setting still experienced significantly lower (A) index ($5777.64 vs $7926.71, p < 0.001) and (B) 30-day costs ($5212.27 vs $6212.12, p < 0.001) relative to inpatient-based care. Differences in index ($6134.84 vs $7926.71, p < 0.001) and 30-day ($4066.35 vs $6212.12, p < 0.001) costs persisted even after accounting for ambulatory procedures requiring admission (*p < 0.001).

Discussion

As the population ages, demand for the surgical management of BPH will continue to grow. ⁹ In a health care system already strained by high costs ¹⁰ with increasing pressure to deliver high-value care, untangling the cost of surgical care is an important step toward containing it. ¹¹ There is a need for solutions maximizing the yield on the value equation, which seeks to maximize surgical outcomes per dollar spent. One such step is the provision of care in the appropriate care setting. ¹² Using all-payer claims data from the states of New York and Florida, we identified several clinical (e.g., age and CCI score) and nonclinical (e.g., insurance status and race) predictors of the care setting in which individuals undergo operation for BOO. We demonstrate that ambulatory procedure is indeed significantly less costly than procedures performed in the inpatient setting, even after risk adjustment and accounting for ambulatory-based procedures requiring hospital admission. Furthermore, patients who had their index surgical procedure in the ambulatory setting were less likely to experience a 30-day revisit compared with patients receiving care in the inpatient setting. These findings hold significant policy implications in the setting of recent value-based purchasing reforms being undertaken in the United States. ⁴

In our multivariable logistic regression analysis, Medicaid coverage was a predictor of receiving care in the inpatient setting relative to Medicare coverage. Provider-level biases may be at play here. Studies have demonstrated that physicians at physician-owned ambulatory centers were more likely to refer well-insured patients to these facilities and direct Medicaid patients to inpatient settings for administrative and financial reasons. ^13,14 Such disadvantages of Medicaid include delayed payments and often lower reimbursement rates for surgical procedures, all which act as disincentives for care in more profitable ambulatory centers. ¹⁵ With the Affordable Care Act leading to increased Medicaid enrollment, routing of Medicaid beneficiaries to high-resource inpatient hospital settings may have future consequences that remain to be seen. ¹⁶ Another predictor of care setting was patients' geographic status. Small metro area, micropolitan, and rural patients were more likely to receive care in the ambulatory setting likely because of reduced access to inpatient care. ¹⁷

When seeking to address the rising costs of care, treating patients in the optimal care setting is one way to reduce low-value care, especially in the context of cost-intensive surgical care. ¹⁸ As has been shown by others, this analysis demonstrates that ambulatory procedures were less costly than procedures performed in the inpatient setting. ^7,15,19 This was true for both the index episode of care and associated 30-day revisits. As these analyses were adjusted for comorbidity status and thus attempted to mitigate confounding by indication, it is unlikely that the etiology of this cost difference is because of routing of sicker patients to the inpatient setting. Rather, it is possible that patients receiving care in the inpatient setting are confronted with structural barriers that were not accounted for in our analyses. Such barriers may include no access to a usual source of care ²⁰ and low health literacy, ²¹ both associated with increased visits to the ED resulting in higher 30-day costs. Regarding lower index episode of care costs in the ambulatory setting, this can potentially be explained by lower surgical facility fees ¹⁹ and fewer overnight admissions. ²² Our analysis also highlights that a nonclinical factor, Medicaid coverage, was an independent predictor of inpatient care. It has been shown that Medicaid beneficiaries spend more on medical services. ²³

Another important consideration for high-value care is the surgical approach selected. Although laser photovaporization of the prostate was more commonly carried out in the ambulatory setting, there were no differences in 30-day revisit rates for laser compared with traditional TURP. This is in line with other studies that have compared these modalities in both the inpatient and outpatient setting and found generally similar short-term outcomes. ^24,25 Similar to Strope and colleagues, there were also no differences in revisits when comparing both therapies by care setting. ²⁵

Medicaid was not correlated with increased 30-day revisits, whereas patients with private insurance, on the contrary, had increased odds of a 30-day revisit. Although it is tempting to attribute these results to inherent differences between the inpatient and ambulatory cohorts, our analysis was risk adjusted and took into account comorbidity status. Rather, these differences in 30-day revisits between payer status may be explained by factors that we did not control for such as the patient's health literacy, ²⁶ care coordination, ²⁷ and social relationships. ²⁸ In a similar vein, a sensitivity analysis was performed comparing 30-day outcomes between inpatient-based procedures and patients treated in the ambulatory setting that required a hospital admission. As receiving care in the ambulatory setting was also protective against experiencing a 30-day revisit in the sensitivity analysis, the etiology of this finding is less likely attributable to disease burden but rather may reflect the aforementioned provider- and facility-level factors not accounted for in the analysis.

This study contributes to the growing body of evidence assessing the impact of care setting on the quality and cost of surgical care. ¹⁵ In the context of value-based health care reforms being undertaken in the United States, our findings highlight the cost and outcome implications of directing patients to the optimal treatment setting. Indeed, we show that care in the ambulatory setting achieves cost savings without compromising 30-day outcomes. These findings are encouraging in the setting of the recent rule change proposal by CMS that will reimburse inpatient and ambulatory procedure similarly. ²⁹ Consequently, it can be argued that developing policies that encourage high-value pathways of surgical care represents a promising means by which to slow, if not reduce, the economic burden of health care in the United States.

This study has some limitations that are common to all retrospective, observational studies using administrative datasets. In this particular study, the lack of granular data is the main limitation. Clinical factors that influence operative decision-making or outcomes were not available, such as prostate size, history of TURP, or secondary indications for operation beyond BPH/lower urinary tract symptoms (retention, infections, bleeding, bladder stones, etc.). Laser and TURP are also too general and do not capture the cost differences between different modalities. Identifying specific cost drivers, such as the use of anesthesia or time spent in the OR in different care settings, was also not possible. Finally, although the 30-day revisit metric is commonly used to evaluate outcomes, it is not the only measure of quality of care and is only an aspect of value of care assessment. Future studies should focus on identifying more granular clinical and nonclinical factors that may help to further risk-stratify patients and thereby direct patients to the highest value care setting possible.

Conclusion

We identified that index care setting and payer status are independent predictors of 30-day readmission after BOO procedures, with the inpatient setting and Medicare insurance associated with higher odds of readmission. Ambulatory procedures are significantly less costly than procedures performed in the inpatient setting, even after accounting for ambulatory procedures leading to an admission. There is an obvious cost benefit of offering BOO procedure in the ambulatory setting to the appropriate patient. In the context of value-based health care initiatives, our findings have important implications for policymakers seeking to reduce variation in nonclinical sources of perioperative costs and outcomes.