Purpose:

The rapid diffusion of the surgical robot has been fraught with controversy because of the technology's high costs and disputed marginal benefit. Some, however, have suggested that adoption of the surgical robot has facilitated partial nephrectomy for renal malignancy, an underutilized procedure considered to be more challenging yet less morbid than radical nephrectomy. We sought to determine whether institutional acquisition of the surgical robot was associated with a higher local rate of partial nephrectomy.

Method:

We used the 2001, 2005 and 2008 Health-care Cost and Utilization Project State In-patient Databases from 7 states to identify 21,569 surgical procedures for renal tumors. These patient-level records were aggregated to the hospital-level then merged with the American Hospital Association Survey and with publicly available data on timing of surgical robot acquisition. We used a difference-in-difference model to assess at the hospital-level whether robot acquisition was associated with an increase in the rate of partial nephrectomy, adjusting for total nephrectomy rate, year of surgery, year of robot acquisition, geographic state and several hospital-level factors. We also performed two sensitivity analyses to determine whether there was a time lag between robot acquisition and changes in the utilization of partial nephrectomy (because of a presumed necessity to develop requisite surgical skill) and to ensure no association existed between robot acquisition and performance of an unrelated procedure (the presence of which might suggest than an unmeasured confounding characteristic, rather than robot acquisition, was the cause for increased surgical volume).

Result:

In the multivariable adjusted differences-in-differences model (Figure 1), hospitals acquiring a robot between 2001-2005 performed more partial nephrectomies in both 2005 (31% increase) and 2008 (36% total increase) (p<0.01 for both). Hospitals acquiring a surgical robot in the time period between 2005-2008 also demonstrated higher rates of partial nephrectomy 2008 (16% increase) (p=0.02). Results of the secondary lag time analysis were not substantially different. As expected, there was no association between robot acquisition and utilization of an unrelated surgical procedure.

Conclusion:

Hospital acquisition of the surgical robot is associated with increased utilization of partial nephrectomy, an underutilized, guideline-encouraged procedure. This is one of the few studies to suggest acquisition of the surgical robot was associated with improvement in quality of patient care.

Figure 1

Purpose: A substantial portion of the economic burden of obesity is the cost of medications to manage obesity-related comorbidities, including hypertension, dyslipidemia, and type 2 diabetes mellitus (T2DM). This post hoc analysis evaluated the effects of magnitude of weight loss (WL) on annual antihypertensive, lipid-lowering, and antidiabetic medication costs in obese/overweight subjects.

Methods: The CONQUER trial was a double-blind, Phase 3 study of 2487 obese/overweight subjects (body-mass index [BMI] ≥27 and ≤45 kg/m²) with ≥2 weight-related comorbidities randomly assigned to placebo (n=994), phentermine (PHEN) 7.5mg/topiramate extended-release (TPM ER) 46mg (7.5/46; n=498), or PHEN 15mg/TPM ER 92mg (15/92; n=995) plus lifestyle modifications for 56 weeks. Subjects included in this post hoc analysis completed ≥12 weeks of therapy and received medications at baseline or endpoint for the treatment of ≥1 of the following comorbidities: hypertension (n=830), dyslipidemia (n=340), or T2DM (n=207). Annual antihypertensive, lipid-lowering, and antidiabetic medication costs were calculated at baseline and end of treatment by multiplying the unit cost (Medi-Span's PriceRx database) by number of doses per day and by 365. Subjects were stratified by magnitude of WL (<5%, ≥5%-<10%, ≥10%-<15%, and ≥15%), and changes in annual medication costs were evaluated from baseline to end of treatment.

Results: Most subjects were female (70%) and Caucasian (86%); mean weight was 103.1±17.9kg and mean BMI was 36.6±4.5kg/m². At treatment end, the majority of subjects with <5% WL were from the placebo group, while the majority of subjects achieving ≥5% WL were from the PHEN/TPM ER groups (Table). Compared with subjects losing <5% body weight, changes in annual medication cost for ≥5%-<10% WL were -$107.27, -$167.86, and -$76.18 for the treatment of hypertension, dyslipidemia, and T2DM, respectively. Similarly, changes in annual medication cost in subjects with ≥10%-<15% WL were
-$99.54, -$242.83, and -$271.17, respectively, and for subjects with ≥15% WL were -$229.26, -$594.48, and -$244.94, respectively. Common treatment-emergent adverse events were constipation, dry mouth, and paraesthesia.

Conclusions: In this obese/overweight population, increasing magnitudes of WL were associated with greater reductions in annual medication costs for the treatment of hypertension, dyslipidemia, and T2DM. This suggests that ≥5% WL may have a meaningful and beneficial impact on the economic burden of obesity.

Dr. Cheskin is a stockholder and member of the National Advisory Board of VIVUS, Inc.

Purpose: There are an estimated 400,000 patients over the age of 65 years in the United States with extracranial internal carotid artery stenosis, which accounts for 15-20% of ischemic strokes. Revascularization has been shown to decrease stroke risk by 45%, but this procedure carries substantial costs and risks. Carotid stenosis patients with image-determined cerebrovascular reserve (CVR) impairments have been shown to be at a four-fold increased risk of stroke. We projected health benefits, risks, and costs of three competing strategies (treat, test, or neither) for carotid stenosis patients.

Methods: We developed a decision analytic model to compare the following interventions for asymptomatic carotid stenosis patients (50-99% extracranial internal carotid artery blockage):  1) treat all with revascularization (carotid endarterectomy); 2) only perform revascularizations for those with image-determined (transcranial Doppler ultrasound [TCD]) CVR impairments, and use medical therapy alone for all others; and 3) medical therapy alone for all patients. Model input parameters were estimated from published sources. Healthcare costs for revascularization, TCD, acute stroke, and annual long-term stroke care were $14,130, $265, $65,800, and $31,000, respectively. Estimates for baseline annual risk of stroke and probability of revascularization complications (death, stroke, or myocardial infarction) were 1.5% and 2%, respectively. Discounted lifetime costs and health benefits (quality-adjusted life years [QALYs]) were projected for each strategy.

Results: The medical therapy alone strategy resulted in higher total costs ($47,000 per person, driven by stroke-related costs) and lower lifetime QALYs (11.379) compared to image-based CVR testing ($40,800, 11.535 QALYs) or revascularization for all ($44,800, 11.555 QALYs). The incremental cost-effectiveness ratio for the revascularization for all versus CVR testing strategy was $210,000/QALY. Cost-effectiveness results were most sensitive to plausible variations in revascularization risks, costs and benefits; strength of association between CVR impairment and future stroke; and baseline stroke risk. Figure 1 shows the two-way sensitivity analysis results for revascularization complication rates and baseline stroke risk. Model results were robust to variations in TCD costs; acute and long-term stroke costs; and stroke utility values.

Conclusions: CVR testing can be a cost-effective tool to identify asymptomatic carotid stenosis patients most likely to benefit from revascularization. The economic value of this tool depends on accurate assessments of baseline stroke risk and the likelihood of procedure complications, factors that vary by patient and provider.