Goal: To know the results of accountable care organizations (ACOs) on use of surgical procedure in sufferers with Alzheimer illness and associated dementias (ADRD).

Examine Design: Retrospective nationwide cohort research of all Medicare beneficiaries recognized in a 20% pattern between 2010 and 2017. The first publicity was participation in ACOs. The first end result was use of 1 of 6 frequent surgical procedures (aortic valve alternative [AVR], stomach aortic aneurysm [AAA] restore, colectomy, carotid artery restore, main joint restore, and prostatectomy).

Strategies: Multivariable logistic regression fashions have been match utilizing beneficiary-year because the unit of research to estimate the chance of present process every process amongst sufferers with ADRD and with out ADRD, stratified by ACO participation. Further fashions have been match to find out how the connection between ACO participation and surgical procedure was altered based mostly on process urgency and the supply of minimally invasive know-how.

Outcomes: Adjusted odds to be used of surgical procedure have been decrease amongst sufferers with ADRD in contrast with sufferers with out ADRD for all procedures. ACO participation had various influence on sufferers with ADRD, with increased odds of AVR and main joint surgical procedure and decrease odds of carotid artery restore. Availability of minimally invasive know-how elevated the chance of AVR and AAA restore amongst sufferers with ADRD; nevertheless, ACO participation diminished these results. The impact of ACO participation on the chance of present process surgical procedure didn’t range by urgency of the process.

Conclusions: The chance of present process surgical procedure is total decrease amongst sufferers with ADRD and should range by ACO participation for particular procedures.

Am J Manag Care. 2023;29(7):In Press


Takeaway Factors

The chance of present process 6 frequent surgical procedures (aortic valve alternative [AVR], stomach aortic aneurysm [AAA] restore, colectomy, carotid artery restore, main joint restore, and prostatectomy) is decrease amongst sufferers with Alzheimer illness and associated dementias (ADRD).

Accountable care group (ACO) participation attenuated the decreased chance of present process AVR and main joint surgical procedure amongst sufferers with ADRD. Conversely, ACO participation additional decreased the chance of present process carotid artery restore.

Availability of minimally invasive know-how tended to extend the chance of present process AVR and AAA restore amongst sufferers with ADRD. ACO participation attenuated these results.


The prevalence of Alzheimer illness and associated dementias (ADRD) is quickly growing and is predicted to triple by 2050 to 13 million people in the US.1 Understanding how this rising inhabitants interacts with the well being care system is changing into more and more vital as annual spending for managing these sufferers exceeds $200 billion nationally.2 This spending partially stems from elevated hospital utilization, which is additional sophisticated by the presence of dementia, leading to increased charges of hostile occasions and mortality.3,4 Surgical procedure poses extra challenges for this inhabitants resulting from operative danger, results of anesthesia, and postoperative delirium.5-7 Contemplating these penalties, the choice to supply surgical procedure to sufferers with ADRD is just not trivial. Suppliers should stability enchancment in high quality of life with subsequent surgical morbidity.

The shift in well being care supply towards value-based fee fashions could have an effect on surgical decision-making amongst sufferers with ADRD. Accountable care organizations (ACOs)—that are held to spending and high quality requirements—would theoretically incentivize suppliers to be considered when contemplating surgical procedure in sufferers at increased danger of problems.5 Nonetheless, it’s unclear how accountability implied by ACO participation impacts use of surgical procedure in sufferers with ADRD. Physicians in ACOs could possibly be extra selective in a number of methods. First, to scale back the danger of morbidity, ACO suppliers could also be extra prone to provide surgical procedure on this susceptible inhabitants if less-invasive and better-tolerated choices can be found, reminiscent of minimally invasive procedures.8,9 Second, physicians could also be extra selective in selecting to whom surgical procedure is obtainable. ADRD varies in severity, with some sufferers requiring nursing dwelling care whereas others reside locally.10 To cut back morbidity and related spending, ACO suppliers could selectively provide surgical procedure to community-dwelling sufferers with ADRD. Third, incentives rewarding worth could encourage physicians to keep away from surgical procedure altogether on this high-risk inhabitants. Lastly, we count on that process indications (eg, emergent, palliative) would mitigate, no less than partially, any variations in use of surgical procedure between these with and with out ADRD.

To raised perceive implications of ACOs for sufferers with ADRD, we carried out a nationwide research utilizing Medicare information to evaluate the impact of participation on charges of main surgical procedure throughout frequent circumstances. We hypothesized that ACOs would attenuate charges of surgical procedure. We anticipated such attenuation to be muted by a larger native availability of minimally invasive surgical procedure and by underlying indications (eg, emergent vs elective).


Knowledge and Examine Inhabitants

We carried out a retrospective nationwide cohort research of all Medicare beneficiaries between 2010 and 2017 inside a 20% pattern who have been 66 years or older to permit for 1-year look-back. Sufferers have been included if they’d steady enrollment in each Medicare elements A and B all through the research interval. Sufferers taking part in Medicare Benefit plans have been excluded resulting from absence of full claims information and ineligibility for participation in Shared Financial savings Plan ACOs. Beneficiary-years have been excluded (4.3%) if the beneficiary didn’t obtain any major care in a given research 12 months as a result of they might be thought of ineligible for ACO alignment. We recognized beneficiaries recognized with ADRD utilizing Worldwide Classification of Ailments, Ninth Revision and Tenth Revision codes (eAppendix Desk [available at ajmc.com]).11


Our major publicity was Medicare Shared Financial savings Program ACO participation. To find out ACO participation, we first assigned sufferers to a major care doctor based mostly on the plurality of analysis and administration codes for major care providers in the course of the research interval.12 Beneficiaries have been attributed to an ACO if their major care doctor was aligned with a Medicare Shared Financial savings Program ACO based mostly on the ACO alignment file. A time various indicator was outlined and set to 1 throughout a given 12 months if the affected person’s major care doctor was aligned with an ACO that 12 months and 0 in any other case. For 2012, there have been 2 ACO begin dates, April 1 and July 1. For many who underwent surgical procedure, ACO participation was outlined relative to the date of surgical procedure. For instance, if surgical procedure occurred previous to the ACO begin date, the beneficiary was characterised as not taking part in an ACO (indicator set to 0). For many who didn’t bear surgical procedure, random allocation to ACO participation was carried out based mostly on ACO begin date to keep away from bias. For instance, for ACOs beginning on April 1, 75% of sufferers who didn’t bear surgical procedure have been randomly allotted as ACO contributors and 25% have been allotted as not taking part in an ACO; these percentages signify the portion of the 12 months after and previous to the beginning date. For ACOs starting July 1, 50% of beneficiaries who didn’t bear surgical procedure have been randomly allotted as ACO contributors and 50% have been allotted as not taking part in an ACO. Our stratification resulted in 4 teams of sufferers for comparisons: ACO contributors with ADRD, ACO contributors with out ADRD, these with ADRD not taking part in ACOs, and people with out ADRD not taking part in ACOs.


Our major end result was use of 1 of 6 surgical procedures, recognized utilizing Healthcare Frequent Process Coding System codes (eAppendix Desk). The surgical procedures of curiosity have been aortic valve alternative (AVR) (open or transcatheter AVR [TAVR]), stomach aortic aneurysm (AAA) restore (open or endovascular restore), colectomy (open or laparoscopic/robotic), carotid artery restore (open or endovascular), main joint restore (whole hip alternative or whole knee alternative), and prostatectomy (open or laparoscopic/robotic). These procedures have been chosen as a result of they’re comparatively frequent, have various levels of invasiveness, embody a number of surgical disciplines, and span a spectrum of potential advantages (eg, enhancing high quality of life, lifesaving, palliative, purely elective). Thus, there have been 6 separate cohorts of sufferers, 1 for every process. The denominator for every cohort included all beneficiaries recognized throughout the 20% pattern.


For every cohort, we assessed for variations in affected person traits between ACO contributors and nonparticipants who underwent surgical procedure utilizing χ2 check for categorical variables and Wilcoxon rank-sum check for steady variables.

We examined the impact of ACO participation on use of surgical procedure amongst beneficiaries with and with out ADRD utilizing multivariable logistic regression fashions. Beneficiary-year was our major unit of research. We match separate fashions for every process, adjusting for 12 months, age, gender, race, socioeconomic standing, nursing dwelling standing 90 days previous to process (June 30 was used as a referent date for many who didn’t bear surgical procedure), and Hierarchical Situation Class (HCC) danger rating. HCC danger rating was used as a measure of medical complexity,13 and socioeconomic standing was measured on the zip code degree utilizing established strategies.14 Given underlying incentives to scale back prices, significantly in at-risk sufferers, we anticipated that ACOs would attenuate use of surgical procedure in every cohort in sufferers with ADRD.

Subsequent, we examined the impact of two potential mitigating elements on this relationship—native availability of know-how (ie, much less invasive approaches to a surgical procedure; additionally known as know-how diffusion) and process indication (ie, emergent vs elective outlined inside Medicare claims). We hypothesized that larger native availability of know-how and an emergent indication would attenuate any variations famous between these with and with out ADRD, unbiased of ACO participation. We outlined native availability of know-how as use of a much less invasive surgical strategy for a given process (eg, TAVR for aortic valve alternative) in a hospital referral area (HRR). This variable was outlined because the p.c of circumstances of a given surgical procedure of curiosity carried out with new know-how in an HRR for a given 12 months. This was handled as a steady variable and lagged 1 12 months in order that native availability of know-how in 1 12 months served because the publicity for the cohort within the following 12 months.

Analyses have been carried out utilizing SAS model 9.4 (SAS Institute) statistical software program. All assessments have been 2-sided and the chance of sort I error was 0.05. The research was deemed exempt by the institutional evaluation board of the College of Michigan.


We recognized a complete of 8,309,944 beneficiaries assembly eligibility standards between 2010 and 2017. Of those, 740,334 underwent one of many procedures, with 121,011 (17%) taking part in an ACO on the time of surgical procedure. Desk 1 compares affected person traits in response to ACO participation and kind of process. Generally, these in ACOs have been in increased socioeconomic strata and extra usually underwent a process utilizing a minimally invasive strategy, when relevant (P < .001). ACO contributors have been additionally much less prone to bear emergent surgical procedure for all procedures (P < .001).Use of surgery was lower among patients with ADRD compared with patients without ADRD for all procedures (Table 2). ACO participation modestly altered this effect for certain procedures. For example, relative to patients without ADRD not participating in ACOs, the odds of undergoing AVR for patients with ADRD decreased by 48% for those not participating in ACOs compared with 36% for those participating in ACOs. Similarly, odds of undergoing major joint surgery decreased by 67% for those not participating in ACOs and 62% for those participating in ACOs. Conversely, relative to patients without ADRD not participating in ACOs, the odds of undergoing carotid artery repair for patients with ADRD decreased by 20% for those not participating in ACOs and by 28% for those participating in ACOs. ACO participation did not alter the likelihood of patients with ADRD undergoing AAA repair, colectomy, or prostatectomy.The impact of technology diffusion on utilization of surgery was mixed (Table 3). Technology diffusion increased the likelihood of receiving AVR and AAA repair but had no effect on use of colectomy or carotid artery repair for patients with ADRD. ACO participation reduced these effects among patients with ADRD undergoing AVR or AAA repair. For example, among patients with ADRD, greater diffusion of technology increased the odds of undergoing AVR by 103% for those not participating in ACOs vs 44% for those participating in ACOs. Similarly, technology diffusion increased the odds of AAA repair in patients with ADRD not participating in ACOs by 61% but had no significant effect among those participating in ACOs. Among patients without ADRD, technology diffusion only increased likelihood of prostatectomy.We then assessed whether the likelihood of surgery among patients with ADRD differed between emergent and elective procedures. Compared with patients without ADRD, those with ADRD were less likely to undergo all procedures, regardless of urgency (Figure). The extent to which the odds decreased varied by procedure and urgency. For example, patients with ADRD were more likely to undergo AAA repair, colectomy, major joint surgery, or carotid artery repair if the procedure was emergent as opposed to elective. This difference was most pronounced for major joint surgery (69% decreased odds for elective vs 37% for emergent). Odds of undergoing AVR or prostatectomy did not significantly differ between emergent and elective procedures.Although we found that the likelihood of receiving elective or emergent surgery was lower among patients with ADRD, we sought to understand how ACOs may moderate utilization in both settings. As shown in Table 4, ACO participation did not differentially affect likelihood of emergent and elective surgery among patients with ADRD (eg, direction of effects was in the same direction). Specifically, ACOs increased the likelihood of patients with ADRD undergoing both emergent and elective AVR and major joint surgery. Conversely, ACO participation decreased the likelihood of undergoing both emergent and elective carotid artery repair. ACOs did not significantly affect likelihood of patients with ADRD undergoing emergent or elective colectomy or AAA repair.DISCUSSIONThe likelihood of undergoing surgery for patients with ADRD was generally lower than that for those without ADRD. Participation in ACOs resulted in a mitigation of the decreased likelihood of undergoing AVR and major joint surgery while further decreasing the likelihood of undergoing carotid artery repair. These findings held true despite the degree of penetration of minimally invasive technology and procedure urgency.Reducing low-value health care in patients with ADRD aligns with policies underlying ACOs that aim to reduce spending and improve quality (eg, by avoiding unnecessary care).15 With 1-year mortality approaching 20% among those with ADRD in Medicare, it is not surprising that their likelihood of receiving surgery was lower.10 However, the effect of ACO participation on use of surgery varied by procedure. We found the reduction in odds was less pronounced for ACO participants undergoing AVR and major joint surgery and more pronounced for those undergoing carotid artery repair, compared with patients with ADRD not participating in ACOs. Such mixed effects on utilization may reflect more selective use of surgery in patients with ADRD by ACO participants. Whereas some procedures are palliative and aimed at improving quality of life, others may lack sufficient benefit to outweigh the high perioperative risk of complications and mortality in the ADRD population.16 For instance, aortic stenosis can result in debilitating symptoms with a significant reduction in quality of life and result in multiple hospitalizations if left untreated.17 Similarly, hip fracture is 3-fold more common among those with dementia and results in a 32% increase in mortality at 6 months.18,19 Thus, surgeries to address aortic stenosis and acute hip fracture have the potential to improve quality of life and mitigate hospitalization risk.Although patients with ADRD are overall less likely to receive surgery and ACO participation partially mitigates this effect for some procedures, surgical technology has the potential to facilitate use of surgery in this high-risk population. Prior work has shown that rates of AVR have increased substantially in ADRD populations, largely driven by diffusion of the minimally invasive approach of TAVR.11 Technology implied by less-invasive alternatives (eg, laparoscopy, robotics, endoscopic, or endovascular), relative to conventional, open approaches, is often associated with decreased requirement for hospitalization, shorter length of hospitalization if required, quicker recovery, and lower morbidity.20 Such technology may allow for expanding indications to a population previously deemed unfit for conventional open surgery, such as those with high medical complexity.21 Therefore, diffusion of these technologies can affect decision-making, particularly in markets with high penetration. In such instances, it is conceivable that minimally invasive approaches may result in more liberal utilization of a procedure, even in clinical circumstances in which benefits are less clear. Interestingly, we found that likelihood of AVR and AAA repair in patients with ADRD is higher in areas with increased use of minimally invasive approaches for each procedure. Participation in an ACO reduced this effect for AVR and eliminated the effect for AAA repair. These findings build on prior work that has shown that rates of adoption of new surgical technologies for many procedures (including those in this study) were similar between ACO hospitals and non-ACO hospitals.22,23 TAVR appears to be cost-effective and safe in patients with ADRD, providing justification for its adoption in this high-risk population.24 Conversely, cost-effectiveness and benefits of endovascular aortic aneurysm repair in older patients are less clear.25,26 In this instance, perioperative risk may be larger than the risk reduction in aneurysm rupture achieved by surgical correction.27,28 Interestingly, areas with higher diffusion of robotic prostatectomy increased the likelihood of surgery for patients without ADRD but had no effect among patients with ADRD. This is reassuring because candidates for prostate cancer treatment are those with greater than 10 years of life expectancy, which many patients with ADRD may not have.29Another factor that could affect use of surgery in patients with ADRD is the imperative nature of the surgery (ie, whether it is emergent or elective). Regardless of procedure urgency, patients with ADRD were less likely to receive surgery compared with patients without ADRD. ACO participation did not differentially affect the odds of undergoing emergent or elective surgery. Reduction in odds of surgery for patients with ADRD compared with those without ADRD was more pronounced for elective procedures compared with emergent procedures. Major joint surgery had the largest difference in odds between emergent and elective surgery (69% reduced odds for elective vs 37% reduced odds for emergent). This is likely due to reasons mentioned earlier; emergent joint repair may reflect a means to provide immediate palliation of symptoms whereas elective repair may not be worth exposure to perioperative risks.6There are several reasons why even emergency surgery may be reduced among patients with ADRD. Typically, emergent procedures are performed when there is an imminent threat to life. However, in patients with dementia, retrospective series have demonstrated significantly high postoperative mortality rates, almost double that for healthy patients, following emergent surgery.30,31 Given the reduced life expectancy of patients with ADRD, emergent surgery may not prolong life as it may in a healthier population.31 Additionally, patients with dementia often present with atypical symptoms that can delay diagnosis to a point at which even emergent surgery would be futile.32 Furthermore, patients and caregivers of those with dementia may choose to avoid intensive care. Qualitative and observational analyses have shown that most families choose comfort as the primary goal among nursing home residents with dementia.33 Therefore, even emergent surgery may not be consistent with goals of care for these patients.LimitationsOur findings must be interpreted in the context of several limitations. First, the underlying pathology leading to use of the surgical procedures can have varying severity, which we are unable to account for using claims. We mitigate this issue by stratifying our analysis by emergent and elective procedures, which provides some context for the nature of the disease. Similarly, patients with ADRD have varying degrees of ADRD severity, which we cannot directly capture. Our models do adjust for several markers of comorbidity, including nursing home stay within 90 days of surgery and HCC risk. Second, we define ACO participation by patients’ primary care physician, and the surgeon or hospital in which surgery was performed may not necessarily be affiliated with the ACO. However, our goal was to understand differential decision-making among patients with ADRD participating in ACOs and those not participating in ACOs. The initial decision point starts with primary care providers within ACOs who guide care and make referrals to specialists for consideration of surgery. Third, ACO participants and nonparticipants vary by demographic characteristics, and although we attempt to adjust for these factors within our models, there remains potential for unmeasured regional and socioeconomic variation.CONCLUSIONSThis study finds that utilization of surgery is overall lower among patients with ADRD. Utilization appears to be influenced by ACO participation for some procedures, regardless of the degree of technology diffusion or the urgency of the procedure, in this high-risk group.Author Affiliations: Division of Health Services Research, Department of Urology (AM, RLD, BKH), and Division of Geriatric Medicine, Department of Medicine (JPWB), University of Michigan, Ann Arbor, MI.Source of Funding: This work was supported by the National Institute on Aging (NIA) grant R01 AG048071-04S1.Author Disclosures: Drs Bynum and Hollenbeck report receiving a grant (NIA R01 AG048071-04S1) to support this work. The remaining authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.Authorship Information: Concept and design (AM, RD, JPWB, BKH); acquisition of data (RD, JPWB, BKH); analysis and interpretation of data (AM, RD, BKH); drafting of the manuscript (AM); critical revision of the manuscript for important intellectual content (AM, RD, JPWB); statistical analysis (RD); obtaining funding (JPWB); and supervision (JPWB).Address Correspondence to: Avinash Maganty, MD, MS, Division of Health Services Research, Department of Urology, University of Michigan, 2800 Plymouth Rd, Bldg 16, Ann Arbor, MI 48109-2800. Email: avmagant@med.umich.edu.REFERENCES1. Hebert LE, Scherr PA, Bienias JL, Bennett DA, Evans DA. Alzheimer disease in the US population: prevalence estimates using the 2000 Census. Arch Neurol. 2003;60(8):1119-1122. doi:10.1001/archneur.60.8.11192. 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