Meta-analysis and systematic review of the relationship between volume and outcome in abdominal aortic aneurysm surgery

Reduction in early mortality outcomes after bariatric surgery in France between 2007 and 2012: A nationwide study of 133,000 obese patients

BACKGROUND

Early postoperative mortality after bariatric surgery has been reported in large national studies before sleeve gastrectomy (SG) was introduced as a stand-alone procedure. The aim of this study was to investigate the 90-day postoperative mortality rates after bariatric surgery in France on a nationwide basis.

METHODS

All morbidly obese patients who underwent adjustable gastric banding (AGB), gastric bypass (GBP), or SG in France between 2007 and 2012 were included in this study. Multivariate analyses were conducted using the French National Health Service Database data to ascertain predictive factors for 90-day postoperative mortality.

RESULTS

Data from 133,804 patients were analyzed. SG was performed in 36.5% of cases, GBP in 31.2%, AGB in 32.3%, and revisional surgery in 5.1%. The postoperative mortality rate (POM) for the 3 procedures was 0.12%. The rate of POM remained stable for AGB (0.01%), and it decreased from 0.25 to 0.08% and from 0.36 to 0.11% for SG and GBP, respectively. POM was greater among male patients and was associated with age, type-2 diabetes, high blood pressure, body mass index, open surgery, and hospital procedural volume.

CONCLUSION

The rate of early mortality after bariatric surgery was low, and has decreased greatly during the past few years. AGB presents a mortality rate close to nil and SG has a risk of early mortality that is about half that of GBP.

Center-Level Experience and Kidney Transplant Outcomes in HIV-Infected Recipients

Excellent outcomes among HIV+ kidney transplant (KT) recipients have been reported by the NIH consortium, but it is unclear if experience with HIV+ KT is required to achieve these outcomes. We studied associations between experience measures and outcomes in 499 HIV+ recipients (SRTR data 2004-2011). Experience measures examined included: (1) center-level participation in the NIH consortium; (2) KT experiential learning curve; and (3) transplant era (2004-2007 vs. 2008-2011). There was no difference in outcomes among centers early in their experience (first 5 HIV+ KT) compared to centers having performed >6 HIV+ KT (GS adjusted hazard ratio [aHR]: 1.05, 95% CI: 0.68-1.61, p = 0.82; PS aHR: 0.93; 95% CI: 0.56-1.53, p = 0.76), and participation in the NIH-study was not associated with any better outcomes (GS aHR: 1.08, 95% CI: 0.71-1.65, p = 0.71; PS aHR: 1.13; 95% CI: 0.68-1.89, p = 0.63). Transplant era was strongly associated with outcomes; HIV+ KTs performed in 2008-2011 had 38% lower risk of graft loss (aHR: 0.62; 95% CI: 0.42-0.92, p = 0.02) and 41% lower risk of death (aHR: 0.59; 95% CI: 0.39-0.90, p = 0.01) than that in 2004-2007. Outcomes after HIV+ KT have improved over time, but center-level experience or consortium participation is not necessary to achieve excellent outcomes, supporting continued expansion of HIV+ KT in the US.

Insights from the clinical assurance of service reconfiguration in the NHS: the drivers of reconfiguration and the evidence that underpins it – a mixed-methods study

Background

Over the life of the NHS, hospital services have been subject to continued reconfiguration. Yet it is rare for the reconfiguration of clinical services to be evaluated, leaving a deficit in the evidence to guide local reconfiguration of services.

Objectives

The objectives of this research are to determine the current pressures for reconfiguration within the NHS in England and the solutions proposed. We also investigate the quality of evidence used in making the case for change, any key evidence gaps, and the opportunities to strengthen the clinical case for change and how it is made.

Methods

We have drawn on two key sources of evidence. First, we reviewed the reports produced by the National Clinical Advisory Team (NCAT) documenting its reviews of reconfiguration proposals. An in-depth multilevel qualitative analysis was conducted of 123 NCAT reviews published between 2007 and 2012. Second, we carried out a search and synthesis of the literature to identify the key evidence available to support reconfiguration decisions. The findings from this literature search were integrated with the analysis of the reviews to develop a narrative for each specialty and the process of reconfiguration as a whole.

Results

The evidence from the NCAT reviews shows significant pressure to reconfigure services within the NHS in England. We found that the majority of reconfiguration proposals are driving an increasing concentration of hospital services, with some accompanying decentralisation and, for some specialist services, the development of supporting clinical networks. The primary drivers of reconfiguration have been workforce (in particular the medical workforce) and finance. Improving outcomes and safety issues have been subsidiary drivers, though many make the link between staffing and clinical safety. Policy has also been a notable driver. Access has been notable by its absence as a driver. Despite significant pressures to reconfigure services, many proposals fail to be implemented owing to public and/or clinical opposition. We found strong evidence that some specialist service reconfiguration including vascular surgery and major trauma can significantly improve clinical outcomes. However, there are notable evidence gaps. The most significant is the absence of evidence that service reconfiguration can deliver significant savings. There is also an absence of evidence about safe staffing models and the interplay between staff numbers, skill mix and outcomes. We found that the advice provided by the NCAT reflects the current evidence, but one of the NCAT’s most valuable contributions has been to encourage greater clinical engagement in service change.

Conclusions

The NHS is continuing to concentrate many district general hospital services to resolve financial and workforce pressures. However, many proposals are not implemented owing to public opposition. We also found no evidence to suggest that this will deliver the savings anticipated. There is a significant gap in the evidence about safe staffing models and the appropriate balance of junior and senior medical as well as other clinical staff. There is an urgent need to carry out research that will help to fill the current evidence gap. There is also a need to retain some national clinical expertise to work alongside Clinical Senates in supporting local service reconfiguration.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Association of hospital volume with readmission rates: a retrospective cross-sectional study

OBJECTIVE

To examine the association of hospital volume (a marker of quality of care) with hospital readmission rates.

DESIGN

Retrospective cross-sectional study.

SETTING

4651 US acute care hospitals.

STUDY DATA

6,916,644 adult discharges, excluding patients receiving psychiatric or medical cancer treatment.

MAIN OUTCOME MEASURES

We used Medicare fee-for-service data from 1 July 2011 to 30 June 2012 to calculate observed-to-expected, unplanned, 30 day, standardized readmission rates for hospitals and for specialty cohorts medicine, surgery/gynecology, cardiorespiratory, cardiovascular, and neurology. We assessed the association of hospital volume by quintiles with 30 day, standardized readmission rates, with and without adjustment for hospital characteristics (safety net status, teaching status, geographic region, urban/rural status, nurse to bed ratio, ownership, and cardiac procedure capability. We also examined associations with the composite outcome of 30 day, standardized readmission or mortality rates.

RESULTS

Mean 30 day, standardized readmission rate among the fifth of hospitals with the lowest volume was 14.7 (standard deviation 5.3) compared with 15.9 (1.7) among the fifth of hospitals with the highest volume (P<0.001). We observed the same pattern of lower readmission rates in the lowest versus highest volume hospitals in the specialty cohorts for medicine (16.6 v 17.4, P<0.001), cardiorespiratory (18.5 v 20.5, P<0.001), and neurology (13.2 v 14.0, p=0.01) cohorts; the cardiovascular cohort, however, had an inverse association (14.6 v 13.7, P<0.001). These associations remained after adjustment for hospital characteristics except in the cardiovascular cohort, which became non-significant, and the surgery/gynecology cohort, in which the lowest volume fifth of hospitals had significantly higher standardized readmission rates than the highest volume fifth (difference 0.63 percentage points (95% confidence interval 0.10 to 1.17), P=0.02). Mean 30 day, standardized mortality or readmission rate was not significantly different between highest and lowest volume fifths (20.4 v 20.2, P=0.19) and was highest in the middle fifth of hospitals (range 20.6-20.8).

CONCLUSIONS

Standardized readmission rates are lowest in the lowest volume hospitals-opposite from the typical association of greater hospital volume with better outcomes. This association was independent of hospital characteristics and was only partially attenuated by examining mortality and readmission together. Our findings suggest that readmissions are associated with different aspects of care than mortality or complications.

Can experience improve hospital management?

BACKGROUND

Experience curve effects were first observed in the industrial arena as demonstrations of the relationship between experience and efficiency. These relationships were largely determined by improvements in management efficiency and quality of care. In the health care industry, volume-outcome relationships have been established with respect to quality of care improvement, but little is known about the effects of experience on management efficiency. Here, we examine the relationship between experience and hospital management in Japanese hospitals.

METHODS

The study sample comprised individuals who had undergone surgery for unruptured abdominal aortic aneurysms and had been discharged from participant hospitals between April 1, 2006 and December 31, 2008. We analyzed the association between case volume (both at the hospital and surgeon level) and postoperative complications using multilevel logistic regression analysis. Multilevel log-linear regression analyses were performed to investigate the associations between case volume and length of stay (LOS) before and after surgery.

RESULTS

We analyzed 909 patients and 849 patients using the hospital-level and surgeon-level analytical models, respectively. The odds ratio of postoperative complication occurrence for an increase of one surgery annually was 0.981 (P < 0.001) at the hospital level and 0.982 (P < 0.001) at the surgeon level. The log-linear regression analyses showed that shorter postoperative LOS was significantly associated with high hospital-level case volume (coefficient for an increase of one surgery: -0.006, P = 0.009) and surgeon-level case volume (coefficient for an increase of one surgery: -0.011, P = 0.022). Although an increase of one surgery annually at the hospital level was statistically associated with a reduction of preoperative LOS by 1.1% (P = 0.006), there was no significant association detected between surgeon-level case volume and preoperative LOS (P = 0.504).

CONCLUSION

Experience at the hospital level may contribute to the improvement of hospital management efficiency.

Hospital volume of thoracoabdominal aneurysm repair does not affect mortality in California

OBJECTIVES

Open thoracoabdominal aneurysm repair (TAAR) is a rarely performed but a complicated and morbid procedure. This study compares the morbidity and mortality of open TAAR at high- versus low-volume hospitals.

METHODS

Included patients from California Office of Statewide Health Policy and Development patient discharge database who underwent an open TAAR between 1995 and 2010. High volume was ≥ 9 cases per year. Outcomes included mortality and postoperative complications. Multivariate analyses compared patients at high- versus low-volume hospitals.

RESULTS

A total of 122 hospitals were included, with 5 designated as high volume. Adjusted analysis found no difference in the odds ratio (OR) of mortality or morbidity at high-volume hospitals compared to low-volume hospitals (OR 0.37, P = .077; OR 0.94, P = .834, respectively). However, there was a decreased OR of mortality in high- versus low-volume hospitals when a high-volume hospital was defined as each year after meeting the initial threshold of 9 cases (OR 0.40, P = .040).

CONCLUSION

We found no difference in mortality between low- and high-volume institutions in California, until high-volume hospitals were defined as each year after meeting initial threshold case volume. This may suggest that the benefits of high-volume hospitals on outcomes are maintained after reaching the requisite case volume.

Effect of regional cooperation on outcomes from ruptured abdominal aortic aneurysm

BACKGROUND

Care for patients with a ruptured abdominal aortic aneurysm (rAAA) in the Amsterdam ambulance region (The Netherlands) was concentrated into vascular centres with a 24-h full emergency vascular service in cooperation with seven referring regional hospitals. Previous population-based survival after rAAA in the Netherlands was 46 (95 per cent confidence interval (c.i.) 43 to 49) per cent. It was hypothesized that regional cooperation would improve survival.

METHODS

This was a prospective observational cohort study carried out simultaneously with the Amsterdam Acute Aneurysm Trial. Consecutive patients with an rAAA between 2004 and 2011 in all ten hospitals in the Amsterdam region were included. The primary outcome was 30-day survival after admission. Multivariable logistic regression, including age, sex, co-morbidity, intervention (endovascular or open repair), preoperative systolic blood pressure, cardiopulmonary resuscitation and year of intervention, was used to assess the influence of hospital setting on survival.

RESULTS

Of 453 patients with rAAA from the Amsterdam ambulance region, 61 did not undergo intervention; 352 patients were treated surgically at a vascular centre and 40 at a referring hospital. The regional survival rate was 58.5 (95 per cent c.i. 53.9 to 62.9) per cent (265 of 453). After multivariable adjustment, patients treated at a vascular centre had a higher survival rate than patients treated surgically at a referring hospital (adjusted odds ratio 3.18, 95 per cent c.i. 1.43 to 7.04).

CONCLUSION

After regional cooperation, overall survival of patients with an rAAA improved. Most patients were treated in a vascular centre and in these patients survival rates were optimal.

Impact of the Establishment of a Specialty Hernia Referral Center

Background. Creating a surgical specialty referral center requires a strong interest, expertise, and a market demand in that particular field, as well as some form of promotion. In 2004, we established a tertiary hernia referral center. Our goal in this study was to examine its impact on institutional volume and economics. Materials and methods. The database of all hernia repairs (2004-2011) was reviewed comparing hernia repair type and volume and center financial performance. The ventral hernia repair (VHR) patient subset was further analyzed with particular attention paid to previous repairs, comorbidities, referral patterns, and the concomitant involvement of plastic surgery. Results. From 2004 to 2011, 4927 hernia repairs were performed: 39.3% inguinal, 35.5% ventral or incisional, 16.2% umbilical, 5.8% diaphragmatic, 1.6% femoral, and 1.5% other. Annual billing increased yearly from 7% to 85% and averaged 37% per year. Comparing 2004 with 2011, procedural volume increased 234%, and billing increased 713%. During that period, there was a 2.5-fold increase in open VHRs, and plastic surgeon involvement increased almost 8-fold, ( P = .004). In 2005, 51 VHR patients had a previous repair, 27.0% with mesh, versus 114 previous VHR in 2011, 58.3% with mesh ( P < .0001). For VHR, in-state referrals from 2004 to 2011 increased 340% while out-of-state referrals jumped 580%. In 2011, 21% of all patients had more than 4 comorbidities, significantly increased from 2004 ( P = .02). Conclusion. The establishment of a tertiary, regional referral center for hernia repair has led to a substantial increase in surgical volume, complexity, referral geography, and financial benefit to the institution.

Observations from the IMPROVE trial concerning the clinical care of patients with ruptured abdominal aortic aneurysm

BACKGROUND

Single-centre series of the management of patients with ruptured abdominal aortic aneurysm (AAA) are usually too small to identify clinical factors that could improve patient outcomes.

METHODS

IMPROVE is a pragmatic, multicentre randomized clinical trial in which eligible patients with a clinical diagnosis of ruptured aneurysm were allocated to a strategy of endovascular aneurysm repair (EVAR) or to open repair. The influences of time and manner of hospital presentation, fluid volume status, type of anaesthesia, type of endovascular repair and time to aneurysm repair on 30-day mortality were investigated according to a prespecified plan, for the subgroup of patients with a proven diagnosis of ruptured or symptomatic AAA. Adjustment was made for potential confounding factors.

RESULTS

Some 558 of 613 randomized patients had a symptomatic or ruptured aneurysm: diagnostic accuracy was 91·0 per cent. Patients randomized outside routine working hours had higher operative mortality (adjusted odds ratio (OR) 1·47, 95 per cent confidence interval 1·00 to 2·17). Mortality rates after primary and secondary presentation were similar. Lowest systolic blood pressure was strongly and independently associated with 30-day mortality (51 per cent among those with pressure below 70 mmHg). Patients who received EVAR under local anaesthesia alone had greatly reduced 30-day mortality compared with those who had general anaesthesia (adjusted OR 0·27, 0·10 to 0·70).

CONCLUSION

These findings suggest that the outcome of ruptured AAA might be improved by wider use of local anaesthesia for EVAR and that a minimum blood pressure of 70 mmHg is too low a threshold for permissive hypotension.

Venous thromboembolism after facelift surgery under local anesthesia: results of a multicenter survey

BACKGROUND

Venous thromboembolism (VTE) is a serious complication of cosmetic surgery, and studies have suggested that the incidence is not insignificant in facelift surgery. Use of local anesthesia over general anesthesia and shorter operative times are probable contributing factors to lower VTE incidence. Because there have been no large-scale assessments of VTE in facelifts as such, we investigated VTE incidence and relevant factors in facelift surgeries performed under local anesthesia only.

METHODS

We conducted a retrospective multicenter survey of facelift surgeons who utilize the American Society of Anesthesiologists level 1 oral anxiolysis and local diluted lidocaine anesthesia technique. Anonymous online surveys were sent to surgeons with questions regarding facelifts performed and VTE incidence over the previous 19 months.

RESULTS

Seventy-seven surgeons (93 % response rate) completed the survey, with 74 eligible surgeons reporting at least one facelift. Respondents reported five VTE events, for an overall VTE incidence of 1 event in 5,844 surgeries. Surgeons who reported performing facelifts at high volumes (>500 facelifts in 19 months) had a significantly lower VTE incidence than lower-volume surgeons (p = 0.011). High-volume surgeons also reported a significantly lower average operative time (p = 0.016), but for surgeries that did or did not result in VTE, there was no significant difference between surgeon-reported average operative times.

CONCLUSION

The low VTE incidence in this facelift series supports prior understanding that there is a low risk of VTE in surgery performed under local anesthesia and in surgery with shorter operative times. Limiting ancillary procedures to the face likely reduces operative time and likely also contributes to a lower VTE rate. The data further suggest that physicians performing facelifts more frequently tend to have shorter average operative times and overall lower VTE incidence.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Rehospitalization to primary versus different facilities following abdominal aortic aneurysm repair

OBJECTIVE

Reducing readmissions represents a unique opportunity to improve care and reduce health care costs and is the focus of major payers. A large number of surgical patients are readmitted to hospitals other than where the primary surgery was performed, resulting in clinical decisions that do not incorporate the primary surgeon and potentially alter outcomes. This study characterizes readmission to primary vs different hospitals after abdominal aortic aneurysm (AAA) repair and examines the implications with regard to mortality and cost.

METHODS

Patients who underwent open or endovascular aneurysm repair for AAA were identified from the Centers for Medicare and Medicaid Services Chronic Conditions Warehouse, a random 5% national sample of Medicare beneficiaries from 2005 to 2009. Outcomes for patients who underwent AAA repair and were readmitted within 30 days of initial discharge were compared based on readmission location (primary vs different hospital).

RESULTS

A total of 885 patients underwent AAA repair and were readmitted within 30 days. Of these, 626 (70.7%) returned to the primary facility, and 259 (29.3%) returned to a different facility. Greater distance from patient residence to the primary hospital was the strongest predictor of readmission to a different facility. Patients living 50 to 100 miles from the primary hospital were more likely to be readmitted to a different hospital compared with patients living <10 miles away (odds ratio, 8.50; P < .001). Patients with diagnoses directly related to the surgery (eg, wound infection) were more likely to be readmitted to the primary hospital, whereas medical diagnoses (eg, pneumonia and congestive heart failure) were more likely to be treated at a different hospital. There was no statistically significant difference in mortality between patients readmitted to a different or the primary hospital. Median total 30-day payments were significantly lower at different vs primary hospitals (primary, $11,978 vs different, $11,168; P = .04).

CONCLUSIONS

Readmission to a different facility after AAA repair is common and occurs more frequently than for the overall Medicare population. Patients travelling a greater distance for AAA repair are more likely to return to different vs the primary hospital when further care is required. For AAA repair, quality healthcare may be achieved at marginally lower cost and with greater patient convenience for selected readmissions at hospitals other than where the initial procedure was performed.

The impact of abdominal aortic aneurysm surgery on intensive care unit resources in an Irish tertiary centre

BACKGROUND

The potential impact of surgical service reconfiguration on intensive care unit (ICU) resources needs to be assessed.

AIMS

To determine the resources required to provide post-operative ICU care to patients undergoing open abdominal aortic aneurysm (AAA) repair or endovascular aneurysm repair (EVAR) at a specialist centre in the HSE South area

METHODS

For 198 patients, we calculated: (1) ICU bed-days; (2) organ support required; and (3) monetary cost of ICU care.

RESULTS

In total, 82.8% (101/122) of patients undergoing open AAA repair required post-operative ICU care (52 emergency and 49 elective). Emergency cases required more ICU bed-days (median 4.2 vs. 1.9, p<0.0005) and were more likely to require ventilation (odds ratio, OR 11.7, p<0.0001), inotropes (OR 3.1, p=0.01) or enteral nutrition (OR 23.3, p<0.0001). Mean cost per patient was €3,956 for elective cases and €16,419 for emergency cases. No patient required ICU admission after EVAR (n=76).

CONCLUSIONS

Open AAA surgery places significant demands on ICU resources. The planned reconfiguration of surgical services in Ireland must provide for parallel investment in ICU facilities and expertise.

Effect of procedure volume on outcomes after iliac artery angioplasty and stenting

Background

Service reorganization to concentrate complex vascular services in hospitals with high caseload volume aims to reduce mortality and complication rates. The present study assessed the relationship between caseload volume and outcome for iliac artery angioplasty and stenting in England using a routinely available national data set (Hospital Episode Statistics, HES).

Methods

Routine administrative data for iliac artery angioplasty and stent procedures performed in England between 2007 and 2011 were analysed. Associations between centre volume and outcomes (death, complications and duration of hospital stay) were tested and compared for two methods of stratification (quartiles and quintiles) and two statistical tests (odds ratios and the Cochran–Armitage test for trend). Multivariable analysis was also performed.

Results

There were 23 308 episodes of care recorded in HES with Office of Population Censuses and Surveys Classification of Surgical Operations and Procedures, fourth revision, codes L54.1 or L54.4 corresponding to iliac artery intervention. There was a gradual increase year by year in number of procedures performed. Univariable and multivariable analysis showed no association between centre volume and either death or complications (multivariable odds ratio, OR 1·00, 95 per cent confidence interval 1·00 to 1·00) for elective and non-elective procedures. Age was associated with higher mortality and complication rates in elective procedures, and with mortality in non-elective procedures. The risk of death after elective iliac angioplasty or stenting was significantly higher in women (multivariable OR 4·98, 2·09 to 13·26).

Conclusion

There was no association between the outcomes of endovascular iliac artery intervention and centre volume, but outcomes were significantly worse with increasing age and female sex.

Inpatient rehabilitation volume and functional outcomes in stroke, lower extremity fracture, and lower extremity joint replacement

BACKGROUND

It is unclear if volume-outcome relationships exist in inpatient rehabilitation.

OBJECTIVES

Assess associations between facility volumes and 2 patient-centered outcomes in the 3 most common diagnostic groups in inpatient rehabilitation.

RESEARCH DESIGN

We used hierarchical linear and generalized linear models to analyze administrative assessment data from patients receiving inpatient rehabilitation services for stroke (n=202,423), lower extremity fracture (n=132,194), or lower extremity joint replacement (n=148,068) between 2006 and 2008 in 717 rehabilitation facilities across the United States. Facilities were assigned to quintiles based on average annual diagnosis-specific patient volumes.

MEASURES

Discharge functional status (FIM instrument) and probability of home discharge.

RESULTS

Facility-level factors accounted for 6%-15% of the variance in discharge FIM total scores and 3%-5% of the variance in home discharge probability across the 3 diagnostic groups. We used the middle volume quintile (Q3) as the reference group for all analyses and detected small, but statistically significant (P<0.01) associations with discharge functional status in all 3 diagnosis groups. Only the highest volume quintile (Q5) reached statistical significance, displaying higher functional status ratings than Q3 each time. The largest effect was observed in FIM total scores among fracture patients, with only a 3.6-point difference in Q5 and Q3 group means. Volume was not independently related to home discharge.

CONCLUSIONS

Outcome-specific volume effects ranged from small (functional status) to none (home discharge) in all 3 diagnostic groups. Patients with these conditions can be treated locally rather than at higher volume regional centers. Further regionalization of inpatient rehabilitation services is not needed for these conditions.

[Treatment of abdominal aortic aneurysms]

The treatment of abdominal aortic aneurysms (AAA) has changed significantly since the introduction of endovascular aortic repair (EVAR). In terms of perioperative morbidity and mortality, randomized multicenter trials revealed results in favour of EVAR compared to open reconstruction. However, EVAR is associated with possible late complications caused by endoleaks, stent migration, kinking and/or overstenting of side branches, making life-long follow-up necessary. Since the majority of patients requiring therapy are elderly and exhibit attendant comorbidities, EVAR has become the procedure of choice in those patients with favourable anatomy. Medicamentous and conservative treatment may be relevant in patients with small to medium-sized aneurysms. Since smoking is one of the major risk factors for the development of AAA, all patients should be advised to stop smoking. Studies on long-term statin therapy in patients following surgical AAA repair showed a reduction in both overall and cardiovascular mortality; AAA patients should therefore receive statins for secondary prevention.

Racial and ethnic disparities in the treatment of unruptured thoracoabdominal aortic aneurysms in the United States

PURPOSE

Previous studies have found increased mortality in minority patients undergoing abdominal aortic aneurysm repair. The goal of this study was to identify racial and ethnic disparities in patients undergoing thoracoabdominal aortic aneurysm repair.

MATERIALS AND METHODS

We queried the Nationwide Inpatient Sample (2005-2009) using International Classification of Diseases, Ninth Revision, Clinical Modification codes for repair of unruptured thoracoabdominal aneurysms. The primary outcome was death. Secondary outcomes included postoperative complications. We performed multivariate analysis adjusting for age, gender, race, comorbidities (Charlson index), insurance type, and surgeon and hospital operative volumes and characteristics.

RESULTS

Overall, 1541 white, 207 black, and 117 Hispanic patients underwent thoracoabdominal aortic aneurysm repair. White patients tended to be older (P = 0.003), whereas black patients had a higher incidence of diabetes mellitus (P = 0.04). Black and Hispanic patients were less likely to have an elective admission (P < 0.001) and more likely to have repair performed at a hospital with a lower average annual surgical volume (P = 0.04). Postoperative complications were similar among the groups (P = 0.31). On multivariate analysis, increased mortality was independently associated with Hispanic ethnicity (relative ratio [RR], 2.57; 95% confidence interval [CI], 1.25-5.25; P = 0.01), cerebrovascular disease (RR, 1.88; 95% CI, 1.10-3.23; P = 0.02), and age (RR, 1.04; 95% CI, 1.01-1.07; P = 0.004).

CONCLUSIONS

Hispanic ethnicity is independently associated with increased mortality after repair of unruptured thoracoabdominal aneurysms. This finding was independent of preoperative comorbidities, postoperative complications, and surgeon and hospital operative volumes. Further studies are necessary to determine whether this mortality difference persists after the index hospitalization.

Regionalization of services improves access to emergency vascular surgical care

Management of vascular surgical emergencies requires rapid access to a vascular surgeon and hospital with the infrastructure necessary to manage vascular emergencies. The purpose of this study was to assess the impact of regionalization of vascular surgery services in Toronto to University Health Network (UHN) and St Michael's Hospital (SMH) on the ability of CritiCall Ontario to transfer patients with life- and limb-threatening vascular emergencies for definitive care. A retrospective review of the CritiCall Ontario database was used to assess the outcome of all calls to CritiCall regarding patients with vascular disease from April 2003 to March 2010. The number of patients with vascular emergencies referred via CritiCall and accepted in transfer by the vascular centers at UHN or SMH increased 500% between 1 April 2003-31 December 2005 and 1 January 2006-31 March 2010. Together, the vascular centers at UHN and SMH accepted 94.8% of the 1002 vascular surgery patients referred via CritiCall from other hospitals between 1 January 2006 and 31 March 2010, and 72% of these patients originated in hospitals outside of the Toronto Central Local Health Integration Network. Across Ontario, the number of physicians contacted before a patient was accepted in transfer fell from 2.9 ± 0.4 before to 1.7 ± 0.3 after the vascular centers opened. In conclusion, the vascular surgery centers at UHN and SMH have become provincial resources that enable the efficient transfer of patients with vascular surgical emergencies from across Ontario. Regionalization of services is a viable model to increase access to emergent care.

Target setting for elective infra-renal AAA surgery: A single mortality figure?

OBJECTIVES

One of the key standards set by the UK NAAASP is that centres performing elective abdominal aortic aneurysm (AAA) repair have a mortality rate of <6%. In light of this, and the current aim to reduce elective AAA repair mortality to 3.5% by 2013, we sought to investigate the statistical validity of such targets.

METHODS

The National Vascular Database (NVD) was interrogated and the degree of AAA missing data and its geographical variation is described. Utilising published data from 2006 to 2008 a funnel plot was used to illustrate NHS Trust level data for current estimates of mortality rate. A binomial distribution model was applied to calculate variation in observed mortality rates in relation to number of patients treated, based on a "true" mortality rate of 3.5%. Funnel plots were constructed using simulated data-sets for units performing 10, 30, 50, 100 or 150 procedures annually with control-limits calculated using a cumulative probability distribution. Finally the effect of case-mix on mortality was modelled and shown graphically.

RESULTS

The NVD AAA data set shows a range of data missingness across variables (median 22%, IQR 10-64%). High levels of missingness typically coincide with non-required, non-preferred variables however this is subject to geographical variation. Funnel plots of simulated data demonstrate that smaller units have greater variability in 3-year mortality (range 0.0-10.0%) than the largest units performing 150 procedures annually (1.3-5.6%). Around 20% of NVD variables are described as "preferred", these typically relate to clinical measurements and patient medications and would inform any risk model of mortality. Data missingness amongst these variables ranges from 5 to 50%.

CONCLUSIONS

There are many problems with the use of a single mortality figure to assess performance. These include the natural statistical variability and the means by which "case-mix" is taken into consideration. This article calls for further research into mortality target setting and suggests strategies which may help provide solutions nationally and facilitate international comparison.

Can technical factors explain the volume-outcome relationship in gastric bypass surgery?

BACKGROUND

The existence of a relationship between surgeon volume and patient outcome has been reported for different complex surgical operations. This relationship has also been confirmed for patients undergoing Roux-en-Y gastric bypass (RYGB) in the Longitudinal Assessment of Bariatric Surgery (LABS) study. Despite multiple studies demonstrating volume-outcome relationships, fewer studies investigate the causes of this relationship.

OBJECTIVE

The purpose of the present study is to understand possible explanations for the volume-outcome relationship in LABS.

METHODS

LABS includes a 10-center, prospective study examining 30-day outcomes after bariatric surgery. The relationship between surgeon annual RYGB volume and incidence of a composite endpoint (CE) has been published previously. Technical aspects of RYGB surgery were compared between high and low volume surgeons. The previously published model was adjusted for select technical factors.

RESULTS

High-volume surgeons (>100 RYGBs/yr) were more likely to perform a linear stapled gastrojejunostomy, use fibrin sealant, and place a drain at the gastrojejunostomy compared with low-volume surgeons (<25 RYGBs/yr), and less likely to perform an intraoperative leak test. After adjusting for the newly identified technical factors, the relative risk of CE was .93 per 10 RYGB/yr increase in volume, compared with .90 for clinical risk adjustment alone.

CONCLUSION

High-volume surgeons exhibited certain differences in technique compared with low-volume surgeons. After adjusting for these differences, the strength of the volume-outcome relationship previously found was reduced only slightly, suggesting that other factors are also involved.

Lower mortality for abdominal aortic aneurysm repair in high-volume hospitals is contingent upon nurse staffing

OBJECTIVE

To determine whether and to what extent the lower mortality rates for patients undergoing abdominal aortic aneurysm (AAA) repair in high-volume hospitals is explained by better nursing.

DATA SOURCES

State hospital discharge data, Multi-State Nursing Care and Patient Safety Survey, and hospital characteristics from the AHA Annual Survey.

STUDY DESIGN

Cross-sectional analysis of linked patient outcomes for individuals undergoing AAA repair in four states.

DATA COLLECTION

Secondary data sources.

PRINCIPAL FINDINGS

Favorable nursing practice environments and higher hospital volumes of AAA repair are associated with lower mortality and fewer failures-to-rescue in main-effects models. Furthermore, nurse staffing interacts with volume such that there is no mortality advantage observed in high-volume hospitals with poor nurse staffing. When hospitals have good nurse staffing, patients in low-volume hospitals are 3.4 times as likely to die and 2.6 times as likely to die from complications as patients in high-volume hospitals (p < .001).

CONCLUSIONS

Nursing is part of the explanation for lower mortality after AAA repair in high-volume hospitals. Importantly, lower mortality is not found in high-volume hospitals if nurse staffing is poor.

Provider volume and long-term outcome after elective abdominal aortic aneurysm repair

Background

Robust risk-adjusted analyses have demonstrated that a reduction in perioperative mortality is associated with the repair of an abdominal aortic aneurysm (AAA) in centres with a high operative caseload (volume). However, the long-term impact of this volume-related effect on mortality remains unknown.

Methods

Demographic and clinical data were extracted from UK Hospital Episodes Statistics for patients undergoing elective repair of an infrarenal AAA from 1 April 2000 to 31 March 2005. The long-term mortality of this cohort was investigated through linkage to the UK Office for National Statistics (ONS) registry. Risk-adjusted survival was analysed using Cox proportional hazards modelling to identify the effect of hospital volume on long-term mortality.

Results

A total of 14 396 patients with mean age of 72 years, of whom 85·7 per cent were men, underwent elective repair of an infrarenal AAA in England. They were linked to follow-up using ONS data. Risk-adjusted analysis of all-cause mortality by Cox proportional hazards modelling demonstrated a significant effect of hospital volume across all quintiles up to 2 years (P = 0·013). Remodelling the data after excluding in-hospital mortality still demonstrated the significant effect of hospital volume on late outcome.

Conclusion

There is a long-term benefit to patients who undergo elective AAA repair in a high-volume hospital.

Use of Hospital Episode Statistics to investigate abdominal aortic aneurysm surgery

BACKGROUND

A coding framework was evaluated to study patients undergoing open surgical replacement of an abdominal aortic aneurysm (AAA) in the English Hospital Episode Statistics (HES) database. The objective was to create groups of patients who are homogeneous with respect to diagnosis, prognosis and treatment.

METHODS

The frequency and consistency of potentially relevant diagnosis (International Classification of Diseases, 10th revision) and procedure (Office of Population Censuses and Surveys Classification, 4th revision) codes were assessed in patients admitted to English National Health Service hospitals between April 2003 and March 2008. Administrative codes were compared with diagnosis and procedure codes to check that patients who had undergone emergency surgery for a ruptured AAA were admitted as an emergency.

RESULTS

Of 20 290 patients undergoing AAA replacement, 19 250 (94·9 per cent) had a consistent diagnosis (unruptured or ruptured AAA); 79·3 per cent of patients with an emergency replacement were coded as having a ruptured AAA and 95·7 per cent of those with a non-emergency replacement as having an unruptured AAA. Of patients who had undergone emergency replacement of a ruptured AAA, 93·3 per cent were coded as having been admitted as an emergency.

CONCLUSION

Coding consistency was high. The proposed framework could define homogeneous groups by combining diagnosis, procedure and administrative codes. It also allows an assessment of potential miscoding at national and hospital level.

The effect of surgical training and hospital characteristics on patient outcomes after pediatric surgery: a systematic review

BACKGROUND/PURPOSE

A systematic review aimed to compare patient outcomes after (1) appendicectomy and (2) pyloromyotomy performed by different surgical specialties, surgeons with different annual volumes, and in different hospital types, to inform the debate surrounding children's surgery provision.

METHODS

Embase, Medline, Cochrane Library, and Health Management Information Consortium were searched from January 1990 to February 2010 to identify relevant articles. Further literature was sought by contacting experts, citation searching, and hand-searching appropriate journals.

RESULTS

Seventeen relevant articles were identified. These showed that (1) rates of wrongly diagnosed appendicitis were higher among general surgeons, but there were little differences in other outcomes and (2) outcomes after pyloromyotomy were superior in patients treated by specialist surgeons. Surgical specialty was a better predictor of morbidity than hospital type, and surgeons with higher operative volumes had better results.

CONCLUSIONS

Existing evidence is largely observational and potentially subject to selection bias, but general pediatric surgery outcomes were clearly dependent on operative volumes. Published evidence suggests that (1) pediatric appendicectomy should not be centralized because children can be managed effectively by general surgeons; (2) pyloromyotomy need not be centralized but should be carried out in children's units by appropriately trained surgeons who expect to see more than 4 cases per year.

Which dressing do donor site wounds need?: study protocol for a randomized controlled trial

Background

Donor site wounds after split-skin grafting are rather 'standard' wounds. At present, lots of dressings and topical agents for donor site wounds are commercially available. This causes large variation in the local care of these wounds, while the optimum 'standard' dressing for local wound care is unclear. This protocol describes a trial in which we investigate the effectiveness of various treatment options for these donor site wounds.

Methods

A 14-center, six-armed randomized clinical trial is being carried out in the Netherlands. An a-priori power analysis and an anticipated dropout rate of 15% indicates that 50 patients per group are necessary, totaling 300 patients, to be able to detect a 25% quicker mean time to complete wound healing. Randomization has been computerized to ensure allocation concealment. Adult patients who need a split-skin grafting operation for any reason, leaving a donor site wound of at least 10 cm² are included and receive one of the following dressings: hydrocolloid, alginate, film, hydrofiber, silicone dressing, or paraffin gauze. No combinations of products from other intervention groups in this trial are allowed. Optimum application and changes of these dressings are pursued according to the protocol as supplied by the dressing manufacturers. Primary outcomes are days to complete wound healing and pain (using a Visual Analogue Scale). Secondary outcomes are adverse effects, scarring, patient satisfaction, and costs. Outcome assessors unaware of the treatment allocation will assess whether or not an outcome has occurred. Results will be analyzed according to the intention to treat principle. The first patient was randomized October 1, 2009.

Discussion

This study will provide comprehensive data on the effectiveness of different treatment options for donor site wounds. The dressing(s) that will prevail in effectiveness, satisfaction and costs will be promoted among clinicians dealing with such patients. Thus, we aim to contribute a well-designed trial, relevant to all clinicians involved in the care for donor site wounds, which will help enhance uniformity and quality of care for these patients.

Trial registration

http://www.trialregister.nl, NTR1849. Date registered: June 9, 2009

Multicentre study of the quality of a large administrative data set and implications for comparing death rates

Background

The aim was to compare the completeness and accuracy of the English Hospital Episode Statistics (HES) with a ‘gold standard’ data set for a sample of hospitals and to determine the effect of data quality on comparisons of hospital death rates.

Methods

A multicentre audit of data quality was undertaken, based on a sample of all elective abdominal aortic aneurysm (AAA) repairs performed in England. All elective AAA repairs in nine collaborating hospital trusts were included over a 2-year interval. Cases were identified from HES, local databases, hospital administration systems and theatre records. The main outcome measures were the numbers of cases and deaths according to HES compared with case-note review. The recording of co-morbidities and the effect of data accuracy on mortality analyses and risk adjustment were quantified.

Results

A total of 1102 elective AAA repairs were identified from HES data. Of 962 procedures with case-note review, 827 (86·0 per cent, 95 per cent confidence interval 84·0 to 88·0 per cent) were confirmed as elective AAA repair. The survival status with HES was 99·8 per cent accurate on comparison with the Office for National Statistics death registry. There was no significant difference in mortality assessment between the HES data and the ‘gold standard’ data set (5·3 versus 5·0 per cent; P = 0·753). Smaller hospitals were more affected by data inaccuracies than larger hospitals.

Conclusion

This study confirmed that HES data can be used effectively to compare mortality between hospitals. Administrative data will be used increasingly for assessing performance and clinicians should accept responsibility to improve coding. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.