Bradley N. Reames

Hospital volume and operative mortality in the modern era.

Objective:To determine whether the relationship between hospital volume and mortality has changed over time. Background:It is generally accepted that hospital volume is associated with mortality in high-risk procedures. However, as surgical safety has improved over the last decade, recent evidence has suggested that the inverse relationship has diminished or been eliminated. Methods:Using national Medicare claims data from 2000 through 2009, we examined mortality among 3,282,127 patients who underwent 1 of 8 gastrointestinal, cardiac, or vascular procedures. Hospitals were stratified into quintiles of operative volume. Using multivariable logistic regression models to adjust for patient characteristics, we examined the relationship between hospital volume and mortality, and assessed for changes over time. We performed sensitivity analyses using hierarchical logistic regression modeling with hospital-level random effects to confirm our results. Results:Throughout the 10-year period, a significant inverse relationship was observed in all procedures. In 5 of the 8 procedures studied, the strength of the volume-outcome relationship increased over time. In esophagectomy, for example, the adjusted odds ratio of mortality in very low volume hospitals compared to very high volume hospitals increased from 2.25 [95% confidence interval (CI): 1.57–3.23] in 2000–2001 to 3.68 (95% CI: 2.66–5.11) in 2008–2009. Only pancreatectomy showed a notable decrease in strength of the relationship over time, from 5.83 (95% CI: 3.64–9.36) in 2000–2001, to 3.08 (95% CI: 2.07–4.57) in 2008–2009. Conclusions:For all procedures examined, higher volume hospitals had significantly lower mortality rates than lower volume hospitals. Despite recent improvements in surgical safety, the strong inverse relationship between hospital volume and mortality persists in the modern era.

Understanding of regional variation in the use of surgery.

The use of common surgical procedures varies widely across regions. Differences in illness burden, diagnostic practices, and patient attitudes about medical intervention explain only a small degree of regional variation in surgery rates. Evidence suggests that surgical variation results mainly from differences in physician beliefs about the indications for surgery, and the extent to which patient preferences are incorporated into treatment decisions. These two components of clinical decision making help to explain the so-called surgical signatures of specific procedures, and why some consistently vary more than others. Variation in clinical decision making is, in turn, affected by broad environmental factors, including technology diffusion, supply of specialists, local training frameworks, financial incentives, and regulatory factors, which vary across countries. Better scientific evidence about the comparative effectiveness of surgical and non-surgical interventions could help to mitigate regional variation, but broader dissemination of shared decision aids will be essential to reduce variation in preference-sensitive disorders.

Changes in Bariatric Surgery Procedure Use in Michigan, 2006-2013

Bariatric surgery is the most effective therapy available for significant and sustainable weight loss in morbidly obese patients.1,2 As a result of the rising prevalence of obesity, improvements in perioperative safety, and expanded insurance coverage, bariatric surgery utilization has increased in the last decade.3,4 Changes in procedure use over time reflect emerging evidence regarding the comparative safety and effectiveness of available procedures.1,2,5 An understanding of current trends in bariatric procedure utilization is essential to primary care physicians counseling morbidly obese patients considering surgical intervention. Though recent reports have documented increased use of sleeve gastrectomy (SG) in certain populations,4,6 the extent to which this procedure has supplanted other procedures, such as Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB), is poorly understood. Moreover, it is unclear if relative utilization differs within clinical subgroups that might be predicted to have better outcomes with a specific procedure. To better understand current trends in bariatric surgery utilization, we examined procedure rates in patients undergoing bariatric surgery in Michigan between 2006 and 2013.

Effects of Resident Involvement on Complication Rates after Laparoscopic Gastric Bypass

BACKGROUND Although resident involvement has been shown to be safe for most procedures, the impact of residents on outcomes after complex laparoscopic procedures is not well understood. We sought to examine the impact of resident involvement on outcomes after bariatric surgery using a population-based clinical registry. STUDY DESIGN We analyzed 17,057 patients who underwent a primary laparoscopic gastric bypass in the 35-hospital Michigan Bariatric Surgery Collaborative from July 2006 to August 2012. Resident involvement was characterized at the surgeon level. Using hierarchical logistic regression, we examined the influence of resident involvement on 30-day complications, accounting for patient characteristics as well as hospital and surgeon case volume. To evaluate potential mediating factors for specific complications, we also adjusted for operative duration. RESULTS Risk-adjusted 30-day complication rates with and without residents were 13.0% and 8.5%, respectively (p < 0.01). Resident involvement was independently associated with wound infection (odds ratio [OR] = 2.06; 95% CI, 1.24-3.43) and venous thromboembolism (OR = 2.01; 95% CI, 1.19-3.40), but not with any other medical or surgical complications. Operative duration was longer with resident involvement (median duration with residents 129 minutes vs 88 minutes without; p < 0.01). After adjusting for operative duration, resident involvement was still independently associated with wound infection (OR = 1.67; 95% CI, 1.01-2.76), but not venous thromboembolism (OR = 1.73; 95% CI, 0.99-3.04). CONCLUSIONS Resident involvement in laparoscopic gastric bypass is independently associated with wound infections and venous thromboembolism. The effect appears to be mediated in part by longer operative times. These findings highlight the importance of strategies to assess and improve resident technical proficiency outside the operating room.

A Checklist-Based Intervention to Improve Surgical Outcomes in Michigan: Evaluation of the Keystone Surgery Program

IMPORTANCE Previous studies of checklist-based quality improvement interventions have reported mixed results. OBJECTIVE To evaluate whether implementation of a checklist-based quality improvement intervention--Keystone Surgery--was associated with improved outcomes in patients in a large statewide population undergoing general surgery. DESIGN, SETTING, AND EXPOSURES A retrospective longitudinal study examined surgical outcomes in 64,891 Michigan patients in 29 hospitals using Michigan Surgical Quality Collaborative clinical registry data from 2006 through 2010. Multivariable logistic regression and difference-in-differences analytic approaches were used to evaluate whether Keystone Surgery program implementation was associated with improved surgical outcomes following general surgery procedures, apart from existing temporal trends toward improved outcomes during the study period. MAIN OUTCOMES AND MEASURES Risk-adjusted rates of superficial surgical site infection, wound complication, any complication, and 30-day mortality. RESULTS Implementation of Keystone Surgery in 14 participating centers was not associated with improvements in surgical outcomes during the study period. Adjusted rates of superficial surgical site infection (3.2% vs 3.2%, P=.91), wound complication (5.9% vs 6.5%, P=.30), any complication (12.4% vs 13.2%, P=.26), and 30-day mortality (2.1% vs 1.9%, P=.32) at participating hospitals were similar before and after implementation. Difference-in-differences analysis accounting for trends in 15 nonparticipating centers and sensitivity analysis excluding patients receiving surgery in the first 6 or 12 months after program implementation yielded similar results. CONCLUSIONS AND RELEVANCE Implementation of a checklist-based quality improvement intervention did not affect rates of adverse surgical outcomes among patients undergoing general surgery in participating Michigan hospitals. Additional research is needed to understand why this program was not successful prior to further dissemination and implementation of this model to other populations.

Influence of median surgeon operative duration on adverse outcomes in bariatric surgery

BACKGROUND Evidence suggests that prolonged operative time adversely affects surgical outcomes. However, whether faster surgeons have better outcomes is unclear, as a surgeon׳s speed could reflect skill and efficiency, but may alternatively reflect haste. This study evaluates whether median surgeon operative time is associated with adverse surgical outcomes after laparoscopic Roux-en-Y gastric bypass. METHODS We performed a retrospective cohort study using statewide clinical registry data from the years 2006 to 2012. Surgeons were ranked by their median operative time and grouped into terciles. Multivariable logistic regression with robust standard errors was used to evaluate the influence of median surgeon operative time on 30-day surgical outcomes, adjusting for patient and surgeon characteristics, trainee involvement, concurrent procedures, and the complex interaction between these variables. RESULTS A total of 16,344 patients underwent surgery during the study period. Compared to surgeons in the fastest tercile, slow surgeons required 53 additional minutes to complete a gastric bypass procedure (median [interquartile range] 139 [133-150] versus 86 [69-91], P<.001). After adjustment for patient characteristic only, slow surgeons had significantly higher adjusted rates of any complication, prolonged length of stay, emergency department visits or readmissions, and venous thromboembolism (VTE). After further adjustment for surgeon characteristics, resident involvement, and the interaction between these variables, slow surgeons had higher rates of any complication (10.5% versus 7.1%, P=.039), prolonged length of stay (14.0% versus 4.4%, P=.002), and VTE (0.39% versus .22%, P<.001). CONCLUSION Median surgeon operative duration is independently associated with adjusted rates of certain adverse outcomes after laparoscopic Roux-en-Y gastric bypass. Improving surgeon efficiency while operating may reduce operative time and improve the safety of bariatric surgery.

Socioeconomic disparities in mortality after cancer surgery: Failure to rescue

IMPORTANCE Disparities in operative mortality due to socioeconomic status (SES) have been consistently demonstrated, but the mechanisms underlying this disparity are not well understood. OBJECTIVE To determine whether variations in failure to rescue (FTR) contribute to socioeconomic disparities in mortality after major cancer surgery. DESIGN, SETTING, AND PARTICIPANTS We performed a retrospective cohort study using the Medicare Provider Analysis and Review File and the Medicare Denominator File. A summary measure of SES was created for each zip code using 2000 US Census data linked to residence. Multivariable logistic regression was used to examine the influence of SES on rates of FTR, and fixed-effects hierarchical regression was used to evaluate the extent to which disparities could be attributed to differences among hospitals. A total of 596,222 patients undergoing esophagectomy, pancreatectomy, partial or total gastrectomy, colectomy, lung resection, and cystectomy for cancer from 2003 through 2007 were studied. MAIN OUTCOMES AND MEASURES Operative mortality, postoperative complications, and FTR (case fatality after ≥1 major complication). RESULTS Patients in the lowest quintile of SES had mildly increased rates of complications (25.6% in the lowest quintile vs 23.8% in the highest quintile, P = .003), a larger increase in mortality (10.2% vs 7.7%, P = .0009), and the greatest increase in rates of FTR (26.7% vs 23.2%, P = .007). Analysis of hospitals revealed a higher FTR rate for all patients (regardless of SES) at centers treating the largest proportion of patients with low SES. The adjusted odds ratios (95% CIs) of FTR according to SES ranged from 1.04 (0.95-1.14) for gastrectomy to 1.45 (1.21-1.73) for pancreatectomy. Additional adjustment for hospital effect nearly eliminated the disparity observed in FTR across levels of SES. CONCLUSIONS AND RELEVANCE Patients in the lowest quintile of SES have significantly increased rates of FTR. This finding appears to be in part a function of the hospital where patients with low SES are treated. Future efforts to improve socioeconomic disparities should concentrate on hospital processes and characteristics that contribute to successful rescue.

Strategies for reducing regional variation in the use of surgery: a systematic review.

Objective:To review the literature evaluating the effect of practice guidelines and decision aids on use of surgery and regional variation. Background:The use of surgical procedures varies widely across geographic regions. Although practice guidelines and decision aids have been promoted for reducing variation, their true effectiveness is uncertain. Methods:Studies evaluating the influence of clinical practice guidelines or consensus statements, shared decision making and decision aids, or provider feedback of comparative utilization, on rates of surgical procedures were identified through literature searches of Ovid MEDLINE, EMBASE, and Web of Science. Results:A total of 1946 studies were identified and 27 were included in the final review. Of the 12 studies evaluating implementation of guidelines, 6 reported a significant effect. Those examining overall population-based rates had mixed effects, but all studies evaluating procedure choice described at least a small increase in use of recommended therapy. Three of 5 studies examining the effect of guidelines on regional variation reported a significant reduction after dissemination. Of the 15 studies examining decision aids, 5 revealed significant effects. Many studies of decision aids reported decreases in population-based procedure rates. Nearly all studies evaluating the impact of decision aids on procedure choice reported increases in rates of less invasive procedures. Only one study of decision aids assessed changes in regional variation and found mixed results. Conclusions:Both practice guidelines and decision aids have been proven effective in many clinical contexts. Expanding the clinical scope of these tools and eliminating barriers to implementation will be essential to further efforts directed toward reducing regional variation in the use of surgery.

Geographic variation in use of laparoscopic colectomy for colon cancer

PURPOSE Emerging evidence supporting the use of laparoscopic colectomy in patients with cancer has led to dramatic increases in utilization. Though certain patient and hospital characteristics may be associated with the use of laparoscopy, the influence of geography is poorly understood. METHODS We used national Medicare claims data from 2009 and 2010 to examine geographic variation in utilization of laparoscopic colectomy for patients with colon cancer. Patients were assigned to hospital referral regions (HRRs) where they were treated. Multivariable logistic regression was used to generate age, sex, and race-adjusted rates of laparoscopic colectomy for each HRR. Patient quintiles of adjusted HRR utilization were used to evaluate differences in patient and hospital characteristics across low and high-utilizing HRRs. RESULTS A total of 93,786 patients underwent colon resections at 3,476 hospitals during the study period, of which 30,502 (32.5%) were performed laparoscopically. Differences in patient characteristics between the lowest and highest quintiles of HRR utilization were negligible, and there was no difference in the availability of laparoscopic technology. Yet adjusted rates of laparoscopic colectomy utilization varied from 0% to 66.8% across 306 HRRs in the United States. CONCLUSION There is wide geographic variation in the utilization of laparoscopic colectomy for Medicare patients with colon cancer, suggesting treatment location may substantially influence a patients options for surgical approach. Future efforts to reduce variation will require increased dissemination of training techniques, novel opportunities for learning among surgeons, and enhanced educational resources for patients.

Preserving operative volume in the setting of the 2011 ACGME duty hour regulations

OBJECTIVES The reported influence of Accreditation Council for Graduate Medical Education resident duty hour limitations on operative case volume has been mixed. Additional restrictions instituted in July 2011 further limited the work hours of postgraduate year 1 (PGY-1) residents, threatening to reduce availability for educational and operative activities. In this study, we evaluate our novel intern call schedule, which we hypothesized would preserve operative experience despite these increased restrictions. DESIGN A retrospective analysis of PGY-1 operative reports was conducted. Operations outside of major case categories were excluded. Operative case volumes in the Section of General Surgery for the same period were analyzed, as were average duty hours for each resident. Comparative statistics were generated using Wilcoxon rank sum tests. SETTING Single-institution study conducted at the University of Michigan, a tertiary-care academic hospital. PARTICIPANTS Overall, 50 categorical general surgery residents from 2005 to present were included. Three residents were subsequently excluded as they were preliminary interns rather than categorical; 2 residents were excluded having completed their intern years at other institutions. RESULTS The median number of major cases done during the PGY-1 for all evaluated residents was 89 (interquartile range [IQR]: 72-101). For interns between the years 2005 and 2011, the median number of major cases was 87 (IQR: 73-101), whereas interns in the 2011 to 2013 academic years performed 91.5 (IQR: 69.5-101.5, p = 0.91). Although case volume varied between intern classes, no significant differences were observed between any 2 individual classes in the study. Analysis of annual case volumes among each PGY revealed a relative increase of 29% (p < 0.001) among PGY-2 residents, and 20% (p = 0.02) by PGY-3 residents. Relative increases among senior residents (8% for both PGY-4 and PGY-5) did not reach statistical significance. CONCLUSIONS Our novel call schedule attempts to minimize prolonged night-float coverage responsibilities for interns in hopes of preserving their operative experience. In spite of increased duty hour restrictions, PGY-1 operative volume has not decreased significantly at our institution. However, in the same time period, PGY-2 and PGY-3 case volume has increased. Our findings highlight the challenges faced by surgical residencies in light of these new restrictions, particularly the 16-hour limit. Additional rigorously designed prospective studies should be conducted to better understand the influence of the most recent Accreditation Council for Graduate Medical Education work hour limitations on the subjective and objective experiences of surgical residents.