Extended Length of Stay After Surgery Complications, Inefficient Practice, or Sick Patients?

Transcription

1 Research Original Investigation Extended Length of Stay After Surgery Complications, Inefficient Practice, or Sick Patients? Robert W. Krell, MD; Micah E. Girotti, MD; Justin B. Dimick, MD, MPH IMPORTANCE With the health policy focus on shifting risk to hospitals and physicians, hospital leaders are increasing efforts to reduce excessive resource use, such as patients with extended length of stay (LOS) after surgery. However, the degree to which extended LOS represents complications, patient illness, or inefficient practice style is unclear. OBJECTIVE To examine the influence of complications on the variance in hospitals extended LOS rates after colorectal resections. DESIGN, SETTING, AND PARTICIPANTS In this retrospective cohort study performed from January 1 through December 31, 9, we analyzed data from the 9 American College of Surgeons National Surgical Quality Improvement Program. Study participants were adults undergoing colorectal resections in 199 hospitals. EXPOSURES Inpatient complications recorded in the American College of Surgeons National Surgical Quality Improvement Program registry. Inpatient complications were identified by the association of the complication's postoperative date with the patient s surgical discharge date. MAIN OUTCOME AND MEASURE Hospitals risk-adjusted extended LOS rates, defined as the proportion of patients with a hospital stay greater than the 7th percentile for the entire cohort. RESULTS A total of 2177 patients (42.8%) with extended LOSs did not have a documented inpatient complication. Although there was wide variation in risk-adjusted extended LOS (14.%-3.3%) and risk-adjusted inpatient complication (12.1%-28.%) rates, there was only a weak correlation (Spearman ρ =.6,P <.1) between the two. Only 2.% of the variation in hospitals extended LOS rates was attributable to hospitals inpatient complication rates. CONCLUSIONS AND RELEVANCE Much of the variation in hospitals risk-adjusted extended LOS rates is not attributable to patient illness or complications and therefore most likely represents differences in practice style. Efforts to reduce excess resource use should focus on efficiency of care, such as increased adoption of enhanced recovery pathways. JAMA Surg. 14;149(8):8-8. doi:.1/jamasurg Published online June, 14. Author Affiliations: Department of Surgery, University of Michigan Health System, Ann Arbor. Corresponding Author: Robert W. Krell, MD, Center for Healthcare Outcomes and Policy, 28 Plymouth Rd, Bldg 16, Office 16-N-13, Ann Arbor, MI 489 (rkrell@med.umich.edu). 8 Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18

2 Research Original Investigation Extended Postoperative Length of Stay With the policy emphasis on shifting risk to hospitals and physicians, such as bundled payments and pay for performance, hospital leaders are looking for ways to improve resource use. 1- Although these policies will encourage hospitals to be more efficient in general, few data are available to help understand costs after surgery. Because hospitals lack detailed cost data, they commonly use length of stay (LOS) as a proxy for resource use. 6,7 In this context of value-based payment, hospitals and physicians are increasing efforts to better understand and improve resource use and unnecessarily long postoperative hospital stays. The best strategy to reduce excessive LOS after surgery is unclear, however. There are 2 common explanations for extended hospital stays after an operation. First, patients experience postoperative complications that extend the LOS through management of the complications (eg, additional operations), so it is possible that hospitals and physicians should focus on preventing and managing complications to improve overall efficiency. Second, differences in LOS are due to practice style differences among hospitals and physicians. There is differential adoption of new surgical technologies, such as minimally invasive approaches, and variable use of other efforts to coordinate care processes, such as enhanced recovery pathways. 8,9 A better understanding of the extent to which extended LOS is attributable to patient illness, complications, or practice style differences is essential to targeting efforts for improvement. In this context, we studied the association between extended postoperative LOS and complications and the extent to which complications account for variation in hospitals extended LOS rates. Methods Data Source and Study Population The study protocol was reviewed and deemed not regulated by the University of Michigan Institutional Review Board, so no informed consent was required. We analyzed data from the 9 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) clinical registry. Details regarding data abstraction and quality control have been described previously. Using relevant Current Procedural Terminology codes, we selected adult patients undergoing inpatient laparoscopic or open colorectal resections from January 1 through December 31, 9, to form our study cohort. Outcomes We examined extended postoperative LOS, which we defined as a postoperative hospital stay greater than the 7th percentile for the entire cohort. We also examined LOS greater than the 9th percentile in sensitivity analyses. Hospitals extended LOS rates were defined as the proportion of patients with extended LOSs. We also assessed complications (eg, wound dehiscence; superficial, deep, or organ-space surgical site infection; myocardial infarction; cardiac arrest; prolonged ventilator requirement; unplanned reintubation; pneumonia; progressive renal insufficiency; acute renal failure; coma; stroke; deep venous thrombosis or pulmonary embolism; bleeding requiring transfusion of >4 U of blood; graft or prosthetic failure; urinary tract infection; and sepsis or septic shock) and severe complications (those listed above but excluding deep venous thrombosis, urinary tract infection, progressive renal insufficiency, and superficial or deep surgical site infection). Because inpatient complications would most likely prolong hospital stay, we focused our assessment on complications that occurred before the patient s discharge date. Independent Variables Patient variables recorded in the clinical registry include age; race; sex; indication for operation (from International Classification of Diseases, Ninth Revision codes); height; weight; functional status; American Society of Anesthesiologists (ASA) class; cardiac, pulmonary, renal, neurologic, endocrine, hematologic and vascular comorbidities; long-term corticosteroid therapy; disseminated cancer; prior operation; % or greater weight loss before operation; preoperative sepsis; open wound or transfusion requirement; and preoperative laboratory values. We reclassified continuous variables as categorical variables with levels for model entry. Statistical Analysis First, we assessed the proportion of patients with extended LOSs who did not experience an inpatient complication or severe complication. Second, we conducted 2 hospital analyses: the first assessed the correlation between hospitals risk-adjusted extended LOS and complication rates, and the second assessed the extent to which different complications explained the variation in hospitals risk-adjusted extended LOS rates. We started by calculating hospitals risk-adjusted extended LOS and complication rates. All risk-adjustment models included patient age, sex, race, ASA class, comorbidities and laboratory variables, and procedural (eg, laparoscopic case and emergency procedure) variables to generate predicted outcome probabilities. Model discrimination was fair (C statistic = ), and calibration was adequate (Hosmer- Lemeshow χ 2 = ). 11 Dividing each hospital s observed outcome rate by the sum of its predicted probabilities generates observed to expected outcome ratios, which when multiplied by the cohort s outcome rate yield hospitals riskadjusted rates. To further account for random outcome variation, we adjusted hospitals risk-adjusted rates using shrinkage estimators derived from hierarchical regression models We then used the Spearman rank correlation test to compare hospitals risk-adjusted extended LOS and complication rates. To assess the extent to which complications explained the variation in hospitals risk-adjusted extended LOS rates, we constructed a hierarchical logistic regression model for extended LOS with the hospital specified as the higher level. We serially assessed the proportional change in hospital-level random intercept variance after adding complications (patient-level and hospital-level complication rates) to the hierarchical model. 14 Finally, we substituted specific severe complication types (eg, surgical site [organ-space surgical site infection or wound dehiscence], pulmonary [unplanned reintubation, prolonged mechanical ventilation, pulmonary embolism, or pneumonia], car- 816 JAMA Surgery August 14 Volume 149, Number 8 jamasurgery.com Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18

3 Extended Postoperative Length of Stay Original Investigation Research diac [cardiac arrest or myocardial infarction], and sepsis or septic shock). All models adjusted for patient age, sex, race, ASA class, comorbidities, laboratory values, and procedural variables as above. We performed all analyses using STATA statistical software, version 12 (Stata Corp). All statistical tests were 2-sided with P <. considered significant. Results We identified patients undergoing colorectal resections in 199 hospitals participating in the ACS-NSQIP in 9. The median, 7th percentile, and 9th percentile LOSs were 6, 9, and 16 days, respectively. Patients with extended LOS were older, had more comorbidities, underwent more emergency procedures, and more often had resections for obstructive reasons (Table 1). Although patients with extended LOS were more likely to have complications, a large proportion (2177 [42.8%]) did not have a documented complication or severe complication (2844 [.9%]) (Table 1). There was wide variation in hospitals risk-adjusted outcome rates but a weak correlation among outcomes (Figure 1 and Figure 2). For example, risk-adjusted extended LOS rates (range, 14.%-3.3%) and complication rates (range, 12.1%- 28.%) had weak correlation (Spearman ρ =.6, P <.1) (Figure 2A). The correlation between extended LOS and severe complications was weaker (Spearman ρ =.49, P <.1) (Figure 2B). When extended LOS was defined as the 9th percentile, the correlation between extended LOS and complications was weaker still (Figure 2C and D). Table 2 provides the proportion of hospitals risk-adjusted extended LOS rate variation attributable to complications. Complications explained more of the hospitals extended LOS rate variation (36.9%) than severe complications (31.2%). Similarly, the hospitals complication rates explained more (2.%) of the extended LOS rate variation than the hospitals severe complication rates (47.%). Surgical site and cardiac complications explained extended LOS rate variation equally (3.% and 3.4%, respectively) and to a greater extent than pulmonary or septic complications (33.6% and.4%, respectively) (Table 2). When LOS was defined as the 9th percentile, cardiac complications accounted for more hospitals extended LOS rate variation (2.1%) than other complication types (surgical site, 47.7%; septic, 32.9%; and pulmonary, 32.3%). Discussion Table 1. Characteristics of Patients Undergoing Colorectal Resections in 199 Hospitals Participating in the American College of Surgeons National Surgical Quality Improvement Program, 9 Patients, % a Normal LOS Extended LOS Characteristic (n = 17 76) (n = 88) Demographics Age, mean, y Male sex White race Independent functional status Diagnosis Neoplasm Diverticular disease Obstruction Comorbidities Total comorbidities, median Coronary artery disease Peripheral vascular disease Diabetes mellitus Chronic obstructive pulmonary disease Cerebrovascular disease Renal failure or dialysis Long-term corticosteroid use. 11. Preoperative SIRS or sepsis Operative characteristics Emergency case Laparoscopic procedure Complications b Inpatient Inpatient severe Surgical site severe Pulmonary Cardiac. 3.7 Sepsis or septic shock Abbreviations: LOS, length of stay; SIRS, systemic inflammatory response syndrome. a Data are presented as percentage of patients unless otherwise indicated. P <.1 for all characteristics. b Surgical site complications include organ-space surgical site infection or wound dehiscence. Pulmonary complications include unplanned reintubation, prolonged mechanical ventilation, pulmonary embolism, and pneumonia. Cardiac complications include cardiac arrest that requires cardiopulmonary resuscitation or myocardial infarction. With policy initiatives, such as bundled payments and pay for performance, hospital leaders have increased efforts to reduce excessive resource use. 3- Postoperative LOS is a common proxy for episode resource use. A better understanding of the association between extended LOS and complications will help hospitals and physicians focus their efforts to reduce resource use. In this study, we found that a considerable proportion of patients with extended LOS do not have documented complications after a common and morbid procedure. There was weak correlation between hospitals riskadjusted extended LOS and complication rates. Moreover, we found that 63.1% of the variation in extended LOS is attributable to hospital complication rates. Studies 7,,16 that used administrative and clinical registry data found that a considerable proportion of patients with apparently uncomplicated hospital courses have extended LOSs. Conversely, another study found that patients with normal LOSs still have clinically relevant complications. 17 Our study affirms these findings and further quantifies how little variation in hospitals extended LOS rates is explained by complications, even after accounting for patient illness. These results suggest that much of the variation in resource use sur- jamasurgery.com JAMA Surgery August 14 Volume 149, Number Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18

4 Research Original Investigation Extended Postoperative Length of Stay Figure 1. Risk-Adjusted Extended Length of Stay (LOS) and Inpatient Complication Rates for Colon Resections, American College of Surgeons National Surgical Quality Improvement Program, 9 A Extended LOS, % B Extended LOS, % C Inpatient Complications, % D Inpatient Severe Complications, % A, Extended LOS in the 7th percentile; B, extended LOS in the 9th percentile; C, inpatient complication rate; and D, inpatient severe complication rate. rounding surgical episodes may be caused by practice style differences rather than differences in technical quality or patient illness. There is increased attention on understanding and implementing measures that address the efficiency of care provision. In other patient populations, care coordination and extended care facility availability influence LOS to a large degree. 8,18 For surgical patients, emerging evidence suggests that process interventions, such as enhanced recovery pathways, are effective at reducing LOS without increasing over- 818 JAMA Surgery August 14 Volume 149, Number 8 jamasurgery.com Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18

5 Extended Postoperative Length of Stay Original Investigation Research Figure 2. Correlation Between Hospitals Inpatient Complication and Extended Length of Stay (LOS) Rates for Colon Resection, American College of Surgeons National Surgical Quality Improvement Program, 9 A Hospitals Inpatient Complication Rate, % 3 4 B Hospitals Inpatient Severe Complication Rate, % 3 4 C Hospitals Inpatient Complication Rate, % D Hospitals Inpatient Severe Complication Rate, % A, Inpatient complications vs extended LOS in the 7th percentile (ρ =.6, P <.1); B, inpatient severe complications vs extended LOS in the 7th percentile (ρ =.49, P <.1); C, inpatient complications vs extended LOS in the 9th percentile (ρ =.46, P <.1); and D, inpatient severe complications vs extended LOS in the 9th percentile (ρ =.47, P <.1). all complication rates, but the efficacy of such interventions on a large scale remains unclear. 9,19-22 With different uptake and implementation of enhanced recovery for patients with colectomies, it would be reasonable to assume that practice style differences underlie at least a portion of the unexplained variation in hospitals extended LOS rates. Our study has some important limitations. First, our data set lacked colectomy-specific complications that may better explain extended LOS, such as prolonged postoperative ileus, although the expected ileus rate for the cohort is far less than the amount of unexplained extended LOS. 23 Second, although our risk-adjustment models accounted for patient illness, procedure type, and acuity, we lacked data on factors such as patient rurality, access to transportation, discharge planning, and care coordination, which undoubtedly influence LOS as well. Third, we analyzed a common gastrointestinal procedure, and our results may not apply to different procedures. Fourth, although LOS is a common proxy for hospital resource use, price index adjusted total payments remain a more fair measure of resource use. 6 Finally, our data represent a subset of hospitals with a presumed interest in quality improvement, and as such our results may not be generalizable to all hospitals. Table 2. Relative Ability of Patient- and Hospital-Level Complications to Explain Variation in Hospitals Extended LOS Rates Variation Explained, % Variable Extended LOS (7th Percentile) Extended LOS (9th Percentile) Complication Any inpatient complication Hospitals inpatient complication rate Any severe inpatient complication Hospitals severe inpatient complication rate Site a Surgical Pulmonary Cardiac Septic Abbreviation: LOS, length of stay. a Surgical site complications include organ-space surgical site infection or wound dehiscence. Pulmonary complications include unplanned reintubation, prolonged mechanical ventilation, pulmonary embolism, and pneumonia. Cardiac complications include cardiac arrest that requires cardiopulmonary resuscitation or myocardial infarction. jamasurgery.com JAMA Surgery August 14 Volume 149, Number Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18

6 Research Original Investigation Extended Postoperative Length of Stay Conclusions Much of the variation among hospitals in their resource use remains unexplained after accounting for patient illness and complications. With increasing emphasis on improving the overall efficiency of episode-based care, a better understanding of practice style variation and how it contributes to differences in resource use should help guide improvement efforts apart from improving complication rates. In addition to focusing efforts on complication prevention, hospitals should also focus efforts on implementing and refining processes that eliminate inefficient practice. ARTICLE INFORMATION Accepted for Publication: December 2, 13. Published Online: June, 14. doi:.1/jamasurg Author Contributions: Dr Dimick had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: All authors. Acquisition, analysis, or interpretation of data: All authors. Drafting of the manuscript: All authors. Critical revision of the manuscript for important intellectual content: All authors. Statistical analysis: All authors. Obtained funding: Dimick. Administrative, technical, or material support: Dimick. Study supervision: Dimick. Conflict of Interest Disclosures: Dr Krell reported having received a payment from Blue Cross/Blue Shield of Michigan for data entry unrelated to the submitted work. Dr Dimick reported having a financial interest in ArborMetrix Inc. No other disclosures were reported. Funding/Support: This study is supported by grant T32CA from the National Institutes of Health (Dr Krell), Career Development Award K8 HS1776 from the Agency for Healthcare Research and Quality ( Dr Dimick), and research grant R21DK84397 from the National Institute of Diabetes and Digestive and Kidney Diseases (Dr Dimick). Role of the Sponsors: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Disclaimer: The ACS-NSQIP and the hospitals participating in the ACS-NSQIP are the source of the original data and cannot verify or be held responsible for the statistical validity of the data analysis or the conclusions derived by the authors. REFERENCES 1. Lindenauer PK, Remus D, Roman S, et al. Public reporting and pay for performance in hospital quality improvement. N Engl J Med. 7;36(): Robinowitz DL, Dudley RA. Public reporting of provider performance: can its impact be made greater? Annu Rev Public Health. 6;27: Rosenthal MB, Landon BE, Normand SL, Frank RG, Epstein AM. Pay for performance in commercial HMOs. N Engl J Med. 6;3(18): Sood N, Huckfeldt PJ, Escarce JJ, Grabowski DC, Newhouse JP. Medicare s bundled payment pilot for acute and postacute care: analysis and recommendations on where to begin. Health Aff (Millwood). 11;(9): Welch WP. Bundled Medicare payment for acute and postacute care. Health Aff (Millwood). 1998;17 (6): Romano P, Hussey P, Ritley D. Selecting Quality and Resource Use Measures: A Decision Guide for Community Quality Collaboratives. Washington, DC: Agency for Healthcare Research and Quality;. AHRQ publication 9() Cohen ME, Bilimoria KY, Ko CY, Richards K, Hall BL. Variability in length of stay after colorectal surgery: assessment of 182 hospitals in the National Surgical Quality Improvement Program. Ann Surg. 9;(6): Hall WB, Willis LE, Medvedev S, Carson SS. The implications of long-term acute care hospital transfer practices for measures of in-hospital mortality and length of stay. Am J Respir Crit Care Med. 12;18(1): Rawlinson A, Kang P, Evans J, Khanna A. A systematic review of enhanced recovery protocols in colorectal surgery. Ann R Coll Surg Engl. 11;93 (8): Shiloach M, Frencher SK Jr, Steeger JE, et al. Toward robust information: data quality and inter-rater reliability in the American College of Surgeons National Surgical Quality Improvement Program.JAm Coll Surg. ;2(1): Merkow RP, Hall BL, Cohen ME, et al. Relevance of the c-statistic when evaluating risk-adjustment models in surgery. J Am Coll Surg. 12;214(): Birkmeyer NJ, Dimick JB, Share D, et al; Michigan Bariatric Surgery Collaborative. Hospital complication rates with bariatric surgery in Michigan. JAMA. ;4(4): Dimick JB, Ghaferi AA, Osborne NH, Ko CY, Hall BL. Reliability adjustment for reporting hospital outcomes with surgery. Ann Surg. 12;(4): Dimick JB, Staiger DO, Baser O, Birkmeyer JD. Composite measures for predicting surgical mortality in the hospital. Health Aff (Millwood). 9;28(4): Fry DE, Pine M, Jones BL, Meimban RJ. Control charts to identify adverse outcomes in elective colon resection.am J Surg. 12;3(3): Raleigh VS, Cooper J, Bremner SA, Scobie S. Patient safety indicators for England from hospital administrative data: case-control analysis and comparison with US data. BMJ. 8;337:a172. doi:.1136/bmj.a Farjah F, Lou F, Rusch VW, Rizk NP. The quality metric prolonged length of stay misses clinically important adverse events. Ann Thorac Surg.12; 94(3): Brasel KJ, Lim HJ, Nirula R, Weigelt JA. Length of stay: an appropriate quality measure? Arch Surg. 7;142(): Aarts MA, Okrainec A, Glicksman A, Pearsall E, Victor JC, McLeod RS. Adoption of enhanced recovery after surgery (ERAS) strategies for colorectal surgery at academic teaching hospitals and impact on total length of hospital stay. Surg Endosc. 12;26(2): Ahmed J, Khan S, Lim M, Chandrasekaran TV, MacFie J. Enhanced recovery after surgery protocols: compliance and variations in practice during routine colorectal surgery. Colorectal Dis. 12;14(9): Gillissen F, Hoff C, Maessen JM, et al. Structured synchronous implementation of an enhanced recovery program in elective colonic surgery in 33 hospitals in The Netherlands. World J Surg.13;37 (): Vlug MS, Wind J, Hollmann MW, et al; LAFA Study Group. Laparoscopy in combination with fast track multimodal management is the best perioperative strategy in patients undergoing colonic surgery: a randomized clinical trial (LAFA-study). Ann Surg. 11;4(6): Harbaugh CM, Al-Holou SN, Bander TS, et al. A statewide, community-based assessment of alvimopan s effect on surgical outcomes. Ann Surg. 13;7(3): JAMA Surgery August 14 Volume 149, Number 8 jamasurgery.com Copyright 14 American Medical Association. All rights reserved. Downloaded From: on 4/29/18