Resident Duty-Hour Reform Associated with Increased Morbidity Following Hip Fracture

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1 This is an enhance PDF from The Journal of Bone an Joint Surgery The PDF of the article you requeste follows this cover page. Resient Duty-Hour Reform Associate with Increase Morbiity Following Hip Fracture James A. Browne, Cha Cook, Steven A. Olson an Michael P. Bolognesi J Bone Joint Surg Am. 2009;91: oi: /jbjs.h This information is current as of October 16, 2009 Supplementary material Reprints an Permissions Publisher Information Commentary an Perspective, ata tables, aitional images, vieo clips an/or translate abstracts are available for this article. This information can be accesse at Click here to orer reprints or request permission to use material from this article, or locate the article citation on jbjs.org an click on the [Reprints an Permissions] link. The Journal of Bone an Joint Surgery 20 Pickering Street, Neeham, MA

2 2079 COPYRIGHT Ó 2009 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Resient Duty-Hour Reform Associate with Increase Morbiity Following Hip Fracture By James A. Browne, MD, Cha Cook, PhD, MBA, PT, Steven A. Olson, MD, an Michael P. Bolognesi, MD Investigation performe at the Division of Orthopaeic Surgery, Department of Surgery, Duke University Meical Center, Durham, North Carolina Backgroun: The Accreitation Council for Grauate Meical Eucation implemente resient uty-hour reform for orthopaeic resient surgeons in the Unite States on July 1, This stuy sought to etermine whether the change in uty-hour regulations was associate with relative changes in mortality an morbiity for patients with a hip fracture treate in hospitals with an without resient teaching involve in the elivery of meical care. Methos: The Nationwie Inpatient Sample atabase was use to ientify 48,430 patients treate for hip fracture uring the years of 2001 to 2002, before resient uty-hour reform, an the years of 2004 to 2005 after reform. Logistic regression was use to examine the change in morbiity an mortality in nonteaching compare with teaching hospitals before an after the reform, ajusting for patient characteristics an comorbiities. Results: An increase in the overall incience of perioperative morbiity was observe in both teaching an nonteaching hospitals, suggesting a general increase in the severity of illness of the patients with a hip fracture. A significant increase in the rate of change in the incience of perioperative pneumonia, hematoma, transfusion, renal complications, nonroutine ischarge, costs, an length of stay was seen in patients who unerwent treatment for a hip fracture in the years after the resient uty-hour reforms at teaching institutions. Resient uty-hour reform was not associate with an increase in mortality. Conclusions: Resient uty-hour reform was associate with an accelerate rate of increasing patient morbiity following treatment of hip fractures in teaching institutions. Further research into this concerning fining is neee. Level of Evience: Therapeutic Level III. See Instructions to Authors for a complete escription of levels of evience. In July 2003, the Accreitation Council for Grauate Meical Eucation (ACGME) implemente work-hour restrictions for resient physicians in the Unite States. Uner these rules, resient surgeons may not work more than eighty hours per week average over a four-week perio, must have one ay in seven free from all eucational an clinical responsibilities, an a ten-hour time perio must be provie between all aily uty perios an after in-house call. Furthermore, in-house call may not occur more than once every three nights an must be limite to twenty-four hours with a six-hour extension for continuity of care. These changes were implemente in an attempt to reuce resient fatigue in orer to improve resient eucation an patient safety 1. Although recent stuies have emonstrate a reuction in resient fatigue, ata on patient outcomes after enactment of work-hour restrictions in meical an surgical patients 2-6 are mixe an the overall impact is unknown. The net effect on orthopaeic patients at teaching hospitals has not been previously examine. The present investigation sought to unerstan this issue further by using an analysis of patient outcomes from both teaching an nonteaching hospitals before an after the institution of ACGME resient uty-hour reform. Our null hypothesis was that the implementation of the reforms woul not affect patient care, as any change in the rates of patient morbiity an mortality following hip fracture treatment woul be similar at both teaching an nonteaching hospitals. Disclosure: The authors i not receive any outsie funing or grants in support of their research for or preparation of this work. One or more of the authors, or a member of his or her immeiate family, receive, in any one year, payments or other benefits in excess of $10,000 or a commitment or agreement to provie such benefits from commercial entities (Zimmer, DePuy, an Wright Meical). A commentary is available with the electronic versions of this article, on our web site ( an on our quarterly CD-ROM/DVD (call our subscription epartment, at , to orer the CD-ROM or DVD). J Bone Joint Surg Am. 2009;91: oi: /jbjs.h.01240

3 2080 Materials an Methos Database Data were extracte from selecte years of the Nationwie Inpatient Sample (NIS), a component of the Healthcare Cost an Utilization Project, which is sponsore by the Agency for Healthcare Research an Quality. Each year, the NIS contains ischarge ata from approximately seven to eight million hospital stays at about 1000 hospitals, ranomly selecte to approximate a 20% stratifie sample of hospitals across the Unite States. The NIS inclues the largest nationwie atabase on all-payer hospital inpatient care in the Unite States an contains ata for patients with Meicare, Meicai, an private insurance, as well as patients without insurance. Data are reflective of ischarge iagnoses, an coing for the atabase is in accorance with the International Classification of Diseases, Ninth Revision, Clinical Moification (ICD-9-CM). The quality control an reliability of the NIS have been escribe previously 7, an the accuracy is at least as goo as the National Hospital Discharge Survey 8. The NIS ischarge ata from 1998 to the present are weighte to better reflect the cross-sectional population of hospitals; thus, the results of this stuy are generalizable to the entire patient population unergoing hip fracture surgery in the Unite States. Sample Selection We selecte the recors of patients over the age of fifty-five years with an ICD-9-CM primary proceure coe inicating a primary fracture of the neck of the femur (820); a close fracture of an unspecifie, intracapsular section of the neck of the femur (820.00); a close fracture of the base of the neck of the femur (820.03); an open fracture of the base of the neck of the femur (820.13); an open fracture of the intertrochanteric section of the femur (820.31); a close fracture of an unspecifie part of the neck of the femur (820.8); or an open fracture of an unspecifie part of the neck of the femur (820.9). Patients were only inclue in the analysis if they receive any of the following surgical proceures: internal fixation of the femur without fracture reuction (78.55), close reuction of the fracture with internal fixation of the femur (79.15), open reuction of the fracture without internal fixation of the femur (79.25), open reuction of the fracture with internal fixation of the femur (79.35), total hip replacement (81.51), or partial hip replacement (81.52). We exclue patients with ICD-9-CM iagnosis coes associate with pathologic fractures or metastatic cancer. Preictive Variables We outline two primary preictor variables for the stuy. First, we capture ata exclusively from the NIS atabase for the years 2001 to 2002 an groupe these finings, an we capture ata from 2004 to 2005, which were also istinctly groupe. These two groups represente the ata from before reform (the years 2001 to 2002) an those from after reform (the years 2004 to 2005). Secon, the ata were organize into three hospital teaching structures: (1) rural, (2) urban nonteaching, an (3) TABLE I Conitions Inclue in the Aapte Charlson Comorbiity Inex as Define by Deyo et al. 9 Conition Assigne Weight 10 Myocarial infarction 1 Congestive heart failure 1 Peripheral vascular isease 1 Cerebrovascular isease 1 Dementia 1 Chronic pulmonary isease 1 Rheumatologic isease 1 Peptic ulcer isease 1 Mil liver isease 1 Diabetes 1 Diabetes with chronic complications 2 Hemiplegia or paraplegia 2 Renal isease 2 Malignancy 2 Moerate or severe liver isease 3 Metastatic soli tumor 6 Human immunoeficiency virus or 6 acquire immune eficiency synrome urban teaching. For the purposes of this stuy, rural an urban nonteaching hospitals were classifie as nonteaching facilities, whereas urban teaching hospitals were classifie as teaching facilities. Main Outcome Measures Outcomes inclue in this stuy were perioperative complications an mortality, length of hospital stay, hospital isposition (i.e., routine or nonroutine ischarge), an hospital costs ajuste for inflation. Specific complications inclue central nervous system complications, respiratory complications, pneumonia, myocarial infarction, peripheral vascular complications, postoperative hypertension, hemorrhage, serum reactions, postoperative infection, systemic inflammatory response synrome or septicemia, elirium, renal complications, igestive complications, ecubitus ulcers, an transfusions. Complications were ientifie in the NIS by ICD-9-CM iagnosis or proceure coes an were reporte as a ichotomous variable when appropriate. Covariates Patient-specific covariates consiere in this stuy inclue age, sex, race, meian househol income (with use of postal zip-coe ata), payer source, hospital be size, hospital region, hospital ownership or control, an Deyo inex for each patient. The Deyo inex summarizes patient comorbiities with use of ICD-9-CM iagnosis coes an takes into account the severity of the specific iagnoses by weighting 9. The Deyo inex, an aaptation of the Charlson inex 10, contains seventeen

4 2081 TABLE II Bivariate Analysis of Logistic Slopes (Comparisons of Slopes) Between Nonteaching an Teaching Facilities Nonteaching Facility Teaching Facility Outcomes Beta Coefficients* Stanar Error Beta Coefficients* Stanar Error P Value Death Central nervous system complications Respiratory complications Pneumonia Cariac complications Vascular complications Postoperative hypertension Hematomas Serum reactions Transfusion <0.01 Intraoperative complications Complications of operative woun Postoperative infection Systemic inflammatory response synrome Delirium Renal complications Digestive complications Other complications Decubitus ulcers Routine ischarge Length of stay Inflation-ajuste cost <0.01 *Beta coefficient represents the estimate average change in stanar eviation units, unique to each outcome variable. P value refers to the ifference between beta an stanar error. weighte conitions as etaile in Table I. We use the Deyo score to ajust for comorbiity an reuce potential confouning of patient health status; the utility an limitations of comorbiity scores in aministrative atabase research have been well escribe 11. For this stuy, values were calculate on the basis of percentile istribution A value of 0 reflecte a lower score for comorbiities, a value of 1 reflecte a higher score, an a value of >1 reflecte representation in a higher percentile of comorbiity within the sample. Statistical Analysis Descriptive statistics, incluing bivariate analyses of ifferences before reform an after reform for teaching an nonteaching hospitals, were use within the stuy, an comparative ifferences in age, sex, race, meian househol income (with use of postal zip-coe ata), payer source, hospital be size, hospital region, hospital ownership or control, an Deyo inex were calculate. Race is routinely not collecte by selecte hospitals, which results in a high level of missing values. To compensate for missing values, moels were run with an without imputation; no ifference was foun. To etermine if there were ifferences in the reporting of complications between teaching facilities an time perios, we performe a multivariate comparison of complications among all four classifie groups: (1) nonteaching hospitals before reform, (2) nonteaching hospitals after reform, (3) teaching hospitals before reform, an (4) teaching hospitals after reform. Chi-square analyses were use to compare the ata; cost an length of stay were analyze with analysis of variance when the ata were normally istribute an with the Kruskal-Wallis test when they were not. Because ifferences in complications between years coul be associate with changes in reporting strategies or aministrative error, we opte to measure the tren or change in complications from before an after reform for nonteaching hospitals an before an after reform for teaching hospitals. The first step involve two logistic regression analyses: one analyzing ata before an after reform for nonteaching hospitals an one analyzing ata before an after reform for teaching hospitals. Both moels involve ajustments for the potential confouners of age, sex, race, meian househol income (with use of postal zip-coe ata), payer source, hospital

5 2082 Fig. 1 Relation of hospital teaching status to postoperative incience of pneumonia, both before an after resient uty-hour reform (RDHR). Regression coefficients (b) were significant. be size, hospital region, hospital ownership or control, an Deyo inex, an both use ata from before reform (an the corresponing teaching or nonteaching classification) as the reference variable. From the logistic regression moeling, we capture the beta coefficients an stanar error measures, which represent the estimate average change in stanar eviation units, unique to each outcome variable. To etermine whether ifferences between teaching an nonteaching hospitals before an after reform were significant, we performe a bivariate analysis of beta or slope coefficients across groups. By analyzing beta coefficients an stanar errors between teaching an nonteaching facilities, we eneavore to etermine if finings among each outcome variable of the two facility types were coinciental in nature (a reflection of reporting changes over time). Furthermore, rather than assuming equality of reporting in teaching an nonteaching facilities, which can lea to misleaing or invali results, we assesse the resiual variation of each outcome variable by calculating for elta hat 12. Resiual variations or resiuals are observable estimates of unobservable statistical error within a sample. No resiual error is represente as 0% error, whereas numbers that are positive or negative, an ifferent from zero, reflect a probability of error specific to that number. A elta hat is use to measure symmetrical error in the reporting of ata. Because we use the NIS atabase, an since aministrative atabases run the risk of variability in coing 3,5, we consiere variations of <15% as low group resiual variation an eeme values below this figure as acceptable. Source of Funing There was no external funing source for this stuy. Results After ata acquisition, 48,430 patients were capture for analysis; 31,002 were from nonteaching facilities an 17,428, from teaching facilities. A number of variables emonstrate significant ifferences in simple emographic ata points (e.g., age, sex, an payer source) from before reform to after reform. The Deyo scores that reflect the severity of patient comorbiity were higher after reform for all patients, suggesting that the patient group as a whole ha greater comorbiity than the comparative group before reform. A table in the Appenix outlines the key univariate clinical statistics of the patient sample. A table in the Appenix provies the multivariate comparisons of complications among the four classifie stratifications. Among the four groups, a number of outcome variables were significantly ifferent, incluing respiratory, cariac, other, an renal complications; pneumonia; transfusions; systemic inflammatory response synrome; elirium; ecubitus ulcers; routine ischarge; length of stay; an inflation-ajuste costs. In most cases, greater complications or longer length of stays were seen after reform. Two separate regression analyses calculate variations in perioperative morbiity an mortality between teaching an nonteaching facilities in the two time perios before an after reform. For both analyses, the beta coefficients an stanar errors were input for bivariate analyses. Bivariate analyses ien-

6 2083 tifie significant ifferences over time between teaching an nonteaching facilities with regar to pneumonia, presence of hematoma, transfusion, renal complications, routine ischarge, length of stay, an inflation-ajuste costs (Table II). In all cases, there was an increase in incience in teaching facilities. In all situations, teaching facilities after reform were associate with greater frequencies of complications, costs, or nonroutine ischarges compare with teaching facilities before reform. As a graphic example of one of the selecte outcomes, Figure 1 shows the relation between the incience of pneumonia in teaching facilities compare with nonteaching facilities both before an after reform, emonstrating the significantly greater relative increase in incience foun after reform in teaching facilities. The elta-hat assessment of resiuals (see Appenix) supports the fining that the ifferences observe between teaching an nonteaching hospitals are not associate with unobserve heterogeneity (resiual variation) between the comparative groups. In all cases of variables that were significant, resiual variation between the two groups was <15%. We were unable to compare resiuals for length of stay an inflation-ajuste costs because of the ata type. Discussion Implementation of resient uty-hour reform by the ACGME in 2003 was met with some concern, protest, an skepticism 13,14. The intention of regulation was to counteract the potential negative effects of sleep eprivation an fatigue on patient care an learning 15. There is little empirical evience to support the assertion that this reform has improve patient care 3,16. This is particularly true in orthopaeic surgery, where there are no ata on which to raw conclusions. A key fining of this stuy was that the implementation of reform was associate with an accelerate rate of increase in morbiity following hip fracture surgery at teaching institutions. Thus, we coul not support our null hypothesis. The internal meicine literature contains several stuies that support the contention that the ACGME restrictions were not eleterious to the survival of meical patients. In parallel stuies, one group foun no evience of increase mortality in Meicare patients an patients in U.S. Veterans Affairs hospitals 2,3. Subgroup analysis actually suggeste a relative improvement in mortality for several meical conitions, although no changes were seen specifically in surgical patients 2. These stuies were limite to mortality rates an i not attempt to examine morbiity associate with treatment. Another recent stuy, with use of the same NIS atabase an similar statistical methos as were use in our analysis, emonstrate some evience of mortality reuctions for meical patients in teaching hospitals following uty-hour restrictions 5. However, that stuy i not emonstrate a reuction in mortality for surgical patients an, in fact, emonstrate a tren towar increasing mortality. Although it was not significant, the authors foun a relative increase in mortality of 3.77% for surgical patients associate with uty-hour restrictions. The authors note that a smaller sample size for surgical patients may have limite their power to etect significant ifferences. Markers of morbiity were not examine in this stuy. Data suggesting averse consequences in patient care associate with resient uty-hour reform are beginning to emerge. Consistent with our results, some recent stuies have suggeste that limiting work hours has ha an averse impact on patient outcome. One recent stuy foun suboptimal meication aministration an longer patient length of stay when patients with heart failure in Veterans Affairs hospitals were amitte by short call resients compare with the patients amitte by resients taking more traitional long call. 17 Other observational stuies have also emonstrate negative effects of iscontinuity of care on the quality of patient care an length of stay 18-20, although conflicting analyses have suggeste a neutral or positive impact associate with restricting work hours Orthopaeic surgery may present several unique challenges that make extrapolation from the internal meicine literature untenable. As note by other authors, a reuction in uty hours may have the greatest impact in the subspecialties in which resients worke the most hours prior to reform (e.g., surgery) 2,3. If the number of resient proviers remains fixe an they are each permitte to work fewer hours, then the number of available resient surgeons at any given time must necessarily ecline, a problem that is amplifie in specialties with relatively few resient proviers. Any potential benefits in terms of reuce fatigue may be offset by increase work intensity 3. The changes in meical coverage create by resient uty-hour reform impact two specific aspects of care that have ha little investigation. The first aspect is the availability of senior-level meical proviers for supervision of on-site junior resient meical coverage. Many programs have implemente a night-float system of call for on-site coverage. While this aresses the uty-hour issue of junior-level resients, it oes not aress the issue of senior-level resient coverage. We foun no report specifically aressing the changes in senior-level supervision of the on-site resients following resient utyhour reform. Furthermore, given the reuction in the number of resients physically in the hospital at any given time, the volume an responsibility of call coverage per resient have likely increase. The secon aspect of meical coverage is an increase in the number of hanoffs by meical proviers to maintain continuity of care. It is our anecotal experience that continuity of care has become more challenging in the orthopaeic teaching environment following uty-hour limitations. Hanoffs, particularly problematic in patient care an known to increase the risk of averse events 14,17,18,22,24-26, appear to occur relatively more frequently in the surgical services after reform. Several hanoffs an cross-coverage in care potentially occur uring the treatment of a patient with a hip fracture an may involve members of the house staff team in various surgical specialties an stages of training. Often, the resient gaining information uring the emergency epartment evaluation

7 2084 iffers from the resient assisting in the operative proceure; the night-float resient then covers the patient in the immeiate postoperative perio, only to again transfer care to the inpatient orthopaeic service the following morning. Orthopaeic patients, particularly those amitte through the emergency epartment, may be subject to more than the two aily hanoffs for meical patients that have been reporte in the literature 26. Furthermore, hanoffs in surgical isciplines may be ifferent from those in other areas of meicine, as acute clinical conitions such as hematoma or compartment synrome that may evolve rapily are best hane off at the patient s besie, where both the resient who is coming on uty an the resient who is going off uty can examine the patient. We use nonteaching hospitals as a control when assessing changes in morbiity before an after resient uty-hour reform. By using nonteaching hospitals as a control, we not only examine changes at teaching facilities over time but also ajuste for variations associate with health-care changes, aministrative atabase anomalies, or other elements not associate with actual patient-care trens. We then compare the slope coefficients across groups. Unlike linear regression coefficients, however, coefficients in these binary regression moels are confoune with resiual variation (unobserve heterogeneity). Differences in the egree of resiual variation across groups can prouce apparent ifferences in coefficients that are not inicative of true ifferences 12. To control for the possible ifferences in resiual variation between groups, we calculate the variable elta hat as escribe by Allison 12. Our assessment of resiuals for each outcome measure ensures that our finings are associate with true change an are not confoune by unobserve heterogeneity within the two groups. Although the statistical methos use in this stuy attempte to control for confouning an to ajust for variations in groups, group ifferences can still influence outcomes. We acknowlege that a small, isproportionate increase in patients with a Deyo score of >1 was observe across the stuy time interval in the teaching hospitals (a 3.43% increase in nonteaching hospitals compare with a 4.86% increase in teaching hospitals). Furthermore, espite our attempts to control for this possibility statistically, earlier referral of sick patients to teaching hospitals might inepenently contribute to the observe escalate rate of complications in teaching hospitals. Some aitional limitations to this stuy require comment. Shortcomings of the NIS atabase have been recognize 3,5. The NIS atabase inclues in-hospital complications only, an any averse perioperative outcomes that may have occurre after ischarge woul not be reflecte in our analysis. As with all aministrative atabases, there is the inherent risk of error base on incorrect or absent coing of ata. One cannot be absolutely certain that the patient unerwent the coe proceure or ha complications from it. Furthermore, the NIS classifies a hospital as teaching if the facility has any type of resiency program, not just orthopaeic surgery. Thus, some of the patients classifie as having receive their care in the setting of a teaching hospital may have ha no interaction with an orthopaeic surgery resient uring their treatment, an it is possible that the NIS variable le to misclassification an incorrect assignment of teaching status. Finally, we only analyze a limite time perio soon after uty-hour restrictions were implemente, an the higher incience of complications may reflect experimentation by the teaching programs with various strategies to accommoate to the changes. This association may not hol up over time as systems are implemente to effectively eal with uty-hour restrictions. Resient performance an health-care elivery are complex processes, particularly within the intricate system of a teaching hospital 6,16. Our investigation ientifie that the rate of change of perioperative morbiity in patients with a hip fracture increase significantly in teaching hospitals following resient uty-hour reform, an we cannot accept our null hypothesis. It shoul be emphasize that our finings emonstrate an association an o not imply causality. Further stuies that examine patient outcomes in orthopaeic surgery following work-hour restrictions are clearly neee. Although it has been suggeste that new ata woul be unlikely to reverse uty-hour reforms 27, empirical evience is neee to evelop a comprehensive unerstaning of the impact of resient utyhour reform on patient care before any further changes in uty-hour regulations are consiere. The short an longterm impact of uty-hour restrictions on both patient care an resient eucation in orthopaeic surgery remains unclear. Appenix Tables showing baseline patient characteristics, the multivariate comparisons, an the elta-hat assessment are available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation an click on Supplementary Material ) an on our quarterly CD/DVD (call our subscription epartment, at , to orer the CD or DVD). n James A. Browne, MD Division of Orthopaeic Surgery, DUMC Box 3000, Orange Zone, Duke Clinics Builing, Trent Drive, Duke University Meical Center, Durham, NC Cha Cook, PhD, MBA, PT Department of Surgery, Duke University Meical Center, DUMC Box 3907, Durham, NC Steven A. Olson, MD Division of Orthopaeic Surgery, Department of Surgery, Duke University Meical Center, 2504 Duke South Blue Zone, Durham, NC Michael P. Bolognesi, MD Division of Orthopaeic Surgery, Department of Surgery, Duke University Meical Center, DUMC Box 3269, Room 5316, Duke Clinics Builing, Durham, NC 27710

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