Resident Involvement Does Not Influence Complication After Total Hip Arthroplasty: An Analysis of 13,109 Cases Bryan D. Haughom MD, William W. Schairer MD, Michael D. Hellman MD, Paul H. Yi BA, Brett R. Levine MD MS PII: DOI: Reference:
S0883-5403(14)00400-8 doi: 10.1016/j.arth.2014.06.003 YARTH 54028
To appear in:
Journal of Arthroplasty
Received date: Revised date: Accepted date:
5 March 2014 5 May 2014 3 June 2014
Please cite this article as: Haughom Bryan D., Schairer William W., Hellman Michael D., Yi Paul H., Levine Brett R., Resident Involvement Does Not Influence Complication After Total Hip Arthroplasty: An Analysis of 13,109 Cases, Journal of Arthroplasty (2014), doi: 10.1016/j.arth.2014.06.003
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Resident Involvement Does Not Influence Complication After Total Hip Arthroplasty: An Analysis of 13,109 Cases
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ED
William W. Schairer, MD Resident Hospital for Special Surgery Department of Orthopaedic Surgery 535 E. 70th St New York, NY 10021 [email protected]
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Running Title: Resident Involvement in Total Hip Arthroplasty Authors: Bryan D. Haughom, MD (Corresponding Author) Resident Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected]
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Michael D. Hellman, MD Resident Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected]
Paul H. Yi, BA Medical Student Boston University School of Medicine 72 E Concord St, Boston, MA 02128 [email protected] Brett R. Levine, MD MS Program Director Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected] Author Involvement: All authors participated substantially in the production of this work, starting with study design, data analysis, writing, and editing.
1
ACCEPTED MANUSCRIPT
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Conflicts of Interest: Each author certifies that he or she has no commercial associations (e.g. Consultancies, stock ownership, equity interest, patent/licensing, etc) that might pose a conflict of interest in connection with the submitted article. Ethical Review Committee Statement: IRB approval was not necessary given that this data was obtained from a de-identified national database. All authors have signed data-use agreements with the ACS. Location: All work was performed at Rush University Medical Center
2
ACCEPTED MANUSCRIPT Abstract: Our study aimed to determine the impact of resident involvement on the 30-day
T
postoperative complication rates following primary total hip arthroplasty (THA). Using
RI P
the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database, 13,109 primary THAs were identified, of which 3,462 (26.4%) had
SC
resident involvement. Neither univariate (4.45% vs 4.52%, p=0.86) nor multivariate (OR
NU
1.04, p = 0.75) analyses demonstrated an increased complication rate with resident involvement following THA. We did find, however, that increased operative time,
MA
comorbidities, age, obesity, prior history of stroke and/or cardiac surgery were all independent risk factors for short-term complication. Our findings suggest that resident
PT
ED
involvement does not increase 30-day complication rates following primary THA.
AC
CE
Level of Evidence: II (Prognostic, Retrospective Study)
3
ACCEPTED MANUSCRIPT Introduction
T
Total hip arthroplasty (THA) is a commonly performed procedure in the United States.
RI P
Estimates have projected a 174% increase in the demand for primary THA, and a twofold increase in the demand for revision THA by the year 2030 [1]. Furthermore, current
SC
estimates predict that the demand for THA will exceed the projected supply of fellowship
NU
trained arthroplasty surgeons in the future [2]. Non-fellowship trained surgeons, relying upon their experience garnered during residency and while in practice will ultimately
MA
perform many of these procedures. This fact underscores the importance of education and
ED
training in regards to performing primary THA during residency.
PT
The current model for surgical residency training is fundamentally based upon the model of William Halsted, with a system of graduated responsibility based upon level of
CE
training and competence [3]. Through both patient choice and provider referrals,
AC
academic medical centers often attract complex patients with multiple medical comorbidities. Resident educators are often tasked with not only caring for these difficult patients but also with teaching the skills required to become a competent orthopaedic surgeon. The tenuous balance between these two potentially competing factors can prove difficult. Ultimately the onus for the surgeon is to provide the highest level of care to the patient by minimizing complications and maximizing outcomes.
In the current healthcare milieu there is a heightened awareness of post-operative morbidity and mortality. In addition to affecting patients, they carry direct financial
4
ACCEPTED MANUSCRIPT implications for the provider and the hospital [4]. Savvy healthcare systems are implementing quality improvement initiatives to avoid such complications [5]. In the
T
setting of academic medical centers, such initiatives must factor in the involvement of
RI P
resident surgeons, as they are an integral component of the care delivery team. Despite this fact the impact of resident involvement on complications has not fully been
SC
elucidated. In the general surgery literature, this question has been evaluated with mixed
NU
results [6-15]. Within orthopaedics, the impact of resident involvement has not been
MA
sufficiently evaluated [16-20].
The goal of this study is to clarify the impact of resident involvement on primary THA
ED
utilizing the American College of Surgeons National Surgical Quality Improvement
PT
Program (ACS-NSQIP) database. Specifically we aimed to 1) Evaluate the impact of resident involvement on perioperative complications during a primary THA; and 2)
CE
Determine the independent preoperative and operative risk factors associated with
Methods
AC
complications following primary THA.
Data Source The National Surgical Quality Improvement Program (NSQIP) is a database of prospectively collected clinical information and outcomes of surgical patients from over 400 hospitals in 2012. Participating hospitals include private, public, academic, and nonacademic hospital in a variety of settings (e.g. urban, suburban, and rural), and of various
5
ACCEPTED MANUSCRIPT sizes. Maintained by the American College of Surgeons [21], patients are tracked for thirty days post-operatively to monitor for any complications, readmissions, or
T
reoperations. The data is collected by a trained Surgical Clinical Reviewer (SCR) who
RI P
records clinical information from patient charts, which has been shown to be more accurate than data inferred by insurance claims [22,23]. The NSQIP dataset has been
SC
used to measure post-surgical outcomes and improve quality of care [24]. In addition to
NU
surgical details (diagnosis, procedure, operative time, estimated blood loss, etc), the
MA
NSQIP contains patient demographics and medical comorbidities.
Patient Selection
ED
We selected patients from the NSQIP who had a primary procedure with a Current
PT
Procedural Terminology (CPT) code for total hip arthroplasty (CPT 27130) who underwent surgery between 2005 and 2012. To ensure that we did not select revision
CE
arthroplasty patients who were improperly coded with a primary arthroplasty CPT code,
AC
we excluded patients who had a primary diagnosis code of infection, fracture, mechanical complication, or malignancy (Appendix B). Additionally, we excluded patients where resident involvement was not recorded, or if there was a discrepancy between two variables that separately indicate 1) whether resident was involved in the case, and 2) whether the attending operated alone or with a resident. Finally, any patient with a wound classification other than “Clean” was excluded because such a classification indicated a pre-existing infection or a miscoded variable.
6
ACCEPTED MANUSCRIPT Patient Demographics In total, 13,109 patients underwent primary THA and met our inclusion criteria between
T
2005 and 2012. Of these, 26.4% (n = 3462) were performed with resident involvement.
RI P
Baseline characteristics were compared in table 1. Significant differences were observed in patient age, race, anesthesia type, rate of COPD, history of percutaneous cardiac
SC
intervention, renal failure, paraplegia, metastatic cancer, history of chemotherapy, steroid
NU
use, hypertension, diabetes, inpatient status, and lab values (albumin, WBC, platelet count). Applying the propensity score to adjust for potential selection bias showed that all
MA
variables were similar between groups with the exception of pre-operative albumin level.
ED
Outcomes
PT
Post-surgical outcomes in the NSQIP are prospectively defined by the NSQIP and, like other clinical information, are obtained from the medical record as opposed to insurance
CE
claims [25]. In brief, the outcomes identified at thirty days include surgical site infection,
AC
wound dehiscence, reoperation, unplanned hospital readmission, pneumonia, unplanned intubation, deep vein thrombosis (DVT), pulmonary embolism (PE), ventilation over 48 hours, renal insufficiency, acute renal failure, urinary tract infection, coma, stroke, peripheral neurological deficit, cardiac arrest, myocardial infarction, sepsis, and death.
Statistical Analysis Because this is a retrospective observational study of prospectively collected data, there may be selection bias about which patients did and did not have a resident involved in their operation. To account for this, we used a propensity score, estimating the
7
ACCEPTED MANUSCRIPT conditional probability of a patient having a resident involved in their operation, incorporating pre-operative variables such as demographics (age, gender), laboratory
T
values, ASA grade, and medical comorbidities in our model... Adjusting statistical
RI P
estimates using the propensity score gives an estimate of causality even in the presence of confounding [26]. The central role of the propensity score in observational studies for
SC
causal effects. The propensity score can be used to control confounding using three
NU
different methods – matching, stratification, and covariate regression adjustment [27]. We used stratification and covariate regression adjustment as two separate models to
MA
adjust for bias that may have influenced whether or not a resident was involved in a surgery. Of note, preoperative albumin level was not included in the propensity score, as
ED
nearly 60% of patients did not have this value recorded. Finally, we stratified our analysis
PT
further by comparing complication rates between non-resident cases and resident cases, as stratified by the post-graduate year level of training (Junior resident [PGY1-3], Senior
AC
CE
resident [PGY4-5], and Fellow).
Preoperative demographic and medical comorbidities were compared using chi-square and t-tests for categorical and continuous data, respectively, generating both unadjusted p-values and adjusted p-values that incorporated the propensity score (Table 1). Similarly, post-operative outcomes (operative time and transfusion requirement) and complications were compared with chi-square and t-tests with unadjusted rates (Table 2). We created a multivariate logistic regression model for the overall risk of any complication by incorporating any variable with a univariate significance of less than 0.1. The final model was included the “resident present” variable, was adjusted using the propensity score, and
8
ACCEPTED MANUSCRIPT limited variables to include only those that were significant p
S0883-5403(14)00400-8 doi: 10.1016/j.arth.2014.06.003 YARTH 54028
To appear in:
Journal of Arthroplasty
Received date: Revised date: Accepted date:
5 March 2014 5 May 2014 3 June 2014
Please cite this article as: Haughom Bryan D., Schairer William W., Hellman Michael D., Yi Paul H., Levine Brett R., Resident Involvement Does Not Influence Complication After Total Hip Arthroplasty: An Analysis of 13,109 Cases, Journal of Arthroplasty (2014), doi: 10.1016/j.arth.2014.06.003
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Resident Involvement Does Not Influence Complication After Total Hip Arthroplasty: An Analysis of 13,109 Cases
MA
ED
William W. Schairer, MD Resident Hospital for Special Surgery Department of Orthopaedic Surgery 535 E. 70th St New York, NY 10021 [email protected]
NU
SC
RI P
T
Running Title: Resident Involvement in Total Hip Arthroplasty Authors: Bryan D. Haughom, MD (Corresponding Author) Resident Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected]
AC
CE
PT
Michael D. Hellman, MD Resident Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected]
Paul H. Yi, BA Medical Student Boston University School of Medicine 72 E Concord St, Boston, MA 02128 [email protected] Brett R. Levine, MD MS Program Director Rush University Department of Orthopaedic Surgery 1611 W. Harrison Blvd, Suite 200 Chicago, IL 60612 [email protected] Author Involvement: All authors participated substantially in the production of this work, starting with study design, data analysis, writing, and editing.
1
ACCEPTED MANUSCRIPT
AC
CE
PT
ED
MA
NU
SC
RI P
T
Conflicts of Interest: Each author certifies that he or she has no commercial associations (e.g. Consultancies, stock ownership, equity interest, patent/licensing, etc) that might pose a conflict of interest in connection with the submitted article. Ethical Review Committee Statement: IRB approval was not necessary given that this data was obtained from a de-identified national database. All authors have signed data-use agreements with the ACS. Location: All work was performed at Rush University Medical Center
2
ACCEPTED MANUSCRIPT Abstract: Our study aimed to determine the impact of resident involvement on the 30-day
T
postoperative complication rates following primary total hip arthroplasty (THA). Using
RI P
the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database, 13,109 primary THAs were identified, of which 3,462 (26.4%) had
SC
resident involvement. Neither univariate (4.45% vs 4.52%, p=0.86) nor multivariate (OR
NU
1.04, p = 0.75) analyses demonstrated an increased complication rate with resident involvement following THA. We did find, however, that increased operative time,
MA
comorbidities, age, obesity, prior history of stroke and/or cardiac surgery were all independent risk factors for short-term complication. Our findings suggest that resident
PT
ED
involvement does not increase 30-day complication rates following primary THA.
AC
CE
Level of Evidence: II (Prognostic, Retrospective Study)
3
ACCEPTED MANUSCRIPT Introduction
T
Total hip arthroplasty (THA) is a commonly performed procedure in the United States.
RI P
Estimates have projected a 174% increase in the demand for primary THA, and a twofold increase in the demand for revision THA by the year 2030 [1]. Furthermore, current
SC
estimates predict that the demand for THA will exceed the projected supply of fellowship
NU
trained arthroplasty surgeons in the future [2]. Non-fellowship trained surgeons, relying upon their experience garnered during residency and while in practice will ultimately
MA
perform many of these procedures. This fact underscores the importance of education and
ED
training in regards to performing primary THA during residency.
PT
The current model for surgical residency training is fundamentally based upon the model of William Halsted, with a system of graduated responsibility based upon level of
CE
training and competence [3]. Through both patient choice and provider referrals,
AC
academic medical centers often attract complex patients with multiple medical comorbidities. Resident educators are often tasked with not only caring for these difficult patients but also with teaching the skills required to become a competent orthopaedic surgeon. The tenuous balance between these two potentially competing factors can prove difficult. Ultimately the onus for the surgeon is to provide the highest level of care to the patient by minimizing complications and maximizing outcomes.
In the current healthcare milieu there is a heightened awareness of post-operative morbidity and mortality. In addition to affecting patients, they carry direct financial
4
ACCEPTED MANUSCRIPT implications for the provider and the hospital [4]. Savvy healthcare systems are implementing quality improvement initiatives to avoid such complications [5]. In the
T
setting of academic medical centers, such initiatives must factor in the involvement of
RI P
resident surgeons, as they are an integral component of the care delivery team. Despite this fact the impact of resident involvement on complications has not fully been
SC
elucidated. In the general surgery literature, this question has been evaluated with mixed
NU
results [6-15]. Within orthopaedics, the impact of resident involvement has not been
MA
sufficiently evaluated [16-20].
The goal of this study is to clarify the impact of resident involvement on primary THA
ED
utilizing the American College of Surgeons National Surgical Quality Improvement
PT
Program (ACS-NSQIP) database. Specifically we aimed to 1) Evaluate the impact of resident involvement on perioperative complications during a primary THA; and 2)
CE
Determine the independent preoperative and operative risk factors associated with
Methods
AC
complications following primary THA.
Data Source The National Surgical Quality Improvement Program (NSQIP) is a database of prospectively collected clinical information and outcomes of surgical patients from over 400 hospitals in 2012. Participating hospitals include private, public, academic, and nonacademic hospital in a variety of settings (e.g. urban, suburban, and rural), and of various
5
ACCEPTED MANUSCRIPT sizes. Maintained by the American College of Surgeons [21], patients are tracked for thirty days post-operatively to monitor for any complications, readmissions, or
T
reoperations. The data is collected by a trained Surgical Clinical Reviewer (SCR) who
RI P
records clinical information from patient charts, which has been shown to be more accurate than data inferred by insurance claims [22,23]. The NSQIP dataset has been
SC
used to measure post-surgical outcomes and improve quality of care [24]. In addition to
NU
surgical details (diagnosis, procedure, operative time, estimated blood loss, etc), the
MA
NSQIP contains patient demographics and medical comorbidities.
Patient Selection
ED
We selected patients from the NSQIP who had a primary procedure with a Current
PT
Procedural Terminology (CPT) code for total hip arthroplasty (CPT 27130) who underwent surgery between 2005 and 2012. To ensure that we did not select revision
CE
arthroplasty patients who were improperly coded with a primary arthroplasty CPT code,
AC
we excluded patients who had a primary diagnosis code of infection, fracture, mechanical complication, or malignancy (Appendix B). Additionally, we excluded patients where resident involvement was not recorded, or if there was a discrepancy between two variables that separately indicate 1) whether resident was involved in the case, and 2) whether the attending operated alone or with a resident. Finally, any patient with a wound classification other than “Clean” was excluded because such a classification indicated a pre-existing infection or a miscoded variable.
6
ACCEPTED MANUSCRIPT Patient Demographics In total, 13,109 patients underwent primary THA and met our inclusion criteria between
T
2005 and 2012. Of these, 26.4% (n = 3462) were performed with resident involvement.
RI P
Baseline characteristics were compared in table 1. Significant differences were observed in patient age, race, anesthesia type, rate of COPD, history of percutaneous cardiac
SC
intervention, renal failure, paraplegia, metastatic cancer, history of chemotherapy, steroid
NU
use, hypertension, diabetes, inpatient status, and lab values (albumin, WBC, platelet count). Applying the propensity score to adjust for potential selection bias showed that all
MA
variables were similar between groups with the exception of pre-operative albumin level.
ED
Outcomes
PT
Post-surgical outcomes in the NSQIP are prospectively defined by the NSQIP and, like other clinical information, are obtained from the medical record as opposed to insurance
CE
claims [25]. In brief, the outcomes identified at thirty days include surgical site infection,
AC
wound dehiscence, reoperation, unplanned hospital readmission, pneumonia, unplanned intubation, deep vein thrombosis (DVT), pulmonary embolism (PE), ventilation over 48 hours, renal insufficiency, acute renal failure, urinary tract infection, coma, stroke, peripheral neurological deficit, cardiac arrest, myocardial infarction, sepsis, and death.
Statistical Analysis Because this is a retrospective observational study of prospectively collected data, there may be selection bias about which patients did and did not have a resident involved in their operation. To account for this, we used a propensity score, estimating the
7
ACCEPTED MANUSCRIPT conditional probability of a patient having a resident involved in their operation, incorporating pre-operative variables such as demographics (age, gender), laboratory
T
values, ASA grade, and medical comorbidities in our model... Adjusting statistical
RI P
estimates using the propensity score gives an estimate of causality even in the presence of confounding [26]. The central role of the propensity score in observational studies for
SC
causal effects. The propensity score can be used to control confounding using three
NU
different methods – matching, stratification, and covariate regression adjustment [27]. We used stratification and covariate regression adjustment as two separate models to
MA
adjust for bias that may have influenced whether or not a resident was involved in a surgery. Of note, preoperative albumin level was not included in the propensity score, as
ED
nearly 60% of patients did not have this value recorded. Finally, we stratified our analysis
PT
further by comparing complication rates between non-resident cases and resident cases, as stratified by the post-graduate year level of training (Junior resident [PGY1-3], Senior
AC
CE
resident [PGY4-5], and Fellow).
Preoperative demographic and medical comorbidities were compared using chi-square and t-tests for categorical and continuous data, respectively, generating both unadjusted p-values and adjusted p-values that incorporated the propensity score (Table 1). Similarly, post-operative outcomes (operative time and transfusion requirement) and complications were compared with chi-square and t-tests with unadjusted rates (Table 2). We created a multivariate logistic regression model for the overall risk of any complication by incorporating any variable with a univariate significance of less than 0.1. The final model was included the “resident present” variable, was adjusted using the propensity score, and
8
ACCEPTED MANUSCRIPT limited variables to include only those that were significant p
