Abstract
Background
Distal radius fractures are among the most common orthopaedic injuries and are managed both surgically and non-surgically. To date, no study has examined the role hospital teaching status plays in the rates of surgical intervention.
Methods
The Nationwide Inpatient Sample (NIS) was queried for years 2003–2014. Patients with a distal radius fracture were identified using International Classification for Disease, Ninth Revision (ICD-9) disease codes. Surgical intervention was determined using ICD-9 procedure codes. Exclusion criteria were patients younger than age 18, polytrauma, open fractures, records with missing data, and records where the primary procedure was something other than open reduction of a radius or ulna fracture, closed reduction of a radius or ulna fracture, or blank. Chi-squared tests were run for demographic and socioeconomic data to identify significant variables. Significant variables were then included alongside hospital teaching status in a binomial logistic regression model. Significance was defined as P < 0.05.
Results
A weighted total of 98,831 patients were included in the study. Of those, 45,234 (45.8 %) were treated at teaching hospitals. Patients in teaching hospitals were more likely to be younger, male, non-white, and non-Medicare insured than non-teaching hospitals. Injuries were treated surgically in 64.6 % of total cases. Surgical intervention was more common in teaching hospitals than non-teaching hospitals (69.1 % vs. 60.8 %, P < 0.01). After controlling for demographic and socioeconomic factors, patients at teaching hospitals were 31 % more likely to undergo surgical treatment than those at non-teaching hospitals. Other factors that were independently predictive of surgical treatment were age, race, and insurance type.
Conclusion
In the setting of distal radius fractures, teaching hospitals have higher rates of surgical intervention than non-teaching hospitals. These results suggest that the involvement of medical trainees may play a role in the surgical decision-making process.
Keywords: Outcomes, Distal radius, Teaching, Residents, NIS
1. Introduction
As the cost of healthcare continues to exponentially rise in the United States, more efforts have been made to make the delivery of healthcare more efficient, cost-effective, and safe. The institutions involved in this process have been increasingly scrutinized, as hospital administrators are forced to become leaner with the advent of alternative payment models including bundled-payment plans and value-based care.1, 2, 3 In an effort to uncover systems-level factors affecting patient care, greater attention has turned to hospital teaching status. Teaching hospitals, otherwise known as academic medical centers, form the framework for the US medical education system, in which resident physicians serve the roles of providers, students, researchers, and educators. Previous research across multiple specialties has consistently shown how the differences in mortality, major complications, and cost are negligible between teaching and non-teaching centers.4, 5, 6 However, the difference in treatment choice for common injuries especially in orthopedic surgery between the two has not been well described. Teaching hospitals face a host of unique financial, personnel, and training factors which could influence decision-making.
Distal radius fractures are among the most common orthopedic injuries, accounting for approximately 200,000 fractures per year in the United States.7 There are two mainstays of management: closed treatment with reduction and immobilization or operative treatment, typically through open reduction and internal fixation, percutaneous pinning, or external fixation.8 Geographic region, year, and surgeon characteristics have been previously identified as being influential in treatment management, however teaching status of hospital has yet to be investigated as a driving factor.9,10 We hypothesized that teaching hospital status would lead to a higher likelihood of operative fixation of distal radius fractures.
2. Materials and methods
The Nationwide Inpatient Sample (NIS) database is the largest available all-payer inpatient database in the United States. It was developed by the Agency for Healthcare Research and Quality (AHRQ) for the Healthcare Cost and Utilization Project (HCUP) and approximates 20 % of all US hospital discharges. The database contains information for over 7 million annual hospital stays; after applying database-provided weighting, this number exceeds 35 million annually.11
This study utilized the NIS database from years 2003–2014. The NIS database records a principal diagnosis, defined as the condition chiefly responsible for the hospital admission, with additional fields available for secondary diagnoses present during the hospital admission.12 This study included records with a primary diagnosis of closed distal radius fracture or closed Colles’ fracture ((International Classification of Disease, Ninth Edition (ICD-9) diagnosis codes 813.41 and 813.42). Open fractures were excluded as they are an absolute indication for operative management. Other exclusion criteria included age under 18, polytrauma, records with missing data, and records where the primary procedure was anything other than the pre-defined procedures (Table 1). Hospital teaching status was determined by the database variable HOSP_LOCTEACH. Those with a value of rural or urban non-teaching were placed into a “non-teaching” group, and those with a value of urban teaching were placed in a “teaching” group.
Table 1.
ICD-9 codes for Inclusion.
| Variable | ICD-9 Code |
|---|---|
| Primary diagnosis code |
813.41 (Closed Colles' fracture) 813.42 (Other closed fractures of distal end of radius (alone)) |
| Primary procedure code – operative |
78.13 (Application of external fixator device, radius and ulna) 78.53 (Internal fixation of bone without fracture reduction, radius and ulna) 79.22 (Open reduction of fracture without internal fixation, radius and ulna) 79.32 (Open reduction of fracture with internal fixation, radius and ulna) 79.52 (Open reduction of separated epiphysis, radius and ulna) |
| Primary procedure code – non-operative | 79.02 (Closed reduction of fracture without internal fixation, radius and ulna) 79.12 (Closed reduction of fracture with internal fixation, radius and ulna) 79.42 (Closed reduction of separated epiphysis, radius and ulna) 93.53 (Application of other cast) 93.54 (Application of splint) Blank (i.e. no procedure logged) |
The primary outcome measure was the rate of operative intervention by hospital teaching status. Patients were determined to have received operative treatment or closed treatment based on the ICD-9 primary procedure codes listed in Table 1. Patients with no primary procedure code were assumed to have been treated with closed reduction. Secondary outcomes were the rate of open treatment by demographic variables age, sex, race, income, and insurance.
Data analysis was performed using R statistical software, version 4.1.0 (R Foundation for Statistical Computing, Vienna, Austria). For calculation of national estimates, the survey package in R was used with weights, primary sampling units, and strata provided in the NIS database. Based on guidance by HCUP, trend weights were applied for records prior to 2012, and regular discharge weights were applied for records from 2012 and beyond.13
This study was retrospective in nature and based on de-identified records; therefore, it was exempt from Institutional Review Board approval.
3. Results
A weighted-total of 98,831 patients were included in the study. Of those, 45,234 (45.8 %) were treated at teaching hospitals. Patients in teaching hospitals were significantly more likely to be younger, male, non-white, and non-Medicare insured than non-teaching hospitals (Table 2).
Table 2.
Descriptive data of distal radius fractures.
|
Variable |
Frequency (%) |
||
|---|---|---|---|
| Overall | Non-Teaching | Teaching | |
| Hospital Teaching Status | |||
| Non-teaching | 53,597 (54.2 %) | 53,597 (100.0 %) | 0 (0.0 %) |
| Teaching | 45,234 (45.8 %) | 0 (0.0 %) | 45,234 (100.0 %) |
| Age | |||
| <40 | 15,623 (15.8 %) | 6620 (12.4 %) | 9003 (19.9 %)a |
| 41-60 | 28,763 (29.1 %) | 13,797 (25.7 %) | 14,967 (33.1 %) |
| 61-80 | 33,294 (33.7 %) | 19,917 (37.2 %) | 13,378 (29.6 %) |
| 80+ | 21,150 (21.4 %) | 13,265 (24.7 %) | 7886 (17.4 %) |
| Sex | |||
| Male | 28,120 (28.5 %) | 13,232 (24.7 %) | 14,888 (32.9 %)a |
| Female | 70,711 (71.5 %) | 40,366 (75.3 %) | 30,345 (67.1 %) |
| Race | |||
| Caucasian | 75,775 (76.7 %) | 44,142 (82.4 %) | 31,633 (69.9 %)a |
| African American | 5899 (6.0 %) | 1950 (3.6 %) | 3949 (8.7 %) |
| Hispanic | 11,854 (12.0 %) | 5168 (9.6 %) | 6686 (14.8 %) |
| Other/Not Reported | 5303 (5.4 %) | 2337 (4.4 %) | 2965 (6.6 %) |
| Income Quartile | |||
| 1 | 27,106 (27.4 %) | 15,575 (29.1 %) | 11,532 (25.5 %)a |
| 2 | 25,400 (25.7 %) | 14,695 (27.4 %) | 10,705 (23.7 %) |
| 3 | 23,578 (23.9 %) | 12,713 (23.7 %) | 10,865 (24.0 %) |
| 4 | 22,747 (23.0 %) | 10,614 (19.8 %) | 12,132 (26.8 %) |
| Insurance | |||
| Private | 28,913 (29.3 %) | 14,616 (27.3 %) | 14,297 (31.6 %)a |
| Medicaid | 6158 (6.2 %) | 2433 (4.5 %) | 3726 (8.2 %) |
| Medicare | 47,006 (47.6 %) | 29,073 (54.2 %) | 17,933 (39.6 %) |
| Uninsured | 8549 (8.7 %) | 3813 (7.1 %) | 4736 (10.5 %) |
| Other/Not Reported | 8204 (8.3 %) | 3662 (6.8 %) | 4542 (10.0 %) |
| Treatment | |||
| Non-operative | 34,974 (35.4 %) | 21,015 (39.2 %) | 13,959 (30.9 %)a |
| Operative | 63,857 (64.6 %) | 32,583 (60.8 %) | 31,275 (69.1 %) |
Indicates significance, defined as P < 0.05.
Injuries were treated surgically in 64.6 % of total cases. Surgical intervention was more common in teaching hospitals than non-teaching hospitals (69.1 % vs. 60.8 %, P < 0.01).
After controlling for significant demographic and socioeconomic factors, patients at teaching hospitals had increased odds of undergoing surgical treatment than those at non-teaching hospitals (OR 1.31, P < 0.01). Compared to patients younger than 40, patients aged 41–60 had increased odds of surgical intervention (OR 1.17, P < 0.01), and patients aged 80 and older had decreased odds of surgical intervention (OR 0.32, P < 0.01). Compared to Caucasians, Hispanics had decreased odds of surgical intervention (OR 0.88, P = 0.04). Compared to patients with private insurance, those with Medicaid (OR 0.74, P < 0.01), Medicare (OR 0.71, P < 0.01), and no insurance (OR 0.73, P < 0.01) had lower odds of operative intervention (Table 3).
Table 3.
Predictors of surgical intervention of distal radius fractures.
| Variable | OR (95 % CI) |
|---|---|
| Age | |
| <40 | Ref |
| 41-60 | 1.17 (1.06, 1.29)a |
| 61-80 | 0.91 (0.81, 1.03) |
| 80+ | 0.32 (0.27, 0.37)a |
| Sex Female (vs. Male) | 1.04 (0.97, 1.12) |
| Race | |
| Caucasian | Ref |
| African American | 0.87 (0.75, 1.01) |
| Hispanic | 0.88 (0.78, 0.99)a |
| Other/Not Reported | 1.04 (0.88, 1.24) |
| Income Quartile | |
| 1 | Ref |
| 2 | 0.98 (0.88, 1.08) |
| 3 | 0.98 (0.88, 1.10) |
| 4 | 1.07 (0.95, 1.20) |
| Insurance | |
| Private | Ref |
| Medicaid | 0.74 (0.64, 0.86)a |
| Medicare | 0.71 (0.64, 0.78)a |
| Uninsured | 0.73 (0.63, 0.85)a |
| Other/Not Reported | 0.92 (0.80, 1.06) |
| Teaching Hospital | 1.31 (1.14, 1.50)a |
Indicates significance, defined as P < 0.05.
4. Discussion
Although distal radius fractures are commonplace in the orthopaedic setting, there remains uncertainty as to the ideal method of treatment.8,14 There are numerous factors which can contribute to pursuing either surgical or non-surgical approaches, many of which are poorly understood or yet to be identified. To date, the relationship between operative management of distal radius fractures and teaching status of treating institution has not been clarified. In agreement with our hypothesis, this study found that there was a 31 % greater chance of a patient being treated surgically for a distal radius fracture if treated at a teaching hospital versus non-teaching hospital, controlling for potential confounders other than severity.
The complex relationship between hospital teaching status and optimal outcomes has been one of much discussion. Burke et al. used the national Medicare database to investigate mortality rates amongst US teaching and non-teaching institutions for common medical and surgical conditions and found that teaching hospital status was associated with lower mortality rates.15 Another study looking at the Nationwide Inpatient Sample found that teaching hospitals had lower rates of post-operative mortality following pancreatic, gastric, or esophageal resections.16 It has been posited that one of the reasons for such discrepancy is secondary to the advanced subspecialty training present at many teaching institutions.16 Furthermore, many studies have found that teaching hospitals have greater Medicare expenditures than their non-teaching peers; this difference could point to a greater preponderance for surgical intervention at teaching institutions, which do not face the same set of financial restrictions present as non-teaching institutions.17 Another possibility is that more severe injuries are routed to teaching hospitals rather than non-teaching hospitals. However, we eliminated polytraumas from our analysis. This should have theoretically reduced the proportion of high-energy injuries in our dataset, making the comparison between teaching and non-teaching hospitals more appropriate.
Our study also found that the elderly, Hispanic patients, and patients without private insurance were more likely to be managed non-operatively for distal radius fractures. Such findings, while interesting, have been previously identified in the literature. Fanuele et al. performed a retrospective review looking at the Medicare Part-B claims database to find frequency of distal radius fractures as well as factors affecting operative versus non-operative treatment including race, sex, age, or hospital referral region.9 Interestingly, they stratified their elderly population into 5-year subgroups and similarly found that those above the age 85 years faced a nearly 3-fold increased likelihood of non-operative treatment compared to those in the 65–69 year cohort. While their study did not find race as an influential factor in treatment choice, they categorized race as a binary variable, with “white” and “non-white”, whereas we stratified our race variable into 4 classes, Caucasian, African-American, Hispanic, and Other/Non-Reported. With regards to our findings regarding insurance status, it is plausible that injury characteristics, such as injury severity or fracture pattern, vary by insurance status. However, other causes must be considered. Studies of other orthopaedic injuries have speculated that privately insured patients may have a higher likelihood of operative fixation due to unconscious bias or higher reimbursement rates.18,19
The limitations of our study are primarily those inherent to retrospective reviews. While we attempted to limit confounding via use of a multivariable regression model, we understandably could not collect or include all known variables known to affect distal radius fracture management. Furthermore, we did not assess indication for surgery for each patient; it has been well-described that surgical intervention with open reduction internal fixation or percutaneous pinning is recommended depending on stability, displacement, comorbidities, and baseline activity status of the individual patient.20 Radiographic parameters and operative notes are not available in the NIS database and thus were not collected for this study, so many of these factors cannot be determined. Another limitation of the NIS database is that distal radius fractures are only able to be queried by ICD code, thereby precluding any more robust classification of these injuries. Furthermore, we chose to group all operative procedures including open reduction internal fixation, percutaneous pinning, and external fixation into one collective surgical intervention outcome; such an approach may limit the granularity of analysis when comparing one surgical approach against another. Another potential confounder that could not be evaluated in our study was surgeon age; Waljee et al. previously examined surgeon age and its effect on management of distal radius fractures among Medicare beneficiaries above 65 years of age.21 They found that younger surgeons were more likely to perform ORIF for distal radius fractures in this population. One could postulate that teaching institutions would skew towards younger surgeons given the presence of resident physicians. However, this study importantly did not investigate teaching status of hospitals, which may have a more consequential impact on management than surgeon age. Further studies should be performed to elucidate this complex relationship between teaching status, surgeon age, and management of distal radius fractures. Our study also did not investigate year of surgery as a potential confounding variable. The advent of volar plates with locking screws has grown in popularity in recent decades and may have skewed more recent fractures to have been treated operatively with open reduction internal fixation. Lastly, the NIS is an inpatient database, and ambulatory surgery centers are not included in the data. Private physicians who operate on distal radius fractures may choose to do so at an outpatient surgical facility rather than a hospital. Thus, the number of the operative cases performed at non-teaching hospitals, where there is a great proportion of private physicians, may be underestimated. However, given the NIS database represents inpatient hospital stays only, we are unable to quantify this subset of patients.
5. Conclusion
While distal radius fractures remain amongst the most common orthopaedic injuries, a thorough understanding of factors influencing their treatment is lacking. This study is the first to identify hospital teaching status as an independent predictor of surgical management of distal radius fractures. Further prospective studies are required to affirm this complex relationship and determine which financial, patient-based, or structural factors intrinsic to teaching institutions make them more likely to err on the side of surgical management.
7. Declaration of ethical approval for study
Institutional Review Board approval was not required for completion of this manuscript.
8. Declaration of informed consent
There is no information in this manuscript that can be used to identify patients.
CRediT authorship contribution statement
Dustin R. Biron: Conceptualization, Methodology, Writing – original draft. Akhil Katakam: Methodology, Writing – original draft. Robert L. DalCortivo: Formal analysis, Data curation, Writing – original draft. Irfan H. Ahmed: Supervision, Writing – review & editing. Michael M. Vosbikian: Supervision, Writing – review & editing.
Declaration of competing interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
Michael Vosbikian reports a relationship with Journal of Bone and Joint Surgery Inc that includes: consulting or advisory. Michael Vosbikian reports a relationship with ePlasty that includes: board membership.
Acknowledgements
None.
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