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 Table of Contents  
Year : 2020  |  Volume : 5  |  Issue : 1  |  Page : 16-21

National readmission rates after surgical stabilization of traumatic rib fractures

Department of Surgery, Stanford University, Stanford, CA, USA

Date of Web Publication24-Dec-2020

Correspondence Address:
Peter I Cha
Division of General Surgery Stanford University Medical Center 300 Pasteur Drive, Rm H3680 Satnford, CA
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jctt.jctt_6_20

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Introduction: Little is known about the risk of readmission after surgical stabilization of rib fractures (SSRFs).
Materials and Methods: We performed a retrospective analysis of the National Readmissions Database, a representative sample of all hospitalized patients in the US, from January 2012 to December 2014. All inpatient encounters with a primary trauma diagnosis of rib fractures were included in the study. Patients who underwent SSRF were compared to those who did not. Outcomes evaluated included readmission frequency and mortality.
Results: There were 411,169 patients admitted after trauma with rib fractures from 2012 to 2014; of these, 382 (<1%) underwent SSRF. Among non-SSRF patients, ≥3 rib fractures (odds ratio = 1.41, 95% confidence interval 1.23–1.62) were associated with readmission. Compared to the non-SSRF group, patients undergoing SSRF had a greater incidence of flail chest (26% vs. 2%; P < 0.0001), were more likely to have an injury severity score >15 (55% vs. 37%; P < 0.0001), and more likely to have a coexisting diagnosis of respiratory failure (35% vs. 18%, P < 0.0001). Despite the increased severity of injury among patients having SSRF, there was neither a statistically significant increase in patient deaths (<1% for SSRF vs. 4% no SSRF, P = 0.03) nor readmissions (<1% for SSRF vs. 1% for non SSRF, P = 1.0).
Conclusions: Long-term readmission rates for traumatic rib fracture patients are low. If nonoperative management is pursued, the presence of ≥3 rib fractures increases the risk of readmission. Patients requiring SSRF do not have higher readmission or mortality rates despite having a higher burden of injury during their initial hospitalization, suggesting the clinical benefit of surgical fixation.

Keywords: Readmission, rib fracture, surgical stabilization of rib fractures

How to cite this article:
Cha PI, Hakes NA, Choi J, Rosenberg G, Tennakoon L, Spain DA, Forrester JD. National readmission rates after surgical stabilization of traumatic rib fractures. J Cardiothorac Trauma 2020;5:16-21

How to cite this URL:
Cha PI, Hakes NA, Choi J, Rosenberg G, Tennakoon L, Spain DA, Forrester JD. National readmission rates after surgical stabilization of traumatic rib fractures. J Cardiothorac Trauma [serial online] 2020 [cited 2022 May 28];5:16-21. Available from: https://www.jctt.org/text.asp?2020/5/1/16/304868

  Introduction Top

Surgical stabilization of rib fractures (SSRFs) is increasingly utilized as an effective treatment modality for patients with rib fractures. In those with flail chest, several randomized controlled trials have shown SSRF to be superior to nonoperative care.[1],[2],[3],[4],[5] Advantages of SSRF over conservative management in appropriately selected patients include fewer pulmonary complications such as pneumonia and respiratory failure, decreased likelihood of tracheostomy, and reduced ventilator days, intensive care unit stay, and hospital length of stay (LOS).[1],[2],[3],[6],[7],[8],[9] To date, literature evaluating the efficacy of SSRF has mostly focused on index admission outcomes. Only two studies have looked into readmission following rib fracture injury – one small study of 315 patients found that no geriatric patients with rib fractures returned to the emergency department within 72 h of discharge and another reported that 8.3% of rib fracture patients had an unplanned reevaluation within 90 days of discharge, of which 3.2% required readmission.[10],[11] To our knowledge, no studies have assessed secondary admissions after SSRF.

Given the number of trauma patients who suffer rib fractures requiring admission nationally, evaluating readmission rates in this population and identifying areas of improvement could have a substantial public health impact. Potential benefits include identifying opportunities for cost savings and optimizing resource utilization.[11] We sought to describe the national readmission patterns for patients who undergo SSRF compared to those who did not. We hypothesized that SSRF as compared to nonoperative management is associated with lower readmission rates.

  Materials and Methods Top

We queried the 2012–2014 Agency for Healthcare and Quality and Healthcare Cost and Utilization Project's (HCUP) National Readmission Database (NRD) to identify all patients readmitted after an index admission for traumatic rib or sternal fractures.[12] NRD is the largest all-payer readmission database in the US which captures both inpatient encounters that result in discharge or transfer and those that result in readmission.[12] Publicly available, NRD is constructed from the HCUP state inpatients databases.[12] When analyzed, NRD is weighted to provide national estimates on the roughly 107 million discharges in the US between 2012 and 2014.[13] The number of hospitals included in the sample ranged from 1715 to 2048.[13] We included all inpatient encounters with the diagnosis code corresponding to traumatic rib or sternal fractures (International Classification of Disease, 9th Revision, Clinical Modification [ICD-9CM] 807.0–807.09, 807.1–807.19, 807.2–4).

SSRF intervention was the main explanatory variable. Patients who underwent SSRF were defined by ICD-9 procedure codes 78.11 and 78.51. The primary outcome of interest was readmission frequency within 1 year; secondary outcomes included rates of pneumonia, empyema, respiratory failure, and mortality. Variables assessed included age, sex, payer status, income quartile, anatomic location of injury, injury severity score (ISS), LOS, discharge destination, need for readmission, and time to readmission. We did not exclude patients <18 years of age. Injury characteristics were further evaluated using the Stata-based ICD Programs for Injury Categorization module.[14]

Pneumonia was defined as ICD-9 codes 480.0–487.0. Respiratory failure was defined as ICD-9 diagnosis codes 518.0, 518.5 (1–3), 518.81, 518.82, 518.84, 799.02, or 799.1. A pneumo- or hemothorax was defined as ICD-9 diagnosis codes 860.0–860.5 or 512.0. An empyema was defined as ICD-9 codes 510.0, 510.9, 513.0, or 513.1. The 2012–2014 time period was chosen, as these databases were both available at the time of analysis and had consistent ICD-9 coding to enable combinatorial analysis. All statistical analyses used NRD sampling strata and discharged weights to produce nationally weighted patient-level estimates and 95% confidence intervals (CIs) that account for the clustering of patients among hospitals. Weighted values are reported unless otherwise specified. Data are presented as mean ± standard deviation; calculated weighted means are reported with 95% CI according to survey statistical methodology.[13]

Fisher's exact and Wilcoxon rank-sum tests were used as appropriate. Bonferroni correction was applied and the a priori P value which was considered significant was P < 0.003. All reported cells with <10 patients were reported as <10 in accordance with the HCUP data use agreement.[13] Stata 12.0 (Stata Corp, College Station, TX) was used for all statistical analyses. The study was classified exempt following institutional review board review as it contained no identifiable data.

  Results Top

We identified 411,169 patients admitted with traumatic rib or sternal fractures from 2012 to 2014; of these, 382 (<1%) underwent SSRF [Table 1]. The 45–64 year age group was the most common age range among both SSRF and non-SSRF populations; of those undergoing SSRF, persons in the age group of 45–64 years represented a higher percentage of patients compared to the non-SSRF population (56% vs. 33%, P < 0.0001). Patients in the SSRF group were more commonly male (n = 296, 77%) compared to those in the non-SSRF group (n = 256,842, 63%; P < 0.0001). There were no statistically significant differences in the payor or income percentile distributions between the SSRF and non-SSRF groups. Compared to the non-SSRF group, patients who underwent SSRF more commonly had >3 rib fracture (85% vs. 59%, P < 0.0001), had higher rates of flail chest (26% vs. 2%; P < 0.0001), concomitant sternal fractures (15% vs. 10%, P < 0.0001), proportion with ISS >15 (55% vs. 37%; P < 0.0001), and respiratory failure (35% vs. 18%, P < 0.0001). Clavicle fractures were infrequently present in both groups (non-SSRF: 5%, SSRF: 7%). Patients undergoing SSRF had longer mean hospital LOS (12.5 ± 10.9 vs. 8.0 ± 11.6 days, P < 0.0001), greater frequency of concomitant pneumo-or hemothorax (69% vs. 38%, P < 0.0001), and higher frequency of concomitant thoracostomy tube (47% vs. 15%, P < 0.0001) than patients who did not undergo SSRF. Despite the increased severity of injury among those undergoing SSRF, there was no statistically significant increase in mortality (SSRF < 1% vs. non-SSRF 4%; P = 0.03) or readmission rates (SSRF: <1% vs. non-SSRF: 1%; P = 1.0).
Table 1: Patients who experienced traumatic rib or sternal fractures at their index trauma admission - United States 2012-2014

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Among the non-SSRF group, the readmission rate was 1% [Table 2]. Those readmitted were older, 84% of whom were >45 years old (vs. 73% of those not readmitted, P < 0.0001). Compared to those not readmitted, readmitted patients more commonly had isolated chest wall injury (40% vs. 26%, P < 0.0001), had ≥ 3 rib fractures (68% vs. 58%, P < 0.0001), had a greater number of associated chronic conditions (4.0 ± 3.0 vs. 3.3 ± 2.9, P < 0.0001) and had shorter initial hospitalization (4.9 ± 8.3 d vs. 8.1 ± 11.6 d, P < 0.0001). On multivariable analysis, ≥3 rib fractures (odds ratio [OR] = 1.41, 95% CI 1.23–1.62), presence of a pneumo-or hemothorax during the index hospitalization (OR = 1.32, 95% CI 1.14–1.52) or a higher number of co-morbid chronic medical conditions (OR = 1.05, 95% CI 1.03–1.08) was associated with readmission. Fewer than ten patients were readmitted after SSRF, so no multivariable analysis was performed. Readmitted patients were older than 85 years, had a primary payor source of Medicare, and had closed rib fractures.
Table 2: Patients not undergoing surgical stabilization of rib fractures at index admission - United States 2012-2014

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  Discussion Top

Trauma readmissions strain our national health-care system; secondary admissions after traumatic injury range from 7.5% to 9.4% with total costs equaling $1.5 billion.[15],[16] In 2013 alone, approximately 500,000 trauma patients presented to the emergency department with bony thoracic injury, of which roughly 200,000 required admissions.[17] Yet, data on readmissions after chest wall injury remain limited. A retrospective study from 2014 to 2016 reviewing 1717 trauma patients found the 90-day readmission rate after moderate-to-severe rib fractures to be low (3.2%).[11] Similarly, using the largest national inpatient dataset, we found 1-year readmission rates for patients with rib fractures of all severity to be low at 1.0%.

Among patient encounters in the NRD sample, patients undergoing SSRF typically had higher ISS scores and greater rates of concomitant injury including hemo- or pneumothorax, flail chest, and respiratory failure. This likely contributed to the increased hospital LOS in the SSRF group compared to those not requiring surgery. Higher ISS and greater hospital LOS are proven risk factors for readmission in the trauma setting.[11],[15],[16],[18] Yet, despite the increased burden of trauma and longer hospital stay among the SSRF group, there was no statistically significant difference in readmission rates between the SSRF and non-SSRF group. Hence, while we were unable to demonstrate a decreased readmission rate among patients undergoing SSRF as previously hypothesized, we were encouraged that there was conversely no increased risk of readmission as the initial injury severity would predict.

To date, our study is the first to demonstrate the presence of ≥3 rib fractures a risk factor for readmission in non-SSRF patients after chest wall injury. One prior study did show that trauma patients requiring readmission did have significantly more rib fractures compared to patients who never re-presented to the emergency department (ED) but was unable to demonstrate the presence >5 rib fractures, the traditional cutoff for clinical significance, a risk factor for neither reevaluation in the ED nor readmission on multivariate analysis.[11],[19] We believe our finding further substantiates the growing indication of SSRF to include nonflail trauma patients suffering ≥3 severely displaced rib fractures with respiratory compromise.

In addition, a higher percentage of patients readmitted in the non-SSRF group also had isolated chest wall injury, suggesting that thoracic pathology may be a significant driver for readmission in non-SSRF patients. There are several possible reasons for this observation. A majority of secondary admissions after bony thoracic trauma are due to pain,[11] so non-SSRF patients readmitted could have been prematurely discharged (3-day shorter initial hospital LOS vs. patients not readmitted) before the pain was adequately controlled. Suboptimal pain management with un-stabilized rib fractures may have also increased the susceptibility and incidence of pneumonias requiring readmission.[11],[15],[16],[18] Finally, patients could have formed delayed hemothorax with an unstable chest wall. Un-stabilized rib fractures may lead to hemothorax by continuing to bleed from the fractured ends, injuring the intercostal vessels, or penetrating lung parenchyma.[20]

In such cases, video-assisted thoracoscopic surgery (VATS) is a proven treatment modality.[21] Patients with rib fractures requiring VATS for retained hemothorax may also benefit from concomitant SSRF. One prospective study of 128 trauma patients requiring VATS demonstrated that those who also underwent concomitant rib fixation had shorter ventilator days and total hospital LOS as well as lower postoperative opioid requirements.[22] Further study is needed to determine if concomitant SSRF has any impact on readmission rates.

This study has several limitations. First, the retrospective nature of this study limits the determination of causal or temporal relationships. Second, microregional variations in readmission may not be captured given the survey methodology. However, National Inpatient Sample is the largest inpatient survey available and so represents the largest available sample. Third, there may be misclassification bias associated with utilizing ICD-9 codes. The integrity of the coding depends on the quality of coders at each participating institution. Fourth, per HCUP agreement, any quantity <10 was not reported, reducing the extent of our quantitative analysis. Fifth, ICD-9 codes used to capture SSRF also included clavicle and scapular repair; however, we do not believe this to have significantly biased our findings given only a minority of patients presented with clavicular fracture (5%–7%). Sixth, the significant imbalance between SSRF and non-SSRF groups (382 vs. 410,799, respectively) may have increased chance bias and limited the power of our study. Next, as this was a survey, it is possible that selection bias is present as hospitals reporting data could more commonly or less commonly utilize SSRF. Finally, readmissions may have been unrelated to rib cage injury, distorting our analysis.

  Conclusion Top

In summary, long-term readmission rates after traumatic rib fractures of all severity are low. If nonoperative management is pursued, the presence of ≥3 rib fractures increases the risk of readmission. Patients requiring SSRF do not have higher readmission or mortality rates despite having a higher burden of injury during their initial hospitalization, suggesting a clinical benefit of surgical fixation. Further studies are needed to assess the long-term efficacy of SSRF in nonflail-type chest wall injury.

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Conflicts of interest

There are no conflicts of interest.

  References Top

1. Tanaka H, Yukioka T, Yamaguti Y, Shimizu S, Goto H, Matsuda H, et al. Surgical stabilization of internal pneumatic stabilization? A prospective randomized study of management of severe flail chest patients. J Trauma 2002;52:727-32.  Back to cited text no. 1
2. Granetzny A, Abd El-Aal M, Emam E, Shalaby A, Boseila A. Surgical versus conservative treatment of flail chest. Evaluation of the pulmonary status. Interact Cardiovasc Thorac Surg 2005;4:583-7.  Back to cited text no. 2
3. Marasco SF, Davies AR, Cooper J, Varma D, Bennett V, Nevill R, et al. Prospective randomized controlled trial of operative rib fixation in traumatic flail chest. J Am Coll Surg 2013;216:924-32.  Back to cited text no. 3
4. Slobogean GP, MacPherson CA, Sun T, Pelletier ME, Hameed SM. Surgical fixation vs nonoperative management of flail chest: A meta-analysis. J Am Coll Surg 2013;216:302-110.  Back to cited text no. 4
5. Leinicke JA, Elmore L, Freeman BD, Colditz GA. Operative management of rib fractures in the setting of flail chest: A systematic review and meta-analysis. Ann Surg 2013;258:914-21.  Back to cited text no. 5
6. Kasotakis G, Hasenboehler EA, Streib EW, Patel N, Patel MB, Alarcon L, et al. Operative fixation of rib fractures after blunt trauma: A practice management guideline from the Eastern Association for the Surgery of Trauma. J Trauma Acute Care Surg 2017;82:618-26.  Back to cited text no. 6
7. Coughlin TA, Ng JW, Rollins KE, Forward DP, Ollivere BJ. Management of rib fractures in traumatic flail chest: A meta-analysis of randomised controlled trials. Bone Joint J 2016;98-B: 1119-25.  Back to cited text no. 7
8. Cataneo AJ, Cataneo DC, de Oliveira FH, Arruda KA, El Dib R, de Oliveira Carvalho PE. Surgical versus nonsurgical interventions for flail chest. Cochrane Database Syst Rev. 2015;7:CD009919.  Back to cited text no. 8
9. Pieracci FM, Lin Y, Rodil M, Synder M, Herbert B, Tran DK, et al. A prospective, controlled clinical evaluation of surgical stabilization of severe rib fractures. J Trauma Acute Care Surg 2016;80:187-94.  Back to cited text no. 9
10. Southerland LT, Richardson DS, Caterino JM, Essenmacher AC, Swor RA. Emergency department recidivism in adults older than 65 years treated for fractures. Am J Emerg Med 2014;32:1089-92.  Back to cited text no. 10
11. Baker JE, Skinner M, Heh V, Pritts TA, Goodman MD, Millar DA, et al. Readmission rates and associated factors following rib cage injury. J Trauma Acute Care Surg 2019;87:1269-76.  Back to cited text no. 11
12. Healthcare Cost and Utilization Project. Overview of the National Readmissions Database (NRD). Available from: https://www.hcup-us.ahrq.gov/nrdoverview.jsp. [Last accessed on 2020 Mar 15].  Back to cited text no. 12
13. Healthcare Cost and Utilization Project. Introduction to the HCUP Nationwide Readmissions Database (NRD) 2010-2016. Available from: https://www.hcup-us.ahrq.gov/db/nation/nrd/Introduction_NRD_2010-2016.pdf. [Last accessed on 2020 Mar 15].  Back to cited text no. 13
14. Clark DE, Osler TM, Hahn DR. ICD Programs for Injury Categorization (ICDPIC), Version 3.0. 2010. http://ideas.repec.org/c/boc/bocode/s457028.html.  Back to cited text no. 14
15. Olufajo OA, Cooper Z, Yorkgitis BK, Najjar PA, Metcalfe D, Havens JM, et al. The truth about trauma readmissions. Am J Surg 2016;211:649-55.  Back to cited text no. 15
16. Parreco J, Buicko J, Cortolillo N, Namias N, Rattan R. Risk factors and costs associated with nationwide nonelective readmission after trauma. J Trauma Acute Care Surg 2017;83:126-34.  Back to cited text no. 16
17. Majercik S, Pieracci FM. Chest Wall Trauma. Thorac Surg Clin 2017;27:113-21.  Back to cited text no. 17
18. Morris DS, Rohrbach J, Sundaram LM, Sonnad S, Sarani B, Pascual J, et al. Early hospital readmission in the trauma population: are the risk factors different? Injury Int J Care Injured 2014;45:56-60.  Back to cited text no. 18
19. Shulzhenko NO, Zens TJ, Beems MV, Jung HS, O'Rourke AP, Liepert AE, et al. Number of rib fractures thresholds independently predict worse outcomes in older patients with blunt trauma. Surgery 2017;161:1083-9.  Back to cited text no. 19
20. DuBose J, Inaba K, Demetriades D, Scalea TM, O'Connor J, Menaker J, et al. Management of post-traumatic retained hemothorax: A prospective, observational, multicenter AAST study. J Trauma Acute Care Surg 2012;72:11-22.  Back to cited text no. 20
21. Meyer DM, Jessen ME, Wait MA, Estrera AS. Early evacuation of traumatic retained hemothoraces using thoracoscopy: A prospective, randomized trial. Ann Thorac Surg 1997;64:1396-400.  Back to cited text no. 21
22. Lin HL, Tarng YW, Wu TH, Huang FD, Huang WY, Chou YP. The advantages of adding rib fixations during VATS for retained hemothorax in serious blunt chest trauma-A prospective cohort study. Int J Surg 2019;65:13-8.Department of Surgery, Stanford University, Stanford, CA, USA  Back to cited text no. 22


  [Table 1], [Table 2]


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