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Comorbidities in Patients Undergoing Total Knee Arthroplasty: Do They Influence Hospital Costs and Length of Stay?

  • Clinical Research
  • Published:
Clinical Orthopaedics and Related Research®

A CORR Insights to this article was published on 04 October 2014

Abstract

Background

Increasing national expenditures and use associated with TKA have resulted in pressure to reduce costs through various reimbursement cuts. However, within the arthroplasty literature, few studies have examined the association of medical comorbidities on resource use and length of stay after joint arthroplasty.

Questions/purposes

The purpose of this study was to examine the association between individual patient characteristics (including demographic factors and medical comorbidities) on resource allocation and length of stay (LOS) after TKA.

Methods

We queried the 2009 Nationwide Inpatient Sample dataset for International Classification of Diseases, 9th Revision code, 81.54, for TKAs. An initial 621,029-patient cohort was narrowed to 516,745 after inclusion of elective TKAs on patients aged between 40 and 95 years. Using generalized linear models, we estimated the effect of comorbidities on resource use (using cost-to-charge conversions to estimate hospital costs) and the LOS controlling for patient and hospital characteristics. Across the 2009 national cohort with TKAs, 12.7% had no comorbidities, whereas 32.6% had three or more. The most common conditions included hypertension (67.8%), diabetes (20.0%), and obesity (19.8%). Mean hospital costs were USD 14,491 (95% confidence interval [CI], 14,455–14,525) and mean hospital LOS was 3.3 days (95% CI, 3.29–3.31) in this data set.

Results

Patients with multiple comorbidities were associated with increased resource use and LOS. Higher marginal costs and LOS were associated with patients who had an inpatient death (USD +8017 [95% CI, 8006–8028], +2.3 [CI, 2.15–2.44] days over baseline), patients with recent weight loss (USD +4587 [95% CI, 4581–4593], +1.5 [CI, 1.45–1.61) days], minority race (USD +1037 [95% CI, 1035–1038], +0.3 [CI, 0.28–0.33] days), pulmonary-circulatory disorders (USD +3218 [95% CI, 3214–3221], +1.3 [CI, 1.25–1.34] days), and electrolyte disturbances (USD +1313 [95% CI, 1312–1314], +0.6 [CI, 0.57–0.60] days). All p values were < 0.001.

Conclusion

Multiple patient comorbidities were associated with additive resource use and LOS after TKA. Current reimbursement may not adequately account for these patient characteristics. To avoid potential loss of access to care for sicker patients, payment needs to be adjusted to reflect actual resource use.

Level of Evidence

Level IV, economic and decision analysis. See the Instructions for Authors for a complete description of levels of evidence.

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References

  1. Atkinson JG. Flaws in the Medicare readmission penalty. N Engl J Med. 2012;367:2056–2057.

    Article  CAS  PubMed  Google Scholar 

  2. Baser O, Fan Z, Dimick JB, Staiger DO, Birkmeyer JD. Outlier payments for cardiac surgery and hospital quality. Health Aff (Millwood). 2009;28:1154–1160.

    Article  PubMed Central  PubMed  Google Scholar 

  3. Bozic KJ, Lau E, Kurtz S, Ong K, Rubash H, Vail TP, Berry DJ. Patient-related risk factors for periprosthetic joint infection and postoperative mortality following total hip arthroplasty in Medicare patients. J Bone Joint Surg Am. 2012;94:794–800.

    PubMed  Google Scholar 

  4. Bozic KJ, Rubash HE, Sculco TP, Berry DJ. An analysis of medicare payment policy for total joint arthroplasty. J Arthroplasty. 2008;23:133–138.

    Article  PubMed  Google Scholar 

  5. Cai X, Cram P, Vaughan-Sarrazin M. Are African American patients more likely to receive a total knee arthroplasty in a low-quality hospital? Clin Orthop Relat Res. 2012;470:1185–1193.

    Article  PubMed Central  PubMed  Google Scholar 

  6. Chen LT, Lee JA, Chua BS, Howe TS. Hip fractures in the elderly: the impact of comorbid illnesses on hospitalisation costs. Ann Acad Med Singapore. 2007;36:784–787.

    PubMed  Google Scholar 

  7. CMS. CMS dry run hospital-specific report for hospital-wide all-cause unplanned readmission (HWR) Measure. 2012. Available at: www.cms.gov. Accessed October 1, 2013.

  8. CMS. Acute Care hospital inpatient prospective payment system. Centers For Medicare and Medicaid Services. 2013. Available at: http://www.cms.gov/Medicare/Medicare-Fee-For-Service-Payment/AcuteInpatientPPS. Accessed October 1, 2013.

  9. Collins TC, Daley J, Henderson WH, Khuri SF. Risk factors for prolonged length of stay after major elective surgery. Ann Surg. 1999;230:251–259.

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  10. Cram P, Ibrahim SA, Lu X, Wolf BR. Impact of alternative coding schemes on incidence rates of key complications after total hip arthroplasty: a risk-adjusted analysis of a national data set. GeriatriOrthop Surg Rehabil. 2012;3:17–26.

    Article  Google Scholar 

  11. Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR. Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991–2010. JAMA. 2012;308:1227–1236.

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  12. Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care. 1998;36:8–27.

    Article  CAS  PubMed  Google Scholar 

  13. Gruskay JA, Fu MC, Bohl DD, Webb ML, Grauer JN. Factors affecting length of stay following elective posterior lumbar spine surgery: a multivariate analysis. Spine J. 2013 Nov 1. pii: S1529-9430(13)01617-3. doi: 10.1016/j.spinee.2013.10.022 [Epub ahead of print].

  14. HCUP. Overview of the National Inpatient Sample (NIS). Agency for Healthcare Research and Quality. Available at: http://www.hcup-us.ahrq.gov/nisoverview.jsp. Accessed April 14, 2013.

  15. Ho DM, Huo MH. Are critical pathways and implant standardization programs effective in reducing costs in total knee replacement operations? J Am Coll Surg. 2007;205:97–100.

    Article  PubMed  Google Scholar 

  16. Huang R, Greenky M, Kerr GJ, Austin MS, Parvizi J. The effect of malnutrition on patients undergoing elective joint arthroplasty. J Arthroplasty. 2013;28:21–24.

    Article  PubMed  Google Scholar 

  17. Joynt KE, Jha AK. Thirty-day readmissions—truth and consequences. N Engl J Med. 2012;366:1366–1369.

    Article  CAS  PubMed  Google Scholar 

  18. Joynt KE, Orav EJ, Jha AK. Thirty-day readmission rates for Medicare beneficiaries by race and site of care. JAMA. 2011;305:675–681.

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  19. Kelly MP, Bozic KJ. Cost drivers in total hip arthroplasty: effects of procedure volume and implant selling price. Am J Orthop (Belle Mead NJ). 2009;38:E1–4.

    PubMed  Google Scholar 

  20. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007;89:780–785.

    Article  PubMed  Google Scholar 

  21. Li Y, Lu X, Wolf BR, Callaghan JJ, Cram P. Variation of Medicare Payments for Total Knee Arthroplasty. J Arthroplasty. 2013;28:1513–1520.

    Article  PubMed Central  PubMed  Google Scholar 

  22. Lin CA, Takemoto S, Kandemir U, Kuo AC. Mid-term outcomes in HIV-positive patients after primary total hip or knee arthroplasty. J Arthroplasty. 2014;29:277–282.

    Article  PubMed  Google Scholar 

  23. Maradit Kremers H, Visscher SL, Kremers WK, Naessens JM, Lewallen DG. Obesity increases length of stay and direct medical costs in total hip arthroplasty. Clin Orthop Relat Res. 2014;472:1232–1239.

    Article  Google Scholar 

  24. Monsef JB, Della Valle AG, Mayman DJ, Marx RG, Ranawat AS, Boettner F. The impact of blood management on length of stay after primary total knee arthroplasty. Open Orthop J. 2014;8:108–113.

  25. Nikkel LE, Fox EJ, Black KP, Davis C, Andersen L, Hollenbeak CS. Impact of comorbidities on hospitalization costs following hip fracture. J Bone Joint Surg Am. 2012;94:9–17.

    Article  PubMed  Google Scholar 

  26. Norian JM, Ries MD, Karp S, Hambleton J. Total knee arthroplasty in hemophilic arthropathy. J Bone Joint Surg Am. 2002;84:1138–1141.

    Article  PubMed  Google Scholar 

  27. Pugely AJ, Martin CT, Gao Y, Mendoza-Lattes S, Callaghan JJ. Differences in short-term complications between spinal and general anesthesia for primary total knee arthroplasty. J Bone Joint Surg Am. 2013;95:193–199.

    Article  PubMed  Google Scholar 

  28. Robinson JC, Pozen A, Tseng S, Bozic KJ. Variability in costs associated with total hip and knee replacement implants. J Bone Joint Surg Am. 2012;94:1693–1698.

    PubMed  Google Scholar 

  29. Shah AN, Vail TP, Taylor D, Pietrobon R. Comorbid illness affects hospital costs related to hip arthroplasty: quantification of health status and implications for fair reimbursement and surgeon comparisons. J Arthroplasty. 2004;19:700–705.

    Article  PubMed  Google Scholar 

  30. Shwartz M, Iezzoni LI, Moskowitz MA, Ash AS, Sawitz E. The importance of comorbidities in explaining differences in patient costs. Med Care. 1996;34:767–782.

    Article  CAS  PubMed  Google Scholar 

  31. Singh JA, Lu X, Rosenthal GE, Ibrahim S, Cram P. Racial disparities in knee and hip total joint arthroplasty: an 18-year analysis of national Medicare data. Ann Rheum Dis. 2013 18 Sep [Epub ahead of print].

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Authors and Affiliations

  1. Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 01008 JPP, Iowa City, IA, 52242, USA

    Andrew J. Pugely MD, Christopher T. Martin MD, Yubo Gao PhD, Daniel A. Belatti BS & John J. Callaghan MD

Authors
  1. Andrew J. Pugely MD
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  2. Christopher T. Martin MD
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  3. Yubo Gao PhD
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  4. Daniel A. Belatti BS
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  5. John J. Callaghan MD
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Corresponding author

Correspondence to Andrew J. Pugely MD.

Additional information

Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.

The study examined inpatient admissions in 2009 using the National Inpatient Sample (NIS) Database, Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality. The HCUP and the hospitals participating in the NIS Program are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.

All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request.

Each author certifies that his or her institution approved or waived approval for the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.

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Pugely, A.J., Martin, C.T., Gao, Y. et al. Comorbidities in Patients Undergoing Total Knee Arthroplasty: Do They Influence Hospital Costs and Length of Stay?. Clin Orthop Relat Res 472, 3943–3950 (2014). https://doi.org/10.1007/s11999-014-3918-x

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  • DOI: https://doi.org/10.1007/s11999-014-3918-x

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