Elsevier

World Neurosurgery

Volume 110, February 2018, Pages e627-e635
World Neurosurgery

Original Article
Risk Factors Associated with Readmission and Reoperation in Patients Undergoing Spine Surgery

https://doi.org/10.1016/j.wneu.2017.11.057Get rights and content

Objective

Reoperation and readmission are often avoidable, costly, and difficult to predict. We sought to identify risk factors for readmission and reoperation after spine surgery and to use these factors to develop a scoring system predictive of readmission and reoperation.

Methods

The National Surgical Quality Improvement Project database for years 2012 to 2014 was reviewed for patients undergoing spinal surgery, and 68 perioperative characteristics were analyzed.

Results

A total of 111,892 patients who underwent spinal surgery were identified. The rate of reoperation was 3.1%, the rate of readmission was 5.2%, and the occurrence of either was 6.6%. Multivariate analysis found 20 perioperative factors significantly associated with both readmission and reoperation. Preoperative and operative factors found significant included age >60 years, African-American race, recent weight loss, chronic steroid use, on dialysis, blood transfusion required, American Society of Anesthesiologists classification ≥3, contaminated wound, >10% probability of experiencing morbidity, and operative time >3 hours. Postoperative associations identified included urinary tract infection, stroke, dehiscence, pulmonary embolism, sepsis, septic shock, deep and superficial surgical site infection, reintubation, and failure to wean from ventilator. An unweighted and weighted risk score were generated that yielded receiver operating characteristic curves with areas under the curve of 0.707 (95% confidence interval [CI]: 0.701–0.713) and 0.743 (95% CI: 0.736–0.749) 0.708 (95% CI: 0.702–0.715), respectively.

Conclusions

Patients with an unweighted score ≥7 had a more than 20-fold increased risk of reoperation or readmission and a more than 1000-fold increased risk of mortality than did patients with a score of 0.

Introduction

According to the Dartmouth Atlas of Health Care, the national average rate of spine surgery has risen 63% from 1992 to 2003.1 The yearly medical expenses of spine care in the United States were estimated to be more than $85 billion in 2006 and rising.2, 3 Surgical complications are an increasing portion of the reducible costs associated with spine surgery.3, 4, 5 In particular, 30-day readmission cost $17 billion in 2008 and has been identified by the Centers for Medicare and Medicaid Services (CMS) as a target for cost reduction.6, 7 The Hospital Readmission Reduction Program (HRRP) and the Bundled Payments for Care Improvement Initiative are aimed at reducing preventable readmissions by decreasing reimbursement to hospitals with high 30-day readmission rates, highlighting the financial importance of readmission rates.8, 9

Spine surgery has rates of readmission, reoperation, and complications reported as high as 7.4%, 16%, and 18%, respectively.10, 11, 12 With the increasing use of spine surgery, associated strain on health expenditures, and hospital reimbursement now directly linked to complications, readmission, and reoperation rates, there is an increasing need to identify predictive factors of these costly events. Previous studies have sought to identify risk factors for readmission or reoperation associated with specific surgeries that are often limited by sample size, but no study has analyzed risk factors for all spine surgeries.13, 14, 15, 16 A single unified risk score for all spine surgeries has advantages in that one can quickly estimate a patient's risk for costly adverse events using a small number of factors and that it is applicable across a wide array of spine procedures with similar surgical approaches. Importantly, a risk score derived from these identified risk factors could estimate a patient's risk of a return-to-hospital event (reoperation, readmission, or both). A risk score would justify better allocation of perioperative care in an attempt to reduce these rates and healthcare costs.2 Our hypothesis is that because of the similar surgical approaches and aspects of various spine surgeries, there are factors associated with readmission and reoperation in all spine surgeries that identify high-risk patients for poor surgical outcomes.

Section snippets

Data Collection

The National Surgical Quality Improvement Project (NSQIP) dataset is a collection of deidentified surgical cases and associated characteristics from over 300 hospitals organized by the American College of Surgeons (ACS). All patient data used in this analysis were from the NSQIP database over the years 2012 the 2014. No data were used from years before 2012 because new variables regarding reoperation and readmission were added to reporting in 2012. The NSQIP data are collected by a Surgical

Results

The rate of reoperation, readmission, and either reoperation or readmission in this cohort was found to be 3.1%, 5.2%, and 6.6%, respectively. Of the 7343 patients who experienced either readmission or reoperation, 1934 (26%) experienced both events. The reported reasons for reoperation and readmission were associated with the initial spine surgery in 81% and 71% of the cases, respectively. The reasons for readmission and reoperation greatly varied, without any cause comprising more than 10% of

Discussion

We sought to identify factors associated with return to hospital events and to develop a predictive risk score for a patient's reoperation and readmission risk. By analyzing variables associated with reoperation and readmission, clinicians can better select patients for spinal surgery and allocate resources in the hope of reducing these costly outcomes. The reduction of these rates could not only improve patient comfort but also help blunt rising healthcare costs associated with postoperative

Conclusions

Whereas the rates of reoperation and readmission in spine surgery are relatively low, the absolute number of patients affected by these undesired outcomes is extensive. Using common perioperative conditions and comorbidities, a risk score was calculated that showed predictability of readmission and reoperation with associated prolonged hospital LOS and increasing mortality rate. Additional studies should aim to validate this scoring system and test whether interventions aimed at patients with

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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