Predictors of serious, preventable, and costly medical complications in a population of adult spinal deformity patients

International Spine Study Group

Research output: Contribution to journalArticlepeer-review


Background Context: In 2008, the Centers for Medicare and Medicaid Services (CMS) established a list of hospital-acquired conditions (HACs) with significant deleterious effects on both patients and providers. Adult spinal deformity (ASD) surgery is complex and highly invasive, and as such may result in significant morbidity including these HACs. Purpose: Identify predictors for developing the most common HACs among adult spinal deformity (ASD) patients undergoing corrective surgery. Study Design/Setting: Retrospective analysis. Patient Sample: One thousand one hundred and seventy-one ASD patients. Outcome Measures: HACs, Health-Related Quality of Life scores(HRQLs), Reoperation, Integrated Health State (IHS) Methods: ASD pts undergoing surgery (>18 years, scoliosis ≥20°, SVA ≥5 cm, PT ≥25° and/or TK >60°) with complete data at BL and up to 2 years post-op were included. Patients were stratified by presence of >1 HAC, defined as at least one superficial/deep SSI, UTI, DVT, or PE within a 30-day post-op window. Random forest analysis generated 5,000 Conditional Inference Trees to compute a variable importance table for top predictors of HACs. An area-under-the-curve (AUC) methodology compared normalized HRQL scores between groups to determine an IHS with 2-year follow-up. Results: Total of 1,171 pts (59.8 years, 76.2%F, 28.1kg/m2) underwent corrective ASD surgery, with 1,053 pts in the non-HAC group and 118 in the HAC group. Of these pts, 25.4% had UTI, 15.4% DVT, 19.2% superficial SSI, 20.8% deep SSI, and 19.2% PE. HAC pts were on average older (63.5 vs 59.3, p=.004) and more often frail (51.3 vs 39.7%, p=.021) than non-HAC pts. Postop LOS and reoperation were most associated with HAC groups: [1] LOS >7 days [2] reoperation. Patient-related predictors of HACs were [3] age >50 yerr, [4] frailty, and [13] BMI >31. Procedure-related predictors of HACs were [5] operative-time >405 minutes, [6] levels fused >9, EBL >1450 mL, and [11] decompression. BL radiographic predictors were [7] PT >20°, [9] PI-LL>6°, [10] TL Cobb angle >15°, [12] SVA C7-S1 >29 mm. No differences were observed between groups with regards to IHS ODI (0.73 vs 0.74, p=.863), SRS (1.3 vs1.3, p=.374), NRS Back (0.6 vs 0.6, p=.158). HAC had higher rates of reoperation than non-HAC (0.08 vs 0.01, p=.066), and any HAC within 30-days of index was a significant predictor of reoperation (OR: 2.448 [1.94–3.09], p<.001). Conclusions: In a population of ASD patients, HACs were associated with length of stay, reoperation, age, and frailty. Radiographic parameters such as pelvic tilt >20°, PI-LL >6°, & SVA >29 mm also increased odds of HACs, and should raise postoperative awareness for HAC development.

Original languageEnglish (US)
Pages (from-to)1559-1566
Number of pages8
JournalSpine Journal
Issue number9
StatePublished - Sep 2021


  • Adult spinal deformity
  • Hospital acquired conditions
  • Infection
  • Predictive modeling

ASJC Scopus subject areas

  • Clinical Neurology
  • Surgery
  • Orthopedics and Sports Medicine


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