Study design: Retrospective database study.
Objective: To assess the association between prolonged length of hospital stay (pLOS) (≥4 d) and unplanned readmission in patients undergoing elective spine surgery by controlling the clinical and statistical confounders.
Summary of background data: pLOS has previously been cited as a risk factor for unplanned hospital readmission. This potentially modifiable risk factor has not been distinguished as an independent risk factor in a large-scale, multi-institutional, risk-adjusted study.
Methods: Data were collected from the American College of Surgeons National Surgical Quality Improvement Program database. A retrospective propensity score-matched analysis was used to reduce baseline differences between the cohorts. Univariate and multivariate analyses were performed to assess the degree of association between pLOS and unplanned readmission.
Results: From the 99,575 patients that fit the inclusion criteria, propensity score matching yielded 16,920 well-matched pairs (mean standard propensity score difference = 0.017). The overall 30-day unplanned readmission rate of these 33,840 patients was 5.5%. The mean length of stay was 2.0 ± 0.9 days and 6.0 ± 4.5 days (P ≤ 0.001) for the control and pLOS groups, respectively. In our univariate analysis, pLOS was associated with postoperative complications, especially medical complications (22.7% vs. 8.3%, P < 0.001). Multivariate analysis of the propensity score-matched population, which adjusted identified confounders (P < 0.02 and ≥10 occurrences), showed pLOS was associated with an increased risk of 30-day unplanned readmission (odds ratio [OR] 1.423, 95% confidence interval [CI] 1.290-1.570, P < 0.001).
Conclusion: Patients who undergo elective spine procedures who have any-cause pLOS (≥4 d) are at greater risk of having unplanned 30-day readmission compared with patients with shorter hospital stays.
Level of evidence: 4.