AM-PAC mobility scores predict non-home discharge following adult spinal deformity surgery

Abstract

Background context: Adult spinal deformity (ASD) surgery requires an extended recovery period and often non-routine discharge. The Activity Measure for Post-Acute Care (AM-PAC) Basic Mobility Inpatient Short Form (6-Clicks) is a prediction tool, validated for other orthopedic procedures, to assess a patient's ability to mobilize after surgery.

Purpose: To assess the thresholds of AM-PAC scores that determine non-home discharge disposition in patients who have undergone ASD surgery.

Study design: Retrospective review PATIENT SAMPLE: Ninety consecutive ASD patients with ≥5 levels fused who underwent surgery from 2015 to 2018, with postoperative AM-PAC scores measured before discharge, were included.

Outcome measures: Non-home discharge disposition METHODS: Patients with routine home discharge were compared to those with non-home discharge. Bivariate analysis was first conducted to compare these groups by preoperative demographics, comorbidities, radiographic alignment, surgical characteristics, HRQOLs, and AM-PAC measurements. Threshold linear regression with Bayesian information criteria was utilized to identify the optimal cutoffs for AM-PAC scores associated with increased likelihood of non-home discharge. Finally, multivariable analysis controlling for age, sex, comorbidities, levels fused, perioperative complication, and home support was conducted to assess each threshold.

Results: Thirty-six (40%) of 90 patients analyzed had non-home discharge. On bivariate analysis, first AM-PAC score (13.5 vs. 17), last AM-PAC score (17 vs. 20), and AM-PAC change per day (+.387 vs. +1) were all significantly associated with non-home discharge. Threshold regression identified that cutoffs of ≤15 for first AM-PAC score, <17 for last AM-PAC score, and <+0.625 for daily AM-PAC change were associated with non-home discharge. On multivariable analysis, first AM-PAC score ≤15 (odds ratio [OR] 11.28; confidence interval [CI] 2.96-42.99; p<.001), last AM-PAC score <17 (OR 33.57; CI 5.85-192.82; p<.001), and AM-PAC change per day <+0.625 (OR 6.24; CI 2.01-19.43; p<.001) were all associated with increased odds of non-home discharge.

Conclusions: First AM-PAC score of 15 or less can help predict non-home discharge. A goal of daily AM-PAC increases of 0.625 points toward a final AM-PAC score of 17 can aid in achieving home discharge. The early AM-PAC mobility threshold of ≤15 may help prepare for non-home discharge, while AM-PAC daily changes per day <0.625 and final AM-PAC <17 may provide goals for mobility improvement during the early postoperative period in order to prevent non-home discharge.

Keywords: AM-PAC, Discharge; Adult spinal deformity; Length of stay; Mobility; Non-home discharge; Non-routine discharge; Threshold regression.