Trajectory Analysis of Health Care Utilization Before and After Major Surgery

To characterize patterns of health care utilization before and after surgery and determine any association with preoperative frailty.

Frail patients experience worse postoperative outcomes and increased costs during the surgical encounter. Evidence is comparatively lacking for the longer-term effects of frailty on postoperative health care utilization.

Retrospective, longitudinal cohort analysis of adult patients undergoing any elective surgical procedure after preoperative frailty assessment with the Risk Analysis Index from February 2016 to December 2020 at a large integrated health care delivery and financing system. Group-based trajectory modeling of claims data estimated distinct clusters of patients with discrete utilization trajectories. Multivariable regression predicted membership in trajectories of interest using preoperative characteristics, including frailty.

Among 29,067 surgical encounters, 4 distinct utilization trajectories emerged in longitudinal data from the 12 months before and after surgery. All cases exhibited a surge in utilization during the surgical month, after which most patients returned to "low" [25,473 (87.6%)], "medium" [1403 (4.8%)], or "high" [528 (1.8%)] baseline utilization states established before surgery. The fourth trajectory identified 1663 (5.7%) cases where surgery occasioned a transition from "low" utilization before surgery to "high" utilization afterward. Risk Analysis Index score alone did not effectively predict membership in this transition group, but a multivariable model with other preoperative variables was effective ( c = 0.859, max rescaled R2 = 0.264).

Surgery occasions the transition from low to high health care utilization for a substantial subgroup of surgical patients. Multivariable modeling may effectively discriminate this utilization trajectory, suggesting an opportunity to tailor care processes for these patients.