Association of perioperative hypotension with subsequent greater healthcare resource utilization

Study objective: Determine if perioperative hypotension, a modifiable risk factor, is associated with increased postoperative healthcare resource utilization (HRU).

Design: Retrospective cohort study.

Setting: Multicenter using the Optum® electronic health record database.

Patients: Patients discharged to the ward after non-cardiac, non-obstetric surgeries between January 1, 2008 and December 31, 2017 with six months of data, before and after the surgical visit.

Interventions/exposure: Perioperative hypotension, a binary variable (presence/absence) at an absolute MAP of ≤65-mmHg, measured during surgery and within 48-h after, to dichotomize patients with greater versus lesser hypotensive exposures.

Measurements: Short-term HRU defined by postoperative length-of-stay (LOS), discharge to a care facility, and 30-day readmission following surgery discharge. Mid-term HRU (within 6 months post-discharge) quantified via number of outpatient and emergency department (ED) visits, and readmission LOS.

Main results: 42,800 distinct patients met study criteria and 37.5% experienced perioperative hypotension. After adjusting for study covariates including patient demographics and comorbidities, patients with perioperative hypotension had: longer LOS (4.01 vs. 3.83 days; LOS ratio, 1.05; 95% CI, 1.04-1.06), higher odds of discharge to a care facility (OR, 1.18; 95% CI, 1.12-1.24; observed rate 22.1% vs. 18.1%) and of 30-day readmission (OR, 1.22; 95% CI, 1.11-1.33; observed rate 6.2% vs. 5.0%) as compared to the non-hypotensive population (all outcomes, p < 0.001). During 6-month follow-up, patients with perioperative hypotension showed significantly greater HRU regarding number of ED visits (0.34 vs. 0.31 visits; visit ratio, 1.10; 95% CI, 1.05-1.15) and readmission LOS (1.06 vs. 0.92 days; LOS ratio, 1.15; 95% CI, 1.07-1.24) but not outpatient visits (10.47 vs. 10.82; visit ratio, 0.97; 95% CI, 0.95-0.99) compared to those without hypotension. There was no difference in HRU during the 6-month period before qualifying surgery.

Conclusions: We report a significant association of perioperative hypotension with an increase in HRU, including additional LOS and readmissions, both important contributors to overall medical costs.