Impact of patient-reported allergies and psychiatric history on lumbar interbody fusion outcomes: a retrospective cohort study in the United States.

STUDY

DESIGN

Retrospective cohort study.

PURPOSE: To determine whether patient-reported allergies (PRAs) are associated with pain, mobility, and functional outcomes following lumbar interbody fusion (LIF).

OVERVIEW OF LITERATURE: Prior studies suggest PRAs may correlate with worse postoperative pain, disability, and satisfaction; however, findings are inconsistent, and their impact on LIF outcomes remains unclear.

METHODS

We retrospectively analyzed 325 adults undergoing elective LIF for degenerative pathology (November 2019-January 2023). Patients were stratified into ≥1 PRA (n=242) and no known allergies (n=83). Demographics, psychiatric history, preoperative opioid use, and allergy type were recorded. Primary outcomes included changes in Patient-reported outcome measures (PROMs; PROMIS overall, physical, and mental health) and Oswestry Disability Index (ODI) from baseline to 1 year. Secondary outcomes included Visual Analog Scale (VAS) and Activity Measure for Post-Acute Care (AMPAC) mobility. Multivariate regression assessed associations with outcomes. Minimal clinically important difference (MCID) thresholds were ODI ≥10 and PROMIS ≥8. Receiver operating characteristic analysis evaluated PRA count as a predictor of MCID.

RESULTS

Patients with PRAs were more frequently female (57%; p=0.002) and had higher rates of psychiatric comorbidities (p=0.02). The PRA group demonstrated greater improvement in PROMIS overall (p=0.049) and mental health (p=0.026) scores, with no difference in ODI change. PRA count was not associated with VAS, AMPAC, or MCID attainment. Psychiatric history independently predicted lower odds of achieving MCID for PROMIS physical (odds ratio [OR], 0.52; p=0.048) and ODI (OR, 0.27; p=0.002). PRA count showed poor predictive value for MCID (area under the curve<0.600).

CONCLUSIONS

PRAs were not associated with worse outcomes after LIF and were linked to greater improvement in PROMIS scores. Psychiatric history, but not allergy count, was a strong predictor of reduced MCID attainment.