Current Smoking and Acute Inpatient Outcomes After Elective Lumbar Spinal Fusion: A Propensity Score-Weighted Analysis of the National Inpatient Sample, 2016 to 2021.

BACKGROUND

Smoking is a well-established risk factor for pseudarthrosis after lumbar spinal fusion, but its relationship to complications during the index hospitalization remains uncertain. Whether this acute smoking-related risk varies by fusion extent is also poorly defined.

METHODS

We used the National Inpatient Sample (2016-2021) to identify adults undergoing elective lumbar fusion for degenerative pathology. Current smoking was defined using International Classification of Diseases, 10th Revision, Clinical Modification codes. Stabilized inverse probability of treatment weighting within a survey-weighted regression framework was used to compare smokers and nonsmokers. The primary outcome was any major perioperative complication. Secondary outcomes included individual complications, red blood cell transfusion, length of stay, and total charges. Interaction testing assessed effect modification by fusion extent.

RESULTS

Among 139,497 hospitalizations, 13.6% had smoking-related coding. After inverse probability of treatment weighting and adjustment for age and sex, smoking was associated with lower odds of the composite complication outcome (adjusted odds ratio [aOR] 0.887), blood loss anemia (aOR 0.857), and transfusion (aOR 0.828), but significantly higher odds of pneumonia (aOR 1.605). Smokers had a shorter length of stay and lower hospital charges. No significant interaction was observed between smoking and fusion extent.

CONCLUSIONS

Smoking was associated with a distinct acute inpatient risk profile after elective lumbar fusion, characterized by increased pneumonia risk without excess overall short-term morbidity. These findings reflect the limited inpatient window of the National Inpatient Sample and do not capture the established long-term adverse effects of smoking on fusion success.

CLINICAL RELEVANCE: Perioperative management should emphasize pulmonary risk mitigation alongside smoking cessation.