Malnutrition and Disability: A Retrospective Study on 2258 Adult Patients Undergoing Elective Spine Surgery

<i>Background and Objectives</i>: Malnutrition's prevalence and its relationship with functional ability in patients with end-stage spine pathologies, i.e., any disease of the vertebral bodies, intervertebral discs, and associated joints requiring surgical intervention, are yet to be explored. This retrospective study aimed to investigate the association between malnutrition, disability, and physical health in patients undergoing elective spine surgery in our Italian hospital. <i>Materials and Methods</i>: Data between 2016 and 2019, recorded at pre-admission visits, were extracted from our institutional spine registry (ClinicalTrials.gov number: NCT03644407), excluding minor patients or those undergoing emergency or oncological surgery. The measures were the Oswestry disability index (ODI) and the physical health (PH) summary of the 36-item Short-Form Health Survey. Clinical data were linked to nine laboratory parameters from pre-operative routine blood tests, and equations to ascertain the risk of malnutrition and its diagnosis were attributed. <i>Results</i>: The study sample included 2258 spine patients (58.15% females) who underwent surgery in our Italian hospital. The ODI and PH significantly varied across body weight difference (BWd) strata in younger adults (adjusted-<i>p</i> = 0.046, η² = 0.04; adjusted-<i>p</i> = 0.036, η² = 0.06) and adults (adjusted-<i>p</i> = 0.001, η² = 0.02; adjusted-<i>p</i> = 0.004, η² = 0.02). Protein malnutrition with acute/chronic inflammation (PMAC) in both adults (adjusted-<i>p</i> < 0.001, η² = 0.04; adjusted-<i>p</i> < 0.001, η² = 0.04) and older adults (adjusted-<i>p</i> = 0.010, η² = 0.04; adjusted-<i>p</i> = 0.009, η² = 0.05) had also a discernible impact in determining the ODI and PH. In older adults, the ODI was associated with iron deficit malnutrition (IDM) (adjusted-<i>p</i> = 0.005, η² = 0.06) and both the ODI and PH were associated with vitamin B deficit (VBD) (adjusted-<i>p</i> = 0.037, η² = 0.01; adjusted-<i>p</i> = 0.049, η² = 0.01). Trend monotonicity was diagnosis- and sex-specific, with meaningful ordered patterns being observed mostly in young males and older females. <i>Conclusions</i>: Functional ability showed an association with malnutrition in younger adults and adults when using BWd, in adults and older adults when using PMAC, and in older adults when using IDM and VBD. The authors advocate for the inclusion of nutritional management in the pre-operative evaluation to potentially enhance recovery after spine surgery.