Sociodemographic Variables Are Rarely Reported in Randomized Controlled Trials Investigating Posterior Spinal Fusion For Adult Spinal Deformity: A Systematic Review

Introduction: Adult spinal deformity (ASD) affects 68.0% of patients over 65 and can significantly impact health-related quality of life (HRQoL). Corrective surgery, particularly posterior spinal fusion (PSF), is a key treatment for restoring alignment and alleviating pain. However, disparities related to sociodemographic factors may influence outcomes. This study evaluates the frequency of sociodemographic variable reporting in randomized controlled trials (RCTs) investigating PSF for ASD, hypothesizing significant under-reporting.

Methods: A literature review, following PRISMA guidelines, was conducted in PubMed, Embase, and Scopus on April 15, 2024, for RCTs on "adult spinal deformity," "posterior spinal fusion," and "randomized controlled trial." Eligible RCTs in English with full texts were included, excluding non-English publications, unavailable texts, cadaver studies, technique articles, and non-RCT designs. Two authors screened studies independently, with a third resolving discrepancies. Data on sociodemographic variables were extracted, and descriptive statistics with chi-squared or Fisher's exact tests were used for analysis (P < 0.05).

Results: The initial search yielded 32 studies, with 4 duplicates removed. After applying inclusion criteria, 19 studies were excluded based on title and abstract. Of the remaining nine, two lacked full text, and others had incorrect interventions, leaving five RCTs for inclusion. Published between 2008 and 2020 in three journals, these studies consistently reported age and sex but omitted other sociodemographic variables. None included race, ethnicity, work, education, housing, or income, and only one reported insurance status. Sociodemographic variables were significantly underreported (insurance: 1/5, 20%) compared to age and sex (5/5, 100%) (P < 0.001). No differences were found between journals or publication year.

Conclusion : This systematic review found that demographic variables such as age and sex are more frequently reported than sociodemographic variables. All five included studies reported age and sex, with one study including insurance status. However, race, ethnicity, housing status, work status, income, and education level were not reported. Trends in unreported variables affecting health outcomes necessitate their inclusion in future studies to enhance ASD care. Including a broader range of sociodemographic factors in RCTs is crucial for understanding and mitigating healthcare disparities in ASD treatment outcomes.