Abstract
Keywords
Introduction
Adolescent idiopathic scoliosis (AIS) is the most common form of scoliosis in adolescents, with an incidence of 0.47%–5.2%, and may require posterior spinal fusion (PSF) for progressive curves exceeding surgical thresholds.1–4 Although PSF is an effective and well-established treatment, access to timely diagnosis, surgical evaluation, and postoperative recovery can be strongly influenced by sociodemographic factors such as race, insurance coverage, and socioeconomic status. 5 These determinants not only shape who receives surgical care but also affect perioperative risks, complication rates, and long-term outcomes. 6 Despite this relevance, sociodemographic characteristics remain inconsistently reported in randomized controlled trials (RCTs), limiting assessment of whether current evidence reflects the populations most affected by AIS.
Disparities in evaluation and perioperative care have been documented across orthopedic subspecialties, including PSF, yet the factors underlying these inequities cannot be adequately assessed when reporting is incomplete.5–9 Sociodemographic variables encompass both demographic characteristics (age, sex, race, ethnicity) and socioeconomic indicators (insurance status, education, income, and housing stability). However, prior work has demonstrated that these variables are frequently underreported in randomized trials across medicine and surgery.10–14 Without their consistent inclusion, it is difficult to determine whether published RCT outcomes are equitable, generalizable, or representative of the broader AIS population.
RCTs are considered the highest level of evidence for evaluating treatment effectiveness; however, when key sociodemographic characteristics are not collected or reported, important effect modifiers may be obscured. Because these variables can influence both access to surgery and postoperative outcomes, underreporting limits the ability to assess confounding, stratify risk, and determine whether findings are externally valid across diverse patient populations. Accordingly, the purpose of this study is to determine the rate of sociodemographic reporting in RCTs investigating PSF for AIS. We hypothesized that these trials would significantly under-report sociodemographic variables.
Methods
Literature review
This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Supplemental A). The databases PubMed, Embase, and Scopus were searched for the terms “posterior spinal fusion,” “randomized controlled trial,” and “adolescent idiopathic scoliosis” on 9 April 2024. Inclusion criteria were RCTs investigating PSF in adolescents with idiopathic scoliosis published in English with an accessible full text. Exclusion criteria were studies not published in English, studies that did not have the full-text available, cadaver studies, technique articles, and study designs other than RCTs. Studies were screened for inclusion by two authors. Any disagreement was resolved by a third author.
Data collection
The title, journal, and year of publication for each article were recorded. Demographic variables, such as sex or gender, race, ethnicity, and age, and socioeconomic variables such as insurance status, income/Childhood Opportunity Index (COI), a surrogate for socioeconomic status, housing status, familial work status, and familial level of education were collected. Two authors thoroughly reviewed each manuscript to determine which variables were included in the paper. The information was collected in a binary manner, categorizing whether each variable was present or absent as either “yes” or “no,” respectively. Data are available from the authors upon reasonable request.
Statistical analysis
Data were analyzed using descriptive statistics. Chi-squared tests were used to compare the reporting frequency of sociodemographic variables (e.g., age/sex vs. race/ethnicity) and to evaluate differences across journals. Fisher’s exact test was used for comparisons across time intervals (pre-2017 vs. post-2017), where cell sizes were small. A
Results
The initial database search identified 148 studies, of which 64 duplicates were removed. An additional 32 studies were removed after title and abstract screening because they did not meet the inclusion criteria. The full text of the remaining 52 studies was assessed for eligibility. Of the 52 studies, 8 studies were excluded because they did not have a full text. In all, 44 RCTs were selected for inclusion (Figure 1).

Study selection process following the PRISMA framework.
The included RCTs were published in 19 journals from 1988 to 2024.15–58 The age of study participants was reported in 43 out of the 44 total studies (97.7%). Sex or gender was reported in 42 of 44 (95.5%) studies. With respect to other sociodemographic variable reporting, race was included in 3 of 44 (6.8%) studies, and ethnicity in 4 of 44 (9.1%) studies. However, familial income/COI, familial work status, familial level of education, insurance status, and housing status were not mentioned in any study (0/44, 0.0%; Table 1). Age and sex/gender were reported significantly more frequently than race or ethnicity (
Variable inclusion in pediatric posterior spinal fusion randomized controlled trials.
COI: Childhood Opportunity Index.
There was no significant difference in reporting of any sociodemographic variables among included journals (
Sociodemographic variable inclusion in any section of the manuscript by journal.
Sociodemographic variable inclusion in any section of the manuscript by publication year.
Discussion
This review addresses a critical gap in the orthopedic literature: the limited reporting of sociodemographic variables in AIS RCTs, which restricts the ability to evaluate whether surgical outcomes are equitable or generalizable across patient populations. Without these data, key effect modifiers related to access to care, baseline risk, and postoperative recovery cannot be assessed, diminishing both interpretability and external validity. Our findings show that although age and sex were consistently reported, socioeconomic indicators, such as insurance status, income, and education, were almost never included, and race and ethnicity were reported only intermittently in more recent trials. This pattern reflects a persistent disconnect between the known influence of social determinants of health and the variables captured within high-level surgical evidence.
As previously mentioned, age and sex were commonly reported in 97.7% and 95.5% of included studies, respectively, thus reflecting their importance in treating AIS. Many studies have reported higher incidence rates for AIS in females and greater initial curve angles compared to males (18.1° vs. 16.7°).
59
Bondar et al.’s
59
retrospective analysis found the highest AIS incidence among 13-year-old girls (958 per 100,000 per year). Helenius et al.
60
found similar preoperative Cobb angles between males and females (55° vs. 56°) but greater postoperative curve correction in females (
Race and ethnicity have been documented to play a role in contributing to worse care outcomes in underrepresented populations, but they have been relatively under-reported compared to age and sex in the literature concerning AIS.
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Among the RCTs included in our review, only three reported race and four reported ethnicity, and none provided stratified outcomes or adjusted analyses, mirroring broader trends in orthopedics where fewer than 6% of RCTs report race and fewer than 2% report ethnicity.
7
Bondar et al.
59
reported that White and African American patients had significantly higher initial curve magnitudes compared to Hispanic patients (
Insurance status has been shown to affect treatment access and care pathways for AIS in retrospective cohorts. Thornley et al.
67
reported that publicly insured Black patients were less likely to seek second opinions and receive bracing (
Education status is another important sociodemographic variable that affects patient outcomes. Berg et al.
69
sought to observe the readability of medical resources concerning PSF in treating pediatric scoliosis. They reported a mean reading grade level of 11.6 ± 2.3 for websites containing information regarding PSF, which may affect patients’ understanding of treatment and the quality of care they receive. This idea was backed by a retrospective study by Yang et al.,
70
revealing fewer mean days (5.6 vs. 8.9,
This systematic review has several limitations. First, limiting inclusion to English-language publications may have introduced language-based publication bias; RCTs published in non-English journals may differ in their sociodemographic reporting practices, which could lead to an underestimation of global reporting trends. Moreover, the binary (“yes/no”) coding of sociodemographic reporting does not capture the level of detail or analytic use of these variables. While this study identified the presence of sociodemographic variables in its analysis of RCTs, it did not provide detailed quantitative or qualitative data for each variable, such as the total number of patients, the mean age of patients, and the percentage of each sex among the patients, which could have enriched the study. In addition, while composite socioeconomic scores such as the Concentrated Disadvantage Index and the COI are emerging, it remains unclear which is most useful. Future studies should explore the utility and applicability of these indices to better assess sociodemographic factors and improve the generalizability of findings. Finally, excluding non-English studies may have resulted in underreporting of sociodemographic variables.
Conclusion
RCTs on PSF for AIS rarely report sociodemographic variables beyond age and sex. This omission limits the ability to determine whether outcomes are consistent across patient populations or whether disparities exist in treatment response, perioperative risk, or recovery. Improved sociodemographic reporting is therefore not only a matter of transparency but a prerequisite for assessing external validity and equity in AIS care.
Supplemental Material
sj-docx-2-cho-10.1177_18632521251411158 – Supplemental material for Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adolescent idiopathic scoliosis: A systematic review
Supplemental material, sj-docx-2-cho-10.1177_18632521251411158 for Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adolescent idiopathic scoliosis: A systematic review by Erin L Brown, Kenneth T Nguyen, Bhavesh R Koppala, Daman P Dhunna, Alexander Kuzma and Nikolas Baksh in Journal of Children's Orthopaedics
Supplemental Material
sj-pdf-1-cho-10.1177_18632521251411158 – Supplemental material for Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adolescent idiopathic scoliosis: A systematic review
Supplemental material, sj-pdf-1-cho-10.1177_18632521251411158 for Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adolescent idiopathic scoliosis: A systematic review by Erin L Brown, Kenneth T Nguyen, Bhavesh R Koppala, Daman P Dhunna, Alexander Kuzma and Nikolas Baksh in Journal of Children's Orthopaedics
Footnotes
Author contributions
Erin L. Brown: Corresponding author, data analysis, study conception and design, manuscript drafting.
Kenneth T. Nguyen: Data analysis, data extraction, manuscript drafting, literature search.
Bhavesh R. Koppala: Data collection, manuscript revisions, verification of extracted data.
Daman P. Dhunna: Critical review of manuscript, data interpretation, manuscript editing.
Alexander Kuzma: Critical revisions of manuscript for important intellectual content, study supervision.
Nikolas Baksh: Critical revisions of manuscript for important intellectual content, study supervision.
All authors read and approved the final manuscript.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical statement
This study is a systematic review of previously published data and did not involve new human or animal participants. Therefore, institutional review board approval and informed consent were not required.
Data availability statement
This study is a systematic review. All data analyzed in this article are drawn from previously published studies, which are cited in the reference list. No new datasets were generated or analyzed.
Supplemental material
Supplemental material for this article is available online.
References
Supplementary Material
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