Atlantoaxial Subluxation in Patients with Psoriatic Arthritis
Bibliographic record
Abstract
Objectives We aimed to determine the incidence and prevalence of atlantoaxial subluxation (AAS) in a cohort of psoriatic arthritis (PsA) patients, describe their characteristics, and identify risk factors associated with AAS development. Methods We included individuals from our prospective observational cohort of PsA patients, excluding those with a history of trauma or cervical spine surgery. We calculated prevalence and incidence of AAS, and we used descriptive statistics to summarize and compare baseline demographic and disease-related characteristics between patients with and without AAS. Additionally, we performed a univariate Cox regression analysis to assess the factors associated with the development of AAS. Results A cohort of 1,535 patients with PsA was assessed, with 34 patients (2.2%) having AAS at any point during clinical follow-up. Of these, 20 presented with AAS at baseline, while 14 developed AAS during follow-up, resulting in an incidence rate of 0.93%. Among the patients with AAS, 41.2% were male, with a mean age at PsA diagnosis of 31.94 years (SD 13.79). Patients with AAS had a significantly higher mean swollen joint count (SJC) of 4.5 compared to 2 in those without AAS (p <0.001). The prevalence of sacroiliitis according to modified New York Criteria (mNY) was higher in the AAS group, at 71% compared to 22% (p <0.001). Radiographic damage to peripheral joints was significantly greater in patients with AAS, with a median radiographic damaged joint count (rDJC) of 7 compared to 1 in those without AAS (p <0.001). The Steinbrocker score was higher in AAS patients, with a median of 20.5 [IQR 6-39] versus 2 [IQR 0-10] in those without AAS (p =0.001). Abnormal erythrocyte sedimentation rate (ESR) was present in 86.7% AAS patients compared to 42.6% in those without AAS (<0.001). While HLA-B27 positivity was more prevalent among AAS patients (24.2% vs 16.4%), this did not meet statistical significance. No significant differences were observed between patients with and without AAS regarding other domains in psoriatic arthritis or treatments. In the univariate Cox regression analysis, significant factors associated with time to development of AAS included a higher Psoriasis Area and Severity Index (PASI), abnormal ESR, higher Steinbrocker score, higher rDJC, and the presence of sacroiliitis (Table 1). Table 1. Univariate Cox Regression Analysis of AAS Risk Factors Conclusion Atlanto-axial subluxation in PsA patients is associated with axial involvement, as evidenced by radiographic sacroiliitis and syndesmophytes, peripheral joint damage, and elevated ESR, which collectively indicate a more severe disease.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".