Multivariate logistic regression analysis of factors associated with severe (psychophysiological) insomnia (Regensburg Insomnia Scale ≥25)
| Predictors | OR | 95% CI | B | P value |
| Female sex | 100.20 | 4.20 to 2390.13 | 4.61 | 0.004 |
| Significant functional impairment (FFbH <60%) | 16.83 | 1.55 to 182.59 | 2.82 | 0.020 |
| Depressive symptoms (BDI-II) | 1.16 | 1.06 to 1.28 | 0.15 | 0.002 |
Multivariable logistic regression adjusted for diagnosis, disease duration, HLA-B27 status, axial involvement, age, body mass index, smoking status, chronic lung disease, chronic kidney disease.
BDI-II, Beck Depression Inventory II ; FFbH, Funktionsfragebogen Hannover questionnaire .