Table 2.

Regression results

Variable	Excluding fixed effects		Including fixed effects
	Coefficient	95% CI	Coefficient	95% CI
Constant	0.9437 ***	0.8893, 0.9982	1.1764 ***	1.0027, 1.3500
PASI	−0.0186 ***	0.0000, 0.0002	−0.0224 ***	−0.0267, −0.0181
PASI squared	0.0001 ***	−0.0017, −0.0003	0.0002 ***	0.0001, 0.0003
Age	−0.0010 ***	−0.0035, −0.0003	−0.0057 ***	−0.0087, −0.0026
BMI	−0.0019 **	0.0000, 0.0000	−0.0003	−0.0031, 0.0026
BMI squared	−2.2 × 10−05 ***	−3.3 × 10−05, −9.91 × 10−06	1.99 × 10−05 ***	−2.57 × 10−05, −1.40 × 10−05
Psoriatic arthritis	−0.0570 *	0.0000, 0.0002	−0.0767	−0.1920, 0.0385
PASI * Age	0.0001 **	−0.0055, 0.0001	0.0001***	0.0000, 0.0002
PASI * Psoriatic arthritis	−0.0027 *	−0.0013, 0.0010	−0.0021*	−0.0045, 0.0002
Age * Psoriatic arthritis	−0.0001	0.0527, 0.0849	0.0015	−0.0006, 0.0035
Male	0.0688 ***	0.8893, 0.9982

*p < 0.10, **p < 0.05, ***p < 0.01; CI: Confidence interval; Patients: 2674; Observations: 14,044

R² = 0.612, Adjusted R² = 0.520