Table 2. Logistic regression analysis identifying predictors of psoriatic arthritis.

Variables		Univariable analysis		Multivariable analysis
		OR	p	Adjusted OR	p
Disease duration		1.02	0.231
Family history		1.35	0.573
Clinical characteristics
	Scalp involvement	1.64	0.307
	Nail change	5.23	0.003	7.88	0.015
PASI score		1.08	0.015	1.07	0.066
Laboratory parameters
	ESR	1.02	0.055
	RDW	1.55	0.021	1.19	0.467
	CRP	1.15	0.001	1.13	0.004
	Negative RF*	0.77	0.807
	HLA-B27 positivity	1.90	0.291	1.93	0.345

OR: odds ratio, PASI: psoriasis area and severity index, ESR: erythrocyte sedimentation rate, RDW: red cell distribution width, CRP: C-reactive protein, RF: rheumatoid factor.

^*Negative RF was defined as <15 IU/ml.