Univariable and multivariable logistic regression analysis for significant dysmorphic concerns (DCQ ≥ 11)
| Univariable analysis | Multivariable analysis | ||||||
| B (SE) | Wald | OR (95% CI) | B (SE) | Wald | OR (95% CI) | VIF | |
| Sociodemographic characteristics | |||||||
| Age | −0.01 (0.02) | 0.47 | 0.99 (0.96, 1.02) | – | – | – | – |
| Gender (0 = male vs 1 = female)† | 1.19 (0.49) | 5.99* | 3.29 (1.27, 8.54) | 0.50 (0.62) | 0.66 | 1.65 (0.49, 5.54) | 1.21 |
| Clinical characteristics | |||||||
| Pruritus (0 = none/mild vs 1 = moderate/severe)† | 1.47 (0.49) | 8.91** | 4.33 (1.65, 11.34) | 0.71 (0.69) | 1.05 | 2.03 (0.53, 7.81) | 1.80 |
| Anogenital involvement (0 = no vs 1 = yes)† | 0.01 (0.51) | 0.00 | 1.01 (0.37, 2.75) | – | – | – | – |
| Intertriginous psoriasis (0 = no vs 1 = yes)† | 0.78 (0.58) | 1.82 | 2.18 (0.70, 6.76) | – | – | – | – |
| Disease duration | < −0.01 (0.02) | 0.01 | 1.00 (0.97, 1.03) | – | – | – | – |
| Biological treatment (0 = no vs 1 = yes)† | −0.52 (0.46) | 1.25 | 0.60 (0.24, 1.48) | – | – | – | – |
| Comorbidities (0 = no vs 1 = yes)† | 1.07 (0.50) | 4.60* | 2.92 (1.10, 7.77) | 0.91 (0.60) | 2.32 | 2.48 (0.77, 8.02) | 1.07 |
| PASI | 0.04 (0.04) | 0.83 | 1.04 (0.96, 1.13) | – | – | – | – |
| PROs of disease/treatment burden | |||||||
| Skin-generic QoL (DLQI) | 0.07 (0.03) | 4.90* | 1.08 (1.01, 1.15) | −0.11 (0.07) | 2.68 | 0.89 (0.78, 1.02) | 3.11 |
| Pruritus-specific QoL (ItchyQoL) | 0.97 (0.28) | 11.76*** | 2.64 (1.52, 4.59) | 0.84 (0.49) | 2.93 | 2.30 (0.89, 5.99) | 3.17 |
| Patient benefit (PBI) | −0.50 (0.20) | 6.47* | 0.61 (0.42, 0.89) | −0.30 (0.28) | 1.15 | 0.74 (0.43, 1.28) | 1.98 |
| Frequency of scratching | 0.02 (0.03) | 0.47 | 1.02 (0.97, 1.08) | – | – | – | – |
| Sleeping problems (0 = no vs 1 = yes)† | 1.05 (0.57) | 3.45 | 2.86 (0.94, 8.69) | – | – | – | – |
| Perceived stigmatisation (PSQ) | 1.27 (0.50) | 6.48* | 3.55 (1.34, 9.40) | 0.70 (0.76) | 0.86 | 2.02 (0.46, 8.95) | 1.33 |
| Sexual dysfunction (RSS) | 0.06 (0.04) | 2.40 | 1.06 (0.99, 1.14) | – | – | – | – |
*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, two tailed.
†The reference category was the first, that is, scored as 0.
B, regression coefficient; CI, confidence interval; DCQ, Dysmorphic Concern Questionnaire; DLQI, Dermatology Life Quality Index; OR, odds ratio; PASI, Psoriasis Area and Severity Index; PBI, Patient Benefit Index; PROs, patient-reported outcomes; PSQ, Perceived Stigmatisation Questionnaire; QoL, quality of life; RSS, Relationship and Sexuality Scale; SE, standard error; VIF, variance inflation factor.