Comparative analyses of patient-reported outcomes of disease and treatment burden across patients with none/mild pruritus (NRS ≤ 3) and with moderate/severe pruritus (NRS ≥ 4), with and without anogenital involvement
| None/mild pruritus | Moderate/severe pruritus | Main effects | Interaction effects | |||||||
| No anogenital involvement | Anogenital psoriasis | No anogenital involvement | Anogenital psoriasis | Pruritus | Anogenital involvement | Pruritus* anogenital | ||||
| Intrapersonal burden | M (SD) | M (SD) | M (SD) | M (SD) | F | ηp2 | F | ηp2 | F | ηp2 |
| Skin-generic QoL (DLQI) | 2.92 (4.37) | 5.92 (5.42) | 11.13 (7.19) | 11.79 (5.56) | 21.46*** | 0.18 | 0.36 | 0.00 | 0.71 | 0.01 |
| Pruritus-specific QoL (Itchy-QoL) | 1.73 (0.73) | 1.98 (0.90) | 3.09 (0.84) | 2.83 (0.72) | 32.93*** | 0.26 | 0.45 | 0.01 | 1.09 | 0.01 |
| Patient benefits (PBI) | 3.08 (1.05) | 2.29 (1.25) | 1.47 (1.10) | 1.75 (1.12) | 12.65*** | 0.13 | 0.02 | 0.00 | 3.47 | 0.04 |
| Depression (PHQ-2) | 0.48 (0.98) | 1.30 (1.83) | 2.38 (2.12) | 1.72 (1.71) | 5.61* | 0.06 | 0.04 | 0.00 | 4.20* | 0.04 |
| Anxiety (GAD-2) | 0.65 (1.25) | 1.17 (1.70) | 2.13 (2.07) | 1.56 (1.25) | 5.60* | 0.06 | 0.28 | 0.00 | 1.76 | 0.02 |
| Dysmorphic concerns (DCQ) | 6.12 (4.31) | 5.50 (5.50) | 9.79 (6.36) | 7.89 (4.00) | 6.08* | 0.06 | 1.46 | 0.02 | 0.18 | 0.00 |
| Frequency of scratching† | 1.23 (1.85) | 1.64 (2.01) | 7.00 (2.25) | 9.63 (14.87) | 12.67*** | 0.11 | 0.50 | 0.01 | 0.33 | 0.00 |
| n (%) | n (%) | n (%) | n (%) | χ2 | χ2 | – | ||||
| Sleeping problems‡ | 21 (40.4) | 5 (41.7) | 24 (100.0) | 18 (94.7) | 21.64*** | 7.43** | – | |||
| Interpersonal burden | M (SD) | M (SD) | M (SD) | M (SD) | F | ηp2 | F | ηp2 | F | ηp2 |
| Perceived stigmatisation (PSQ) | 1.76 (0.41) | 1.79 (0.50) | 2.06 (0.56) | 1.74 (0.32) | 0.14 | 0.00 | 2.78 | 0.03 | 3.86* | 0.04 |
| Sexual dysfunction (RSS) | 15.04 (5.90) | 18.83 (8.21) | 16.77 (5.53) | 20.67 (6.16) | 0.16 | 0.00 | 3.30 | 0.03 | 0.01 | 0.00 |
The presence of intertriginous psoriasis, biological treatment and Psoriasis Area and Severity Index were included in the models as covariates.
*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, two tailed.
†Assessed by the patients through the questions ‘Did you have to scratch yourself within the last 24 hours?’ and ‘How often have you had to scratch within the last 24 hours?’, using a yes/no and a 0–10 NRS, respectively, whereby patients reporting no pruritus and/or no scratching in the last 24 hours were assumed as NRS = 0.
‡Assessed by the patients through the question ‘Did you have any sleeping problems within the last 24 hours because of the itching?’, using a yes/no response scale, whereby patients reporting no pruritus (not applicable) were assumed as having no sleeping problems.
DCQ, Dysmorphic Concerns Questionnaire (range 0−21, whereby higher values indicate higher dysmorphic concerns and scores ≥ 11 represent significant concerns in bodily appearance); DLQI, Dermatology Life Quality Index (range 0−30, with higher values indicating more QoL impairments); F, two-way univariate analysis of covariance; GAD-2, Generalised Anxiety Disorder (range 0−6, with cut-off scores of ≥ 3 as indicators of clinically significant symptoms of anxiety); ItchyQoL, (range 1−5, with higher scores representing more QoL impairments); M, mean; NRS, Numeric Rating Scale; PBI, Patient Benefit Index (range from 0 = “no benefit” to 4 = “maximal benefit”); PHQ-2, Patient Health Questionnaire (range 0−6, with cut-off scores of ≥ 3 as indicators of clinically significant symptoms of depression); PSQ, Perceived Stigmatisation Questionnaire (range 1−5, with higher scores indicating higher levels of perceived stigmatisation); QoL, quality of life; RSS, Relationship and Sexuality Scale (range 0−36, whereby a higher score indicates higher problem level); SD, standard deviation.