Table 3-.
Univariate and multivariable analysis of factors associated with pruritus at entry in the study
| Univariate analysis* | Multivariable analysis** | ||||
|---|---|---|---|---|---|
| VAS Pruritus mean (SD) |
P | VAS pruritus variation (95% CI) |
P | ||
| Age, yrs | 18–29 | 4.7 (3.1) | 0.20 | - | - |
| 30–44 | 4.6 (3.3) | - | - | ||
| 45–59 | 4.6 (3.2) | - | - | ||
| 60+ | 4.5 (3.2) | - | - | ||
| Gender | Male | 4.4 (3.2) | <0.001 | Ref | |
| Female | 5.0 (3.3) | 0.74 (0.59, 0.89) | <0.001 | ||
| BMI, kg/m2 | <20.0 | 4.9 (3.3) | 0.03 | - | - |
| 20.0 – 24.9 | 4.5 (3.2) | (0.21) | - | - | |
| 25.0 – 29.9 | 4.6 (3.2) | - | - | ||
| 30.0+ | 4.7 (3.3) | - | - | ||
| Smoking habits | Never/Ex | 4.5 (3.2) | <0.001 | - | - |
| Current | 4.7 (3.3) | - | - | ||
| Drinker | No/Occasionally/Ex | 4.6 (3.2) | 0.96 | - | - |
| Regular | 4.6 (3.2) | - | - | ||
| Education, yrs | 0–5 (primary) | 4.9 (3.3) | <0.001 | 0.40 (0.14, 0.67) | 0.003 |
| 6–8 (lower secondary) | 4.7 (3.2) | (<0.001) | 0.41 (0.18, 0.65) | 0.001 | |
| 9–13 (upper secondary) | 4.4 (3.2) | 0.18 (−0.06, 0.41) | 0.14 | ||
| ≥14 (university or higher) | 4.3 (3.2) | Ref | |||
| Marital status | Unmarried | 4.5 (3.2) | 0.04 | - | - |
| Married / Common-law husband/wife | 4.6 (3.2) | - | - | ||
| Divorced | 4.8 (3.4) | - | - | ||
| Widowed | 5.0 (3.4) | - | - | ||
| PASI score | <10 | 3.5 (3.2) | <0.001 | Ref | |
| 10–20 | 4.6 (3.1) | (<0.001) | 1.01 (0.83, 1.20) | <0.001 | |
| >20 | 5.3 (3.1) | 1.63 (1.42, 1.84) | <0.001 | ||
| Disease duration, yrs | 0–4 | 4.7 (3.3) | <0.001 | 0.42 (0.17, 0.66) | 0.001 |
| 5–14 | 4.7 (3.2) | (<0.001) | 0.40 (0.18, 0.61) | <0.001 | |
| 15–29 | 4.5 (3.2) | 0.09 (−0.12, 0.31) | 0.39 | ||
| ≥30 | 4.4 (3.2) | Ref | |||
| CCI | 0 | 4.5 (3.2) | 0.001 | - | - |
| 1–2 | 4.7 (3.3) | (<0.001) | - | - | |
| >2 | 5.0 (3.3) | - | - | ||
| Pustular Ps | No | 4.6 (3.2) | 0.06 | Ref | |
| Yes | 4.9 (3.3) | 0.46 (0.0, 0.81) | 0.049 | ||
| PsA | No | 4.7 (3.2) | <0.001 | - | - |
| Yes | 4.3 (3.3) | - | - | ||
| Affected body areas | |||||
| Head | No | 4.1 (3.3) | <0.001 | Ref | |
| Yes | 4.8 (3.2) | 0.48 (0.31, 0.65) | <0.001 | ||
| Face | No | 4.4 (3.2) | <0.001 | Ref | |
| Yes | 5.0 (3.3) | 0.27 (0.10, 0.44) | 0.002 | ||
| Trunk | No | 4.1 (3.3) | <0.001 | - | - |
| Yes | 4.7 (3.2) | - | - | ||
| Limbs | No | 4.2 (3.3) | <0.001 | - | - |
| Yes | 4.6 (3.2) | - | - | ||
| Nails | No | 4.5 (3.2) | 0.005 | - | - |
| Yes | 4.7 (3.3) | - | - | ||
| Palms/Feet | No | 4.5 (3.2) | <0.001 | Ref | |
| Yes | 5.0 (3.3) | 0.37 (0.20, 0.54) | <0.001 | ||
| Folds | No | 4.4 (3.2) | <0.001 | Ref | |
| Yes | 5.3 (3.2) | 0.34 (0.16, 0.52) | <0.001 | ||
| Genitalia | No | 4.4 (3.2) | <0.001 | Ref | |
| Yes | 5.4 (3.3) | 0.51 (0.31, 0.71) | <0.001 | ||
| Previous systemic treatments for Ps | 0 | 4.7 (3.2) | 0.08 | 0.44 (0.21, 0.66) | <0.001 |
| 1 | 4.6 (3.2) | (0.01) | 0.27 (0.04, 0.51) | 0.02 | |
| 2 | 4.5 (3.3) | 0.13 (−0.11, 0.36) | 0.29 | ||
| 3+ | 4.5 (3.3) | Ref | |||
| Hospital admission for Ps in the last 5 yrs | No | 4.5 (3.2) | 0.002 | - | - |
| Yes | 4.7 (3.3) | - | - | ||
| Previous clinical remission for Ps | No | 4.6 (3.2) | 0.37 | - | - |
| Yes | 4.5 (3.2) | - | - | ||
BMI: body mass index, CCI: Charlson comorbidity index, CI: confidence interval, PASI: psoriasis area severity index, PsA: psoriasis arthritis, Ref: reference category, SD: standard deviation, VAS: visual analogue scale
*
Mann-Whitney U test for dichotomous variables or Kruskal-Wallis test for variables with three or more categories. In case of ordinal data, when the first test was significant (P-value <0.05), Cuzick’s test for trend was also performed
**
Independent factors selected in multiple linear regression analysis with forward stepwise selection algorithm
Non significant after multivariable analysis.