|Outcome measures||Intervention group*||Control group||Difference between means (95% CI)|
|Unadjusted parametric analysis||P for difference||Adjusted† parametric analysis||P for difference|
|HECSI score||4.97 (4.14 to 5.88)||8.53 (7.45 to 9.63)||−3.56 (−4.92 to −2.14)||<0.001||−3.47 (−4.80 to −2.14)||<0.001|
|DLQI score||1.22 (0.88 to 1.61)||2.00 (1.58 to 2.48)||−0.78 (NA)||0.003‡||−0.92 (−1.48 to −0.37)||<0.001|
|Score of knowledge of hand eczema and skin protection||10 (1)||10 (0)||—||0.42§||—||NA|
HECSI=hand eczema severity index; DLQI=dermatology life quality index; NA=not applicable.
Non-parametric test (Mann Whitney) was used if assumptions of the general linear univariate model were not fulfilled.
*Values were square root transformed before calculations. Means (95% CI) were then squared.
†Adjusted by stratification variables and baseline values.
‡Standardised residuals were not normally distributed (Shapiro Wilk’s test P<0.001 and distribution significantly right skewed). Therefore the non-parametric Mann Whitney test was used and the P value of that test is shown. By contrast when the analysis was adjusted the fit of the general linear model was perfect.
§Non-parametric test used (Mann Whitney) at it was not possible to transform quantities for acceptable model fit.