Validity and feasibility of the self-assessment vitiligo extent score among Egyptian patients

Sir,

Vitiligo extent score is one of the reliable instruments recently validated and used by physicians to assess the extent of non-segmental vitiligo.¹ However, according to the World Health Organization, if the patients themselves could score the extent of their vitiligo, it could bring about the participation of the patients in assessing the prognosis of their disease. Self-assessment vitiligo extent score was previously validated in patients with fairer skin types allowing them to score their vitiligo extent in an easy way.² Both vitiligo extent score and self-assessment vitiligo extent score are available online and easy to calculate (https://www.vitiligo-calculator.com/Calculator for vitiligo extent score, https://www.vitiligo-calculator.com/Calculator?sa=trueforself-assessmentvitiligoextentscore). Further validation of the self-assessment vitiligo extent score on a different ethnic population (Middle East/North African), darker skin types with various cultural and educational levels would add to the generalisability of the new scoring system, as recommended by van Geel et al.²

After getting the approval of the university’s ethical committeee for the current case series (FMASU R 27/2017) and informed consent from all participants, 206 nonsegmental vitiligo patients were recruited. Patients with skin type I were excluded. Patients were of different educational levels including adult illiterates, since Ain Shams University Hospital is a government run non-profit hospital attended mostly by patients with low to low- medium socioeconomic levels. Validity for self-assessment vitiligo extent score was determined by comparing the results of both self-assessment vitiligo extent score and vitiligo extent score, while feasibility was determined by recording the completion time (1–4 min, 5–9 min, 10-15 min and >15 min), patient’s required mental ability level, ease of administration and comprehensibility of self-assessment vitiligo extent score.

Quantitative variables which were normally distributed were described using mean and standard deviation and those with skewed distribution were described using median and interquartile range. The statistical tests used for comparison were Mann Whitney, ANOVA and Kruskal–Wallis. The Cronbach alpha test was used to examine the internal consistency of vitiligo extent score and self-assessment vitiligo extent score.

Our study included 206 patients with vitiligo, of all age groups (adults [≥16 y, mean age 37.89 ± SD 16.12 y] and children [9.36 ± SD 3.58 y]), educational levels and skin types prevalent in Egypt. Almost half of the patients were children below the age of 16 and 82% were of skin types III and IV [Table 1].

In concordance with the study done by van Geel et al in 2017,² the mean vitiligo extent score (1.93 ± SD 3.55) and self-assessment vitiligo extent score (1.79 ± SD 3.63) [Table 2] showed a significant bilateral positive correlation (r= + 0.923, P < 0.001) [Figure 1] and there was internal consistency of the assessment of vitiligo extent by the two scores (Cronbach alpha test = 0.96), indicating validity. Moreover, both the scores were not affected by gender (P = 0.977, 0.811) [Table 2], skin type (P = 0.977, 0.151) and educational level (P = 0.350, 0.632), respectively. However, both were less in children compared to adults (P = 0.009 and P = 0.033, respectively) which may be due to the progressive nature of disease with milder disease in childhood. Alternatively, it could be due to increased awareness and more concern of the parents resulting in early and prompt diagnosis and hence presenting with less/small surface area of lesions.

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Figure 1:

Positive correlation between vitiligo extent score and self-assessment vitiligo extent score with high correlation coefficient (Pearson correlation coefficient, r = +0.923, P < 0.001).

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The score was feasible, as the mean self-assessment vitiligo extent score time (done by 130 patients) was 3.19 ± SD 2.17 min. Most of the participants (101, 77.69 %) completed self-assessment vitiligo extent score in 1–4 min, 26 (20%) in 5–9 minutes, three (2.31%) in ten min and no one exceeded ten minutes. It was not affected by age (P = 0.65), gender (P = 0.436) [Table 2], skin type (P = 0.57) (Kruskal–Wallis) or educational level (P = 0.21) (Kruskal–Wallis). This is in agreement with study by van Geel et al in 2017,² where none of the patients rated the self-assessment vitiligo extent score scoring as difficult or very difficult.

Self-assessment vitiligo extent score was easy and needed less time to complete than the patient’s self-assessment scores of the vitiligo area severity index (SA-VASI), where only 35% of the patients were able to complete the questionnaire in five minutes.³ Self-assessment vitiligo extent score is a visually illustrated tool which makes it easier to comprehend and complete. Assistance was minimal in patients older than nine years (only 16% were assisted). Assistance required in adults was significantly less than that in children (P = 0.0001). There was a statistically significant association between low educational level and need for assistance (P = 0.0001). Adult illiterates were the group who needed more assistance and took the longest time (4.60 ± SD2.92 vs. 2.25 ± SD 1.58 min for university graduates) in completing self-assessment vitiligo extent score.

Thus, clearly, there are some discrepancies in self-assessment vitiligo extent score among patients related to their age. Most of the children presented with milder form of the disease as evidenced by having lower score compared to adults. In addition, a significant number of children, in contrast to adults, required assistance; nevertheless, patients’ age did not influence the timing needed to complete the questionnaire.

In conclusion, self-assessment vitiligo extent score demonstrated excellent feasibility and validity (highly significant correlation with vitiligo extent score) in an Egyptian patient population. It could be implemented in different cultural groups, in darker skin types and in different age groups. It represents a valuable tool in everyday clinical practice as well as in clinical trials.