Quality of life in people with vitiligo: a systematic review and meta-analysis

Dear Editor, Vitiligo is cosmetically disfiguring and has profound psychosocial effects because of stigmatization, problems in sexual function, anxiety, self‐esteem and difficulty finding employment.1 Previous studies suggest a reduction in quality of life (QoL), but no systematic review has quantified this in comparison with people without vitiligo. The review protocol was registered with PROSPERO (CRD42016050704) and the reporting follows the PRISMA guidelines.2 In October 2016, we searched MEDLINE, PsycINFO, Embase and CINAHL for observational studies meeting the inclusion criteria (see protocol for further details). Grey literature was assessed using the EThOS library. Three authors independently performed study screening, data extraction and quality assessment, using a modified Joanna Briggs Institute (JBI) critical appraisal tool.3 Disagreements were resolved by discussion. We identified a total of 1025 records. Of these, 47 full‐text articles were assessed for eligibility. We included 13 studies in the review and 12 in the meta‐analyses (Appendix S1; see Supporting Information), and one study that used the Skindex‐29 was described narratively as its score could not be converted to calibrate with the other QoL tools.4 Meta‐analysis was conducted using a random‐effects model, determining the pooled standardized mean difference (SMD) for the QoL score in people with vitiligo compared with those without vitiligo (healthy controls or other skin conditions). Subgroup analyses were conducted to explore heterogeneity. All studies were hospital based and sample size ranged from 16 to 1010 people with vitiligo. QoL was mainly assessed with dermatology‐specific tools. Only three studies were deemed to be high quality, scoring between 5 and 7 on the JBI tool.3 The main reason for poor quality was lack of comparability between the vitiligo and control groups in terms of age and sex. There was only one study that reported the presence of associated autoimmune conditions. (Further details about the studies included and their quality are available on request from the author). The meta‐analysis included 1799 people with vitiligo; the results are shown in Figure 1. In the meta‐analyses comparing vitiligo with healthy controls and people with psoriasis (Fig. 1a, b), all the SMDs are on one side of the forest plot therefore showing all the studies have an effect in the same direction for (a) and (b) separately. However, in Figure 1(c, d) not all the SMDs are on the same side, therefore it is uncertain which group has the better QoL, and this greatly limits these results and is reflected in the overall confidence interval (CI) crossing zero. Forest plot for meta‐analysis of quality of life (QoL) scores in vitiligo compared with (a) healthy controls, (b) psoriasis, (c) atopic dermatitis and (d) acne. If the standardized mean difference (SMD) and confidence intervals (CIs) are to the left of the zero line it indicates that QoL is worse in the control. If the SMD and CIs are to the right of the zero line it indicates worse QoL in people with vitiligo. Appendix S1 contains details of the studies cited in this figure (see Supporting Information). Subgroup analyses on age, sex, quality score and region could not explain the heterogeneity seen, but the small number of studies limited this analysis. The study4 that was analysed narratively suggests patients with vitiligo are highly affected in the emotional and functional subscales, with sex differences. The mean Skindex‐29 for patients with vitiligo was not statistically significantly different from that of people with mild dermatology conditions such as localized eczematous dermatitis (30·7 vs. 27·4, P = 0·18). This review demonstrates QoL impairment in patients with vitiligo compared with healthy controls, thus emphasizing the importance of assessing QoL in consultations, as recommended by the British Association of Dermatologists.5 Patients with vitiligo exhibited less QoL impairment than patients with psoriasis. These results are unsurprising given the severity of physical symptoms that may be associated with psoriasis.6 The comparisons with acne and atopic dermatitis were inconclusive as there were few included studies and they gave different results. Meta‐analyses allowed a pooled SMD to be calculated for studies that used different QoL measurement tools. However, the review is limited by high heterogeneity because of methodological and clinical differences between the studies, and this could not be explained by the factors we were able to extract data for. There has been substantial research conducted that shows specific subgroups of people with vitiligo are more likely to have loss of QoL, for example those with darker skin or from southern Asian cultures.7,8 The main methodological limitation was the use of the Dermatology Life Quality Index (DLQI) in healthy controls in five studies, as it is a dermatology‐specific tool and may not be valid for healthy controls. Also, given the asymptomatic nature of vitiligo, the DLQI may not be as sensitive as vitiligo‐specific QoL tools, thus underestimating the impact vitiligo has on QoL. Future research implications include using a valid QoL measurement tool for vitiligo, or a combination of tools should be applied. Population‐based studies with appropriate controls are needed in this area to improve external validity and provide more accurate results. Funding sources: none. Conflicts of interest: none declared. Appendix S1 Details of studies included in the meta‐analysis.