Rosacea is a chronic skin disease that can also damage the eyes. It typically occurs in middle-aged and older adults with fair skin, especially women. Symptoms include redness, papules, and pustules, and in some patients, thickening and fibrosis of the skin, known as phyma.1

Rosacea negatively impacts the patients’ quality of life and mental health due to the presence of erythema and facial lesions that severely alter self-image and self-esteem.2,3

Health-related quality of life (HRQoL) measurement tools aim to objectively evaluate how a certain disease affects the life of an individual. These questionnaires offer insights into the impact of the disease on overall quality of life or specific areas, such as functionality, emotions, etc.4.

HRQoL measurement can be done in 2 ways: using generic instruments that assess quality of life globally, such as the SF-12 questionnaire,5 and specific instruments to deal with problems associated with particular disorders, patient types, or functional areas,6,7 such as the Dermatology Life Quality Index [DLQI]8 or the SKINDEX-29,9 both validated in Spanish language).

The SF-12 scale, widely used in research, has been associated with specific scales such as the DLQI in atopic dermatitis.10 However, these generic scales may not adequately capture the impact of certain diseases like rosacea. The Rosacea Quality of Life (RosaQoL) scale—which is specific to rosacea—is available in English and measures the impact of its symptoms on quality of life, being more precise than generalist scales.11 Having a validated tool in Spanish will allow for assessing the impact on the patient's quality of life, and individualizing treatment effectively.4,5

The objectives of this study are: 1) to validate and culturally adapt the RosaQoL scale into Spanish and 2) to analyze the correlation between the RosaQoL scale and the SF-12 scale.

The translated RosaQoL questionnaire (Table 1) was submitted to 531 participants with a mean age of 47 years (SD, 13.4 [95%CI, 45.8-48.1]), 71 of whom (n=369) were women and 29% (n=151), men. Among those with rosacea, the papulopustular type was the most common, representing 65.9% of the cases.

According to the IGA scale, IGA grade 2 was the most common one found in 44.4% of the cases (Table 2).

Statistically significant differences were reported between men and women in the overall score of the RosaQoL questionnaire, as well as in each of the 3 dimensions of the scale (symptoms, functionality, and emotional state; p <0.001) (Table 3), although these differences were non statistically significant when analyzed by age (Table 4).

No significant differences were found in the RosaQoL score between the control group (healthy patients [n=50], mean overall score, 43.5 [SD, 13.7]) and the patient group ([n=468], mean overall score, 47.3 [SD, 13.3]; p=0.052).

Similarly, the score obtained in RosaQoL was higher in more severe grades of rosacea, with a greater impact being reported in the symptomatology dimension (Figure 1).

Figure 1.

Impact of various RosaQoL dimensions based on the severity of rosacea measured by IGA. Significant p-values for all dimensions (p=0.0000 for all dimensions except for the functional dimension where p=0.00631). V0: initial visit.

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The internal consistency method, based on Cronbach's alpha, estimates the reliability of a measurement instrument through a set of items expected to measure the same construct or theoretical dimension. Cronbach's alpha value evaluated across all questionnaires was 0.96, which is consistent with the general criterion recommended by George and Mallery21, where values > 0.9 are indicative of high internal consistency.

When each item was individually removed from the scale, no improvement in Cronbach's alpha was obtained. Therefore, it is established that no item is prone to elimination. The questionnaire statistical power to discriminate cases using the ROC curve yielded an area under the curve (AUC) of 0.96 (95%CI, 0.92-0.99). Considering that values > 0.9 indicate high discriminative power, we can say that the questionnaire has a high capacity to detect cases.

The evaluation of sensitivity and specificity using Youden's criterion yielded a cutoff in the RosaQoL score > 1.476, thusproviding the questionnaire with high sensitivity, with a value of 0.99, and a specificity to detect cases of 0.85. For this cutoff, 425 true positives, 43 true negatives, 7 false positives, and 3 false negatives were reported.

The Varimax rotated component matrix for 3 factors contributes to the validation of the scale construct, showing that items tend to group into the functional, emotional, and symptomatic factors proposed in the original scale26 (Table 5).

All the items of the questionnaire are categorized as in the original questionnaire, except for slight discrepancies in 4 of them. Item #11 “I am bothered by the look of my skin (redness, spots)” and item #14 “I am bothered by the persistence/recurrence of my rosacea,” which in the original scale are grouped in the emotional dimension and seem to have a slightly more specific weight in the symptomatic dimension in the Spanish version. Although item #16 “My skin looks bumpy (uneven, not smooth, irregular)” should be represented in the symptomatic dimension, it is somehow better represented in the emotional one. Finally, although item #19 “My eyes bother me (I can feel how dry or gritty they are),” should be better represented in the symptomatic dimension, it was better represented in the functional one. Since the specific weight difference of these 4 items was minimal, we decided to maintain the original dimension classification for comparative evaluation purposes with other versions of the scale.

When analyzing the correlation between the RosaQoL scale and the more generalist SF-12 scale, most studied correlations were statistically significant and entirely negative. A higher score on the RosaQoL scale in any dimension (whether functional, emotional, or symptomatic) is associated with a worse quality of life in all dimensions of the SF-12 scale (Table 6).

The temporal reliability of the questionnaire was confirmed through the test-retest method, as no discrepancies were detected over time between patients’ responses.

To evaluate sensitivity to change, a follow-up visit was conducted 3 months after the start of the study, when rosacea patients were asked to complete both the RosaQoL and SF-12 questionnaires again. In most calculated correlations, a statistically significant negative correlation was reported. A greater increase in the RosaQoL scale and all its dimensions (functional, emotional, and symptomatic) was associated with a worse progression of quality of life in all dimensions of the SF-12 scale. This same correlation was also seen when analyzed by age group and disease severity.

To consider a scale valid as an instrument for measuring HRQoL, a simple translation is not sufficient; rather, a series of structured and guided steps are necessary.13 To make sure that the reliability and validity requirements of such tools are met, the measurement properties of the translated version in a population need to be evaluated with similar characteristics and then submitted to a validation process.25

The study of measurement properties demonstrates that the Spanish-translated and culturally adapted version of the RosaQoL questionnaire allows us, like the original version, to obtain statistically significant differences between the healthy population and the population with rosacea. The level of impact on the RosaQoL scale in all dimensions was directly proportional to the severity of rosacea, with the highest degree of impact being reported in the symptomatology dimension.

Nicholson et al.11 highlighted the validity of RosaQoL in discriminating rosacea patients vs the SKINDEX-29. In its original version, the specific RosaQoL scale showed a higher response level at 4-6 months vs the SKINDEX-29 for the total score in patients reporting improvement in their rosacea, showing greater specificity.

The reliability study of the RosaQoL questionnaire demonstrates that the tool has a high degree of internal consistency, obtaining a Cronbach's alpha value of 0.96, and that its discriminative power to detect cases is extremely high, obtaining a ROC AUC score of 0.96.

Reproducibility is one of the important points we should consider when evaluating a tool for measuring HRQoL. To assess reproducibility, it is checked whether similar scores can be obtained when applied in 2 different points in time to the same population by the same evaluators using the exact same method. Since it is important to avoid the “learning effect,” the time between the initial test and the retest should not be too long.27 In our study, the score obtained with the RosaQoL questionnaire does not vary significantly between the test and retest results of the same patient (interval of 1 to 2 days). Our test-retest results show a very high correlation between both tests in the 3 dimensions of the questionnaire, indicating a high degree of reliability.

The construct validity study through factor analysis showed that the items of the RosaQoL scale tend to group based on the functional, emotional, and symptomatic dimensions, as in the original version of the scale, and that the items that make up each one of them tend to group consistently in each dimension.

Our study also analyzed the convergence (“correlation”) between the RosaQoL scale and the more generalist SF-12 scale and found that it was positive, evidencing that the scales are conceptually congruent or similar:25 higher increases in the RosaQoL scale and all its sub-dimensions (functional, emotional, and symptomatic) were associated with worse quality of life in all dimensions of the SF-12 scale.

The RosaQoL scale, adapted to Spanish, has proven to be a valid, sensitive, and reliable tool for measuring quality of life, in all its dimensions (symptoms, functionality, and emotional state) among the Spanish population with rosacea. Results indicate that the greater the severity of rosacea, the greater the impact on quality of life, with the dimensions of symptomatology and emotional state being the most affected ones, especially in women.

This project has received funding and support from Laboratorios Galderma S.A.U. Dr. Salleras and Dr. Pozo declared no conflicts of interest whatsoever. Dr. Ribera received grants and fees related to research, consulting, and training from the following companies: AbbVie, Almirall, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Galderma, Gebro Pharma, Janssen, LEO Pharma, Eli Lilly, Novartis, Pfizer, Pierre-Fabre, Sandoz, SKB, and UCB.