Assessment of Frequency of Rosacea Subtypes in Patients With Rosacea: A Systematic Review and Meta-analysis

Importance: Four distinct rosacea subtypes have traditionally been recognized, but the frequency of these subtypes among patients with rosacea remains unknown. Objective: To assess the frequency of 4 rosacea subtypes. Data sources: This systemic review and meta-analysis included a search of 2 databases, PubMed and Embase, from inception of the databases to November 2, 2021. The search was filtered to include only studies of human participants published in English, French, and German. Study selection: Studies were screened independently by 2 of the authors and were included if they were original with a sample size of 25 or more patients and reported absolute numbers or frequency of patients affected by rosacea subtypes. Studies that did not report sufficient data to calculate the proportions of subtypes were excluded. Data extraction and synthesis: Data extraction was performed independently and in duplicate by 2 of the authors, using the search term rosacea, according to the Preferred Reporting items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The search term, objectives, and study protocol methods were defined before the study was initiated. A total of 292 studies were included for full-text assessment. Owing to the heterogeneity of the included studies, a random-effects model was used. Main outcome and measures: The main outcome was the proportion of patients with rosacea in each of the 4 major subtype groups defined by the 2002 National Rosacea Society classification system. Measures were absolute numbers or frequency of patients affected by each of the 4 rosacea subtypes. Results: A total of 39 studies examining 9190 patients with rosacea were included. The pooled proportion of erythematotelangiectatic rosacea was 56.7% (95% CI, 51.4%-62.0%), of papulopustular rosacea was 43.2% (95% CI, 38.8%-47.6%), of phymatous rosacea was 7.4% (95% CI, 6.1%-8.9%), and of ocular rosacea was 11.1% (95% CI, 6.7%-16.3%). Subtype distribution occurred equally among men and women except for phymatous rosacea, which was more prevalent in men. Studies from Africa showed the lowest proportion of erythematotelangiectatic rosacea. Differences in frequency of subtypes were observed when stratification by publication year was performed. Conclusion and relevance: In this systematic review and meta-analysis, differences were found in rosacea subtypes by patient sex and by continent of origin and publication year of included studies. Erythematotelangiectatic and papulopustular rosacea were the most prevalent subtypes, but data should be interpreted with caution. Future studies should use the phenotype-based rosacea approach