The Effectivity of pH 4 Emulsion on Skin Barrier Function in The Elderly: A Systematic review and meta-analysis

Abstract

Background: The pH of the skin surface is elevated in the elderly therefore it may cause impaired barrier function manifest as various cutaneous abnormalities, including xerosis, pruritus, dermatitis, and skin infections. Consequently, skin care products for the elderly should contain moisturizing ingredients which are formulated to normalize the skin surface pH. Application of pH 4 emulsion is potentially beneficial to improve barrier function in the elderly and promoting skin health. We aimed to determine the difference of effectiveness of pH 4 emulsion compared to identical non pH 4 emulsion on decreasing TEWL in the elderly. A systematic review and meta-analysis was performed of randomized clinical trials assessing the effects of pH 4 emulsion on skin barrier function in the elderly. Methods: Medline Pubmed, Scopus, ProQuest, Cochrane library, ClinicalTrials.gov, the reference list, conference proceedings, researchers in the field of eligible studies were searched. Four studies (n=98 subjects) were included in qualitative analysis of which two studies (n=45 subjects) were included in the meta-analysis. The mean age of the participants was 71.1 years old. Interventions use the application of pH 4 water in oil emulsion (n=2) and pH 4 oil in water emulsion (n=2). Duration of intervention (24 hours-7 weeks) and outcomes of interest varied among included studies. Results: Pooling of data using random-effects model found lower TEWL score in the pH 4 emulsion than in non pH 4 emulsion, with no significant difference (overall effect mean difference -0.068, 95% confidence interval -0.485 – 0.348, p = 0.11, I2=60.1, two RCTs). In addition to that, the qualitative analysis found that the application of pH 4 emulsion increased stratum corneum hydration, decreased skin surface roughness and scaliness, decreased DASI, and improved ICLL length and lamellar organization. Conclusion: The meta-analysis result of the mean differences of TEWL scores lowering effect between pH 4 emulsion and non pH 4 emulsion is statistically inconclusive. This is despite the observation that the pH 4 emulsion appears to be more effective comparatively. The qualitative analysis found that the application of pH 4 emulsion had improved skin barrier function in the elderly. Larger scale, well-designed RCTs assessing the effects of pH 4 emulsion on skin barrier function in the elderly, are still needed.