The burden of atopic dermatitis & the art of systematic reviews

This dissertation includes four chapters on the burden of atopic dermatitis (part I), and four on systematic reviews (part II). Part I – The burden of atopic dermatitis Atopic dermatitis, also called atopic eczema (AE), is a common chronic skin disease. Its burden ranks fifteenth worldwide for nonfatal diseases. Burdens addressed in these chapters: symptoms, quality of life, mood, economic burden, emotional consequences, and food choices. In chapter 2 we assessed the burden of 1189 adults with more severe AE in nine EU countries. Despite current treatment, 45% still had moderate to very severe AE assessed with the Patient-Oriented Eczema Measure. The Dermatology Life Quality Index showed moderate to extremely large impairment in 55%. On the Hospital Anxiety and Depression Scale, 10% scored on or above the threshold of eight points with signs of depressive symptoms. In chapter 3 we analysed the economic burden. The mean extra spending was €927 per patient per year for healthcare. In German participants, mean costs were higher than German adults with psoriasis or rheumatoid arthritis. Chapter 4 reported on the emotional consequences of AE. We developed a 28-item patient reported questionnaire: the Atopic Eczema Score of Emotional Consequences. More than half of the 1189 respondents were emotionally burdened. Large to very large emotional consequences were reported by 43.8% of those with currently moderate AE, 62.2% with severe AE, and 66.7% with very severe AE. In chapter 5 we addressed the differences in diet and nutritional intake between adults with and without AD. Data were available of 428 respondents (AD 240; control 188). Of those with AD, 66.3% reported that food influenced AD severity; 7.9% of them followed a cow’s milk protein free diet, versus 1.6% of controls. Part II -The art of systematic reviews This dissertation contains four systematic reviews: one on an intervention, one on outcome measures, and two on the methodological quality of clinical practice guidelines (CPGs). Chapter 6 is regarding a systematic review to assess the efficacy and safety of the use of moisturizers in eczema. We included 77 randomized controlled trials. The quality of the evidence was mainly low or moderate. With moisturizers fewer flares were seen, rate of flares was reduced, and topical treatment was more effective. No differences in adverse events were observed. Chapter 7 described a systematic review to identify and appraise a validated Patient Reported Outcome Measure on patient satisfaction in acne treatment. Only one study could be included, and this outcome measure was assessed as inadequate. Additionally, we analysed the methods of 188 studies having measured treatment satisfaction. Chapters 8 and 9 are part of the Global Guidelines in Dermatology Mapping Project (GUIDEMAP), with the aim to assess the methodological quality of CPGs on the 12 most burdensome skin diseases. We did this for AD (chapter 8) and contact dermatitis (CD; chapter 9). Chapter 8 reported on forty AD CPGs, mostly from countries with a high sociodemographic index. The reported quality varied enormously. Three CPGs scored ‘Excellent’ on all domains of the Appraisal of Guidelines for Research and Evaluation (AGREEII) Reporting Checklist. Three CPGs scored ‘Poor’ on all domains. We found no association between AGREEII-scores and a country’s gross domestic product. Overall, many CPGs for AD are not clear, unbiased, trustworthy or evidence based enough and lack applicability. In Chapter 9 we reported on twenty-three CPGs for CD, predominantly from countries with a high sociodemographic index. Three CPGs scored ‘Excellent’ on all six domains of AGREEII and one CPG scored ‘Poor’ on all domains. Areas that require improvement were ‘Strength and wording of recommendations’, ‘Applicability,’ ‘Update dates’, and ‘External review’.