Using the Dermatology Index of Disease Severity (DIDS) to assess the responsiveness of dermatitis

Background. The Dermatology Index of Disease Severity (DIDS) is designed as an instrument for staging severity of inflammatory dermatoses. It measures the therapeutic effectiveness and magnitude of clinical improvement in several types of dermatitis, eczema and psoriasis. When used in the Psoriasis Outcomes Study, it was simpler and easier than the Psoriasis Area and Severity Index. The reliability and validity of DIDS have already been established in our previous study. Aim. To test the responsiveness of the DIDS in patients with various types of dermatitis following treatment. Methods. The DIDS was used to stage patients with dermatitis over time. In total, 142 patients with dermatitis were enrolled into the study. Only 55 patients completed the follow-ups on days 30 or 60, thus the data from these 55 patients only were analysed. The Wilcoxon signed rank test for paired comparisons was used to test for significance of shift in the individual's DIDS staging over the time period. Results. 35 patients were seen on or close to day 30 after the initial visit, of whom 34 patients (76%) had an improvement of at least one stage on DIDS. There were 51 patients seen at or close to day 60, of whom 40 patients (78%) had an improvement of at least one stage on DIDS. The remaining 22-24% of patients did not improve, but neither did they worsen. The joint shift of each individual's DIDS staging from baseline to follow-up was statistically significant (P < 10(-5), two-sided t-test). Conclusion. The results of this study support the responsiveness of the DIDS for tracking severity of disease over time in patients with various types of dermatitis.