#2247 Influence of the diagnosis of atopic dermatitis in childhood on the course of kidney function in young adulthood: a single-center study
Authors: Wiegand Sarah , Wagner Andreas , Hornung Roman , Fischereder Michael 
Published: May 2024

Abstract

Background and Aims
Several studies demonstrated non-osmotic sodium-storage, especially in the skin. Patients with chronic kidney disease often suffer from skin symptoms and furthermore an association of advanced CKD-stages with inflammatory skin diseases has been shown. Additionally, in inflammatory skin disease atopic dermatitis an increased salt content was found in the affected skin areas. Thus we hypothesized that atopic dermatitis might have a detrimental effect on kidney function later in life.

Method
The retrospective case-control study using the patient files of a general medical practice included a randomly selected sample with a 2:1 matching technique. Initially, data of 114 patients who underwent J1-screening exam for adolescents (age 12-14) and also a follow-up examination in adulthood (over the age of 18) between January 1980 and April 2022 have been examined. By the time of inclusion they had to be over 18 years old and did not suffer knowingly from a kidney disease. Over the course of the study, patients for whom no creatinine value was recorded during the following examinations were excluded. Serum creatinine levels and eGFR were compared between the two groups at two assessment times (J1 in adolescence and Follow-Up in young adulthood) and within each group using a one-tailed t-test. A point-biserial correlation analysis was then performed.

Results
Biometric characteristics, gender distribution and kidney function for J1 as the first measurement point and for follow-up in young adulthood as the second one for both atopic dermatitis and control group are shown in Table 1. The statistical analysis showed that the two groups did not differ significantly in terms of gender distribution at both the first (X²(89) = 0.4918, p = 0.483103) and the second measuring point (X²(73) = 0.45, p = 0.50), therefore a gender bias in the results is unlikely. Furthermore, it was shown by a one-tailed, unpaired t-test for serum creatinine levels ​​at time J1 did not differ from those in the control group (t = 0.60, p = 0.28). This applies too for the corresponding eGFR according to Schwartz-Bedside (t = -0.47, p = 0.32). At the time of follow-up, 16 patients, 8 per group, were excluded due to a lack of creatinine values ​​- in this study using a hypothesis test, no significant difference in the creatinine values ​​was found between the two groups (t = 0.91, p = 0.18), consequently also not in the comparison of eGFR after CKD-Epi (t = -1.28, p = 0.10). Only when comparing creatinine values ​​and eGFR over time within the individual groups, a significant difference for each group was found. In the atopic dermatitis group, the creatinine levels and the eGFR differed significantly in between J1 and the follow-up examination (creatinin: t = 4.29, p = 0.00015, eGFR: t = 1.83, p = 0.042). Likewise did the creatinine levels and the eGFR differ significantly over time in the control group (creatinine: t = 4.77, p &lt; 0.00001 and eGFR: t = 5.72, p &lt; 0.0001). In the point-biserial correlation analysis, no connection between the presence of atopic dermatitis and the level of the serum creatinine value could be confirmed (t = 0.6, df = 89, p = 0.55, 95% CI [-0.14, 0.27], r = 0.063).

Conclusion
In our study, the diagnosis of atopic dermatitis in childhood does not seem to be a determinant risk factor for a decline in kidney function in young adulthood.