#3689 RELATIONSHIP BETWEEN STAPHYLOCOCCUS AUREUS NASAL CARRIAGE AND URAEMIC PRURITUS IN HAEMODIALYSIS PATIENTS AND ITS INFLUENCE ON INFECTION
Authors: Wu Hon-Yen , Tsai Ping-Hsiu , Hsu Shih-Ping , Liao Chun-Hsing , Ko Mei-Ju 
Published: June 2023

Abstract

Background and Aims
Uraemic pruritus is a common and distressing comorbid disease among patients undergoing haemodialysis (HD). The aetiology of uraemic pruritus is multifactorial and not fully understood. The role of skin microbiota in chronic inflammatory skin disease has long been discussed, but evidence regarding the relationship between uraemic pruritus and Staphylococcus aureus (SA) colonization is limited. The rate of SA nasal carriage in HD patients was more than double that of healthy individuals, and the phage type of SA infection was often the same as the type of SA carried in the HD patients' nares. SA colonization is associated with greater skin barrier disruption, which suggests a possibility to increase the risk of infection in patients with uraemic pruritus. This study aimed to assess the role of SA nasal carriage in uraemic pruritus, as well as the interplay among SA colonization, uraemic pruritus, and SA infection in HD patients.

Method
We conducted a prospective cohort study to enrol adult HD patients in the Far Eastern Memorial Hospital, a tertiary medical centre in Taiwan, in April 2019. Eligible patients should had received maintenance HD for more than three months. Patients were excluded if they had active infection or primary skin diseases. The intensity of uraemic pruritus was assessed using a visual analogue scale (VAS) from 0 to 10 (0 = no pruritus, 10 = the worst pruritus imaginable). Nasal swab culture was performed to examine the status of SA nasal carriage. Patients were followed until SA infection, death, or January 2020, whichever had occurred earlier. The definition of SA infection should fulfil both the clinical diagnosis and the results of microbiological culture. Multivariate linear regression models were used to assess the potential predictors for a higher pruritus intensity. Multivariate Cox proportional hazard models were used to analyse the risk of SA nasal carriage on SA infection among the HD patients.

Results
A total of 100 HD patients were enrolled, the mean age was 61.7 years and 69% were men. The mean dialysis vintage was 6.7 years. Among the participants, 55% had uraemic pruritus and the mean VAS score of pruritus intensity was 4.0. The prevalence of SA nasal carriage was higher in patients with uraemic pruritus than that in patients without uraemic pruritus (33% vs 13%, P = 0.024). The multivariate linear regression model showed that SA nasal carriage was an independent predictor of a higher VAS score of pruritus intensity (parameter estimate, 1.18; 95% CI 0.05-2.30; P = 0.04) (Table 1). After follow-up for 10 months, there were four SA infection events in the pruritus patients and one event in the non-pruritus patients. The multivariate Cox proportional hazard model showed that patients with SA nasal carriage had a borderline higher risk for SA infection (adjusted hazard ratio, 50.9; 95% CI, 0.62-3689; P = 0.08) (Table 2).

Conclusion
SA nasal carriage is independently associated with uraemic pruritus, and is also an independent predictor for a higher pruritus intensity among HD patients. Moreover, SA colonization might predict SA infection in later follow-up period. This study provide evidence for future studies regarding the survey for SA colonization and application of nasal decolonization among HD patients with uraemic pruritus.