# Sitz bath with different concentrations of diluted povidone-iodine for prevention of perianal infection in patients with hematological malignancies undergoing chemotherapy: a randomized controlled trial in a tertiary hospital in China

## TL;DR

This study found that sitz baths with diluted povidone-iodine can reduce perianal infections in cancer patients undergoing chemotherapy, with lower concentrations causing fewer side effects.

## Contribution

The study evaluates the effectiveness of different povidone-iodine concentrations in sitz baths for preventing perianal infections in chemotherapy patients.

## Key findings

- Both 1:50 and 1:200 povidone-iodine sitz baths reduced infection incidence compared to routine care.
- The 1:200 dilution caused fewer adverse reactions than the 1:50 dilution.
- Perianal infection severity was significantly lower in the intervention groups.

## Abstract

The incidence of perianal infection in patients with hematologic malignancies undergoing chemotherapy can reach 40–50%. Despite advances in medical technology and improved management strategies, the rate of perianal infection following chemotherapy remains substantial. Currently medicated sitz baths are not widely adopted in clinical practice due to their side effects and limited applicability. Povidone-iodine (PI) is a commonly used clinical broad-spectrum antiseptic, yet its efficacy in preventing perianal infection has not been adequately studied. Therefore, we aimed to evaluate the effect of different concentrations of diluted povidone-iodine in sitz baths on the incidence and severity of perianal infection, and to determine an appropriate concentration that minimizes adverse reactions.

We recruited 180 patients from the Department of Hematology, West China Hospital, Sichuan University, between May 2021 and May 2023. Eligible patients received 14 days of perianal care consisting of either routine cleaning alone or routine cleaning plus sitz baths with povidone-iodine solution. They were randomly assigned to a control group (routine perianal cleaning and care, n = 60), a low-concentration intervention group (sitz bath with 1:200-diluted povidone-iodine, n = 59), and a high-concentration intervention group (sitz bath with 1:50-diluted povidone-iodine, n = 61).

A total of 171 patients aged 18–80 years undergoing chemotherapy for hematologic malignancies were included. The incidence of perianal infection significantly differed between the control group and both intervention groups with different concentrations (OR = 0.144, ARR = 0.221, 95% CI 0.038–0.054, P = 0.004; OR = 0.178, ARR = 0.197, 95% CI 0.053–0.590, P = 0.005). Compared with the control group (n = 60), the risk of perianal infection was reduced by 22.1% in the low-concentration group (n = 54) and by 19.7% in the high-concentration group (n = 57). No significant difference in infection incidence was observed between the two intervention groups (P > 0.05). The severity of perianal infection differed significantly between the intervention and control groups (P < 0.001). The risk of adverse reactions was 4.7 times higher in the high-concentration group than that in the low-concentration group (P = 0.001).

Both 1:50- and 1:200-diluted povidone-iodine sitz baths are more effective than routine care in preventing perianal infections and can effectively reduce both the incidence and severity of perianal infections. However, the 1:50 dilution was associated with more perianal adverse events (AEs) compared with the 1:200 dilution.

It was registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR 2000041073) on December 17, 2020.