Restricted Cubic Spline Model Analysis of the Association between Anal Fistula and Anorectal Abscess incidence and Body Mass Index

Abstract

Background The epidemiological profile of anal fistula and anorectal abscess has not been well studied. Based on the results of a retrospective cross-sectional survey, we aimed to investigate the potential influential factors associated with anal fistula and anorectal abscess. Methods We conducted a retrospective analysis of patients between January 2017 and May 2022. A comprehensive questionnaire was designed to collect potential influential factors, all the participants were divided into patients with anal fistula or perianal abscess and healthy control group. Multiple logistic regression was used to identify factors in significant association with anal fistula and perianal abscess. Additionally, we combined restricted cubic spline regression to examine the dose-response relationship between factors and the risk of developing anal fistula or anorectal abscess. Results The present study included 1223 participants, with 275 anal fistulas, 184 anorectal abscesses, and 765 healthy controls. We found no statistically significant differences between patients and controls in basic information and preoperative assessment of life factors, except for body mass index. It was indicated that people with overweight or obesity were more prone to anal fistula or anorectal abscess than normal-weight individuals. The dose-response research indicated the J-shaped trend between the ascending BMI levels and the higher risk of suffering from anal fistula and anorectal abscess. Conclusions Our findings indicate that overweight and obesity are risk factors for anal fistula and anorectal abscess, which plays a role in the prevention of anorectal diseases. This provides some theoretical basis for clinicians to provide health education to their patients.

Causal relationship between obesity and anorectal abscess: a Mendelian randomization study

“…In addition, obesity is a recognized risk factor for the development of comorbid conditions such as cardiovascular disease, type 2 diabetes mellitus, malignancy, asthma, osteoarthritis, chronic back pain, obstructive sleep apnoea, non-alcoholic fatty liver disease, and gallbladder diseases (25). Anorectal abscess (ARB) is a suppurative infection resulting from the obstruction of anal glands (35). Clinical manifestations include perianal redness, swelling, pain, and sometimes systemic symptoms such as fever and chills.…”

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“…Studies in European populations have noted a higher prevalence of ARB among obese individuals compared to the general population, along with a notable increase in ARB recurrence rates among obese patients over time (2). Additionally, a retrospective study conducted in Asia indicated that the risk of perianorectal abscesses progressively increased with rising BMI (35). These observational studies demonstrate a clear association between obesity and ARB.…”

“…Long-term systemic inflammation in obese patients can weaken immunity and reduce the capability of immune cells to eliminate bacteria, thus elevating the risk of bacterial infections and potentially leading to ARB. Additionally, obese patients often exhibit abnormal lipid and glucose metabolism; high blood sugar and lipid levels can predispose the anal sinuses and glands to infections, which may progress to abscesses as pus moves from the anal glands to the intersphincteric space (35).…”

“…In addition, obesity is a recognized risk factor for the development of comorbid conditions such as cardiovascular disease, type 2 diabetes mellitus, malignancy, asthma, osteoarthritis, chronic back pain, obstructive sleep apnoea, non-alcoholic fatty liver disease, and gallbladder diseases (25). Anorectal abscess (ARB) is a suppurative infection resulting from the obstruction of anal glands (35). Clinical manifestations include perianal redness, swelling, pain, and sometimes systemic symptoms such as fever and chills.…”

“…A retrospective study observed that the risk of ARB was 2.24 times higher in obese patients, and exhibited a J-shaped trend between elevated BMI levels and increased ARB risk (35). Additionally, a study involving 18,877 patients with perianal abscesses from 1997 to 2009 revealed that the ratio between the prevalence of obesity in patients with ARB and the prevalence of the same in the normal population was 1.59 (2).…”