This study was designed to determine factors that contribute to chronic anal fistula or recurrent sepsis after initial perianal abscess.A retrospective cohort study was conducted in patients with a first-time perianal abscess who were treated at Kaiser Permanente Los Angeles between 1995 and 2007. Univariate and multivariable analyses were performed with the Cox proportional hazards model to determine predictors of risk for recurrent disease.One hundred and forty-eight patients met inclusion criteria (105 men, 43 women; mean age, 43.6 years). During a mean follow-up of 38 months, the cumulative incidence of chronic anal fistula or recurrent sepsis was 36.5 percent. Univariate and multivariable analyses showed more than two-fold increased risk of recurrence in patients <40 years vs. those >/=40 years (P < 0.01), and univariate analysis showed nondiabetics were 2.69 times as likely to experience recurrence as diabetics (P = 0.04). No significant differences in risk of recurrence were noted for men vs. women (HR = 0.78; P = 0.39), nonsmokers vs. smokers (HR = 1.17; P = 0.58); perioperative antibiotics vs. no antibiotics (HR = 1.51; P = 0.19); or HIV-positive vs. HIV- negative status (HR = 0.72; P = 0.44).Age younger than 40 years significantly increased risk of chronic anal fistula or recurrent anal sepsis after a first-time episode of perianal abscess. Patients with diabetes may have a decreased risk compared with nondiabetic patients. Gender, smoking history, perioperative antibiotic treatment, and HIV status were not risk factors for chronic anal fistula or recurrent anal sepsis.