Hysterectomy for benign indications and risk of pelvic organ fistula disease.

OBJECTIVE

To study the association between hysterectomy for benign indications and pelvic organ fistula disease.

METHODS

We conducted a nationwide cohort study based on Swedish health care registers. The cohort consisted of 182,641 women having hysterectomy (exposed cohort) and 525,826 women not undergoing the procedure (unexposed cohort) from the Swedish Inpatient Register 1973-2003. The outcome was defined as surgery for pelvic organ fistula disease. We calculated incidence rates for fistula disease and hazard ratios (HRs) with 95% confidence intervals (CIs) as a measure of relative risk.

RESULTS

We identified 853 cases of pelvic organ fistula surgery: 469 among the exposed women and 384 among the unexposed. The overall rate of fistula surgery was four times higher in the exposed compared with the unexposed cohort (rate 23.8 and 6.3 per 100,000 person-years, respectively). Overall number needed to harm was 5,700. Compared with unexposed, the risk for fistula disease was more than 20 times higher the first year after surgery (HR 21.2, 95% CI 14.9-30.2). The most common type of fistula was intestinogenital fistula (404 cases, 47%), followed by urogenital fistula (220 cases, 26%). Laparoscopic hysterectomy was associated with the highest rate of fistula surgery, and subtotal abdominal hysterectomy was associated with the lowest (rate 95.9 and 13.7 per 100,000 person-years, respectively).

CONCLUSION

Pelvic organ fistula surgery is four times more common in women after hysterectomy compared with women not having the procedure. The highest fistula rates were observed the first year after surgery, after laparoscopic and total abdominal hysterectomy, and among older women.

LEVEL OF EVIDENCE

II.