In this national database of privately insured individuals from 2000 to 2009, there were a total of 32.9 million women aged 18 to 64 years. Of these women, 168,844 underwent one or more SUI procedures, and for each of these women, we identified their first SUI surgery. Among 155,458 women who met our inclusion criteria, the median age of women who underwent an index SUI surgery was 49 years (interquartile range 43–56, range 18– 64). depicts the SUI surgery type-specific details regarding age, region, and calendar year in which the surgery was performed. Patients who had a Burch were nearly 2 years older, on average, than those who had a sling (median age 47.1 compared with 49.0 years). The median year of the index procedure was 2007 (interquartile range 2005–2008). The median length of follow-up after the index procedure was 1.3 years (interquartile range 0.5–2.7 years, range 0–9.75 years), which represented a total of 294,855 person-years. The median length of follow-up was not longer because the database includes many more individuals in recent years and, thus, the majority of SUI surgeries included in the analysis occurred during those years. For example, 3.7 million individuals were in the database in 2000 compared with 40.0 million in 2009. Thus, the opportunity to follow up women before administrative censoring on December 31, 2009, was shortened and this decreased the overall median length of follow-up. The cumulative incidence of repeat SUI surgery for all types of surgery at 9 years of follow-up was 14.5% (95% CI 13.4–15.5). The type of repeat surgery performed was sling (70.5%) followed by bulking agents (20.1%), Burch (6.5%), laparoscopic (1.5%), needle (0.8%), total vaginal hysterectomy (0.5%), and Kelly (0.2%). depicts the rate of repeat surgery for each year after the index surgery, stratified by type of index procedure. As expected, bulking agents had the highest incidence of repeat surgery followed by needle suspension; the Burch procedure had the lowest incidence, which was 10.8% (95% CI 9.3–12.3) at 9 years of follow-up. Kaplan-Meier survival curves depict the cumulative proportion of patients who underwent repeat SUI surgery over time and accounts for the fact that not all patients were followed for the full 9 years (). The Kaplan-Meier survival analysis demonstrates that there is a statistically significant difference among the groups (P<.001). Because the rate of repeat surgery for bulking agents was so high, we also estimated the incidence of repeat surgery after excluding this procedure. With bulking agents excluded, the cumulative incidence of repeat SUI surgery remained unchanged at 14.5% (95% CI 13.4–15.5), which reflects the fact that bulking agents represented only a small fraction of the total number of surgeries.
Demographic Characteristics of Women Aged 18 to 64 in the Health Care Claims Database Population Having Any Type of Stress Urinary Incontinence Surgery and Women Having One of Seven Specific Stress Urinary Incontinence Surgeries
Cumulative Incidence of Repeat Stress Urinary Incontinence Surgery (95% Confidence Interval) for Each Year of Follow-up, Stratified by Type of Index Surgery
Fig. 1 Kaplan-Meier survival curve after index stress urinary incontinence (SUI) surgery. This survival curve depicts the cumulative incidence of repeat SUI surgery after each type of procedure, and there is a statistically significant difference among the groups (more ...)
To assess predictors of repeat surgery, we performed a Cox proportional hazards model and evaluated age, calendar year when the index surgery was performed, region of the United States, and type of index SUI procedure (). Women aged 35 to 44 years and 45 to 54 years did not have a significant difference in rate of repeat surgery compared with women aged 18 to 34 years. However, women aged 55 to 64 years had a 14% higher rate of repeat surgery compared with women aged 18 to 34 years (adjusted HR 1.14, 95% CI 1.04–1.25). Compared with women who had the index surgery in 2000, the rate of repeat surgery was significantly lower in all subsequent years (2001–2009). When compared with the Northeast region of the United States, the rate of repeat surgery was elevated in the South (adjusted HR 1.66, 95% CI 1.52–1.82) and in the West (adjusted HR 1.24, 95% CI 1.12–1.38) but was not significantly different in the Midwest (adjusted HR 1.06, 95% CI 0.96–1.17).
Cox Proportional Hazards Regression Analysis for Time to Repeat Stress Urinary Incontinence Surgery
After adjusting for age, calendar year of index surgery, and region, the rate of repeat surgery was 8-fold higher for bulking agents (adjusted HR 8.19, 95% CI 7.53–8.90) compared with Burch. For slings, the rate of repeat surgery was 28% higher than the rate for Burch procedures (adjusted HR 1.28, 95% CI 1.19–1.37). Needle suspensions and laparoscopic SUI surgeries also had significantly higher rates of repeat surgery compared with the Burch, whereas the Kelly plication and total vaginal hysterectomy plus colpo-urethrocystopexy were not significantly different (). Notably, the total number of Kelly plications was quite low (less than 0.3% of the total procedures), and therefore, we were limited in our ability to detect a statistically significant difference between this procedure and the Burch.
The CPT code for slings (57288) does not distinguish between a midurethral sling compared with traditional bladder neck sling. Because a bladder neck sling is less likely to be performed on an outpatient basis, we conducted a subgroup analysis limited to outpatient slings to better assess the outcomes of midurethral slings in particular. Overall, 66.4% of slings were performed on an outpatient basis. In an adjusted Cox proportional hazards model, the rate of repeat surgery remained elevated when we compared outpatient slings to the Burch (both inpatient and outpatient) (adjusted HR 1.50, 95% CI 1.40–1.61).
Because midurethral slings were relatively recently FDA-approved in 19985
and have become the most common procedure performed, we wanted to focus on the relative rate of repeat surgery between the sling and the Burch, the previous gold standard. In the adjusted Cox proportional hazards model, the rate of repeat surgery was higher, on average, for slings compared with Burch (). However, this estimate assumes that any difference in long-term outcomes is the same regardless of the calendar year in which the procedure was performed. In other words, this model includes the main effects for calendar year and type of procedure, but does not allow for an interaction between calendar year and type of procedure. In a sensitivity analysis, we included the necessary interaction terms to allow the hazard ratio to vary by age and calendar year. None of the interaction terms for age were statistically significant (P>
.05). For calendar year, depicts the adjusted HR for sling compared with Burch, separately for each calendar year at the time of the index surgery. In 2000 and 2001, the hazard rate was lower for sling than Burch; however, between 2002 and 2009, the hazard rate was significantly higher for sling than Burch, meaning that the rate of repeat surgery was significantly higher for women who had a sling in any year from 2002 to 2009 compared with women who had a Burch in that same time period.
The hazard ratio and confidence intervals of repeat surgery after sling compared with Burch for each calendar year. The Y axis uses a logarithmic scale.