Surgical treatment for urinary incontinence in women - Danish nationwide cohort studies .

This PhD thesis is based on three original articles. The studies were performed at the Department of Obstetrics and Gynaecology, Herlev University Hospital and at the Center for Clinical Epidemiology, Odense University Hospital. 
Urinary incontinence (UI) is a frequent disorder among women, which for the individual can have physical, psychological and social consequences. The current standard of surgical treatment is the synthetic midurethral sling (MUS), which is a minimal invasive procedure.
As the synthetic MUSs (TVT,TVT-O,TOT) were introduced in the late 1990s, there are only a few studies at the long-term follow-up based on nationwide populations; only a few have reported on the risk of reoperation and there is sparse evidence on which treatment should be used subsequently to failure of synthetic MUSs.
Several surgical specialties have documented that department volume, surgeon volume and patient-related factors influence the quality of care. There is little knowledge regarding this in the surgical treatment for UI.
 The aims of the thesis were therefore:
1. To describe the five-year incidence of reoperation after different surgical procedures for UI based on a nationwide population over a ten-year period (1998-2007) and to evaluate the influence of department volume (Study I).
2. To describe the choice of repeat surgery after failed synthetic MUSs and the departmental volume for the surgical treatment at reoperation over a ten-year period (1998-2007) based on a nationwide background population (Study II).
3. To evaluate efficacy of urethral injection therapy (UIT) based on patient reported outcome measures (PROMs) and hospital contacts within 30 days for women registered in the Danish Urogynaecological Database (DugaBase) over a five-year period (2007-2011) and the influence of department volume, surgeon volume and patient-related factors (Study III).
 Study I: A total of 8671 women were recorded in the Danish National Patient Registry as having undergone surgical treatment for UI from 1998 through 2007.
The lowest rate of reoperation within five years was observed among women who had pubovaginal slings (6%), TVT (6%) and Burch colposuspension (6%) followed TOT (9%), and miscellaneous operations (12%), while the highest observed risk was for UIT (44%). After adjustment for patient´s age, department volume and calendar effect TOT carried a 2-fold higher risk of reoperation (HR, 2.1; 95% CI, 1.5 -2.9) compared with TVT.

 Study II: A total of 5820 women had synthetic MUSs at baseline from 1998 through 2007 and were registered in the Danish National Patient Registry and 354 (6%) of these women had a reoperation.
The first choice treatment for reoperation was a synthetic MUS and UIT was a frequent second choice. At reoperation, 289 (82%) of the women were treated at the department where they had undergone the primary synthetic MUS. Fewer treatment modalities were in usage and significantly more TOTs were implanted at low volume departments compared to high volume departments. 

Study III: A total of 731 women of age 18 or older with first time UITs were registered with first-time UIT in the DugaBase from 2007 through 2011. Logistic regression was used to predict the odds of success pertaining to department volume, surgeon volume and patient-related factors on the Incontinence Questionnaire-Short Form (ICIQ-SF) (frequency of UI, amount of leakage and impact of UI on daily life) and the rate of 30-day hospital contacts. 

We applied the definition of "cure" as set out by the steering committee of the DugaBase where a satisfactory result is leakage once a week or less, often or never based on the frequency score and similarly "no leakage at all" based on the frequency score as answering never to leakage.

Among the 252 women who pre- and postoperatively had answered both questionnaires, 75 (29.8%) were cured and 23 (9.1%) achieved no leakage at all at three months follow-up. There was a statistically significant improvement on all three scores of the ICIQ-SF. The mean total ICIQ-SF score was 16.0 (SD 3.8) and after injection at three months follow-up 10.6 (SD 6.2) (p < 0.001).

UIT was performed at 16 departments, of which four high volume departments performed 547 of 814 UITs (67.2%). The risk of hospital contacts was lower for women treated at a high volume department (adjusted OR 0.27; 95% CI 0.09-0.76). Women treated by a high volume surgeon (> 75 UITs during the career as a surgeon) had a higher chance of cure on the frequency score than the low volume surgeon (≤ 25 UITs) (adjusted OR 4.51; 95% CI, 1.21-16.82) and a lower risk of 30-day hospital contacts (adjusted OR 0.35; 95% CI, 0.16-0.79). Women with severe UI had less likelihood of cure in all ICIQ-SF scores. A preoperative use of antimuscarinic drugs lowered the chance of cure on the frequency (adjusted OR 0.14; 95%, CI 0.04-0.41) and the amount score (adjusted OR 0.33; 95%, CI 0.13-0.82). 

Conclusions:
 Study I: The study provided physicians with a representative evaluation of the rate of reoperations after different surgical procedures for UI. The observation that TOT was associated with a significantly higher risk of reoperation than TVT is novel in the literature and has important implications for both surgeons and patients when they consider surgical options for UI. 

Study II: The majority of women had reoperation at the same department as the primary synthetic MUS. Fewer treatment modalities were in use at low volume departments compared with high volume departments. It seems appropriate in the absence of evidence for the best treatment after failed synthetic MUSs, that women are referred to highly specialized departments for diagnosing and treatment.

 Study III: This national population-based cohort study represented cure among women who had UIT in an everyday life setting. Results seemed to be in the lower end of the spectrum compared to the literature. A learning curve for UIT indicated that the treatment should be restricted to fewer hands to improve the surgical education and consequently be a success for women with UIT. The severity of UI was a strong predictor for a lower degree of cure. Similarly, the use of antimuscarinic drug preoperatively decreased the likelihood of cure indicating that women with severe MUI or UUI also have less chance of cure.