Hysterectomy and incontinence: a study from the Swedish national register for gynecological surgery
Abstract
Background. Hysterectomy is one factor that has been suggested to be a risk factor for developing stress incontinence. In Sweden, with a population of 8.86 million, a national register was set up in 1997 in order to have data for assessing the quality of gynecological surgery for benign disorders. Methods. Data in the Swedish national register for gynecological surgery during the period 1997–2002 were investigated. Surgical methods compared during this time period were: total hysterectomy (abdominal/laparoscopic, n=198/116), subtotal hysterectomy (abdominal/laparoscopic, n=163/86), and total hysterectomy (vaginal/laparoscopic assisted vaginal, n=265/7). Patients who underwent endometrial destruction (endometrial ablation, endometrial balloon treatment, n=187) were used as a control group. Only patients with no preoperative complaints were included. Outcome measures were answers to subjective questions asked pre- and postoperatively regarding urinary problems and incontinence. Results. De novo symptoms of stress incontinence, urgency and urgency incontinence, and/or mixed incontinence were noted in all groups. No differences were found among the groups. Conclusion. Factors other than hysterectomy should be discussed causing stress incontinence in women.
Introduction
Incontinence has long been recognized as a troublesome condition in middle-aged and older women. It is clearly established that some of the factors contributing to incontinence are age, parity, and weight (1). Other factors discussed are concurrent diseases such as diabetes, asthma, and neurological diseases (2). Hysterectomy has been suggested to be a risk factor for developing incontinence (1, 3). Mode of hysterectomy has also been suggested to be of relevance, with more incontinence developing after vaginal hysterectomies than after abdominal hysterectomies (4).
In Sweden, with a population of 8.86 million, a national register was set up in 1997 in order to have data for assessing the quality of gynecological surgery for benign disorders (http://www.gynop.com). Pre- and postoperative information is collected using questionnaires as part of routine medical care. The register has been shown to be well accepted by patients (5). By the year 2003, half of all Swedish departments of gynecology and obstetrics were participating. Data on 15,000 patients have been registered to date. The register has been used to evaluate postoperative infections and antibiotic prophylaxis for hysterectomy (6). The postoperative questionnaires focus mainly on the patients’ well-being and treatment-related complications in addition to general follow-up questions. To investigate whether or not hysterectomy has any impact on incontinence and whether mode of hysterectomy is of importance for developing incontinence, data from the national register were analyzed.
Material and methods
Data in the Swedish national register for uterine surgery during the period 1997–2002 were investigated. Only patient questionnaires were analyzed. Surgical methods compared during this time period were: total hysterectomy (abdominal/laparoscopic, n=198/116), subtotal hysterectomy (abdominal/laparoscopic, n=163/86), and total hysterectomy (vaginal/laparoscopic assisted vaginal, n=265/7). We kept the patients in the groups relating to the technique that were determined preoperatively irrespective of what technique was actually used, in accordance to “the intention to treat principle”. To be able to exclude other factors than the hysterectomy itself, patients undergoing endometrial destruction (endometrial ablation, endometrial balloon treatment, n=187) were used as a control group. Thus the inclusion criteria were tailored in order to suit this group of patients. The selection process is shown in Figure 1. Patients with preoperative symptoms were excluded to be able to investigate the frequency of de novo urinary symptoms. To obtain equivalent groups with regards to parity, a correction was made whereby patients with more than six vaginal deliveries were excluded. The number of patients who did not respond to the postoperative questionnaire was regarded as the drop-out frequency, n=196. The reasons for not answering the postoperative questionnaire have been analyzed. The questionnaire was not administered to the patients in 73.4% (144/196) of cases owing to technical errors. The remaining 26.5% (52/196) patients could not be analyzed, as they did not answer the questionnaire in spite of one or two reminders. The questions asked pre- and postoperatively regarding urinary problems and incontinence were simple questions (Yes/No). The answers enabled us to divide the patients into four groups: i. Patients with incontinence without urgency; interpreted as having stress incontinence. ii. Patients with urgency without incontinence; interpreted as having urgency problems. iii. Patients with urgency and incontinence interpreted as having either mixed incontinence or urgency incontinence. iv. Patients with no urinary problems.
Flow diagram of selection of subjects in the uterine surgery register eligible for the study.
Statistics
Categorical variables were analyzed using χ2 tests. Continuous variables were tested using ANOVA. Holms corrected Bonferroni method has been used to correct for multiple testing. All statistical analyses were performed using SPSS 11.0. A p-value less than 0.05 was considered significant.
The study was approved by the local ethics committee of Umeå University, Umeå, Sweden.
Results
Patient characteristics were the same in all groups (Table I).
| Total abdominal/laparoscopic N=314 | Subtotal abdominal/laparoscopic N=249 | Total vaginal/laparoscopically assisted N=272 | Endometrial destruction N=187 | |
|---|---|---|---|---|
| Age, years (SD) | 45.1 (3.6) | 44.5 (3.4) | 45.2 (3.8) | 44.7 (3.6) |
| Body mass index, kg/m2 (SD) | 25.3 (3.9) | 25.4 (4.1) | 25.4 (5.0) | 25.6 (4.2) |
| Parity (SD) | 2.1 (1.1) | 2.3 (1.1) | 2.4 (1.1) | 2.5(1.0) |
| Professionals | 81.2 | 83.9 | 83.3 | 84.5 |
| Smoking (%) | 36.8 | 31.2 | 34.8 | 28.1 |
| Asthmatic symptoms (%) | 7.6 | 8.8 | 9.2 | 10.2 |
| Diabetes (%) | 2.2 | 1.2 | 1.8 | 2.0 |
| ASA I (%) | 94.0 | 97.0 | 99.3 | 95.8 |
- Mean values±standard deviation (SD) are given. N, number of patients in each group answering the questionnaire.
- There were no significant differences between the groups. ASA, American Society of Anesthesiologists physical status classification system.
There was development of de novo symptoms of stress incontinence, urgency and urgency incontinence, and/or mixed incontinence in all groups. No differences among the groups were found (Table II). An initial difference in climacteric symptoms between endometrial destruction and all types of hysterectomies was found (p<0.02). The difference was abolished, however, when the Bonferroni test for multiple testing (Table III) was used.
| Total abdominal/laparoscopic N=314 | Subtotal abdominal/laparoscopic N=249 | Total vaginal/laparoscopically assisted N=272 | Endometrial destruction N=187 | |||||
|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | |
| No reported symptoms | 236 | (75.2) | 186 | (74.7) | 210 | (77.2) | 138 | (73.8.) |
| Stress incontinence | 43 | (13.7) | 36 | (14.5) | 39 | (14.3) | 26 | (13.9) |
| Urgency problems | 25 | (8.0) | 15 | (6.0) | 12 | (4.4) | 16 | (8.6) |
| Incontinence and urgency | 10 | (3.2) | 12 | (4.8) | 11 | (4.0) | 7 | (3.7) |
- N, number of patients in each group answering the questionnaire.
- n, number of patients reporting no or any symptom.
| Total abdominal/laparoscopic N=314 | Subtotal abdominal/laparoscopic N=249 | Total vaginal/laparoscopically assisted N=272 | Endometrial destruction N=187 | |||||
|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | |
| Preoperative climacteric symptoms (%) | 76 | (24.2) | 53 | (21.3) | 52 | (19.1) | 28 | (15.0) |
| Postoperative climacteric symptoms (%) | 84 | (26.8) | 63 | (25.3) | 61 | (22.4) | 33 | (17.6) |
| Preoperative HRT (%) | 41 | (13.1) | 23 | (9.2) | 25 | (9.2) | 18 | (9.6) |
| Postoperative HRT (%) | 75 | (23.9) | 52 | (20.9) | 50 | (18.4) | 24 | (12.8) |
- N, number of patients in each group answering the questionnaire.
- n, number of patients reporting any symptom or behavior.
Discussion
Two years after surgery, there was an increase in reported subjective urinary symptoms including stress incontinence in patients who had undergone hysterectomy as compared with preoperative values. The results were shown to be similar for patients who had undergone endometrial destruction. This suggests that factors other than hysterectomy have to be sought to explain these results. It remains uncertain whether the increase in prevalence of stress incontinence is attributable to the fall in circulating estrogens at the time of menopause or is simply part of the aging process. Studies have shown conflicting results (1, 7). Other urinary symptoms, however, have been shown to correlate to treatment with estrogen (8). There was a tendency for patients with endometrial ablation to have less climacteric symptoms. This was not mirrored in reported symptoms of incontinence. No difference was detected between vaginal hysterectomy and other modes of hysterectomy. This has been suggested by other authors (4). Previous findings might be explained by selection among patients undergoing vaginal hysterectomy.
There were no differences between the type of hysterectomy (total/subtotal). For many years there has been an ongoing debate concerning the effects of subtotal and total hysterectomy on incontinence. Recent well designed randomized studies have shown conflicting results (9, 10).
Randomized trials are appreciated as the golden standard for evidence-based medicine. There are some limitations, however, such as small numbers of patients who can be included and the fact that the study is often performed under ideal conditions. Data from registers can be supplementary to randomized trials and add valuable information from a large number of patients treated in “real life”. Only half of the gynecology departments in Sweden are now participating in the national register. There could be many reasons for this. It is always very demanding to introduce a new system of reporting adding to the workload for the participating doctors and secretaries. The general attitude to registers in the Nordic countries has been shown to be positive, with 80.4% of the departments stating that they wanted to participate (11). Several departments were hesitant to participate however if it would incur financial costs and/or extra work. Some computer systems can also be incompatible with that of the register. There is scarcely any reason to believe that the participating clinics do not provide representative samples of all of Swedish patients who have undergone hysterectomy, but no validation in this respect has been performed.
It has been suggested that the effects of hysterectomy-induced incontinence do not develop until many years after surgery (3). Patients in the Swedish national register for gynecological surgery are only followed for two years. The question of long-term influence is therefore not answered in this study. However since preoperative data is collected it will be possible to follow these patients in the years to come.
Acknowledgement
This study was supported by the Swedish National Board of Health and Welfare. Håkan Lindkvist, Department of Mathematical Statistics is acknowledged for skilful statistical advice.
