Assumptions used in estimating a population benchmark

The assumptions used in estimating a female population benchmark for a hysterectomy service of 0.143% per year are based on the following sources of information:

• ‘Hospital episode statistics' data to establish the current levels of activity commissioned
• published research on the care of women with heavy menstrual bleeding (HMB)
• expert clinical opinion of the topic-specific advisory group, based on experience in clinical practice and literature review.

Activity data - ‘Hospital episode statistics'

The ‘Hospital episode statistics (HES)' database contains details of all admissions to NHS hospitals in England. It includes private patients treated in NHS hospitals, patients who were resident outside England and care delivered by treatment centres (including those in the independent sector) funded by the NHS.

Analysis of HES data suggests that the number of hysterectomies performed for the treatment of HMB within English trusts has been declining since 1994/95^[1], and the number of endometrial ablations is increasing.

Figure 1 illustrates the rolling (3-year) averages for the numbers of endometrial ablations and hysterectomies, and the total of the two procedures, performed for the treatment of HMB between 1989 and 2004 (adapted from Reid 2006 with permission).

The fall in the number of hysterectomies for the treatment of HMB is not due to the rise in endometrial ablations alone, as there has been a steady decline in the total number of procedures being performed for HMB^[1]. This decline has plateaued in more recent years.

HES data (see figure 2) give an indication of the rates at which hysterectomies for HMB are being performed. Average rates do not necessarily correlate with the rate that would be expected if NICE clinical guideline CG44 on heavy menstrual bleeding was uniformly followed.

The mean directly standardised rate for hysterectomy for HMB for all English primary care organisations for the year 2005/06 is 30 per 100,000 female population.

As well as HMB, hysterectomy is also indicated for the treatment of other conditions such as malignancy and genital prolapse. The current rate of hysterectomy for all conditions is 150 per 100,000 female population.

HMB may also be a secondary diagnosis in those women who have hysterectomy for the treatment of, for example, fibroids or endometriosis, but these women have been excluded from the analysis of rates of hysterectomy for the treatment of HMB.

The average rate of hysterectomy for the treatment of HMB hides large variations. Procedure rates vary among primary care organisations from fewer than 10 per 100,000 to 100 per 100,000 female population. Thus, there is a 10-fold variation in rates across England.

Some of the variation in procedure rates for hysterectomies is likely to be due to symptom prevalence, the treatment preferences held by women and other clinical reasons. However, these alone are unlikely to account for all of the variation, and there may be other factors that influence it, such as variations in service capacity and differences in the management of HMB within primary care^[2]. Notably, areas with high hysterectomy rates also have high rates of endometrial ablation. See the commissioning guide on endometrial ablation.

Published research

The relation between medical management, referral and surgery is complex^[2]. There are wide variations in patterns of referral into secondary care for women with HMB. More effective management of HMB in primary care may reduce the number of referrals into secondary care and surgery rates^[2],^[3].

Active education in relation to good management and the promotion of effective medical management in primary care has been shown to reduce the number of referrals into secondary care by between 30%^[3]and 50%^[4].

A randomised controlled trial^[5] found that the provision of structured information around treatment options for women with HMB resulted in a significant decrease in the number of women who stated a preference for hysterectomy, from 48% to 38%.

A review of women undergoing hysterectomy found that 70% were not offered medical management by their GP and that 39% had a hysterectomy as primary treatment for HMB^[6]. In addition not all women undergoing hysterectomy for HMB are offered endometrial ablation as an alternative where it is clinically appropriate to do so^[6],^[7]; this figure is estimated to be between 50%^[7]and 56% (Owen P, Welsh J: unpublished data 2007). A midpoint of 53% is used below.

The failure rate following endometrial ablation varies between studies and depends on the length of time of follow-up. A recent Cochrane review reported that the need for re-treatment following endometrial ablation varied between 20% and 27% over 3 to 5 years, and that the rate of hysterectomy among the re-treatment groups was around 18%^[8].

A reduction in the rate of hysterectomy for the treatment of HMB of 27% may be considered appropriate given the following:

• 53% of women undergoing hysterectomy are not offered endometrial ablation as an alternative
• 38% of women may express an explicit preference for hysterectomy when given information around alternative treatment options
• 18% of women who have endometrial ablation will go on to have a hysterectomy.

This does not take into account any reduction due to optimal management within primary care and the use of levonorgestrel-releasing intrauterine system (LNG-IUS) devices.

Expert clinical opinion

The topic-specific advisory group agreed that, given optimal management of HMB across the whole care pathway, a reduction in the current national average rate of hysterectomy for the treatment of HMB of around 25% to 27% could be achieved.

The topic-specific advisory group advised that commissioners should examine local referral patterns, prescribing practice, procedure rates and differences in local populations to ensure that women with HMB receive optimal care and that appropriate rates of hysterectomies are achieved.

Conclusions

Based on the activity data and other information outlined above, it is concluded that a benchmark rate of hysterectomy of 143 per 100,000 female population, of which 23 per 100,000 female population is for the treatment of HMB, is considered appropriate. This is based on the following assumptions:

• the current rate of hysterectomy for the treatment of HMB is 30 per 100,000 female population
• the current rate of hysterectomy for conditions other than HMB is 120 per 100,000 female population
• a reduction of 25% in the rate of hysterectomy for the treatment of HMB could be achieved, based on published research on current practice
• the consensus of the topic-specific advisory group.

Therefore the total population benchmark for hysterectomy for all causes is estimated to be 0.143%.

Use the hysterectomy service commissioning and benchmarking tool to determine the level of service that might be needed locally and to calculate the cost of commissioning the service using the indicative benchmark and/or your own local data.

References

1. Reid PC (2007) Endometrial ablation in England - coming of age? An examination of hospital episode statistics 1989/1990 to 2004/2005. European Journal of Obstetrics and Gynecology
2. Grant C, Gallier L, Fahey T et al.(2000) Management of menorrhagia in primary care - impact on referral and hysterectomy: data from the Somerset Morbidity Project. Journal of Epidemiology and Community Health 54: 709-13.
3. Nixon RM, Duffy SW, Fender GRK et al. (2001) Randomization at the level of primary care practice: use of pre-intervention data and random effects models. Statistics in Medicine 20: 1727-38.
4. Zachariah M, Fender G (2005) Managing menorrhagia in primary care. Women's Health Medicine 2: 17-20.
5. Kennedy ADM, Sculpher MJ, Coulter A et al. (2003) A multicentre randomised controlled trial assessing the costs and benefits of using structured information and analysis of women's preferences in the management of menorrhagia. Health Technology Assessment 7(8).
6. Onyeka BA, Rahman KM (2001) Treatment of Menorrhagia before hysterectomy in a district general hospital. A retrospective review. Journal of Obstetrics and Gynaecology 21: 64-6.
7. Ali CR, Suchetha M, Arthur ID (2007) Compliance with the published RCOG guidelines in women undergoing hysterectomy in a district general hospital. Journal of Obstetrics and Gynaecology 27: 171-3.
8. Marjoribanks J, Lethaby A, Farquhar C (2006) Surgery versus medical therapy for heavy menstrual bleeding. The Cochrane Database of Systematic Reviews. Issue 2