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In this chapter, we present evidence from WP 2 on how the rates of surgery for female SUI vary across England. This addresses the second objective of the project that was to assess variation between NHS CCGs and other regional units in the rate of surgery for UI and to examine the impact of the supply-side factors on local surgical rates.
The methods are described in detail in Chapter 3. In summary, we used the HES database to identify women aged ≥ 20 years who had surgical treatment for SUI between 1 April 2013 and 31 March 2016 in NHS England. The outcome measure was the rate of surgery for SUI per 100,000 women per year at two geographic levels across 209 CCG areas with an average population size of 104,000 adult women and 44 STP areas with an average population size of about 493,000 adult women. Multilevel Poisson regression models were used to produce empirical Bayes’ estimates of the SUI surgery rates for each CCG and STP area, adjusted for age, socioeconomic deprivation, ethnicity and limiting long-term illness.
There were 33,708 inpatient episodes with a surgical procedure for SUI between April 2013 and March 2016. In total, 4996 episodes were excluded because, for example, they did not have a SUI diagnosis recorded at the time of the procedure. We focused on the first SUI procedure in the study period, which equated to 27,997 procedures, capturing > 97% of all SUI procedures in the study period. In total, 90% of procedures were MUT insertions and this did not vary between the first and later procedures.
The national annual rate of surgery was 40 procedures per 100,000 women. The adjusted SUI procedure rates for CCGs ranged from 20 to 106 procedures per 100,000 women per year [unadjusted rates ranged from 11 to 120 procedures per 100,000 women per year ()]. Risk adjustment reduced the number of CCGs marked as ‘outliers’ (in which the national average was not within the 99.8% credibility interval of their rate) from 99 (47.4%) to 75 (36%), with the standard deviation (SD) of the CCG-level variation in adjusted rates [SD 0.27, 95% confidence interval (CI) 0.24 to 0.30] 16% lower than the SD of the unadjusted rates (SD 0.32, 95% CI 0.29 to 0.36).
Variation in SUI surgery rates by CCG. (a) Variation in the unadjusted empirical Bayes’ estimates of SUI procedure rates across CCGs; (b) adjusted for patients’ age and the CCG-level characteristics: IMD, percentage of the population reporting (more...)
The adjusted SUI procedure rates for the STPs ranged from 24 to 69 procedures [unadjusted rates ranged from 20 to 77 procedures per 100,000 women per year ()]. Risk adjustment reduced the number of STPs identified as outliers from 23 (52%) to 22 (50%). The amount of variation observed declined by 35% after risk adjustment, that is, unadjusted (SD 0.23, 95% CI 0.17 to 0.31) and adjusted (SD 0.15, 95% CI 0.11 to 0.22).
Variation in SUI surgery rates by STP. (a) Variation in the unadjusted empirical Bayes’ estimates of SUI procedure rates across STPs; (b) adjusted for patients’ age and the CCG-level characteristics: IMD, percentage of the population reporting (more...)
Annual SUI procedure rates declined over the study period from 52 per 100,000 women in 2013 to 36 per 100,000 women in 2015. However, there was no evidence that CCG- or STP-level variation changed over time. In separate (adjusted) regression models run by year, the SD of CCG-level variation was 0.26 (95% CI 0.23 to 0.30) in 2013, 0.27 (95% CI 0.23 to 0.31) in 2014 and 0.29 (95% CI 0.25 to 0.34) in 2015. For STP-level variation (adjusted) the SD was 0.13 (95% CI 0.08 to 0.20) in 2013, 0.17 (95% CI 0.11 to 0.25) in 2014 and 0.18 (95% CI 0.12 to 0.26) in 2015.
Stress UI surgery rates were lowest for those women aged 20–39 years (16 per 100,000 women per year) and highest for those women aged 40–49 years (84 per 100,000 women per year), declining with age (beyond 50 years). Compared with the rate among women aged 40–49 years, the surgery rate for women aged 50–59 years was 20% lower (IRR 0.80, 95% CI 0.78 to 0.83) and 46% lower for women aged 60–69 years (IRR 0.54, 95% CI 0.52 to 0.56). Rates were lower in areas with higher proportions of BAME populations (highest vs. lowest quintile IRR 0.63, 95% CI 0.49 to 0.81). There were no differences in surgery rates according to the proportion of people with long-term limiting illness or CCG-level socioeconomic deprivation.
Key findings
The rate of surgery for SUI was 40 procedures per 100,000 women per year.
Risk-adjusted rates ranged from 20 to 106 procedures per 100,000 women per year across CCGs and from 24 to 69 procedures per 100,000 women per year across the STP areas.
These regional differences were only partially explained by demographic characteristics, as adjustment reduced variance of surgery rates by 16% among the CCGs and 35% among the STPs.
describes the distribution of regional characteristics and the association between these factors and SUI procedure rates.
Patient and regional characteristics associated with SUI surgery rates
