In this chapter we present findings from WP 4, addressing the first element of the fourth project objective, which was to identify determinants of referrals and surgical treatment for UI.
The methods are described in detail in Chapter 3. Briefly, the cohort for identifying determinants of referral to a UI specialist was derived from the CPRD data set45 and comprised women aged ≥ 18 years who had an index diagnosis of UI between 1 April 2004 and 31 March 2014. An index diagnosis of UI was defined among women who had no earlier record of UI diagnosis or treatment within the 12 months prior to the date of their first diagnosis in the study period. Women with < 12 months of UTS data prior to index diagnosis or with a follow-up period of < 30 days were excluded. Women were followed up until the date of a referral to a UI specialist, transfer out of the practice, death or 1 April 2014, whichever was earliest. The primary outcome measure was referral to a UI specialist within 30 days of diagnosis.
The cohort for identifying determinants of surgery comprised women aged ≥ 18 years who had an index UI diagnosis (defined as above) and a referral to a UI specialist in secondary care between 1 April 2004 and 31 March 2014. This cohort for surgery after referral was derived from the CPRD linked to HES (APC and Outpatient) data set and was therefore restricted to women registered in primary care practices that had linked CPRD–HES data (England only). Women were followed up until the date of surgery, transfer out of the practice, death or 1 April 2014, whichever was earliest. The primary outcome measure was time to first UI surgery after referral.
Diagnoses of UI were defined using Read codes (see Appendix 2, Table 16). Referral to a UI specialist was defined using a combination of Read codes and referral specialty codes (see Appendix 4, Tables 18 and 19). UI surgery was defined using OPCS-4 codes (see Appendix 1, Tables 13–15).
Referrals
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Between April 2004 and March 2014, 104,466 women had at least one UI diagnosis code and met the cohort criteria. The median age of women in the cohort was 58 years [interquartile range (IQR) 45–73 years]. Almost one-third of women (32%) were overweight (i.e. with a BMI of 25–29 kg/m2) and 29% were obese (i.e. with a BMI of 30–39 kg/m2). Ethnicity data were missing for over half (55%) of the referrals cohort; 92% were white, 4% were Asian/Asian British and 2% were black/black British. Of the comorbidities considered, CVD and anxiety or depression were the most common, each recorded for approximately 12% of women ().
Patient and practice characteristics associated with referral within 30 days
Of the 104,466 women with UI, 47,838 (45.8%) had a referral to a UI specialist (). Of these, 28,476 women (27.3% of the 104,466 women with UI, 59.5% of the 47,838 women referred) were referred within 30 days of their index UI diagnosis. The cumulative incidence of referral (with death as a competing risk) at 30 days, 1 year and 9 years was 25.5% (95% CI 25.3% to 25.8%), 34.0% (95% CI 33.7% to 34.3%) and 54.5% (95% CI 53.9% to 55.2%), respectively ().
Referrals analysis cohort. Parts of this figure have been reproduced with permission from Gurol-Urganci et al. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution (more...)
Cumulative incidence of any referral within the study period.
Patient/practice characteristics associated with referral within 30 days
The likelihood of being referred within 30 days declined with increasing age. Women in all age groups ≥ 50 years (i.e. 50–59, 60–69, 70–79 and ≥ 80 years) were less likely to have been referred than those aged 40–49 years. Compared with those women aged 40–49 years, women aged ≥ 80 years were 66% less likely to have been referred within 30 days [adjusted odds ratio (aOR) 0.34, 95% CI 0.31 to 0.37] and women aged 70–79 years were 49% less likely to have been referred within 30 days (aOR 0.51, 95% CI 0.49 to 0.54). Women from an Asian/Asian British and black/black British minority ethnic background were less likely to have been referred than white women (aOR 0.76, 95% CI 0.65 to 0.89 for Asian vs. white women; aOR 0.76, 95% CI 0.62 to 0.92 for black vs. white women).
Women with a BMI indicating that they were underweight (aOR 0.85, 95% CI 0.79 to 0.91) or severely obese (aOR 0.84, 95% CI 0.78 to 0.90) were less likely to have been referred than women with a normal range BMI. Current smokers were less likely to have been referred than non-smokers (aOR 0.94, 95% CI 0.90 to 0.98). Three comorbidities were associated with the likelihood of referral within 30 days. Women with a POP diagnosis were 23% less likely to have been referred for UI than women without a diagnosis of POP (aOR 0.77, 95% CI 0.68 to 0.87). Women with T2DM were slightly less likely to have been referred than those without (aOR 0.92, 95% CI 0.85 to 0.99). Finally, women with any type of cancer recorded in the previous 12 months were less likely to have been referred within 30 days (aOR 0.84, 95% CI 0.75 to 0.94). Other comorbidities were not associated with referral.
The country in which women accessed primary care for their ‘index’ UI diagnosis was also associated with the likelihood of referral within 30 days. Women in Scotland were 40% less likely to be referred than those accessing care in England (aOR 0.60, 95% CI 0.46 to 0.78), whereas women in Northern Ireland were 83% more likely to have been referred than those in England (aOR 1.83, 95% CI 1.40 to 2.39).
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Parts of this text have been reproduced with permission from Gurol-Urganci et al.68 This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. The text includes minor additions and formatting changes to the original text.
Surgical treatment
A total of 30,312 women in the linked CPRD–HES data set were identified as having been referred for UI between 1 April 2004 and 31 March 2014 (see Box 1). The median follow-up time was 4.6 years for women alive at the end of follow-up (IQR 2.4–6.9 years). The median age of women in the ‘determinants of surgery’ cohort was 53.6 years (IQR 43.4–67.6 years) and > 90% had a white ethnicity recorded. As in the referrals cohort, two-thirds of women (66.4%) were overweight, obese or severely obese and less than one-fifth (17%) were current smokers. Of the comorbidities considered, anxiety or depression and CVD were the most common, recorded for approximately 8.4% and 6.8% of women, respectively ().
Rate of SUI surgery following initial referral from primary care
Of the 30,312 women in the CPRD–HES ‘determinants of surgery’ cohort, 4307 (14.2%) underwent a UI procedure (), of which 4050 (94.5%) were SUI procedures and 257 (5.5%) were UUI procedures. Of the SUI procedures, 89% (n = 3606) were MUT insertions.
The rate of UI surgery was 7.3% (95% CI 7.0% to 7.6%) at 1 year, 13.4% (95% CI 13.0% to 13.8%) at 3 years, 15.5% (95% CI 15.0% to 15.9%) at 5 years, and 18.1% of the women (95% CI 17.5% to 18.7%) at 9 years after the initial referral (with death as a competing risk; , see ).
Cumulative incidence of any UI operation after referral within the study period.
Patient/practice characteristics associated with surgery
As in the findings with respect to referrals, age and ethnicity were associated with being less likely to have received surgical treatment. The rate of surgery was lower among older women (aged ≥ 50 years) than among those aged 40–49 years. The rate of surgery was lowest among those women aged 70–79 years [11.7% at 9 years after referral compared with 26.7% among women aged 40–49 years (sdHR 0.42, 95% CI 0.37 to 0.48); see ] and ≥ 80 years [3.4% at 9 years after referral compared with 26.7% among women aged 40–49 years (sdHR 0.12, 95% CI 0.10 to 0.16); see ]. Asian/Asian British and black/black British women had a lower rate of surgery than white women [Asian/Asian British women: 9.4% at 9 years after referral compared with 19.2% for white women (sdHR 0.50, 95% CI 0.38 to 0.67); black/black British women: 11.5% at 9 years compared with 17.8% for white women (sdHR 0.57, 95% CI 0.43 to 0.76)].
Similar associations between BMI and surgery were observed as between BMI and referral. Women whose BMI placed them in the severely obese group had a lower rate of surgical treatment than women with a BMI in the normal range [12.4% for severely obese women 9 years after referral compared with 18.5% for women with a normal BMI (sdHR 0.64, 95% CI 0.53 to 0.77)]. Women whose BMI indicated that they were underweight also had a lower rate of surgery than women with a normal range BMI [11.1% for underweight women at 9 years compared with 18.5% for women with a normal BMI (sdHR 0.63, 95% CI 0.51 to 0.78)]. Three comorbidities were associated with the rate of surgical treatment. Women with a diagnosis of POP had a higher rate of surgery than women without a POP diagnosis (sdHR 1.30, 95% CI 1.11 to 1.52). Women with T2DM or anxiety/depression had a lower rate of surgery than women without a diagnosis of these conditions (sdHR 0.62, 95% CI 0.50 to 0.79 and sdHR 0.84, 95% CI 0.76 to 0.94, respectively). There was substantial variation in the rate of surgery by region of referring general practice, ranging from 14.4% in London at 9 years after referral to 21.7% in the South East Coast region ().
Geographical variation in rate of referral and UI surgery in England. (a) Referral after a new diagnosis; and (b) UI surgery after referral.
illustrates geographical variation in the rate of referral and SUI surgery in England. For this figure, we have restricted the referrals cohort to England only for comparability with the surgery cohort, which is England only as a result of the linkage of CPRD data (UK wide) with HES (English hospital data). demonstrates that two regions, the South East and Yorkshire and The Humber, have high rates of both referrals and surgical treatment, whereas, in the North East, both referral and surgery rates are relatively low. suggests that geographical variation in the overall rate of surgery (as demonstrated in WP 2, Chapter 4) is likely to arise from differences in both primary care (in terms of referrals) and secondary care.
Key findings
Almost half of women newly diagnosed with UI in primary care in the UK between April 2004 and March 2014 were referred to secondary care within 9 years. Of those women, 59.5% were referred within 30 days.
Referral rates were lower for older women, women from a minority ethnic background, women who were underweight (BMI of < 20 kg/m2) and women who were severely obese (BMI of ≥ 40 kg/m2).
Of the women who had been referred for UI, 7.3% underwent a UI procedure within 1 year of referral, 15.5% within 5 years and 18.1% within 9 years.
Surgery rates were lower in older women, women from a minority ethnic background and women who were underweight or severely obese.
