Presentation on theme: "Which women are having a Hysterectomy and why? A plain English presentation of the methodology and findings of a database linkage study Dr Helen Stokes-Lampard."— Presentation transcript:
Which women are having a Hysterectomy and why? A plain English presentation of the methodology and findings of a database linkage study Dr Helen Stokes-Lampard
Background Hysterectomy: Commonest major surgical operation in women in western world – 20% women in UK –>95% total hysterectomy (cervix removed too) Vault cytology* only applies when cervix removed (‘total’) Evidence for national guidelines = poor (expert opinion) Evidence that guidelines not being followed * = vault smears
Inpatient Data HES 1.4.02 – 30.3.03 Hysterectomy, W Mids Cervical Screening Exeter Lifetime cytology records for same women Unique SPSS Database 1. Identify which women are having a hysterectomy 2. Establish why (diagnosis) 3. Identify which subsequently have vault testing 4. Establish if this is in accordance with guidelines The Database Linkage Study
Methodology 1: Reality check Multiple ethical approvals for use of data without explicit patient consent (inc PIAG) HES located next to Buncefield Oil depot: destroyed in fire of Dec 2005, along with my application… Pipe delimited text file: Excel easiest to handle 6,168 lines, 62 fields NHS no, Postcode, DOB
Methodology 2 - Exeter Remove duplicates in HES first Batch searching on NHS number possible: Comma Separated Variable files (CSV) NHS no, Postcode, DOB 5,857 batch searched, 284 manually Output into multiple small Excel files Manual validation of 3% records Merged to one large Excel file Conversion to one line per patient
Methodology 3 - Linkage Linkage then done in Access: –merge file using NHS number –a ‘make table’ query = 98.7% records linked –>200 original data fields Further enhanced with DOB & postcode Verified (100%) Unique identifier added Anonymised: pseudo for coding, then complete Converted to SPSS v15 for analysis
Source Data HES 6,168 records –27 duplicated –284 missing NHS no DOB & Postcode data 100% Ethnicity only 69% 16 Mids hospitals = 84.6% Operation data 100% Exeter 6,065 records matched –1 missing NHS No DOB & Postcode 100% Data on every cytology test: Date, test result, recommended follow up Cytology data available or women known to have been never screened for all Final study population 6,141 women
Validation and coding HES: only concern was ethnicity (69%) and site of treatment (2 hospitals no patients but 11.5% coding errors may correspond). Need to classify by diagnosis (ranking) Exeter: Imputing ‘anticipated’ numbers of screening tests, based on age at time of surgery
6,141 Women, resident in the West Mids region, undergoing hysterectomy: April 2002 - March 2003 23 / 10,000 women pa. Age 17-94 years 299 Post op cytology 5,697 Total Hysterectomy = 92.77% 444 Sub-total operation 395 Benign 3 Pre invasive 35 Malignant 11 Diagnosis not specified 439 Post op cytology (Vault) 114 Post op cytology (Vault) 135 Post op cytology (Vault) 4,695 Benign 181 CIN or carcinoma in situ 678 Malignancy 143 Unknown 145 No Post op cytology 4,256 No Post op cytology 29 Post op cytology (Vault) 543 No Post op cytology 114 No post op cytology 67 No Post op cytology Results 1: Which women have a hysterectomy?
Results 2: Demographics & Diagnosis Deprivation: More deprived than UK population, increased incidence with greater deprivation Ethnicity: Black women had greatest incidence of hysterectomy (33 per 10,000) Diagnosis: –Any Cancer 12% –CIN / In situ disease 3% –Benign 83% –Unclassifiable 2% Deaths: 10 women, 5 with malignancy
Results 3: Which women are having vault cytology testing? Several patient factors varied between women who did /did not have vault cytology –Decreased age –Increased deprivation More likely to have –White/ Mixed ethnicity vault cytology –Shorter hospital stay –Surgical diagnosis: CIN>Cancer>Benign –Index test : Invasive>Dyskaryosis>Normal NOT CLINICALLY MEANINGFUL
Usefulness of vault cytology? No clinically meaningful differences established between those who women who did vs did not have vault cytology Poor adherence to the guidelines commonplace Role of a test mainly used out-with guidelines must be questioned…
Summary of results Hysterectomy is very common (23 per 10,000 pa) and carries significant mortality Deprivation: a significant association still exists Poor adherence to vault cytology guidelines Many associations with having vault cytology but few clinically meaningful
Recommendations Vault cytology should only be done in secondary care hereafter: –Gynaecologist should be aware of guidelines, responsible surgeon has full picture, option for opportunistic biopsy –Primary care clinicians not up to date with guidelines, training does not include vault sampling, too few per clinician to retain QA.
Acknowledgements This research could not have been conducted without generous funding from the NIHR by means of a Researcher Development Award Professor Sue Wilson & Dr John Macleod: PhD supervisors of distinction The Department of Primary Care and General Practice, within the School of Health and Population Sciences Dr Christine Waddell of the Cytopathology department BWH
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