Development and validation of a prognostic model for death 30 days after adult emergency laparotomy.

The probability of death after emergency laparotomy varies greatly between patients. Accurate pre-operative risk prediction is fundamental to planning care and improving outcomes. We aimed to develop a model limited to a few pre-operative factors that performed well irrespective of surgical indication: obstruction; sepsis; ischaemia; bleeding; and other. We derived a model with data from the National Emergency Laparotomy Audit for patients who had emergency laparotomy between December 2016 and November 2018. We tested the model on patients who underwent emergency laparotomy between December 2018 and November 2019. There were 4077/40,816 (10%) deaths 30 days after surgery in the derivation cohort. The final model had 13 pre-operative variables: surgical indication; age; blood pressure; heart rate; respiratory history; urgency; biochemical markers; anticipated malignancy; anticipated peritoneal soiling; and ASA physical status. The predicted mortality probability deciles ranged from 0.1% to 47%. There were 1888/11,187 deaths in the test cohort. The scaled Brier score, integrated calibration index and concordance for the model were 20%, 0.006 and 0.86, respectively. Model metrics were similar for the five surgical indications. In conclusion, we think that this prognostic model is suitable to support decision-making before emergency laparotomy as well as for risk adjustment for comparing organisations.

Surgical decisions in older women with early breast cancer: patient and disease factors.

BACKGROUND: Studies reporting lower rates of surgery for older women with early invasive breast cancer have focused on women with oestrogen receptor (ER)-positive tumours. This study examined the factors that influence receipt of breast surgery in older women with ER-positive and ER-negative early invasive breast cancer . METHODS: Women aged 50 years or above with unilateral stage 1-3A early invasive breast cancer diagnosed in 2014-2017 were identified from linked English and Welsh cancer registration and routine hospital data sets. Logistic regression analysis was used to evaluate the influence of tumour and patient factors on receipt of surgery. RESULTS: Among 83 188 women, 86.8 per cent had ER-positive and 13.2 per cent had ER-negative early invasive breast cancer. These proportions were unaffected by age at diagnosis. Compared with women with ER-negative breast cancer, a higher proportion of women with ER-positive breast cancer presented with low risk tumour characteristics: G1 (20.0 versus 1.5 per cent), T1 (60.8 versus 44.2 per cent) and N0 (73.9 versus 68.8 per cent). The proportions of women with any recorded co-morbidity (13.7 versus 14.3 per cent) or degree of frailty (25 versus 25.8 per cent) were similar among women with ER-positive and ER-negative disease respectively. In women with ER-positive early invasive breast cancer aged 70-74, 75-79 and 80 years or above, the rate of no surgery was 5.6, 11.0 and 41.9 per cent respectively. Among women with ER-negative early invasive breast cancer, the corresponding rates were 3.8, 3.7 and 12.3 per cent. The relatively lower rate of surgery for ER-positive breast cancer persisted in women with good fitness. CONCLUSION: The reasons for the observer differences should be further explored to ensure consistency in treatment decisions.

Prediction of long-term survival after gastrectomy using random survival forests.

BACKGROUND: No well validated and contemporaneous tools for personalized prognostication of gastric adenocarcinoma exist. This study aimed to derive and validate a prognostic model for overall survival after surgery for gastric adenocarcinoma using a large national dataset. METHODS: National audit data from England and Wales were used to identify patients who underwent a potentially curative gastrectomy for adenocarcinoma of the stomach. A total of 2931 patients were included and 29 clinical and pathological variables were considered for their impact on survival. A non-linear random survival forest methodology was then trained and validated internally using bootstrapping with calibration and discrimination (time-dependent area under the receiver operator curve (tAUC)) assessed. RESULTS: The median survival of the cohort was 69 months, with a 5-year survival of 53.2 per cent. Ten variables were found to influence survival significantly and were included in the final model, with the most important being lymph node positivity, pT stage and achieving an R0 resection. Patient characteristics including ASA grade and age were also influential. On validation the model achieved excellent performance with a 5-year tAUC of 0.80 (95 per cent c.i. 0.78 to 0.82) and good agreement between observed and predicted survival probabilities. A wide spread of predictions for 3-year (14.8-98.3 (i.q.r. 43.2-84.4) per cent) and 5-year (9.4-96.1 (i.q.r. 31.7-73.8) per cent) survival were seen. CONCLUSIONS: A prognostic model for survival after a potentially curative resection for gastric adenocarcinoma was derived and exhibited excellent discrimination and calibration of predictions.

In this study the authors used a large nationwide dataset from England and Wales and tried to make a predictive model that estimated how long patients would survive after surgery for gastric cancer. They found that using a machine learning methodology provided excellent results and accuracy in predictions, significantly in excess of any other published model and traditional staging methods. The model will be useful to provide individualized prediction of survival to patients and in the future could be used to stratify treatments.

Long-term survival after endovascular and open repair of unruptured abdominal aortic aneurysm.

BACKGROUND: The aim of this study was to examine patterns of 10-year survival after elective repair of unruptured abdominal aortic aneurysms (AAAs) in different patient groups. METHODS: Patients having open repair or endovascular aneurysm repair (EVAR) in the English National Health Service between January 2006 and December 2015 were identified from Hospital Episode Statistics data. Postoperative survival among patients of different age and Royal College of Surgeons of England (RCS) modified Charlson co-morbidity score profiles were analysed using flexible parametric survival models. The relationship between patient characteristics and risk of rupture after repair was also analysed. RESULTS: Some 37 138 patients underwent elective AAA repair, of which 15 523 were open and 21 615 were endovascular. The 10-year mortality rate was 38·1 per cent for patients aged under 70 years, and the survival trajectories for open repair and EVAR were similar when patients had no RCS-modified Charlson co-morbidity. Among older patients or those with co-morbidity, the 10-year mortality rate rose, exceeding 70 per cent for patients aged 80 years. Mean survival times over 10 years for open repair and EVAR were often similar in subgroups of older and more co-morbid patients, but their survival trajectories became increasingly dissimilar, with open repair showing greater short-term risk within 6 months but lower 10-year mortality rates. The risk of rupture over 9 years was 3·4 per cent for EVAR and 0·9 per cent for open repair, and was weakly associated with patient factors. CONCLUSION: Long-term survival patterns after elective open repair and EVAR for unruptured AAA vary markedly across patients with different age and co-morbidity profiles.

ANTECEDENTES: El objetivo de este artículo fue examinar los patrones de supervivencia a 10 aáos tras reparación electiva de aneurismas de la aorta abdominal sin rotura (abdominal aortic aneurysms, AAA) en diferentes grupos de pacientes. MÉTODOS: Se identificaron pacientes sometidos a reparación abierta (open repair, OR) o reparación endovascular (endovascular aneurysm repair, EVAR) del aneurisma en el Sistema Nacional de Salud Inglés entre enero de 2006 y diciembre de 2015, a partir de los datos del Hospital Episode Statistics. Se analizaron la supervivencia postoperatoria entre los pacientes de diferentes edades y los perfiles de comorbilidad con la puntuación de Charlson modificada del Royal College of Surgeons of England (RCS) utilizando modelos de supervivencia paramétricos flexibles. También se analizó la relación entre las características de los pacientes y el riesgo de rotura tras la reparación. RESULTADOS: Un total de 37.138 pacientes fueron sometidos a reparaciones electivas de AAA, de las cuales 15.523 fueron reparaciones abiertas y 21.615 endovasculares. La mortalidad a los 10 aáos fue del 38% para los pacientes de edad inferior a los 70 aáos, y las curvas de supervivencia de la OR y EVAR fueron similares cuando los pacientes no tenían comorbilidad con el Charlson modificado del RCS. Entre los pacientes de edad avanzada y aquellos pacientes con comorbilidad, la mortalidad a los 10 aáos aumentó, excediendo el 70% para los pacientes de más de 80 aáos de edad. La media de los tiempos de supervivencia superior a 10 aáos para OR y EVAR fueron similares dentro de los subgrupos de pacientes de edad avanzada y más comorbilidad, pero las curvas de supervivencia se hicieron cada vez más diferentes, con la OR mostrando un mayor riesgo a corto plazo en los primeros 6 meses pero tasas de mortalidad a los 10 aáos más bajas. El riesgo de rotura mas allá de los 9 aáos fue 3,4% para EVAR y 0,9% para la reparación abierta, con una débil asociación con los factores inherentes a los pacientes. CONCLUSIÓN: Los patrones de supervivencia a largo plazo tras OR y EVAR electivas para AAA sin rotura varían notablemente entre pacientes con perfiles de edad y comorbilidad diferentes.

Population-based study of mortality and major amputation following lower limb revascularization.

BACKGROUND: The aim of this study was to estimate separate risks of major lower limb amputation and death following revascularization for peripheral artery disease (PAD) using competing risks analysis. METHODS: Routinely collected data from Hospital Episode Statistics (HES) were used to identify patients who underwent endovascular or open lower limb revascularization for PAD in England from 2005 to 2015. The primary outcomes were major lower limb amputation and death within 5 years of revascularization. Cox proportional hazards and Fine-Gray competing risks regression were used to examine the competing risks of these outcomes. RESULTS: Some 164 845 patients underwent their first lower limb revascularization for PAD during the study interval. Most were men (64·6 per cent) and the median age was 71 (i.q.r. 62-78) years. Following endovascular revascularization, the 5-year cumulative incidence of amputation was 4·2 per cent in patients with intermittent claudication and 18·0 per cent in those with a record of tissue loss. The corresponding rates were 10·8 and 25·3 per cent respectively after open revascularization, and 8·1 and 25·0 per cent after combined procedures. The 5-year cumulative incidence of death varied from 24·5 to 39·8 per cent, depending on procedure type. Competing risks methods consistently produced lower estimates than standard methods. CONCLUSION: The 5-year risk of major amputation following lower limb revascularization for PAD appears lower than estimated previously. Patients undergoing revascularization for tissue loss and those who require an open procedure are at highest risk of limb loss.

A step-wise approach to developing indicators to compare the performance of maternity units using hospital administrative data.

Hospital administrative data are attractive for comparing performance of maternity units because of their often large sample sizes, lack of selection bias and the relatively low costs of accessing these data compared with conducting primary data collection. However, using administrative data to develop indicators can also present challenges including varying data quality, the limited detail on clinical risk factors and a lack of structural and user experience measures. This review illustrates how to develop performance indicators for maternity units using hospital administrative data, including methods to address the challenges that administrative data pose. TWEETABLE ABSTRACT: How to develop maternity indicators from administrative data.

Development and internal validation of a novel risk adjustment model for adult patients undergoing emergency laparotomy surgery: the National Emergency Laparotomy Audit risk model.

BACKGROUND: Among patients undergoing emergency laparotomy, 30-day postoperative mortality is around 10-15%. The risk of death among these patients, however, varies greatly because of their clinical characteristics. We developed a risk prediction model for 30-day postoperative mortality to enable better comparison of outcomes between hospitals. METHODS: We analysed data from the National Emergency Laparotomy Audit (NELA) on patients having an emergency laparotomy between December 2013 and November 2015. A prediction model was developed using multivariable logistic regression, with potential risk factors identified from existing prediction models, national guidelines, and clinical experts. Continuous risk factors were transformed if necessary to reflect their non-linear relationship with 30-day mortality. The performance of the model was assessed in terms of its calibration and discrimination. Interval validation was conducted using bootstrap resampling. RESULTS: There were 4458 (11.5%) deaths within 30-days among the 38 830 patients undergoing emergency laparotomy. Variables associated with death included (among others): age, blood pressure, heart rate, physiological variables, malignancy, and ASA physical status classification. The predicted risk of death among patients ranged from 1% to 50%. The model demonstrated excellent calibration and discrimination, with a C-statistic of 0.863 (95% confidence interval, 0.858-0.867). The model retained its high discrimination during internal validation, with a bootstrap derived C-statistic of 0.861. CONCLUSIONS: The NELA risk prediction model for emergency laparotomies discriminates well between low- and high-risk patients and is suitable for producing risk-adjusted provider mortality statistics.

Association between age and access to immediate breast reconstruction in women undergoing mastectomy for breast cancer.

BACKGROUND: National guidelines state that patients with breast cancer undergoing mastectomy in England should be offered immediate breast reconstruction (IR), unless precluded by their fitness for surgery or the need for adjuvant therapies. METHODS: A national study investigated factors that influenced clinicians' decision to offer IR, and collected data on case mix, operative procedures and reconstructive decision-making among women with breast cancer having a mastectomy with or without IR in the English National Health Service between 1 January 2008 and 31 March 2009. Multivariable logistic regression was used to examine the relationship between whether or not women were offered IR and their characteristics (tumour burden, functional status, planned radiotherapy, planned chemotherapy, perioperative fitness, obesity, smoking status and age). RESULTS: Of 13 225 women, 6458 (48·8 per cent) were offered IR. Among factors the guidelines highlighted as relevant to decision-making, the three most strongly associated with the likelihood of an offer were tumour burden, planned radiotherapy and performance status. Depending on the combination of their values, the probability of an IR offer ranged from 7·4 to 85·1 per cent. A regression model that included all available factors discriminated well between whether or not women were offered IR (c-statistic 0·773), but revealed that increasing age was associated with a fall in the probability of an IR offer beyond that expected from older patients' tumour and co-morbidity characteristics. CONCLUSION: Clinicians are broadly following guidance on the offer of IR, except with respect to patients' age.

Surveillance of Gram-negative bacteria: impact of variation in current European laboratory reporting practice on apparent multidrug resistance prevalence in paediatric bloodstream isolates.

This study evaluates whether estimated multidrug resistance (MDR) levels are dependent on the design of the surveillance system when using routine microbiological data. We used antimicrobial resistance data from the Antibiotic Resistance and Prescribing in European Children (ARPEC) project. The MDR status of bloodstream isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was defined using European Centre for Disease Prevention and Control (ECDC)-endorsed standardised algorithms (non-susceptible to at least one agent in three or more antibiotic classes). Assessment of MDR status was based on specified combinations of antibiotic classes reportable as part of routine surveillance activities. The agreement between MDR status and resistance to specific pathogen-antibiotic class combinations (PACCs) was assessed. Based on all available antibiotic susceptibility testing, the proportion of MDR isolates was 31% for E. coli, 30% for K. pneumoniae and 28% for P. aeruginosa isolates. These proportions fell to 9, 14 and 25%, respectively, when based only on classes collected by current ECDC surveillance methods. Resistance percentages for specific PACCs were lower compared with MDR percentages, except for P. aeruginosa. Accordingly, MDR detection based on these had low sensitivity for E. coli (2-41%) and K. pneumoniae (21-85%). Estimates of MDR percentages for Gram-negative bacteria are strongly influenced by the antibiotic classes reported. When a complete set of results requested by the algorithm is not available, inclusion of classes frequently tested as part of routine clinical care greatly improves the detection of MDR. Resistance to individual PACCs should not be considered reflective of MDR percentages in Enterobacteriaceae.

Risk adjustment models for short-term outcomes after surgical resection for oesophagogastric cancer.

BACKGROUND: Outcomes for oesophagogastric cancer surgery are compared with the aim of benchmarking quality of care. Adjusting for patient characteristics is crucial to avoid biased comparisons between providers. The study objective was to develop a case-mix adjustment model for comparing 30- and 90-day mortality and anastomotic leakage rates after oesophagogastric cancer resections. METHODS: The study reviewed existing models, considered expert opinion and examined audit data in order to select predictors that were consequently used to develop a case-mix adjustment model for the National Oesophago-Gastric Cancer Audit, covering England and Wales. Models were developed on patients undergoing surgical resection between April 2011 and March 2013 using logistic regression. Model calibration and discrimination was quantified using a bootstrap procedure. RESULTS: Most existing risk models for oesophagogastric resections were methodologically weak, outdated or based on detailed laboratory data that are not generally available. In 4882 patients with oesophagogastric cancer used for model development, 30- and 90-day mortality rates were 2·3 and 4·4 per cent respectively, and 6·2 per cent of patients developed an anastomotic leak. The internally validated models, based on predictors selected from the literature, showed moderate discrimination (area under the receiver operating characteristic (ROC) curve 0·646 for 30-day mortality, 0·664 for 90-day mortality and 0·587 for anastomotic leakage) and good calibration. CONCLUSION: Based on available data, three case-mix adjustment models for postoperative outcomes in patients undergoing curative surgery for oesophagogastric cancer were developed. These models should be used for risk adjustment when assessing hospital performance in the National Health Service, and tested in other large health systems.

National trends and regional variation in immediate breast reconstruction rates.

BACKGROUND: Previous studies have identified variation in immediate reconstruction (IR) rates following mastectomy for breast cancer across English regions during a period of service reorganization, a national audit and changing guidelines. This study analysed current variations in regional rates of IR in England. METHODS: Patient-level data from Hospital Episode Statistics were used to define a cohort of women who underwent primary mastectomy for invasive or in situ breast carcinoma in English National Health Service (NHS) hospitals between April 2000 and March 2014. A time series of IR rates was calculated nationally and within regions in 28 cancer networks. Regional IR rates before and after the national audit were compared, using logistic regression to adjust for patient demographics, tumour type, co-morbidity and year of mastectomy. RESULTS: Between 2000 and 2014, a total of 167 343 women had a mastectomy. The national IR rate was stable at around 10 per cent until 2005; it then increased to 23·3 per cent by 2013-2014. Preaudit (before January 2008), adjusted cancer network-level IR rates ranged from 4·3 to 22·6 per cent. Postaudit (after April 2009) adjusted IR rates ranged from 13·1 to 36·7 per cent, with 20 networks having IR rates between 15 and 24 per cent. The degree of change was not greatest amongst those that started with the lowest IR rates, with four networks with the largest absolute increase also starting with relatively high IR rates. CONCLUSION: The national IR rate increased throughout the study period. Substantial regional variation remains, although considerable time has elapsed since a period of service reorganization, guideline revision and a national audit.

Population-based cohort study of the management and survival of patients with early-stage oesophageal adenocarcinoma in England.

BACKGROUND: Until recently, oesophagectomy was the treatment of choice for early oesophageal cancer. Endoscopic treatment has been introduced relatively recently. This observational national database study aimed to describe how endoscopic therapy has been introduced in England and to examine the safety of this approach. METHODS: A population-based cohort study was undertaken of patients diagnosed with oesophageal adenocarcinoma between October 2007 and June 2009 using three linked national databases. Patients with early-stage disease (T1 tumours with no evidence of spread) were identified, along with the primary treatment modality where treatment intent was curative. Short-term outcomes after treatment and 5-year survival were evaluated. RESULTS: Of 5192 patients diagnosed with oesophageal adenocarcinoma, 306 (5·9 per cent) were considered to have early-stage disease before any treatment, of whom 239 (79·9 per cent of 299 patients with data on treatment intent) were managed with curative intent. Of 175 patients who had an oesophagectomy, 114 (65·1 (95 per cent c.i. 57·6 to 72·7) per cent) survived for 5 years. Among these, 47 (30·3 per cent of 155 patients with tissue results available) had their disease upstaged after pathological staging; this occurred more often in patients who did not have staging endoscopic ultrasonography before surgery. Of 41 patients who had an endoscopic resection, 27 (66 (95 per cent c.i. 49 to 80) per cent) survived for 5 years. Repeat endoscopic therapy was required by 23 (56 per cent) of these 41 patients. CONCLUSION: Between 2007 and 2009, oesophagectomy remained the initial treatment of choice (73·2 per cent) among patients with early-stage oesophageal cancer treated with curative intent; one in five patients were managed endoscopically, and this treatment was more common in elderly patients. Although the groups had different patient characteristics, 5-year survival rates were similar.

Editor's Choice - Delays to Surgery and Procedural Risks Following Carotid Endarterectomy in the UK National Vascular Registry.

OBJECTIVE: Guidelines recommend that patients suffering an ischaemic transient ischaemic attack (TIA) or stroke caused by carotid artery stenosis should undergo carotid endarterectomy (CEA) within 14 days. METHOD: The degree to which UK vascular units met this standard was examined and whether rapid interventions were associated with procedural risks. The study analysed patients undergoing CEA between January 2009 and December 2014 from 100 UK NHS hospitals. Data were collected on patient characteristics, intervals of time from symptoms to surgery, and 30-day postoperative outcomes. The relationship between outcomes and time from symptom to surgery was evaluated using multilevel multivariable logistic regression. RESULTS: In 23,235 patients, the median time from TIA/stroke to CEA decreased over time, from 22 days (IQR 10-56) in 2009 to 12 days (IQR 7-26) in 2014. The proportion of patients treated within 14 days increased from 37% to 58%. This improvement was produced by shorter times across the care pathway: symptoms to referral, from medical review to being seen by a vascular surgeon, and then to surgery. The spread of the median time from symptom to surgery among NHS hospitals shrank between 2009 and 2013 but then grew slightly. Low-, medium-, and high-volume NHS hospitals all improved their performance similarly. Performing CEA within 48 h of symptom onset was associated with a small increase in the 30-day stroke and death rate: 3.1% (0-2 days) compared with 2.0% (3-7 days); adjusted odds ratio 1.64 (95% CI 1.04-2.59) but not with longer delays. CONCLUSIONS: The delay from symptom to CEA in symptomatic patients with ipsilateral 50-99% carotid stenoses has reduced substantially, although 42% of patients underwent CEA after the recommended 14 days. The risk of stroke after CEA was low, but there may be a small increase in risk during the first 48 h after symptoms.

The risk of ureteric injury associated with hysterectomy: a 10-year retrospective cohort study.

OBJECTIVE: To evaluate the rates of ureteric injury among women undergoing hysterectomy. DESIGN: Retrospective cohort. SETTING: English National Health Service hospitals. POPULATION: Women undergoing hysterectomy in 2001-2010. METHODS: Unadjusted rates of ureteric injury, within 1 year of hysterectomy, calculated by indication and type of procedure. Multivariable logistic regression used to assess the risk of ureteric injury with year of surgery. MAIN OUTCOME MEASURES: Ureteric injury within a year of the hysterectomy. RESULTS: In 2001-2010, 377 073 women underwent hysterectomy, of whom 1792 (0.5%) experienced a ureteric injury. In both benign and malignant groups the rate of injury was higher in 2006-2010 than 2001-2005. After 2006, ureteric injuries were most common for abdominal radical hysterectomy for uterine cancer (10.7%; 95% CI 7.3-15.1%). The proportion of women having a ureteric injury was similar for ovarian and cervical cancer (1.9-4.0% depending on type of procedure). For benign conditions, the rate of injury tended to be lower, typically <1%. Women with endometriosis had the highest risk among this group (1.7% following total abdominal hysterectomy; 95% CI 1.4-2.0%). CONCLUSION: The risk of ureteric injury within 1 year of hysterectomy varied by type of hysterectomy for benign and malignant conditions. The rates of injury have increased between 2001 and 2010. TWEETABLE ABSTRACT: Ten-year study shows ureteric injury rates have increased.

Socioeconomic deprivation and inpatient complication rates following mastectomy and breast reconstruction surgery.

BACKGROUND: Socioeconomic deprivation is known to influence the presentation of patients with breast cancer and their subsequent treatments, but its relationship with surgical outcomes has not been investigated. A national prospective cohort study was undertaken to examine the effect of deprivation on the outcomes of mastectomy with or without immediate breast reconstruction. METHODS: Data were collected on patient case mix, operative procedures and inpatient complications following mastectomy with or without immediate breast reconstruction in the English National Health Service between 1 January 2008 and 31 March 2009. Multivariable logistic regression was used to examine the relationship between patients' level of (regional) deprivation and the likelihood of local (mastectomy site, flap, flap donor and implant) and distant or systemic complications, after adjusting for potential confounding factors. RESULTS: Of 13,689 patients who had a mastectomy, 2849 (20.8 per cent) underwent immediate reconstruction. In total, 1819 women (13.3 per cent) experienced inpatient complications. The proportion with complications increased from 11.2 per cent among the least deprived quintile (Q1) to 16.1 per cent in the most deprived (Q5). Complication rates were higher among smokers, the obese and those with poorer performance status, but were not affected by age, tumour type or Nottingham Prognostic Index. Adjustment for patient-related factors only marginally reduced the association between deprivation and complication incidence, to 11.4 per cent in Q1 and 15.4 per cent in Q5. Further adjustment for length of hospital stay, hospital case volume and immediate reconstruction rate had minimal effect. CONCLUSION: Rates of postoperative complications after mastectomy and breast reconstruction surgery were higher among women from more deprived backgrounds.

A population-based cohort study of the effect of Caesarean section on subsequent fertility.

STUDY QUESTION: Is there an association between Caesarean section and subsequent fertility? SUMMARY ANSWER: There is no or only a slight effect of Caesarean section on future fertility. WHAT IS KNOWN ALREADY: Previous studies have reported that delivery by a Caesarean section is associated with fewer subsequent pregnancies and longer inter-pregnancy intervals. The interpretation of these findings is difficult because of significant weaknesses in study designs and analytical methods, notably the potential effect of the indication for Caesarean section on subsequent delivery. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study of 1 047 644 first births to low-risk women using routinely collected, national administrative data of deliveries in English maternity units between 1 April 2000 and 31 March 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: Primiparous women aged 15-40 years who had a singleton, term, live birth in the English National Health Service were included. Women with high-risk pregnancies involving placenta praevia, pre-eclampsia, eclampsia (gestational or pre-existing), hypertension or diabetes were excluded from the main analysis. Kaplan-Meier analyses and Cox proportional hazard models were used to assess the effect of mode of delivery on time to subsequent birth, adjusted for age, ethnicity, socio-economic deprivation and year of index delivery. MAIN RESULTS AND THE ROLE OF CHANCE: Among low-risk primiparous women, 224 024 (21.4%) were delivered by Caesarean section. The Kaplan-Meier estimate of the subsequent birth rate at 10 years for the cohort was 74.7%. Compared with vaginal delivery, subsequent birth rates were marginally lower after elective Caesarean for breech (adjusted hazard ratio, HR 0.96, 95% CI 0.94-0.98). Larger effects were observed after elective Caesarean for other indications (adjusted HR 0.81, 95% CI 0.78-0.83), and emergency Caesarean (adjusted HR 0.91, 95% CI 0.90-0.93). The effect was smallest for elective Caesarean for breech, and this was not statistically significant in women younger than 30 years of age (adjusted HR 0.98, 95% CI 0.96-1.01). LIMITATIONS, REASONS FOR CAUTION: We used birth cohorts from maternity units with good quality parity information. The data are likely to be nationally representative because the characteristics of the deliveries in included and omitted units were similar. There may be residual bias in our adjusted results due to unmeasured maternal factors such as obesity and voluntary absence of conception. Any residual bias would lead to an overestimate of the effect of Caesarean section on fertility, and the true effect is therefore likely to be smaller than the effect reported in our study. WIDER IMPLICATIONS OF THE FINDINGS: Our results provide strong evidence that there is no or only a slight effect of Caesarean section on future fertility. The clinical and social circumstances leading to the Caesarean section have a greater effect on future fertility than the Caesarean section itself. This finding is important in light of rising Caesarean section rates. STUDY FUNDING/COMPETING INTEREST(S): IG-U is supported by the Lindsay Stewart R&D Centre, Royal College of Obstetricians and Gynaecologists, UK. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: n/a.

Vaginal birth after caesarean section: a cohort study investigating factors associated with its uptake and success.

OBJECTIVES: To investigate the demographic and obstetric factors associated with the uptake and success rate of vaginal birth after caesarean section (VBAC). DESIGN: Cohort study using data from Hospital Episode Statistics. SETTING: English National Health Service. POPULATION: Women whose first birth resulted in a live singleton delivery by caesarean section between 1 April 2004 and 31 March 2011, and who had a second birth before 31 March 2012. METHODS: Logistic regression to estimate adjusted odds ratios (OR). MAIN OUTCOME MEASURES: Attempted and successful VBAC. RESULTS: Among the 143,970 women in the cohort, 75,086 (52.2%) attempted a VBAC for their second birth. Younger women, those of non-white ethnicity and those living in a more deprived area had higher rates of attempted VBAC. Overall, 47,602 women (63.4%) who attempted a VBAC had a successful vaginal birth. Younger women and women of white ethnicity had higher success rates. Black women had a particularly low success rate (OR, 0.54; 95% confidence interval [CI], 0.50-0.57). Women who had an emergency caesarean section in their first birth also had a lower VBAC success rate, particularly those with a history of failed induction of labour (OR, 0.59; 95% CI, 0.53-0.67). CONCLUSION: In this national cohort, just over one-half of women with a primary caesarean section who were eligible for a trial of labour attempted a VBAC for their second birth. Of these, almost two-thirds successfully achieved a vaginal delivery.

Impact of third- and fourth-degree perineal tears at first birth on subsequent pregnancy outcomes: a cohort study.

OBJECTIVE: To investigate, among women who have had a third- or fourth-degree perineal tear, the mode of delivery in subsequent pregnancies as well as the recurrence rate of third- or fourth-degree tears. DESIGN: A retrospective cohort study of deliveries using a national administrative database. SETTING: The English National Health Service between 1 April 2004 and 31 March 2012. POPULATION: A total of 639,402 primiparous women who had a singleton, term, vaginal live birth between April 2004 and March 2011, and a second birth before April 2012. METHODS: Multivariable logistic regression models were used to estimate odds ratios, adjusted for other risk factors. MAIN OUTCOME MEASURES: Mode of delivery and recurrence of tears at second birth. RESULTS: The rate of elective caesarean at second birth was 24.2% for women with a third- or fourth-degree tear at first birth, and 1.5% for women without (adjusted odds ratio, aOR 18.3, 95% confidence interval, 95% CI 16.4-20.4). Among women who had a vaginal delivery at second birth, the rate of third- or fourth-degree tears was 7.2% for women with a third- or fourth-degree tear at first birth, compared with 1.3% for women without (aOR 5.5, 95% CI 5.2-5.9). CONCLUSIONS: The risk of a severe perineal tear is increased five-fold in women who had a third- or fourth-degree tear in their first delivery. This increased risk should be taken into account when decisions about mode of delivery are made.

Impact of Caesarean section on subsequent fertility: a systematic review and meta-analysis.

STUDY QUESTION: Is there an association between a Caesarean section and subsequent fertility? SUMMARY ANSWER: Most studies report that fertility is reduced after Caesarean section compared with vaginal delivery. However, studies with a more robust design show smaller effects and it is uncertain whether the association is causal. WHAT IS KNOWN ALREADY: A previous systematic review published in 1996 summarizing six studies including 85 728 women suggested that Caesarean section reduces subsequent fertility. The included studies suffer from severe methodological limitations. STUDY DESIGN, SIZE, DURATION: Systematic review and meta-analysis of cohort studies comparing subsequent reproductive outcomes of women who had a Caesarean section with those who delivered vaginally. PARTICIPANTS/MATERIALS, SETTING, METHODS: Searches of Cochrane Library, Medline, Embase, CINAHL Plus and Maternity and Infant Care databases were conducted in December 2011 to identify randomized and non-randomized studies that compared the subsequent fertility outcomes after a Caesarean section and after a vaginal delivery. Eighteen cohort studies including 591 850 women matched the inclusion criteria. Risk of bias was assessed by the Newcastle-Ottawa scale (NOS). Data extraction was done independently by two reviewers. The meta-analysis was based on a random-effects model. Subgroup analyses were performed to assess whether the estimated effect was influenced by parity, risk adjustment, maternal choice, cohort period, and study quality and size. MAIN RESULTS AND THE ROLE OF CHANCE: The impact of Caesarean section on subsequent pregnancies could be analysed in 10 studies and on subsequent births in 16 studies. A meta-analysis suggests that patients who had undergone a Caesarean section had a 9% lower subsequent pregnancy rate [risk ratio (RR) 0.91, 95% confidence interval (CI) (0.87, 0.95)] and 11% lower birth rate [RR 0.89, 95% CI (0.87, 0.92)], compared with patients who had delivered vaginally. Studies that controlled for maternal age or specifically analysed primary elective Caesarean section for breech delivery, and those that were least prone to bias according to the NOS reported smaller effects. LIMITATIONS, REASONS FOR CAUTION: There is significant variation in the design and methods of included studies. Residual bias in the adjusted results is likely as no study was able to control for a number of important maternal characteristics, such as a history of infertility or maternal obesity. WIDER IMPLICATIONS OF THE FINDINGS: Further research is needed to reduce the impact of selection bias by indication through creating more comparable patient groups and applying risk adjustment.