Risk adjustment models for interhospital comparison of CS rates using Robson's ten group classification system and other socio-demographic and clinical variables

Comparison of Cesarean Deliveries in a Multicenter U.S. Cohort Using the 10-Group Classification System

OBJECTIVE

 We sought to (1) use the Robson 10-Group Classification System (TGCS), which classifies deliveries into 10 mutually exclusive groups, to characterize the groups that are primary contributors to cesarean delivery frequencies, (2) describe inter-hospital variations in cesarean delivery frequencies, and (3) evaluate the contribution of patient characteristics by TGCS group to hospital variation in cesarean delivery frequencies.

STUDY DESIGN

 This was a secondary analysis of an observational cohort of 115,502 deliveries from 25 hospitals between 2008 and 2011. The TGCS was applied to the cohort and each hospital. We identified and compared the TGCS groups with the greatest relative contributions to cohort and hospital cesarean delivery frequencies. We assessed variation in hospital cesarean deliveries attributable to patient characteristics within TGCS groups using hierarchical logistic regression.

RESULTS

 A total of 115,211 patients were classifiable in the TGCS (99.7%). The cohort cesarean delivery frequency was 31.4% (hospital range: 19.1-39.3%). Term singletons in vertex presentation with a prior cesarean delivery (group 5) were the greatest relative contributor to cohort (34.8%) and hospital cesarean delivery frequencies (median: 33.6%; range: 23.8-45.5%). Nulliparous term singletons in vertex (NTSV) presentation (groups 1 [spontaneous labor] and 2 [induced or absent labor]: 28.9%), term singletons in vertex presentation with a prior cesarean delivery (group 5: 34.8%), and preterm singletons in vertex presentation (group 10: 9.8%) contributed to 73.2% of the relative cesarean delivery frequency for the cohort and were correlated with hospital cesarean delivery frequencies (Spearman's rho = 0.96). Differences in patient characteristics accounted for 34.1% of hospital-level cesarean delivery variation in group 2.

CONCLUSION

 The TGCS highlights the contribution of NTSV presentation to cesarean delivery frequencies and the impact of patient characteristics on hospital-level variation in cesarean deliveries among nulliparous patients with induced or absent labor.

KEY POINTS

· We report on the cesarean delivery frequencies in a multicenter U.S.

COHORT

. · NTSV gestations (groups 1 and 2) are a primary driver of cesarean deliveries.. · Patient characteristics contributed most to hospital variation in cesarean deliveries in group 2..

Errors in the classification of pregnant women according to Robson ten-group classification system

OBJECTIVES

The Robson Ten-Group Classification System (TGCS) is widely used as a classification system for perinatal analyses such as Caesarean section (CS) rates. In Germany, standardised data sets on deliveries are classified by quality assurance institutions using the TGCS. This observational study aims to evaluate potential errors in the TCGS classification of deliveries.

STUDY DESIGN

Manual TGCS classification of all 1370 deliveries in an obstetric unit in 2018 and comparison with semi-automatic TGCS classifications of the quality assurance institution.

RESULTS

In the manual classification, 259 out of 1370 births (18.9 %) were assigned to a different Robson group than in the semi-automatic classification. The proportions of births by Robson group were significantly different in TGCS group 1 (32.2 % vs. 37.6 %, p = 0.0034) and group 2 (18.4 % vs. 14.4 %, p = 0.0053). Concordance between manual and semi-automatic classifications ranged from 59.5 % in group 2 to 100.0 % in groups 6, 7, 8, and 9. The most frequent mismatches were for the parameters "onset of labour" in 184 cases (13.4 %), "parity" in 42 cases (3.1 %) and "previous uterine scars" in 23 cases (1.7 %). In the manual classification, there were significant differences in the CS rate in group 1 (7.9 % vs. 2.5 %, p < 0.0001), group 2 (30.2 % vs. 48.2 %, p < 0.0001), and group 4 (14.1 % vs. 37.4 %, p = 0.0004), compared to the semi-automatic classification.

CONCLUSIONS

Due to incorrect data entry and unclear definitions of criteria, quality assurance data in obstetric databases may contain a relevant proportion of errors, which could influence statistics with TGCS in context of CS rates in international comparisons.

Impact of SARS-CoV-2 Positivity on Delivery Outcomes for Pregnant Women between 2020 and 2021: A Single-Center Population-Based Analysis

Despite the existing body of evidence, there is still limited knowledge about the impact of SARS-CoV-2 positivity on delivery outcomes. We aimed to assess the impact of SARS-CoV-2 infection in women who gave birth at the University Hospital "Federico II" of Naples, Italy, between 2020 and 2021. We conducted a retrospective single-center population-based observational study to assess the differences in the caesarean section and preterm labor rates and the length of stay between women who tested positive for SARS-CoV-2 and those who tested negative at the time of labor. We further stratified the analyses considering the time period, dividing them into three-month intervals, and changes in SARS-CoV-2 as the most prevalent variant. The study included 5236 women with 353 positive cases. After vaccination availability, only 4% had undergone a complete vaccination cycle. The Obstetric Comorbidity Index was higher than 0 in 41% of the sample. When compared with negative women, positive ones had 80% increased odds of caesarean section, and it was confirmed by adjusting for the SARS-CoV-2 variant. No significant differences were found in preterm birth risks. The length of stay was 11% higher in positive cases but was not significant after adjusting for the SARS-CoV-2 variant. When considering only positive women in the seventh study period (July-September 2021), they had a 61% decrease in the odds of receiving a caesarean section compared to the fourth (October-December 2020). Guidelines should be implemented to improve the safety and efficiency of the delivery process, considering the transition of SARS-CoV-2 from pandemic to endemic. Furthermore, these guidelines should aim to improve the management of airborne infections in pregnant women.

Crude and adjusted comparisons of cesarean delivery rates using the Robson classification: A population-based cohort study in Canada and Sweden, 2004 to 2016

BACKGROUND

The Robson classification has become a global standard for comparing and monitoring cesarean delivery (CD) rates across populations and over time; however, this classification does not account for differences in important maternal, fetal, and obstetric practice factors known to impact CD rates. The objectives of our study were to identify subgroups of women contributing to differences in the CD rate in Sweden and British Columbia (BC), Canada using the Robson classification and to estimate the contribution of maternal, fetal/infant, and obstetric practice factors to differences in CD rates between countries and over time.

METHODS AND FINDINGS

We conducted a population-based cohort study of deliveries in Sweden (January 1, 2004 to December 31, 2016; n = 1,392,779) and BC (March 1, 2004 to April 31, 2017; n = 559,205). Deliveries were stratified into Robson categories and the CD rate, relative size of each group and its contribution to the overall CD rate were compared between the Swedish and the Canadian cohorts. Poisson and log-binomial regression were used to assess the contribution of maternal, fetal, and obstetric practice factors to spatiotemporal differences in Robson group-specific CD rates between Sweden and BC. Nulliparous women comprised 44.8% of the study population, while women of advanced maternal age (≥35 years) and women with overweight/obesity (≥25 kg/m2) constituted 23.5% and 32.4% of the study population, respectively. The CD rate in Sweden was stable at approximately 17.0% from 2004 to 2016 (p for trend = 0.10), while the CD rate increased in BC from 29.4% to 33.9% (p for trend < 0.001). Differences in CD rates between Sweden and BC varied by Robson group, for example, in Group 1 (nullipara with a term, single, cephalic fetus with spontaneous labor), the CD rate was 8.1% in Sweden and 20.4% in BC (rate ratio [RR] for BC versus Sweden = 2.52, 95% confidence interval [CI] 2.49 to 2.56, p < 0.001) and in Group 2 (nullipara, single, cephalic fetus, term gestation with induction of labor or prelabor CD), the rate of CD was 37.3% in Sweden and 45.9% in BC (RR = 1.23, 95% CI 1.22 to 1.25, p < 0.001). The effect of adjustment for maternal characteristics (e.g., age, body mass index), maternal comorbidity (e.g., preeclampsia), fetal characteristics (e.g., head position), and obstetric practice factors (e.g., epidural) ranged from no effect (e.g., among breech deliveries; Groups 6 and 7) to explaining up to 5.2% of the absolute difference in the CD rate (Group 2: adjusted CD rate in BC 40.7%, adjusted RR = 1.09, 95% CI 1.08 to 1.12, p < 0.001). Adjustment also explained a substantial fraction of the temporal change in CD rates among some Robson groups in BC. Limitations of the study include a lack of information on intrapartum details, such as labor duration as well as maternal and perinatal outcomes associated with the observed differences in CD rates.

CONCLUSIONS

In this study, we found that several factors not included in the Robson classification explain a significant proportion of the spatiotemporal difference in CD rates in some Robson groups. These findings suggest that incorporating these factors into explanatory models using the Robson classification may be useful for ensuring that public health initiatives regarding CD rates are evidence informed.

Analysis of cesarean section rates in two German hospitals applying the 10-Group Classification System

OBJECTIVES

In Germany, cesarean section (CS) rates more than doubled within the past two decades. For analysis, auditing and inter-hospital comparison, the 10-Group Classification System (TGCS) is recommended. We used the TGCS to analyze CS rates in two German hospitals of different levels of care.

METHODS

From October 2017 to September 2018, data were prospectively collected. Unit A is a level three university hospital, unit B a level one district hospital. The German birth registry was used for comparison with national data. We performed two-sample Z tests and bootstrapping to compare aggregated (unit A + B) with national data and unit A with unit B.

RESULTS

In both datasets (national data and aggregated data unit A + B), Robson group (RG) 5 was the largest contributor to the overall CS rate. Compared to national data, group sizes in RG 1 and 3 were significantly smaller in the units under investigation, RG 8 and 10 significantly larger. Total CS rates between the two units differed (40.7 vs. 28.4%, p<0.001). The CS rate in RG 5 and RG 10 was different (p<0.01 for both). The most relative frequent RG in both units consisted of group 5, followed by group 10 and 2a.

CONCLUSIONS

The analysis allowed us to explain different CS rates with differences in the study population and with differences in the clinical practice. These results serve as a starting point for audits, inter-hospital comparisons and for interventions aiming to reduce CS rates.

Variation between hospital caesarean delivery rates when Robson's classification is considered: An observational study from a French perinatal network

INTRODUCTION

WHO has recommended using Robson's Ten Group Classification System (TGCS) to monitor and analyze CD rates. Its failure to take some maternal and organizational factors into account, however, could limit the interpretation of CD rate comparisons, because it may contribute to variations in hospital CD rates.

OBJECTIVE

To study the contribution of maternal socioeconomic and clinical characteristics and hospital organizational factors to the variation in CD rates when using Robson's ten-group classification system for CD rate comparisons.

METHODS

This prospective, observational, population-based study included all deliveries at a gestational age > 24 weeks at the 10 hospitals of the French MYPA perinatal network in the Paris area. CD rates were calculated for each TGCS group in each hospital. Interhospital variations in these rates were investigated with hierarchical logistic regression models to quantify the variation explained by differences in patient and hospital characteristics when the TGCS is considered. Variations in CD rates between hospitals were estimated with median odds ratios (MOR) to express interhospital variance on the standard odds ratio scale. The percentage of variation explained by TGCS and maternal and hospital characteristics was also calculated.

RESULTS

The global CD rate was 24.0% (interhospital range: 17-32%). CD rates within each TGCS group differed significantly between hospitals (P<0.001). CD was significantly associated with maternal age (>40 years), severe preeclampsia, and two organizational factors: hospital status (private maternities) and the deliveries per staff member per 24 hours. The MOR in the empty model was 1.27 and did not change after taking the TGCS into account. Adding maternal characteristics and hospital organizational factors lowered the MOR to 1.14 and reduced the variation between hospital CD rates by 70%.

CONCLUSION

Maternal characteristics and hospital factors are needed to address variation in CD rates among the TGCS groups. Therefore, comparisons of these rates that do not consider these factors should be interpreted carefully.

Do obstetrics trainees working hours affect caesarean section rates in normal risk women?

OBJECTIVES

The rate of caesarean section (CS) is increasing globally. The nulliparous, term, singleton, vertex presentation, spontaneously labouring woman (Robson Group 1/RG1) is considered low risk for CS. It has been hypothesized that more CS occur at nighttime or at weekends due to doctor fatigue. The European Working Time Directive (EWTD) was implemented in our institution in 2013 to limit doctor working hours, which aimed at reducing fatigue but arguably fractures continuity of care. This study aimed to determine the effect of nocturnal hours and weekend on-call as well as the implementation of EWTD on our RG1 CS rates.

STUDY DESIGN

This was a population-based study in a tertiary referral centre from 2008-2017. The inclusion criteria for our study were limited to RG1. Data were analysed from an established clinical database, including mode and time of delivery. Descriptive statistics are presented as number and percent for categorical variables. Relative frequencies were tested using chi-squared test. All statistical analyses were performed using SPSS Version 26. Statistical significance was defined as p < .05.

RESULTS

There were 86,473 deliveries over the 10-year study period. There were 18,761 women in RG1. Overall the RG1 CS rate was 12.9 % (n = 2415). Rates of CS in the RG1 were not statistically different between those delivering on weekdays (12.9 %, n = 1726/13,430) and weekends (12.9 %, n = 689/5,331, OR 0.99, 95 % CI = 0.90-1.09, p = .89). During daytime hours the CS rate was 12.1 % (n = 777/6411) and at nighttime was 13.3 % (n = 1638/12,350, OR 1.10, 95 % CI = 1.01-1.21, p = .03). Comparing the time periods pre and post EWTD implementation, there was a significant increase in CS rates (12.1 % n = 1319/10,873 V 13.9 % n = 1096/7,888, OR 1.17, 95 % CI = 1.07-1.27 p < .001). With respect to other modes of delivery in RG1 pre and post EWTD, there was a statistically significant decrease in operative vaginal delivery (OVD) rates (40.1%, n=4,360 V 37.7%, n=2,973, OR 0.90, 95% CI = 0.85-0.95, p = .001) CONCLUSION: This study shows an association between obstetric trainee working practices, RG1 CS and OVD rates; this is most pronounced at night and after the introduction of the EWTD. It is unlikely that obstetric trainee working practices are the only factor related to the increasing CS rate and reduced OVD rate. Consideration should be giving to addressing the needs of obstetric trainees in relation to achieving their competencies with now reduced labour ward exposure. Further study is required to see if alternate arrangements in relation to simulation training could increase the OVD rate and reduce the CS rate.

"An unnecessary cut?" multilevel health systems analysis of drivers of caesarean sections rates in Italy: a systematic review

BACKGROUND

Improvements in medical technologies have seen over-medicalization of childbirth. Caesarean section (CS) is a lifesaving procedure proven effective in reducing maternal and perinatal mortality across the globe. However, as with any medical procedure, the CS intrinsically carries some risk to its beneficiaries. In recent years, CS rates have risen alarmingly in high-income countries. Many exceeding the World Health Organisation (WHO) recommendation of a 10 to 15% annual CS rate. While this situation poses an increased risk to women and their children, it also represents an excess human and financial burden on health systems. Therefore, from a health system perspective this study systematically summarizes existing evidence relevant to the factors driving the phenomenon of increasing CS rates using Italy as a case study.

METHODS

Employing the WHO Health System Framework (WHOHSF), this systematic review used the PRISMA guidelines to report findings. PubMed, SCOPUS, MEDLINE, Cochrane Library and Google Scholar databases were searched up until April 1, 2020. Findings were organised through the six dimensions of the WHOHSF framework: service delivery, health workforce, health system information; medical products vaccine and technologies, financing; and leadership and governance.

RESULTS

CS rates in Italy are affected by complex interactions among several stakeholder groups and contextual factors such as the hyper-medicalisation of delivery, differences in policy and practice across units and the national context, issues pertaining to the legal and social environment, and women's attitudes towards pregnancy and childbirth.

CONCLUSION

Mitigating the high rates of CS will require a synergistic multi-stakeholder intervention. Specifically, with processes able to attract the official endorsement of policy makers, encourage concensus between regional authorities and local governments and guide the systematic compliance of delivery units with its clinical guidelines.

The Robson classification for caesarean section-A proposed method based on routinely collected health data

BACKGROUND

With an increasing rate of caesarean sections as well as rising numbers of multiple pregnancies, valid classifications for benchmarking are needed. The Robson classification provides a method to group cases with caesarean section in order to assess differences in outcome across regions and sites. In this study we set up a novel method of classification by using routinely collected health data. We hypothesize i that routinely collected health data can be used to apply complex medical classifications and ii that the Robson classification is capable of classifying mothers and their corresponding newborn into meaningful groups with regard to outcome.

METHODS AND FINDINGS

The study was conducted at the coding department and the department of obstetrics and gynecology Inselspital, University Hospital of Bern, Switzerland. The study population contained inpatient cases from 2014 until 2017. Administrative and health data were extracted from the Data Warehouse. Cases were classified by a Structured Query Language code according to the Robson criteria using data from the administrative system, the electronic health record and from the laboratory system. An automated query to classify the cases according to Robson could be implemented and successfully validated. A linkage of the mother's class to the corresponding newborn could be established. The distribution of clinical indicators was described. It could be shown that the Robson classes are associated to outcome parameters and case related costs.

CONCLUSIONS

With this study it could be demonstrated, that a complex query on routinely collected health data would serve for medical classification and monitoring of quality and outcome. Risk-stratification might be conducted using this data set and should be the next step in order to evaluate the Robson criteria and outcome. This study will enhance the discussion to adopt an automated classification on routinely collected health data for quality assurance purposes.

Design characteristics of studies on medical practice variation of caesarean section rates: a scoping review

BACKGROUND

Medical practice variation in caesarean section rates is the most studied type of practice variation in the field of obstetrics and gynaecology. This has not resulted in increased homogeneity of treatment between geographic areas or healthcare providers. Our study aim was to evaluate whether current study designs on medical practice variation of caesarean section rates were optimized to identify the unwarranted share of practice variation and could contribute to the reduction of unwarranted practice variation by meeting criteria for audit and feedback.

METHODS

We searched PubMed, Embase, EBSCO/CINAHL and Wiley/Cochrane Library from inception to March 24th, 2020. Studies that compared the rate of caesarean sections between individuals, institutions or geographic areas were included. Study design was assessed on: selection procedure of study population, data source, case-mix correction, patient preference, aggregation level of analysis, maternal and neonatal outcome, and determinants (professional and organizational characteristics).

RESULTS

A total of 284 studies were included. Most studies (64%) measured the caesarean section rate in the entire study population instead of using a sample (30%). (National) databases were most often used as information source (57%). Case-mix correction was performed in 87 studies (31%). The Robson classification was used in 20% of the studies following its endorsement by the WHO in 2015. The most common levels of aggregation were hospital level (35%) and grouped hospitals (35%) e.g. private versus public. The percentage of studies that assessed the relationship between variation in caesarean section rates and maternal outcome was 9%, neonatal outcome 19%, determinants (professional and organizational characteristics) 21% and patient preference 2%.

CONCLUSIONS

Study designs of practice variation in caesarean sections varied considerably, raising questions about their appropriateness. Studies focused on measuring practice variation, rather than contributing to the reduction of unwarranted practice variation. Future studies should correct for differences in patient characteristics (case-mix) and patient preference to identify unwarranted practice variation. Practice variation studies could be used for audit and feedback if results are presented at lower levels of aggregation, and appeal to intrinsic motivation of physicians, for example by including the health effects on mother and child.

Role of maternal characteristics and epidural analgesia on caesarean section rate in groups 1 and 3 according to Robson's classification: a cohort study in an Italian university hospital setting

OBJECTIVE

To investigate the role of maternal characteristics and epidural analgesia (EA) on caesarean section (CS) rates in selected groups by using the Robson 10-Group Classification System (RTGCS).

DESIGN

Cohort study.

SETTING

Department of Obstetrics and Gynaecology, Fondazione Policlinico Universitario 'A. Gemelli', Rome, Italy.

PATIENTS

A total of 12 098 deliveries in periods I (1998-1999) and II (2010-2011).

MAIN OUTCOME MEASURES

CS rates in groups 1 and 3 of RTGCS.

RESULTS

In group 1, 1144 (20%) patients were assigned to period I and 1302 (20.4%) to period II, while in group 3, 1587 (27.8%) were assigned to period I and 1502 (23.5%) to period II. CS rates were 16.4% and 23.1% in group 1 and 12.7% and 10.9% in group 3 in periods I and II, respectively. In group 1, significant and independent contributions to CS rate were provided by maternal age (p=0.018; OR 0.95 (95% CI 0.85 to 0.97)), body mass index (BMI) (p=0.022; OR 0.89 (95% CI 0.85 to 0.91)) and EA administration (p=0.037; OR 0.59 (95% CI 0.43 to 0.77)). In group 3, maternal age (p<0.001; OR 0.93 (95% CI 0.89 to 0.96)) and BMI (p=0.023; OR 0.98 (95% CI 0.96 to 0.99)) were found to be significantly associated with CS.

CONCLUSIONS

RTGCS is an effective tool for analysing changes in obstetric care, allowing for the recognition of maternal age, BMI and EA administration in the strategic planning for mitigation of CS rates in selected groups.

Use of the 10-Group Classification System to analyze how the population control policy change in China has affected cesarean delivery

OBJECTIVE

To analyze the initial effect following the relaxation of China's population control policy on the cesarean delivery (CD) rate using the 10-Group Classification System (TGCS).

METHODS

A retrospective study included all deliveries at a center in Nanjing, China, during 2014-2015. The deliveries were classified using the TGCS. The obstetric populations and the CD rates in each group were compared between 2014 and 2015.

RESULTS

Overall, 11 006 deliveries were analyzed. The overall CD rate increased from 28.3% (1623/5737) in 2014 to 33.8% (1782/5269) in 2015 (P<0.001). The largest contributor to the overall CD rate-accounting for approximately one-third of all CDs-were nulliparous women with a single cephalic term pregnancy and induced labor or prelabor CD (group 2); the CD rate in this group increased from 27.2% to 31.4%. Moreover, the proportion of women with a single cephalic term pregnancy with previous CD (group 5) steeply increased from 6.4% to 10.4% of all deliveries; the CD rate in this group during 2014-2015 was 76.6%.

CONCLUSION

With China ending its one-child policy, the characteristics of the obstetric population changed. Women with a single cephalic term pregnancy with previous CD were the largest contributor to the CD rate increase.

Is the Robson's classification system burdened by obstetric pathologies, maternal characteristics and assistential levels in comparing hospitals cesarean rates? A regional analysis of class 1 and 3

OBJECTIVE

To assess if maternal risk profile and Hospital assistential levels were able to influence the inter-Hospitals comparison in the class 1 and 3 of the "The Ten Group Classification System" (TGCS).

METHODS

A population-based analysis using data from Institutional data-base of an Italian Region was carried out. The 11 maternity wards were divided into two categories: second-level hospitals (SLH), and first-level hospitals (FLH). The recorded deliveries were classified according to the TGCS. To analyze if different maternal characteristics and the hospitals assistential level could influence the cesarean section (CS) risk, a multivariate analysis was done considering separately women in the TGCS class 1 and 3.

RESULTS

From January 2011 to December 2013 were recorded 19,987 deliveries. Of those 7,693 were in the TGCS class 1 and 4,919 in the class 3. The CS rates were 20.8% and 14.7% in class 1 (p < 0.0001) and 6.9% and 5.3% (p < 0.0230) in class 3, respectively in the FLH and SLH. The multivariate logistic regression showed that the FLH, older maternal age and gestational diabetes were independent risk factors for CS in groups 1 and 3. Obesity and gestational hypertension were also independent risk factors for group 1.

CONCLUSIONS

TGCS is a useful tool to analyze the incidence of CS in a single center but in comparing different Hospitals, maternal characteristics and different assistential levels should be considered as potential bias.

A global reference for caesarean section rates (C-Model): a multicountry cross-sectional study

Objective

To generate a global reference for caesarean section (CS) rates at health facilities.

Design

Cross‐sectional study.

Setting

Health facilities from 43 countries.

Population/Sample

Thirty eight thousand three hundred and twenty‐four women giving birth from 22 countries for model building and 10 045 875 women giving birth from 43 countries for model testing.

Methods

We hypothesised that mathematical models could determine the relationship between clinical‐obstetric characteristics and CS. These models generated probabilities of CS that could be compared with the observed CS rates. We devised a three‐step approach to generate the global benchmark of CS rates at health facilities: creation of a multi‐country reference population, building mathematical models, and testing these models.

Main outcome measures

Area under the ROC curves, diagnostic odds ratio, expected CS rate, observed CS rate.

Results

According to the different versions of the model, areas under the ROC curves suggested a good discriminatory capacity of C‐Model, with summary estimates ranging from 0.832 to 0.844. The C‐Model was able to generate expected CS rates adjusted for the case‐mix of the obstetric population. We have also prepared an e‐calculator to facilitate use of C‐Model (www.who.int/reproductivehealth/publications/maternal_perinatal_health/c-model/en/).

Conclusions

This article describes the development of a global reference for CS rates. Based on maternal characteristics, this tool was able to generate an individualised expected CS rate for health facilities or groups of health facilities. With C‐Model, obstetric teams, health system managers, health facilities, health insurance companies, and governments can produce a customised reference CS rate for assessing use (and overuse) of CS.

Tweetable abstract

The C‐Model provides a customized benchmark for caesarean section rates in health facilities and systems.

The C‐Model provides a customized benchmark for caesarean section rates in health facilities and systems.

The Robson ten-group classification system for appraising deliveries at a tertiary referral hospital in Brazil

OBJECTIVE

To evaluate the distribution of women according to the Robson 10-group classification system (RTGCS) and the occurrence of severe maternal morbidity (SMM) by mode of delivery at a tertiary referral hospital.

METHODS

A retrospective cross-sectional study was conducted of all women admitted to the Women's Hospital at the University of Campinas (Campinas, Brazil) for delivery between January 2009 and July 2013. Women were grouped according to RTGCS. Mode of delivery and SMM (defined as need for admission to the intensive care unit) were assessed.

RESULTS

Among 12 771 women, 5957 (46.6%) delivered by cesarean. Overall, 3594 (28.1%) women were in group 1 (nulliparous, single pregnancy, cephalic, term, spontaneous labor), 2328 (18.2%) in group 5 (≥1 previous cesarean, single pregnancy, cephalic, term), and 2112 (16.5%) in group 3 (multiparous excluding previous cesarean, single pregnancy, cephalic, term, spontaneous labor). Group 5 contributed the most cesarean deliveries (1626 [27.3%]), followed by group 2 (nulliparous, single pregnancy, cephalic, term, induced labor or cesarean before labor; 1049 [17.6%]). SMM was more common among women undergoing cesarean delivery than among those delivering vaginally in groups 1-5.

CONCLUSION

The RTGCS allowed the identification of groups with the highest frequency of cesarean delivery and an assessment of SMM. This should be considered in related health policies.

Differential misclassification of confounders in comparative evaluation of hospital care quality: caesarean sections in Italy

BACKGROUND

Despite extensive studies on exposure and disease misclassification, few studies have investigated misclassification of confounders. This study aimed to identify differentially misclassified confounders in a comparative evaluation of hospital care quality and to quantify their impact on hospital-specific risk-adjusted estimates, focusing on the appropriateness of caesarean sections (CS).

METHODS

We gathered data from the Hospital Information System in Italy for women admitted in 2005-2010. We estimated adjusted proportions of CS with logistic regression models. Among several confounders, we focused on high fetal head at term (HFH), which is seldom objectively documentable in medical records.

RESULTS

A total of 540 maternity units were compared. The median HFH prevalence was 0.9%, ranging from 0 to 70%. In some units, HFH was coded so frequently that it was unlikely to reflect a natural heterogeneity. This "over-coding" was conditional on the outcome because it occurred more frequently for women that underwent CS. This suggested an opportunistic coding to justify the choice of a CS. HFH misclassification was not randomly distributed over Italy; it had an excess in the Campania region where, in some units, the proportion of HFHs gradually increased from 2005 to 2010 (e.g., from 0 to 26%), but the national average remained constant (2.5%). The inclusion of the misclassified diagnosis in the models favored those hospitals that codified in a less-than-fair manner.

CONCLUSIONS

Our findings emphasized the importance of rigorously inspecting for differential misclassification of confounders. Their validity may be subject to substantial heterogeneity over hospitals, over time and geographical areas.

Determinants of cesarean delivery: a classification tree analysis

BACKGROUND

Cesarean delivery (CD) rates are rising in many parts of the world. To define strategies to reduce them, it is important to identify their clinical and organizational determinants. The objective of this cross-sectional study is to identify sub-types of women at higher risk of CD using demographic, clinical and organizational variables.

METHODS

All hospital discharge records of women who delivered between 2005 and mid-2010 in the Emilia-Romagna Region of Italy were retrieved and linked with birth certificates. Sociodemographic and clinical information was retrieved from the two data sources. Organizational variables included activity volume (number of births per year), hospital type, and hour and day of delivery. A classification tree analysis was used to identify the variables and the combinations of variables that best discriminated cesarean from vaginal delivery.

RESULTS

The classification tree analysis indicated that the most important variables discriminating the sub-groups of women at different risk of cesarean section were: previous cesarean, mal-position/mal-presentation, fetal distress, and abruptio placentae or placenta previa or ante-partum hemorrhage. These variables account for more than 60% of all cesarean deliveries. A sensitivity analysis identified multiparity and fetal weight as additional discriminatory variables.

CONCLUSIONS

Clinical variables are important predictors of CD. To reduce the CD rate, audit activities should examine in more detail the clinical conditions for which the need of CD is questionable or inappropriate.

A systematic review of the Robson classification for caesarean section: what works, doesn't work and how to improve it

BACKGROUND

Caesarean sections (CS) rates continue to increase worldwide without a clear understanding of the main drivers and consequences. The lack of a standardized internationally-accepted classification system to monitor and compare CS rates is one of the barriers to a better understanding of this trend. The Robson's 10-group classification is based on simple obstetrical parameters (parity, previous CS, gestational age, onset of labour, fetal presentation and number of fetuses) and does not involve the indication for CS. This classification has become very popular over the last years in many countries. We conducted a systematic review to synthesize the experience of users on the implementation of this classification and proposed adaptations.

METHODS

Four electronic databases were searched. A three-step thematic synthesis approach and a qualitative metasummary method were used.

RESULTS

232 unique reports were identified, 97 were selected for full-text evaluation and 73 were included. These publications reported on the use of Robson's classification in over 33 million women from 31 countries. According to users, the main strengths of the classification are its simplicity, robustness, reliability and flexibility. However, missing data, misclassification of women and lack of definition or consensus on core variables of the classification are challenges. To improve the classification for local use and to decrease heterogeneity within groups, several subdivisions in each of the 10 groups have been proposed. Group 5 (women with previous CS) received the largest number of suggestions.

CONCLUSIONS

The use of the Robson classification is increasing rapidly and spontaneously worldwide. Despite some limitations, this classification is easy to implement and interpret. Several suggested modifications could be useful to help facilities and countries as they work towards its implementation.

Unexplained variation in hospital caesarean section rates

OBJECTIVES

To assess recent hospital caesarean section (CS) rates in New South Wales, adjusted for case mix; to quantify the amount of variation that can be explained by case mix differences; and to examine the potential impact on the overall CS rate of reducing variation in practice.

DESIGN AND SETTING

Population-based record linkage study of births in 81 hospitals in New South Wales, 2009-2010, using the Robson classification to categorise births, and multilevel logistic regression to examine variation in hospital CS rates within Robson groups.

MAIN OUTCOME MEASURES

Hospital CS rates.

RESULTS

The overall CS rate was 30.9%, ranging from 11.8% to 47.4% (interquartile range, 23.9%-33.1%) among hospitals. The three groups contributing most to the overall CS rate all comprised women with a single cephalic pregnancy who gave birth at term, including: those who had had a previous CS (36.4% of all CSs); nulliparous women with an elective delivery (prelabour CS or labour induction, 23.4%); and nulliparous women with spontaneous labour (11.1%). After adjustment for case mix, marked unexplained variation in hospital CS rates persisted for: nulliparous women at term; women who had had a previous CS; multifetal pregnancies; and preterm births. If variation in practice was reduced for these risk-based groups by achieving the "best practice" rate, this would lower the overall rate by an absolute reduction of 3.6%, from 30.9% to 27.3%.

CONCLUSION

Understanding hospital heterogeneity in performing CS and implementing evidence-based practices may result in improved maternity care. We have identified five risk-based groups as priority targets for reducing practice variation in CS rates.

The application of the Ten Group classification system (TGCS) in caesarean delivery case mix adjustment. A multicenter prospective study

Background

Caesarean delivery (CD) rates are commonly used as an indicator of quality in obstetric care and risk adjustment evaluation is recommended to assess inter-institutional variations. The aim of this study was to evaluate whether the Ten Group classification system (TGCS) can be used in case-mix adjustment.

Methods

Standardized data on 15,255 deliveries from 11 different regional centers were prospectively collected. Crude Risk Ratios of CDs were calculated for each center. Two multiple logistic regression models were herein considered by using: Model 1- maternal (age, Body Mass Index), obstetric variables (gestational age, fetal presentation, single or multiple, previous scar, parity, neonatal birth weight) and presence of risk factors; Model 2- TGCS either with or without maternal characteristics and presence of risk factors. Receiver Operating Characteristic (ROC) curves of the multivariate logistic regression analyses were used to assess the diagnostic accuracy of each model. The null hypothesis that Areas under ROC Curve (AUC) were not different from each other was verified with a Chi Square test and post hoc pairwise comparisons by using a Bonferroni correction.

Results

Crude evaluation of CD rates showed all centers had significantly higher Risk Ratios than the referent. Both multiple logistic regression models reduced these variations. However the two methods ranked institutions differently: model 1 and model 2 (adjusted for TGCS) identified respectively nine and eight centers with significantly higher CD rates than the referent with slightly different AUCs (0.8758 and 0.8929 respectively). In the adjusted model for TGCS and maternal characteristics/presence of risk factors, three centers had CD rates similar to the referent with the best AUC (0.9024).

Conclusions

The TGCS might be considered as a reliable variable to adjust CD rates. The addition of maternal characteristics and risk factors to TGCS substantially increase the predictive discrimination of the risk adjusted model.

Methods of achieving and maintaining an appropriate caesarean section rate

Caesarean section rates continue to increase worldwide. The appropriate caesarean section rate remains a topic of debate among women and professionals. Evidence-based medicine has not provided an answer and depends on interpretation of the literature. Overall caesarean section rates are unhelpful, and caesarean section rates should not be judged in isolation from other outcomes and epidemiological characteristics. Better understanding of caesarean section rates, their consequences and their benefits will improve care, and enable learning between delivery units nationally and internationally. To achieve and maintain an appropriate caesarean section rate requires a Multidisciplinary Quality Assurance Programme in each delivery unit, recognising caesarean section rates as one of many factors that determine quality. Women will always choose the type of delivery that seems safest to them and their babies. Professionals need to monitor the quality of their practice continuously in a standardised way to ensure that women can make the right choice.