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

BACKGROUND: Caesarean section (CS) rate is a quality of health care indicator frequently used at national and international level . The aim of this study was to assess whether adjustment for Robson's Ten Group Classification System (TGCS), and clinical and socio-demographic of the mother and the fetus is necessary for inter-hospital comparisons of CS rates. METHODS: The study population includes 64,423 deliveries in Emilia-Romagna between January 1, 2003 and December 31, 2004, classified according to theTGCS. Poisson regression was used to estimate crude and adjusted hospital relative risks of CS compared to a reference category. Analyses were carried out in the overall population and separately according to the Robson groups (groups I, II, III, IV and V-X combined). Adjusted relative risks (RR) of CS were estimated using two risk-adjustment models; the first (M1) including the TGCS group as the only adjustment factor; the second (M2) including in addition demographic and clinical confounders identified using a stepwise selection procedure. Percentage variations between crude and adjusted RRs by hospital were calculated to evaluate the confounding effect of covariates. RESULTS: The percentage variations from crude to adjusted RR proved to be similar in M1 and M2 model. However, stratified analyses by Robson's classification groups showed that residual confounding for clinical and demographic variables was present in groups I (nulliparous, single, cephalic, [greater than or equal to]37 weeks, spontaneous labour) and III (multiparous, excluding previous CS, single, cephalic, [greater than or equal to]37 weeks, spontaneous labour) and IV (multiparous, excluding previous CS, single, cephalic, [greater than or equal to]37 weeks, induced or CS before labour) and to a minor extent in groups II (nulliparous, single, cephalic, [greater than or equal to]37 weeks, induced or CS before labour) and IV (multiparous, excluding previous CS, single, cephalic, [greater than or equal to]37 weeks, induced or CS before labour). CONCLUSIONS: The TGCS classification is useful for inter-hospital comparison of CS section rates, but residual confounding is present in the TGCS strata

Ambient Particulate Matter Air Pollution and Venous Thromboembolism in the Women’s Health Initiative Hormone Therapy Trials

BackgroundThe putative effects of postmenopausal hormone therapy on the association between particulate matter (PM) air pollution and venous thromboembolism (VTE) have not been assessed in a randomized trial of hormone therapy, despite its widespread use among postmenopausal women.ObjectiveIn this study, we examined whether hormone therapy modifies the association of PM with VTE risk.MethodsPostmenopausal women 50–79 years of age (n = 26,450) who did not have a history of VTE and who were not taking anticoagulants were enrolled in the Women’s Health Initiative Hormone Therapy trials at 40 geographically diverse U.S. clinical centers. The women were randomized to treatment with estrogen versus placebo (E trial) or to estrogen plus progestin versus placebo (E + P trial). We used age-stratified Cox proportional hazard models to examine the association between time to incident, centrally adjudicated VTE, and daily mean PM concentrations spatially interpolated at geocoded addresses of the participants and averaged over 1, 7, 30, and 365 days.ResultsDuring the follow-up period (mean, 7.7 years), 508 participants (2.0%) had VTEs at a rate of 2.6 events per 1,000 person-years. Unadjusted and covariate-adjusted VTE risk was not associated with concentrations of PM 0.05) regardless of PM averaging period, either before or after combining data from both trials [e.g., combined trial-adjusted hazard ratios (95% confidence intervals) per 10 μg/m3 increase in annual mean PM2.5 and PM10, were 0.93 (0.54–1.60) and 1.05 (0.72–1.53), respectively]. Findings were insensitive to alternative exposure metrics, outcome definitions, time scales, analytic methods, and censoring dates.ConclusionsIn contrast to prior research, our findings provide little evidence of an association between short-term or long-term PM exposure and VTE, or clinically important modification by randomized exposure to exogenous estrogens among postmenopausal women

Risk adjusted inter-hospital comparison for caesarean section considering the first four Robson classification groups

Background The caesarean section (CS) rate continues to rise in many countries around the world even though this increase is not associated with improvement in maternal and perinatal mortality or morbility. The CS rate can be analysed by using the Robson Ten Group Classification System (TGCS), which categorizes women in ten mutually exclusive groups. We decided to concentrate on the first four Robson groups as primary caesarean deliveries are an important target for reduction and there is no clear evidence about risks and benefits of CS in pre-term birth or breech presentation. The aim was to identify an overall predictive model for CS in order to perform a risk adjusted hospital comparison. Methods All women who delivered in Emilia-Romagna from 1 January 2003 to 31 December 2004 were identified by linking Hospital Discharge Abstracts and Birth Certificate databases. Sociodemographic variables and maternal and neonatal clinical factors were collected. We considered all the identified groupspecific risk factors and the statistically significant risk differences of CS determinants among groups and constructed an overall predictive model to perform a risk adjusted comparison among birth units. Results In total, 64 672 women were enrolled. The first four TGCS groups included 79.6% of total deliveries and 47.1% of CS. Considering the overall predictive model the highest adjusted RRs were found for ante-partum haemorrhage and severe co-morbid illness of mothers. The first and third Robson groups had the higher RRs than the second and fourth groups. After risk-adjusted comparison the Units ranking varied considering the four TGCS groups together or separately. Conclusions In order to improve comparisons among hospital performances to promote a reduction of unnecessary CS, our study focused on the first four TGCS groups. Examining the overall predictive model in each group, it will be possible to understand differences in order to implement specific audit activities

Vaginal birth after caesarean birth in Italy: Variations among areas of residence and hospitals 11 Medical and Health Sciences 1117 Public Health and Health Services

Background: The rates of caesarean section (CS) are increasing globally. CS rates are one of the most frequently used indicators of health care quality. Vaginal Birth After Caesarean (VBAC) could be considered a reasonable and safe option for most women with a previous CS. Despite this fact, in some European countries, many women who had a previous CS will have a routine CS subsequently and VBAC rates are extremely variable across countries. VBAC use is inversely related to caesarean use. The objective of the present study was to analyze VBAC rates with respect to caesarean rates and the variations among areas of residence, hospitals and hospital ownership types in Italy.Methods: This study was based on information from the Hospital Information System (HIS). We collected data from all deliveries in Italy from January 1, 2010 to December 31, 2014 and we considered only deliveries with a previous caesarean section. Applying multivariate logistic regression analysis, the adjusted proportions of VBAC for each Local Health Units (LHU), each hospital and by hospital ownership types were calculated. Cross-classified logistic multilevel models were performed to analyze within geographic, hospitals and hospital ownership types variations.Results: We studied a total of 77,850 deliveries with a previous caesarean section in Italy between January 1, 2010 and December 31, 2014. The proportion of VBAC in Italy slightly increased in the last few years, from 5.8% in 2010 to 7.5% in 2014. Proportions of VBAC ranged from 0.29 to 50.05% in Italian LHUs. The LHUs with lower proportions of VBAC deliveries were characterized by higher values for primary caesarean deliveries. Private hospitals showed the lowest mean of crude VBAC proportions but the highest variation among hospitals, ranging from 0 to 47.1%.Conclusions: Hospital rates of caesarean section for women with at least one previous caesarean section vary widely, and only some of the variation can be explained by case-mix and hospital-level factors, suggesting that additional factors influence practices. Identifying disparities in VBAC may have important implications for health services planning and targeted efforts to reduce overall rates of caesarean deliveries

The effects of particulate air pollution on hospital admissions for cardiac diseases in potentially sensitive subgroups. a multicity case-crossover analysis.

Backgrounds and aims. Several studies have shown that particulate air pollution with aerodynamic diameter less than 10 micrometers (PM10) is associated with increased risk of hospital admissions for cardiovascular causes. However, only few studies focused on subgroups of population especially susceptible to these effects. The objective of the present study was to estimate the short-term association between PM10 and cardiac hospital admissions, and to identify susceptible groups. Methods. A “time-stratified” case-crossover study was carried out in 9 Italian cities from 2001 to 2005. The associations between daily PM10 and all cardiac diseases (CD), acute coronary syndrome (ACS), arrhythmias and conduction disorders (ACD), and heart failure (HF) were estimated for hospitalizations of 65+ year-old subjects. The effect modification was assessed assuming age, gender and hospital diagnoses from the previous two-years as susceptibility factors. Results. A total of 167,895 hospitalizations of 65+ year old with a diagnosis of cardiac diseases were considered. The excess risk of CD was 1.03% (95% confidence interval: 0.69-1.38) per 10 ug/m3 PM10 at lag 0 and was lower on the following days. The effect was slightly higher for HF (1.37%; 0.74%-2.00%, lag 0) and ACS (1.13%; 0.37%-1.89%, lag 0-1) than for ACD (1.00%; 0.22%-1.78%, lag 0). Women were at higher risk of PM10-related HF admissions (1.99%; 1.17%-2.82%; p-interaction = 0.022) and 75-84-year-old subjects were at higher risk of ACS admissions (2.61%; 1.49%-3.75%; p-interaction = 0.001). Previously diagnosed hypertension, arrhythmias and heart failure were suggested as effect modifiers of the PM10-heart failure association. Conclusions. An important effect of PM10 on hospitalizations for cardiac diseases was found in Italian cities. Women, 75-84 year-old subjects and subjects whit previous cardiovascular diseases were susceptible to the PM10 effect