Linkage of four administrative datasets to examine blood transfusion in pregnancy

Currently collected hospital data records fact of transfusion, but lacks detail on quantity of blood transfused, and timing of transfusions. A number of administrative datasets collect information on blood transfusion including quantity and timing. Linkage of multiple datasources has the potential to give increase the depth of information available for researchers. This study aims to describe the linkage of four administrative datasets to identify transfusions among women giving birth in NSW and to describe the population represented by this linked data. Hospital, birth, blood issue and blood pack databases were linked to identify women receiving red blood cell transfusions in NSW between July 2006 and December 2010. Characteristics of the linked data population are compared with the population of all women giving birth, and births in public hospitals. Between July 2006-December 2010 there were 425,036 births in NSW hospitals, including 235,796 in a population with additional blood issue data available, of which, 4642(2%) received a transfusion. Hospitals supplying blood issue data were more likely to be larger urban or tertiary hospitals, and had a higher risk population than the state overall and public hospitals generally. Linkage of multiple data sources provides additional detail compared with hospital data alone, providing a wealth of data for researchers. The population identified through linkage differs from the overall birthing population, and to a lesser extent from women birthing in public hospitals. In some cases this may affect generalisability of research findings, but in other cases may be beneficial

Haemoglobin changes during pregnancy: a retrospective cohort study of consecutive pregnancies

NHMR

Trends and outcomes of postpartum haemorrhage, 2003-2011

Background: While rates of postpartum haemorrhage (PPH) have continued to rise, it is not clear if the association with other morbidity and transfusion has changed over time. This study explores the recent trend in postpartum haemorrhage and risk factors for transfusion and other severe adverse maternal outcomes following postpartum haemorrhage, stratified by mode of delivery. Methods: Linked birth and hospital data were used to examine ICD-10AM coded PPH and outcomes in maternal birth admission records, 2003-2011 in hospitals in New South Wales (NSW), Australia (N= 818,965 singleton pregnancies). Trends were calculated on the whole population, and among subgroups, and tested using the Cochran Armitage test for trend. Logistic regression models were developed separately for vaginal and caesarean births, and for a maternal morbidity composite indicator (excluding transfusion) and red cell transfusion. Adjusted odds ratios (aOR) for yearly change and 95% confidence intervals (CI) are presented. Adjustment included maternal (eg. age, country of birth) and pregnancy factors (eg. parity, interventions, pregnancy complications). Results: Overall, there was a significant increase in the PPH rate, from 6.1% in 2003 to 8.3% in 2011 (p<0.0001). Having accounted for maternal and pregnancy factors, there was no significant increase in morbidity among women delivering vaginally with a PPH (aOR for yearly change 0.97 (0.94-1.00); p=0.36), and a slight decrease among women delivered by caesarean section (aOR 0.96 (0.92-0.99); p<0.01). There was a slight increase in transfusions for vaginal births (aOR 1.02 (1.00-1.03); p<0.01), however there was no significant trend amongst caesarean births (aOR 0.99 (0.97-1.01); p=0.30). Conclusions: PPH has become more frequent, however this has not been associated with increased maternal morbidity. This suggests that the increase in PPH may represent fewer severe haemorrhages, well-managed haemorrhage or better recording of PPH.NHMRC, AR

Variation in hospital caesarean section rates for preterm births

Background: Evidence about optimal mode of delivery for preterm birth is lacking and there is thought to be considerable variation in practice. Objective: To assess whether variation in hospital preterm caesarean section rates (Robson Classification Group 10) and outcomes are explained by casemix, labour or hospital characteristics. Materials and Methods: Population-based cohort study in NSW, 2007-2011. Births were categorised according to degree of prematurity and hospital service capability: 26-31 weeks, 32-33 weeks and 34-36 weeks. Hospital preterm caesarean rates were investigated using multilevel logistic regression models, progressively adjusting for casemix, labour and hospital factors. The association between hospital caesarean rates, and severe maternal and neonatal morbidity rates was assessed. Results: At 26-31 weeks the caesarean rate was 55.2% (7 hospitals, range 43.4-58.4%); 50.9% at 32-33 weeks (12 hospitals, 43.4- 58.1%); and 36.4% at 34-36 weeks (51 hospitals, 17.4-48.3%). At 26-31 weeks and 32-33 weeks, 81% and 59% of the variation between hospitals was explained with no hospital significantly different from the state average after adjustment. At 34-36 weeks, although 59% of the variation was explained, substantial unexplained variation persisted. Hospital caesarean rates were not associated with severe maternal morbidity rates at any gestational age. At 26-31 weeks medium and high caesarean rates were associated with higher severe neonatal morbidity rates, but there was no evidence of this association ≥32 weeks. 3 Conclusion: Both casemix and practice differences contributed to the variation in hospital caesarean rates. Low preterm caesarean rates were not associated with worse outcomes.Australian National Health and Medical Research Council; Australian Research Counci

Pre-notification letter type and response rate to a postal survey among women who have recently given birth

Background: Surveys are commonly used in health research to assess patient satisfaction with hospital care. Achieving an adequate response rate, in the face of declining trends over time, threatens the quality and reliability of survey results. This paper reports on a postal satisfaction survey conducted with women who had recently given birth, and explores the effect of two strategies on response rates. Methods: A sample of 2048 Australian women who had recently given birth were invited to participate in a postal survey about their recent experiences with maternity care. The study design included two different strategies intended to increase response rates: a randomised controlled trial testing two types of pre-notification letter (with or without the option of opting out of the survey), and a request for consent to link survey data with existing routinely collected health data (omitting the latter data items from the survey reduced survey length and participant burden). Results: The survey had an overall response rate of 46%. Women receiving the pre-notification letter with the option of opting out of the survey were more likely to actively decline to participate than women receiving the letter without this option, although the overall numbers of women were small (27 versus 12). Letter type was not significantly associated with the return of a completed survey. Among women who completed the survey, 97% gave consent to link their survey data with existing health data. Conclusions: Seeking consent for record linkage was highly acceptable to women who completed the survey, and represents an important strategy to add to the arsenal for designing and implementing effective surveys. In addition to aspects of survey design, future research should explore how to more effectively influence personal constructs that contribute to the decision to participate in surveys.NHMR