Reporting of prognostic markers: current problems and development of guidelines for evidence-based practice in the future

Prognostic markers help to stratify patients for treatment by identifying patients with different risks of outcome (e.g. recurrence of disease), and are important tools in the management of cancer and many other diseases. Systematic review and meta-analytical approaches to identifying the most valuable prognostic markers are needed because (sometimes conflicting) evidence relating to markers is often published across a number of studies. To investigate the practicality of this approach, an empirical investigation of a systematic review of tumour markers for neuroblastoma was performed; 260 studies of prognostic markers were identified, which considered 130 different markers

Cardiovascular Risk with Non-Steroidal Anti-Inflammatory Drugs: Systematic Review of Population-Based Controlled Observational Studies

David Henry and colleagues reevaluate the evidence from observational studies on the cardiovascular risk associated with non-steroidal anti-inflammatory drugs

The re-identification risk of Canadians from longitudinal demographics

<p>Abstract</p> <p>Background</p> <p>The public is less willing to allow their personal health information to be disclosed for research purposes if they do not trust researchers and how researchers manage their data. However, the public is more comfortable with their data being used for research if the risk of re-identification is low. There are few studies on the risk of re-identification of Canadians from their basic demographics, and no studies on their risk from their longitudinal data. Our objective was to estimate the risk of re-identification from the basic cross-sectional and longitudinal demographics of Canadians.</p> <p>Methods</p> <p>Uniqueness is a common measure of re-identification risk. Demographic data on a 25% random sample of the population of Montreal were analyzed to estimate population uniqueness on postal code, date of birth, and gender as well as their generalizations, for periods ranging from 1 year to 11 years.</p> <p>Results</p> <p>Almost 98% of the population was unique on full postal code, date of birth and gender: these three variables are effectively a unique identifier for Montrealers. Uniqueness increased for longitudinal data. Considerable generalization was required to reach acceptably low uniqueness levels, especially for longitudinal data. Detailed guidelines and disclosure policies on how to ensure that the re-identification risk is low are provided.</p> <p>Conclusions</p> <p>A large percentage of Montreal residents are unique on basic demographics. For non-longitudinal data sets, the three character postal code, gender, and month/year of birth represent sufficiently low re-identification risk. Data custodians need to generalize their demographic information further for longitudinal data sets.</p

De-identifying a public use microdata file from the Canadian national discharge abstract database

<p>Abstract</p> <p>Background</p> <p>The Canadian Institute for Health Information (CIHI) collects hospital discharge abstract data (DAD) from Canadian provinces and territories. There are many demands for the disclosure of this data for research and analysis to inform policy making. To expedite the disclosure of data for some of these purposes, the construction of a DAD public use microdata file (PUMF) was considered. Such purposes include: confirming some published results, providing broader feedback to CIHI to improve data quality, training students and fellows, providing an easily accessible data set for researchers to prepare for analyses on the full DAD data set, and serve as a large health data set for computer scientists and statisticians to evaluate analysis and data mining techniques. The objective of this study was to measure the probability of re-identification for records in a PUMF, and to de-identify a national DAD PUMF consisting of 10% of records.</p> <p>Methods</p> <p>Plausible attacks on a PUMF were evaluated. Based on these attacks, the 2008-2009 national DAD was de-identified. A new algorithm was developed to minimize the amount of suppression while maximizing the precision of the data. The acceptable threshold for the probability of correct re-identification of a record was set at between 0.04 and 0.05. Information loss was measured in terms of the extent of suppression and entropy.</p> <p>Results</p> <p>Two different PUMF files were produced, one with geographic information, and one with no geographic information but more clinical information. At a threshold of 0.05, the maximum proportion of records with the diagnosis code suppressed was 20%, but these suppressions represented only 8-9% of all values in the DAD. Our suppression algorithm has less information loss than a more traditional approach to suppression. Smaller regions, patients with longer stays, and age groups that are infrequently admitted to hospitals tend to be the ones with the highest rates of suppression.</p> <p>Conclusions</p> <p>The strategies we used to maximize data utility and minimize information loss can result in a PUMF that would be useful for the specific purposes noted earlier. However, to create a more detailed file with less information loss suitable for more complex health services research, the risk would need to be mitigated by requiring the data recipient to commit to a data sharing agreement.</p

Timing of prophylactic uterotonics for the third stage of labour after vaginal birth.

Background: Administration of the uterotonic drugs is one of the main components of the active management of the third stage of labour. The timing of uterotonics varies considerably across the globe and it may have significant implications on the well-being of the mothers and their babies. Objectives: To assess the effect of the timing of administration of prophylactic uterotonics (before compared to after placental delivery) on the outcomes related to the third stage of labour. Search strategy: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2009). Selection criteria: Randomised controlled trials examining the timing of prophylactic uterotonic drugs in the third stage of labour. Data collection and analysis: Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data entry was checked. Main results: We included three trials involving 1671 participants; oxytocin was the only uterotonic drug that was used. The dose and route of administration of oxytocin varied among the included studies. Administration of oxytocin before and after the expulsion of placenta does not significantly influence the incidence of postpartum haemorrhage (blood loss greater than 500 ml) (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.62 to 1.04; n = 1667, three trials); retained placenta (RR 1.54, 95% CI 0.76 to 3.11; n = 1667, three trials); length of third stage of labour (minutes) (mean difference (MD) -0.30, 95% CI -0.95 to 0.36; n = 1667, three trials); postpartum blood loss (ml) (MD 22.32, 95% CI -58.21 to 102.86; n = 181, two trials); changes in haemoglobin (g/dL) (MD 0.06, 95% CI -0.60 to 0.72; n = 51, one trial); blood transfusion (RR 0.79, 95% CI 0.23 to 2.73; n = 1667, three trials); the use of additional uterotonics (RR 1.10, 95% CI 0.80 to 1.52; n = 1667, three trials); the incidence of maternal hypotension (RR 2.48, 95% CI 0.23 to 26.70; n = 130, one trial) and the incidence of severe postpartum haemorrhage (blood loss 1000 ml or more) (RR 0.98, 95% CI 0.48 to 1.98; n = 130, one trial). No data on other maternal or neonatal outcome measures were available. Authors' conclusions: Administration of oxytocin before and after the expulsion of placenta did not have any significant influence on many clinically important outcomes such as the incidence of postpartum haemorrhage, rate of placental retention and the length of the third stage of labour. However, the number of available studies were limited. The only uterotonic drug used was oxytocin, mainly through intravenous infusion, therefore its extrapolation to other routes of administration should be interpreted cautiously. More studies are required to examine other maternal and neonatal outcomes using consistent approaches. This record should be cited as: Soltani H, Hutchon DR, Poulose TA. Timing of prophylactic uterotonics for the third stage of labour after vaginal birth. Cochrane Database of Systematic Reviews 2010, Issue 8. Art. No.: CD006173. DOI: 10.1002/14651858.CD006173.pub