Quality of data in perinatal population health databases: a systematic review.

BACKGROUND: Administrative or population health datasets (PHDS) are increasingly being used for research related to maternal and infant health. However, the accuracy and completeness of the information in the PHDS is important to ensure validity of the results of this research. OBJECTIVE: To compile and review studies that validate the reporting of conditions and procedures related to pregnancy, childbirth, and newborns and provide a tool of reference for researchers. METHODS: A systematic search was conducted of Medline and EMBASE databases to find studies that validated routinely collected datasets containing diagnoses and procedures related to pregnancy, childbirth, and newborns. To be included datasets had to be validated against a gold standard, such as review of medical records, maternal interview or survey, specialized register, or laboratory data. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and/or κ statistic for each diagnosis or procedure code were calculated. RESULTS: Forty-three validation studies were included. Under-enumeration was common, with the level of ascertainment increasing as time from diagnosis/procedure to birth decreased. Most conditions and procedures had high specificities indicating few false positives, and procedures were more accurately reported than diagnoses. Hospital discharge data were generally more accurate than birth data, however identifying cases from more than 1 dataset further increased ascertainment. CONCLUSIONS: This comprehensive collection of validation studies summarizing the quality of perinatal population data will be an invaluable resource to all researchers working with PHDS.

Validation and application of a death proxy in adult cancer patients.

PURPOSE: Fact of death is not always available on data sets used for pharmacoepidemiological research. Proxies may be an appropriate substitute in the absence of death data. The purposes of this study were to validate a proxy for death in adult cancer patients and to assess its performance when estimating survival in two cohorts of cancer patients. METHODS: We evaluated 30-, 60-, 90- and 180-day proxies overall and by cancer type using data from 12 394 Australian veterans with lung, colorectal, breast or prostate cancer. The proxy indicated death if the difference between the last dispensing record and the end of the observational period exceeded the proxy cutoff. We then compared actual survival to 90-day proxy estimates in a subset of 4090 veterans with 'full entitlements' for pharmaceutical items and in 3704 Australian women receiving trastuzumab for HER2+ metastatic breast cancer. RESULTS: The 90-day proxy was optimal with an overall sensitivity of 99.3% (95%CI: 98.4-99.7) and a specificity of 97.6% (95%CI: 91.8-99.4). These measures remained high when evaluated by cancer type and spread of disease. The application of the proxy using the most conservative date of death estimate (date of last dispensing) generally underestimated survival, with estimates up to 3 months shorter than survival based on fact of death. CONCLUSIONS: A 90-day death proxy is a robust substitute to identify death in a chronic population when fact of death is not available. The proxy is likely to be valid across a range of chronic diseases as it relies on the presence of 'regular' dispensing records for individual patients. Copyright © 2011 John Wiley & Sons, Ltd.

Investigation of relative risk estimates from studies of the same population with contrasting response rates and designs.

BACKGROUND: There is little empirical evidence regarding the generalisability of relative risk estimates from studies which have relatively low response rates or are of limited representativeness. The aim of this study was to investigate variation in exposure-outcome relationships in studies of the same population with different response rates and designs by comparing estimates from the 45 and Up Study, a population-based cohort study (self-administered postal questionnaire, response rate 18%), and the New South Wales Population Health Survey (PHS) (computer-assisted telephone interview, response rate ~60%). METHODS: Logistic regression analysis of questionnaire data from 45 and Up Study participants (n = 101,812) and 2006/2007 PHS participants (n = 14,796) was used to calculate prevalence estimates and odds ratios (ORs) for comparable variables, adjusting for age, sex and remoteness. ORs were compared using Wald tests modelling each study separately, with and without sampling weights. RESULTS: Prevalence of some outcomes (smoking, private health insurance, diabetes, hypertension, asthma) varied between the two studies. For highly comparable questionnaire items, exposure-outcome relationship patterns were almost identical between the studies and ORs for eight of the ten relationships examined did not differ significantly. For questionnaire items that were only moderately comparable, the nature of the observed relationships did not differ materially between the two studies, although many ORs differed significantly. CONCLUSIONS: These findings show that for a broad range of risk factors, two studies of the same population with varying response rate, sampling frame and mode of questionnaire administration yielded consistent estimates of exposure-outcome relationships. However, ORs varied between the studies where they did not use identical questionnaire items.

Serum glucose levels for predicting death in patients admitted to hospital for community acquired pneumonia: prospective cohort study.

OBJECTIVE: To examine whether acute dysglycaemia predicts death in people admitted to hospital with community acquired pneumonia. DESIGN: Multicentre prospective cohort study. SETTING: Hospitals and private practices in Germany, Switzerland, and Austria. PARTICIPANTS: 6891 patients with community acquired pneumonia included in the German community acquired pneumonia competence network (CAPNETZ) study between 2003 and 2009. MAIN OUTCOME MEASURES: Univariable and multivariable hazard ratios adjusted for sex, age, current smoking status, severity of community acquired pneumonia using the CRB-65 score (confusion, respiratory rate >30/min, systolic blood pressure ≤ 90 mm Hg or diastolic blood pressure ≤ 60 mm Hg, and age ≥ 65 years), and various comorbidities for death at 28, 90, and 180 days according to serum glucose levels on admission. RESULTS: An increased serum glucose level at admission to hospital in participants with community acquired pneumonia and no pre-existing diabetes was a predictor of death at 28 and 90 days. Compared with participants with normal serum glucose levels on admission, those with mild acute hyperglycaemia (serum glucose concentration 6-10.99 mmol/L) had a significantly increased risk of death at 90 days (1.56, 95% confidence interval 1.22 to 2.01; P<0.001), and this risk increased to 2.37 (1.62 to 3.46; P<0.001) when serum glucose concentrations were ≥ 14 mmol/L. In sensitivity analyses the predictive value of serum glucose levels on admission for death was confirmed at 28 days and 90 days. Patients with pre-existing diabetes had a significantly increased overall mortality compared with those without diabetes (crude hazard ratio 2.47, 95% confidence interval 2.05 to 2.98; P<0.001). This outcome was not significantly affected by serum glucose levels on admission (P = 0.18 for interaction). CONCLUSIONS: Serum glucose levels on admission to hospital can predict death in patients with community acquired pneumonia without pre-existing diabetes. Acute hyperglycaemia may therefore identify patients in need of intensified care to reduce the risk of death from community acquired pneumonia.

Impact of scoring algorithm on physical activity prevalence estimates in Australian adults.

Public health recommendations for physical activity are operationalised by defining thresholds for frequency (sessions/week), duration (min/week), or volume (MET-min/week). This study compared estimates of meeting physical activity recommendations when scoring algorithms varied in specifications for frequency and duration but were comparable in volume. Data were obtained from 13,105 Australian adult respondents to the 2006 Exercise, Recreation and Sport Survey (ERASS). Prevalence estimates were calculated using algorithms defined by (i) frequency only (≥5 sessions/week); (ii) duration only (≥150 min/week); (iii) duration only when minutes of vigorous activity were weighted by 2 (≥150 weighted-min/week); (iv) frequency and duration (≥5 sessions/week, ≥150 min/week); (v) volume only (≥600 MET-min/week); and (vi) volume and frequency (≥600 MET-min/week, ≥5 sessions/week). The proportion of adults who met recommendations operationalised without a frequency requirement was twice the proportions obtained for algorithms with frequency requirements. Volume or duration-based algorithms yielded higher estimates for men than women, and for the younger age groups (<35 years) than the older groups, with the opposite observation for frequency-based algorithms. Consistent for all algorithms, people classified at the highest educational attainment had the highest prevalence of meeting recommendations. Agreement in achieving 600 MET-min/week when activities were categorised using activity-specific MET values versus median MET values was 98.3%. Prevalence rates based on 600 MET-min/week were similar to 150 weighted-min/week. In conclusion, varying frequency and duration requirements of scoring algorithms can yield different population estimates and patterns by population subgroup of physical activity for a health benefit.

Strategies for increasing high-quality intervention research in Aboriginal and Torres Strait Islander health: views of leading researchers.

OBJECTIVE: To identify policy strategies that are perceived by researchers active in Aboriginal and Torres Strait Islander health as effective in increasing the amount of high-quality intervention research undertaken in this field. DESIGN AND SETTING: A cross-sectional study using a web-based survey was emailed to researchers based in clinical, public health and other academic institutions. PARTICIPANTS: Researchers who had published more than once in Aboriginal health between 1 January 2005 and 1 August 2009, based on a MEDLINE search. MAIN OUTCOME MEASURES: Participants selected and weighted 17 strategies that were, in their opinion, important for increasing the amount of high-quality intervention research being conducted in Aboriginal health. RESULTS: We invited 157 researchers to complete the survey, and received 74 completed surveys. The most highly weighted strategies were: for research funding bodies to give funding priority to intervention research proposals that target Aboriginal populations (median weighted score,15%); for peak bodies representing Aboriginal communities to clearly specify intervention research priorities in a national Aboriginal health research agenda (median weighted score, 10%); for research funding bodies to fund research to develop reliable measures of health for Aboriginal people (median weighted score, 9.5%); for health care organisations to participate more in intervention research targeting Aboriginal populations (median, 8.5%); and for research review panels to accept intervention research designs other than the randomised controlled trial (median weighted score, 8%). CONCLUSIONS: Researchers who are active in Aboriginal health research perceive that improvements in funding mechanisms, priority setting and research systems are required to increase the amount of high-quality intervention research being conducted in this field. A national intervention research agenda that encourages multidisciplinary research teams and community partnerships may offer a solution.