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.

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.

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.

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.