Effects on the Underlying Water Column by Extensive Floating Treatment Wetlands.

Floating treatment wetlands (FTWs) are an emerging engineering option with promise for simultaneous water quality improvement and habitat creation. Relatively little research has been published regarding their construction or effects on the underlying water column. In this field-scale experiment, four different extensive FTW designs were constructed using minimal materials, including drainpipe, burlap, mulch, utility netting, and reused polyethylene bottles. The FTWs were then planted with spp. (cattail) and L. (common rush). Over 28 mo, the water column beneath FTWs in two test ponds was compared to that in an open water control pond. The ponds (190 ± 10 m) were fed with well water enriched with nitrate to emulate agricultural ponds. Although observed differences were relatively small, statistically significant differences were noted. With respect to the control, waters underneath FTWs had lower dissolved oxygen, sulfate, nitrate, and pH, dampened diurnal temperature fluctuations, and greater alkalinity. The FTWs created habitat and were colonized by species of insects, birds, amphibians, snails, and spiders. Results indicated that spp. is suitable for FTW creation. However, a more supportive planting matrix is suggested to encourage faster plant growth and protect against wind and wave action damage. Although plant growth was limited, results suggest that FTWs may be applied to encourage less aerobic and more organic rich and thermally insulated conditions for water quality improvement in agricultural ponds and other aquatic systems while also creating valuable habitat.

Identifying cases of congestive heart failure from administrative data: a validation study using primary care patient records.

INTRODUCTION: To determine if using a combination of hospital administrative data and ambulatory care physician billings can accurately identify patients with congestive heart failure (CHF), we tested 9 algorithms for identifying individuals with CHF from administrative data. METHODS: The validation cohort against which the 9 algorithms were tested combined data from a random sample of adult patients from EMRALD, an electronic medical record database of primary care physicians in Ontario, Canada, and data collected in 2004/05 from a random sample of primary care patients for a study of hypertension. Algorithms were evaluated on sensitivity, specificity, positive predictive value, area under the curve on the ROC graph and the combination of likelihood ratio positive and negative. RESULTS: We found that that one hospital record or one physician billing followed by a second record from either source within one year had the best result, with a sensitivity of 84.8% and a specificity of 97.0%. CONCLUSION: Population prevalence of CHF can be accurately measured using combined administrative data from hospitalization and ambulatory care.

TITLE: Repérage des cas d'insuffisance cardiaque congestive à partir de données administratives : étude de validation utilisant des dossiers de patients en soins primaires. INTRODUCTION: En vue de déterminer si l'utilisation conjuguée des données administratives hospitalières et des factures présentées par les médecins au titre des soins ambulatoires pouvait permettre de repérer avec exactitude les patients souffrant d'insuffisance cardiaque congestive (ICC), nous avons mis à l'essai neuf algorithmes pour repérer à partir de données administratives les personnes souffrant d'ICC. MÉTHODOLOGIE: La cohorte de validation par rapport à laquelle les essais ont été effectués combinait des données provenant d'un échantillon aléatoire de patients adultes inscrits dans la base de données EMRALD de dossiers médicaux électroniques des médecins de premier recours en Ontario, au Canada, et des données recueillies en 2004-2005 à partir d'un échantillon aléatoire de patients en soins primaires pour une étude sur l'hypertension. On a évalué la sensibilité, la spécificité, la valeur prédictive positive, l'aire sous la courbe ROC et la combinaison des rapports de vraisemblance positif et négatif des algorithmes. RÉSULTATS: Nous avons constaté qu'un dossier d'hospitalisation ou de facturation de médecin suivi d'un second dossier provenant de l'une ou l'autre de ces sources dans la même année produisait les meilleurs résultats, avec une sensibilité de 84,8 % et une spécificité de 97,0 %. CONCLUSION: Nous concluons que la prévalence de l'ICC dans la population peut être mesurée avec exactitude à partir de données administratives issues de l'hospitalisation et des soins ambulatoires.

Prevalence of screening in patients newly diagnosed with colorectal cancer in Ontario.

OBJECTIVES: The primary objective was to determine the proportion of individuals with a new diagnosis of colorectal cancer (CRC) in Ontario in whom the cancer was screen detected. The secondary objectives were to determine the cancer stage at diagnosis and the indications for the procedure in patients who received their first colonoscopy. PATIENTS AND METHODS: Individuals admitted to a hospital with a new diagnosis of CRC were randomly selected after stratifying by hospital type (teaching or community). The Canadian Institute for Health Information's Discharge Abstract Database was used to identify individuals with a first diagnosis of CRC during calendar year (CY) 2000, and Ontario Health Insurance Plan data were used to identify people 50 to 74 years of age who had their first colonoscopy during CY 2000. Up to 20 individuals were selected for each group (CRC or colonoscopy) in each of seven randomly selected community hospitals and three randomly selected teaching hospitals. Data were abstracted from the hospital charts. RESULTS: The hospital charts of 152 patients with a new diagnosis of CRC were examined. Of the 133 patients in whom screening status could be determined, eight had screen-detected cancers (6.0%). Of the 99 patients (65% of the sample) in whom stage could be determined, 43 (43.4%) had advanced disease (tumour-node-metastasis stage III or IV) at diagnosis. The hospital charts of 184 patients who underwent their first colonoscopy were examined. Of the 175 patients in whom the indication for colonoscopy could be determined, 45 underwent the procedure for screening purposes, 10 were for diagnostic workup of anemia and 120 for evaluation of symptoms. CONCLUSIONS: The low proportion (6%) of screen-detected CRC and the high proportion of patients (43.4%) with advanced disease at diagnosis reflect the lack of an organized screening program.

Measuring the health burden of chronic disease and injury using health adjusted life expectancy and the Health Utilities Index.

OBJECTIVES: To estimate the burden of illness from chronic disease and injury using a population based health survey, which contains both measures of chronic disease and a utility based health related quality of life (HRQOL) measure. DESIGN: An adapted Sullivan method was used to calculate cause deleted health adjusted life expectancies for chronic conditions. SETTING: Ontario, Canada, 1996/97. SUBJECTS: The 1996/97 Ontario Health Survey (n=35 527) was used to estimate the prevalence of chronic conditions. A cause deleted approach was used to estimate the impact of these conditions on the Health Utilities Index (HUI). Cause deleted probabilities of dying were derived with the cause eliminated life table technique and death data from vital statistics for Ontario 1996/97 (n=156 610). RESULTS: Eliminating cardiovascular disease and cancer will cause an "expansion of morbidity", while eliminating mental conditions and musculosketal disorders will result in a "contraction of morbidity". The HUI score varies depending on chronic condition, age, and sex-most of which were assumed not to vary in previous summary measures of population health. CONCLUSIONS: Health adjusted life expectancy estimated for chronic conditions using a utility based measure of health related quality of life from population health surveys addresses several limitations of previous studies that estimate the burden of disease using either a categorical measure of disability or expert opinion and related epidemiological evidence.

Can the health utilities index measure change?

BACKGROUND: The Health Utilities Index (HUI) is a multidimensional, preference-weighted measure of health status. It comprises eight health attributes, aggregated into a single utility score. OBJECTIVES: The purpose of the study was to investigate the ability of the HUI to detect changes in health status in a general population cohort. RESEARCH DESIGN: Health status changes were analyzed in the full cohort and in persons who were diagnosed with chronic conditions, hospitalized, or became restricted in daily activities. SUBJECTS: To assess responsiveness, longitudinal data was used from the National Population Health Survey conducted in Canada in 1994 - 1995 and 1996 - 1997. We used cross-sectional data from the 1996 sample to classify chronic conditions into mild, moderate, and severe. MEASURES: Two measures of responsiveness were calculated: Standardized Response Mean (SRM) and Sensitivity Coefficient (SC). The HUI was compared with a global health index-the Self-Rated Health (SRH) scale. RESULTS: HUI scores improved between the two NPHS cycles in all age-sex groups, except men 65 years of age and older. Among the respondents who remained free of chronic conditions, improvements were seen primarily in the cognitive and emotional domains. The HUI deteriorated among persons who were diagnosed between the two cycles with a severe chronic condition, were hospitalized, or became restricted in activity, but not in those diagnosed with a moderate condition. The SRMs were generally smaller for the HUI compared with the SRH. CONCLUSIONS: The HUI responds to changes in health status associated with serious chronic illnesses. However, changes in the HUI do not always coincide with changes in self-reported health. Properties of the HUI scales require further study.

Effects of ischemia on metabolite concentrations in dog renal cortex.

To investigate the effects of ischemia on renal metabolites, sequential slices of renal cortex were removed during 5 min of renal artery occlusion and for 5 min after release of occlusion. ATP concentrations rapidly fell during ischemia and rose during the postischemic period. Based on the rate of decline of ATP concentrations, the rate of ATP production was estimated to be 0.5 mumol ATP/g/min. This is considerably less than the rate of ATP production estimated from renal O2 consumption. During ischemia, AMP concentrations rose, confirming the activity of adenylate kinase. The control lactate/pyruvate ratio suggested that dog kidney cytosol is more reduced than the cytosol of rat liver and kidney. During ischemia, the lactate concentrations and the lactate/pyruvate ratio of dog renal cortex increased as expected, and fell after restoration of blood flow. beta-Hydroxybutyrate concentrations are considerably lower than those previously reported for rat liver and kidney. The beta-hydroxybutyrate/acetoacetate ratio was not measurable during ischemia. However, the mitochondrial redox state, calculated from the glutamate/alpha-ketoglutarate . NH+4 ratio, was similar to previous reports and this ratio appropriately changed during the ischemic and post-ischemic period.