Biomedical subjects

Rhonda J Rosychuk

Publications and source records attributed to Rhonda J Rosychuk.

11 recordsLinked to original sources

PubMed2026

A 4-year longitudinal wastewater surveillance of five gastroenteritis viruses and the correlation with clinical cases in Alberta, Canada.

Viruses are common causes of acute gastroenteritis worldwide. They are detected in large quantities in raw sewage making them amenable to wastewater-based surveillance (WBS). To monitor the prevalence of gastroenteritis viruses in wastewater and assess their correlation with clinical cases, wastewater samples collected between July 2020 and June 2024 from 12 wastewater treatment plants across Alberta, Canada were analyzed for norovirus (NoV) GI & GII, rotavirus (RoV), adenovirus (AdV), sapovirus (SaV) and astrovirus (AsV). Among the 5726 wastewater samples tested, AdV (80.5%) had the highest detection rate followed by NoV GII (75.6%), SaV (63.2%), NoV GI (59.4%), RoV (42.2%) and AsV (20.2%). Winter and spring seasonality was found for NoV and RoV in both wastewater and clinical disease. Public health interventions especially in the 1st year of the COVID-19 pandemic had a significant impact on their burden with marked reduction in wastewater detected viruses and clinical cases. NoV showed a strong correlation between its level in wastewater and the number of clinical cases, while moderate correlation was observed for the other four viruses. Cross-correlation analysis showed that changes of viral RNA concentration in wastewater lagged behind reported gastroenteritis cases by approximately 6 days to 3 weeks. To our knowledge, this is the longest multi-region WBS study monitoring multiple gastroenteritis viruses spanning both COVID-19 pandemic and post-pandemic periods. The data obtained from this study supported WBS as a complementary tool to track population-based circulation of gastroenteritis viruses, providing actionable public health data.

Clinical cases↗

PubMed2024

The association between neighbourhood marginalization and SARS-CoV-2 outcomes in patients presenting to emergency departments.

OBJECTIVE: Social and economic marginalizations have been associated with inferior health outcomes in Canada. Our objective was to describe the relationship between neighbourhood marginalization and COVID-19 outcomes among patients presenting to Canadian emergency departments (ED). METHODS: We conducted an observational study among consecutive COVID-19 patients recruited from 47 hospitals participating in the Canadian COVID-19 ED Rapid Response Network (CCEDRRN) between March 3, 2020, and July 24, 2022. We linked data with the Canadian Marginalization Index (CAN-Marg). We used multivariable, multi-level logistic regression models to understand the association between dimensions of neighbourhood marginalization, and severe COVID-19 and in-hospital mortality. RESULTS: There were 55,588 eligible patients. Those from neighbourhoods with a higher proportion of recent immigrants (OR = 0.86 per unit increase [0.81, 0.92]), lower workforce participation (OR = 0.84 per unit increase [0.75, 0.94]), and more housing insecurity (OR = 0.81 per unit increase [0.77, 0.86]) were less likely to present to EDs with severe COVID-19. However, patients from materially marginalized neighbourhoods had increased odds of dying in hospital (OR = 1.19 per unit increase [95% CI 1.09, 1.30]) compared to patients from less materially marginalized neighbourhoods. Patients living in neighbourhoods with a higher proportion of recent immigrants (OR = 0.83 per unit increase [0.78, 0.91]) and lower participation in the workforce (OR = 0.77 per unit increase [0.66, 0.87]) experienced lower odds of dying. CONCLUSION: Despite no association with severe COVID-19 at ED presentation, the only marginalization domain associated with in-hospital mortality was material deprivation. Our findings present insights on ED-seeking behaviour, hospital access, and care that population studies could not.

Humans↗

PubMed2006

Identifying geographic areas with high disease rates: when do confidence intervals for rates and a disease cluster detection method agree?

BACKGROUND: Geographic regions are often routinely monitored to identify areas with excess cases of disease. Further epidemiological investigations can be targeted to areas with higher disease rates than expected. Surveillance strategies typically include the calculation of sub-regional rates, and their associated confidence intervals, that are compared with the rate of the entire geographic region. More sophisticated approaches use disease cluster detection methods that require specialized software. These approaches are not the same but may lead to similar results in specific situations. A natural question arises as to when these different approaches lead to the same conclusions. We compare the Besag and Newell 1 cluster detection method, suitable for geographic areas with diverse population sizes, with confidence intervals for crude and directly standardized rates. The cluster detection method tests each area at a pre-specified cluster size. Conditions when these methods agree and disagree are provided. We use a dataset on self-inflicted injuries requiring medical attention as an illustration and give power comparisons for a variety of situations. RESULTS: Three conditions must be satisfied for the confidence interval and cluster detection methods to both provide statistically significant higher rates for an individual administrative area. These criteria are based on observed and expected cases above specific thresholds. In our dataset, two areas are significant with both methods and one additional area is identified with the cluster detection method. Power comparisons for different scenarios suggest that the methods have similar power for detecting rates that are twice as large as the overall rate and when the overall rate and sample sizes are not too small. The cluster detection method has better power when the size of the cluster is relatively small. CONCLUSION: The cluster size plays a key role in the comparability of methods. The cluster detection method is preferred when the cluster size exceeds the number of cases in an administrative area or when the expected number of cases exceeds a threshold.

Cluster Analysis↗

PubMed2006

Characteristics of patients who leave emergency departments without being seen.

OBJECTIVES: Patients leaving the emergency department (ED) without being seen (LWBS) by a physician have become a growing concern in overcrowded EDs. The purpose of this study was to determine the acuity level, reasons, and outcomes of LWBS cases. METHODS: LWBS patients (or their guardians) from two linked Canadian EDs (one adult, one pediatric), identified during 11 sampling periods of seven days' duration each, were contacted by telephone. Descriptive statistics are provided. RESULTS: A total of 711 (4.5%) of 15,660 registered emergency patients left without being seen (50% male; median age, 33 years). Triage-matched controls waited a median of 87 minutes before seeing a physician. Of the 711 LWBS cases, 512 (72%) were contacted and 498 agreed to participate. The most common major reason for leaving was "fed up with waiting" (44.8%). Overall, 60% of LWBS cases sought medical attention within one week; 14 patients were hospitalized, and one required urgent surgery. Triage level was not associated with the probability of subsequently seeking medical attention (61%, 61%, and 60% in triage levels 3, 4, and 5, respectively). Of the 198 (39%) who did not subsequently seek medical attention, 50 patients (26%) had been triaged as urgent and one patient died six days after ED registration. CONCLUSIONS: The most common reason for LWBS is impatience during peak ED periods. Many of these patients seek medical care within one week. Complications occurred rarely; however, "high-risk" patients who leave without being seen do experience adverse health outcomes. Further research is required to examine ways to reduce LWBS cases.

Adult↗

PubMed2006

Spatial event cluster detection using a compound Poisson distribution.

Geographic disease surveillance methods identify regions that have higher disease rates than expected. These approaches are generally applied to incident or prevalent cases of disease. In some contexts, disease-related events rather than individuals are the appropriate units of analysis for geographic surveillance. We propose a compound Poisson approach that detects event clusters by testing individual areas that may be combined with their nearest neighbors. The method is applicable to situations where the population sizes are diverse and the population distribution by important strata may differ by area. For example, a geographical region might have sparse population in the northern areas, and other areas which are predominantly retirement communities. The approach requires a coarse geographical relationship and administrative data for the numbers of population, cases, and events in each area. Pediatric self-inflicted injuries requiring presentation to Alberta emergency departments provide an illustration.

Alberta↗

PubMed2006

Statistical disease cluster surveillance of medically treated self-inflicted injuries in Alberta, Canada.

Routine surveillance of cases of disease can highlight geographic regions that need further study and intervention. Statistical disease cluster detection methods are one way to statistically assess the number of cases in administrative areas. Traditionally, disease cluster detection methods are used to monitor the incident cases of disease. We review a statistical cluster detection method that is applicable for regions with diverse administrative area population sizes. We apply the method to assess clustering of self-inflicted injury presentations to emergency departments in Alberta, Canada. Analyses focus on the pediatric population and are adjusted by the age and gender distributions of subregional health authorities. Fifteen clusters of self-inflicted injuries are identified and, based on age and gender distributions, the clusters are not likely chance occurrences. We believe that these clusters represent areas of excessive self-inflicted injury and that special intervention programs should be considered.

Adolescent↗

PubMed2005

Effectiveness of a home-based balance-training program in reducing sports-related injuries among healthy adolescents: a cluster randomized controlled trial.

BACKGROUND: Sport is the leading cause of injury requiring medical attention among adolescents. We studied the effectiveness of a home-based balance-training program using a wobble board in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents. METHODS: In this cluster randomized controlled trial, we randomly selected 10 of 15 high schools in Calgary to participate in the fall of 2001. We then recruited students from physical education classes and randomly assigned them, by school, to either the intervention (n = 66) or the control (n = 61) group. Students in the intervention group participated in a daily 6-week and then a weekly 6-month home-based balance-training program using a wobble board. Students at the control schools received testing only. The primary outcome measures were timed static and dynamic balance, 20-m shuttle run and vertical jump, which were measured at baseline and biweekly for 6 weeks. Self-reported injury data were collected over the 6-month follow-up period. RESULTS: At 6 weeks, improvements in static and dynamic balance were observed in the intervention group but not in the control group (difference in static balance 20.7 seconds, 95% confidence interval [CI] 10.8 to 30.6 seconds; difference in dynamic balance 2.3 seconds, 95% CI 0.7 to 4.0 seconds). There was evidence of a protective effect of balance training in over 6 months (relative risk of injury 0.2, 95% CI 0.05 to 0.88). The number needed to treat to avoid 1 injury over 6 months was 8 (95% CI 4 to 35). INTERPRETATION: Balance training using a wobble board is effective in improving static and dynamic balance and reducing sports-related injuries among healthy adolescents.

Adolescent↗

PubMed2005

Development of a clinical static and dynamic standing balance measurement tool appropriate for use in adolescents.

BACKGROUND AND PURPOSE: There is a need in sports medicine for a static and dynamic standing balance measure to quantify balance ability in adolescents. The purposes of this study were to determine the test-retest reliability of timed static (eyes open) and dynamic (eyes open and eyes closed) unipedal balance measurements and to examine factors associated with balance. SUBJECTS: Adolescents (n=123) were randomly selected from 10 Calgary high schools. METHODS: This study used a repeated-measures design. One rater measured unipedal standing balance, including timed eyes-closed static (ECS), eyes-open dynamic (EOD), and eyes-closed dynamic (ECD) balance at baseline and 1 week later. Dynamic balance was measured on a foam surface. Reliability was examined using both intraclass correlation coefficients (ICCs) and Bland and Altman statistical techniques. Multiple linear regressions were used to examine other potentially influencing factors. RESULTS: Based on ICCs, test-retest reliability was adequate for ECS, EOD, and ECD balance (ICC=.69, .59, and .46, respectively). The results of Bland and Altman methods, however, suggest that caution is required in interpreting reliability based on ICCs alone. Although both ECS balance and ECD balance appear to demonstrate adequate test-retest reliability by ICC, Bland and Altman methods of agreement demonstrate sufficient reliability for ECD balance only. Thirty percent of the subjects reached the 180-second maximum on EOD balance, suggesting that this test is not appropriate for use in this population. Balance ability (ECS and ECD) was better in adolescents with no past history of lower-extremity injury. DISCUSSION AND CONCLUSION: Timed ECD balance is an appropriate and reliable clinical measurement for use in adolescents and is influenced by previous injury.

Adolescent↗

PubMed2004

The safety and use of short-acting nifedipine in hospitalized hypertensive children.

Recent reports suggest that calcium channel blockers are harmful in the treatment of acute hypertension in adults. However, short-acting nifedipine is an effective and useful medication in pediatric hypertension and is currently utilized for hypertensive emergencies. This study will address these safety concerns in hypertensive children. Medical records (from five Canadian pediatric hospitals) of all pediatric hypertensive hospitalized children who were treated with short-acting nifedipine from January 1995 to December 1998 were retrospectively reviewed for patient demographics, dosing regimen, use of concomitant medications, co-morbid conditions, and presence/absence of minor and serious adverse events. Final data were extracted from 182 patients. Each patient had an average of 2.6 episodes of hypertension in hospital that required treatment, totaling 477 episodes. Within the 477 episodes, 1,162 doses of short-acting nifedipine were administered. The mean dose was 0.22 mg/kg (range 0.043-0.67 mg/kg, median 0.19 mg/kg) with 55.6% (260/468 episodes) receiving the drug via the sublingual route. Hypertension resolved in 85.5% (408/477) of the episodes. There were only 29 of 574 (5.1%) minor adverse events that were definitely or probably related to short-acting nifedipine administration. Two patients experienced a serious adverse event that involved of a reduction in blood pressure of more than 40%, but neither had any symptomatology from the serious adverse event and recovered spontaneously within 2 h. Short-acting nifedipine in hypertensive, hospitalized children appears to be a safe and efficacious medication with minimal side effects.

Adolescent↗

PubMed2003

Bias correction of two-state latent Markov process parameter estimates under misclassification.

A discretely observed two-state process may misclassify the state of an unobservable continuous-time, two-state Markov process. We examine the behaviour of maximum likelihood transition probability estimates as functions of known misclassification probabilities. Since maximum likelihood estimators are not available in closed form, we provide two alternatives for bias-adjusted estimation. In the case of large samples, the asymptotic bias is quantified and estimators are constructed iteratively using transition counts and specified misclassification probabilities. For finite samples, we provide an approximation based on partial derivatives. Estimators that are bias-adjusted to a first approximation are easily constructed and may serve well when misclassification probabilities are known to be small. Simulation studies reveal the effect of misclassification on estimation. Repeated diagnostic testing data illustrate the approaches.

Animals↗

PubMed2003

Circumstances surrounding end of life in a pediatric intensive care unit.

OBJECTIVE: Approximately 60% of deaths in pediatric intensive care units follow limitation or withdrawal of life-sustaining treatment (LST). We aimed to describe the circumstances surrounding decision making and end-of-life care in this setting. METHODS: We conducted a prospective, descriptive study based on a survey with the intensivist after every consecutive death during an 8-month period in a single multidisciplinary pediatric intensive care unit. Summary statistics are presented as percentage, mean +/- standard deviation, or median and range; data are compared using the Mantel-Haenszel test and shown as survival curves. RESULTS: Of the 99 observed deaths, 27 involved failed cardiopulmonary resuscitation; of the remaining 72, 39 followed withdrawal/limitation (W/LT) of LST, 20 were do not resuscitate (DNR), and 13 were brain deaths (BDs). Families initiated discussions about forgoing LST in 24% (17 of 72) of cases. Consensus between caregivers and staff about forgoing LST as the best approach was reached after the first meeting with 51% (35 of 68) of families; 46% (31 of 68) required >or=2 meetings (4 not reported). In the DNR group, the median time to death after consensus was 24 hours and for W/LT was 3 hours. LST was later withdrawn in 11 of 20 DNR cases. The family was present in 76% (45 of 59) of cases when LST was forgone. The dying patient was held by the family in 78% (35 of 45) of these occasions. CONCLUSIONS: More than 1 formal meeting was required to reach consensus with families about forgoing LST in almost half of the patients. Families often held their child at the time of death. The majority of children died quickly after the end-of-life decision was made.

Adolescent↗