Mitigating bias in estimating epidemic severity due to heterogeneity of epidemic onset and data aggregation.

Outbreaks of infectious diseases, such as influenza, are a major societal burden. Mitigation policies during an outbreak or pandemic are guided by the analysis of data of ongoing or preceding epidemics. The reproduction number, R0, defined as the expected number of secondary infections arising from a single individual in a population of susceptibles is critical to epidemiology. For typical compartmental models such as the Susceptible-Infected-Recovered (SIR) R0 represents the severity of an epidemic. It is an estimate of the early-stage growth rate of an epidemic and is an important threshold parameter used to gain insights into the spread or decay of an outbreak. Models typically use incidence counts as indicators of cases within a single large population; however, epidemic data are the result of a hierarchical aggregation, where incidence counts from spatially separated monitoring sites (or sub-regions) are pooled and used to infer R0. Is this aggregation approach valid when the epidemic has different dynamics across the regions monitored? We characterize bias in the estimation of R0 from a merged data set when the epidemics of the sub-regions, used in the merger, exhibit delays in onset. We propose a method to mitigate this bias, and study its efficacy on synthetic data as well as real-world influenza and COVID-19 data.

Reliability of the radiographic variables in the International Spinal Cord Injury Spinal Column Injury Basic Data Set compared with the AO classification.

STUDY DESIGN: Intra- and interrater reliability study for radiological variables of the International Spinal Cord Injury (SCI) Spinal Column Injury Basic Data Set. OBJECTIVES: To test reliability of the radiological variables in the International SCI Spinal Column Injury Basic Data Set and compare it with the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification. SETTING: The database of Eastern Denmark Regional SCI Referral Center, Copenhagen, Denmark. METHODS: Ratings of the International SCI Spinal Column Injury Basic Data Set radiological variables and AO classification were obtained by two international observers for all the surgically treated spine trauma patients between 1st October 2010 and 31st December 2012 at the Spine Unit, Rigshospitalet, Denmark. Statistical analyses for intra- and interrater crude agreement and Cohen's unweighted kappa (κ) coefficients were performed. RESULTS: For 283 spine injuries, the intra- and interrater reliability for the individual radiological variables of the International SCI Spinal Column Injury Basic Data Set was at least substantial (κ=0.67-0.97 for interrater, κ=0.79-0.89 for the intrarater agreement). For the AO classification, intrarater reliability was moderate-to-substantial (κ=0.57-0.75), whereas interrater reliability was substantial (κ=0.67-0.69). The crude intra- and interrater agreement for a combined radiographic SCI Spinal Column Injury Basic Data Set variable showed no significant difference compared with the AO classification (P=0.067-0.895). CONCLUSIONS: The reliability of International SCI Spinal Column Injury Basic Data Set radiological variables is comparable to the AO classification system. We encourage its use for spinal column injury description, thus facilitating data collection and comparison between centres and countries.

Tissue plasminogen activator for blocked peritoneal dialysis catheters.

Tissue plasminogen activator was used for a blocked peritoneal dialysis catheter in a child with no vascular access. The catheter was salvaged using tissue plasminogen activator and dialysis could be carried out without any difficulty.

Recombinant human erythropoietin therapy for treatment of anemia of prematurity in very low birth weight infants: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To evaluate the efficacy and safety of recombinant human erythropoietin (rHuEPO) in very low birth weight infants with anemia of prematurity. STUDY DESIGN: Thirty infants were randomly assigned to receive either rHuEPO (300 U/kg per dose) or placebo twice a week. Hematologic parameters, transfusion requirements, caloric intake, and growth were monitored. RESULTS: The number and volume of erythrocyte transfusions were significantly lower in infants treated with rHuEPO. Serum ferritin levels, similar in both groups at study entry, fell and were significantly lower in rHuEPO-group infants at the completion of the study. An inverse correlation was observed between reticulocyte count and absolute neutrophil count both at entry and at completion of the study. CONCLUSION: Twice-a-week administration of rHuEPO significantly reduces the need for erythrocyte transfusion in very low birth weight infants in stable condition. A significant decrease in serum ferritin levels in infants receiving rHuEPO suggests the need to determine the optimal dose of iron supplementation in these infants.