The associations between invasive group A streptococcal disease and infection with influenza, varicella, or hepatitis C viruses: A data linkage study, Victoria, Australia.

OBJECTIVES: To quantify the associations between invasive group A streptococcal disease (iGAS) incidence and influenza, varicella, and chronic hepatitis C virus (HCV). METHODS: We used individual-level linked data of iGAS cases from Victoria, Australia (2007-2017) to assess associations between these viral infections and iGAS. A self-controlled case series method was used to estimate the relative incidence of iGAS following an influenza or varicella infection, while the relative incidence of iGAS among HCV cases, and HCV cases who inject drugs, was estimated using population-level data and a negative binomial regression model. RESULTS: Of the 1949 individuals with at least one iGAS diagnosis, 82 were diagnosed with influenza at least once, 30 with varicella, and 118 with HCV during the study period. The relative incidence of iGAS increased substantially following infection with influenza (incidence rate ratio [IRR]: 34.5, 95% confidence interval [CI]: 21.3-55.8) or varicella (IRR: 22.4, 95% CI: 10.3-48.8). iGAS incidence was higher among HCV cases (IRR: 5.7, 95% CI: 4.4-7.3) compared to individuals without HCV. iGAS incidence was also higher among HCV cases who inject drugs (IRR: 17.9, 95% CI: 13.0-24.4) compared to individuals without HCV who did not inject drugs. CONCLUSIONS: We found a significantly higher risk of iGAS following an influenza or varicella infection and for chronic HCV cases, particularly those who inject drugs. These findings are relevant to public health practice and support the timely identification of iGAS cases.

Treatment complexity index for assessing the relationship of treatment duration and outcomes in a graduate orthodontics clinic.

INTRODUCTION: Clinical cases completed by the Indiana University School of Dentistry (IUSD) graduating orthodontic classes of 2004, 2005, and 2006 were assessed to determine factors that affect orthodontic treatment duration. METHODS: The sample consisted of 455 consecutively finished patients who received comprehensive treatment in the full permanent dentition. They included optimally finished and prematurely terminated (early debond) patients. The American Board of Orthodontics (ABO) discrepancy index (DI) was used to evaluate the severity of the pretreatment malocclusion. A specifically designed treatment complexity index (TCI) was used to evaluate complexity based on treatment modalities. The ABO objective grading system (OGS) and the IUSD comprehensive clinical assessment (CCA) were used to evaluate the clinical outcome for all patients. RESULTS: The average treatment duration was 29 months. The mean DI, OGS, and CCA scores were 15.30, 23.34, and 4.48, respectively. Increased treatment length was associated with 0.022-in slot size brackets, percent of treatment spent in nickel-titanium wires, Class II malocclusion, increased DI score, and increased TCI score. In evaluating outcomes for 2004 through 2006, there was no significant relationship between treatment duration and clinical outcome as measured by the OGS and CCA scores. CONCLUSIONS: The DI and TCI are sensitive prospective indicators of treatment duration. After the introduction of a rigorous clinical protocol for controlling poor outcomes, because of patients exceeding predicted treatment times, the clinical results for this sample are independent of treatment duration.