• Use of antimicrobials and carriage of penicillin-resistant pneumococci in children : repeated cross-sectional studies covering 10 years [PhD Thesis]

      Vilhjálmur Ari Arason (Háskólaútgáfan, 2006-10-01)
      Objectives: The overall aim of this thesis was to analyse the use of antimicrobials in pre-school children in Iceland and the connection between such use and the carriage of penicillin-nonsusceptible pneumococci(PNSP). Study populations and methods: Prescription data and medical histories from 2,612 children, aged 1 to 6 years, living in different geographically welldefined study areas in Iceland, and nasopharyngeal specimens from 2,486 children were analysed in three crosssectional studies covering 10 years (Phase I 1993, II 1998, and III 2003). Participation varied from 75% to 88%. Annual analysis of oral antimicrobial sales/prescriptions for whole communities (hospital use excluded) were based on 22,132 prescriptions in 1993, and 15,153 in 1998. Main outcome measures: The prevalence and risk factors for nasopharyngeal carriage of PNSP, total antimicrobial use, antimicrobial use for acute otitis media (AOM), parental expectations and tympanostomy tube placements. Results: • Antimicrobial prescription rates among GPs diminished by about 1/3 over the study period. Prescription habits varied greatly between communites especially because of AOM. • Parents’ expectations of antimicrobial prescriptions were associated with the antimicrobial prescription rate in each area. • The cumulative prevalence of tympanostomy tube placement among pre-school children is high in Iceland (over 30%). In vi areas where the prescription rate was high, broad-spectrum antimicrobials were prescribed relatively more often than in other areas, and the tympanostomy tube placement rate was increasing (up to 44% of all children). In other areas, tympanostomy tube rate among children deceased (down to 17%) at the same time as antimicrobial use for AOM diminished. • There was a strong association between antimicrobial use on the individual level and the nasopharyngeal carriage of PNSP. • PNSP, multiresistant, serotype 6B (phenotypically identical to the Spain6B-2 clone) appeared and disappeared over a 10-year period, in communities with both high and low antimicrobial use. Conclusions: There is a strong association between antimicrobial use for individual children and the nasopharyngeal carriage of PNSP. Pneumococcus is acquired from other children, usually in day-care settings and PNSP selectively colonised when receiving antimicrobials. Spread of novel resistant clones appears to be the main reason for marked changes in pneumococcal resistance rates in individual communities over time. Antimicrobial drug (over)use for AOM my be associated with future episodes of AOM and tympanostomy tube placements.
    • Users of hospital emergency department who are discharged home

      Oddný Sigurborg Gunnarsdóttir; Landspitali The National University Hospital, Reykjavík, Iceland. (2012-01-27)
      The overall aim of the studies was to determine characteristics and prognosis of Emergency Department users, who were discharged home. The specific aims were to record the annual number of discharged users of the ED according to age and gender, their annual number of visits and to assess whether a higher frequency of visits predicted higher mortality; to describe the pattern of discharged diagnoses; to evaluate the association of non-causative diagnoses with mortality in general, and in particular with external causes of death, drug intoxication and suicide; to evaluate risk factors for suicide and fatal drug poisoning; to evaluate the association between death within eight days after discharge home from the ED and non-causative discharge diagnoses. Material and Methods: The data were records of patients, 18 years and older, who attended the Landspitali ED during the years 1995 to 2001. The main diagnoses were registered according to the International Classification of Diseases (ICD). Annual increase in visits was evaluated in relation to the annual population of Reykjavik capital area using the Poisson regression model and 95% Confidence Interval (CI). The pattern of each diagnosis category during the period was analyzed by calculating chi-squares for the linear trend (Mantel extension). Patients’ vital status was obtained by record linking to Statistics Iceland. The mortality of ED users was compared with the mortality of the general population of Iceland using conventional methods of calculating the standard mortality ratio (SMR) and 95% CI. The Hazard ratios (HR) and 95% CI were calculated for all causes and selected causes of death in a time-dependent analysis in which annual visits to the ED were taken into account. Furthermore, the same method was used when comparing groups with different diagnoses at discharge. In the case control studies the discharged diagnoses of mental disorders, use of alcohol, drug intoxication, non-causative diagnoses and factors influencing health status were risk factors for suicide and fatal drug poisoning, and were calculated in a multivariate logistic regression analysis. The adjusted Odd ratio (OR) and exact computation of 95% CI were calculated. Deaths within 8, 15 and 30 days among individuals with a non-causative diagnosis were compared with deaths among those with a causative diagnosis. HR and 95% CI were computed for all causes of death in a time-dependent analysis. Results: Of all visits to the ED in the year 1995, 2,888 or 54.5% resulted in discharge and of all visits in the year 2001, 5,604 or 72.5% resulted in discharge. Discharged patients in total over the study period numbered 19,259 and they made 30,221 visits, with visits by women slightly more frequent than by men. About 84% of users made one visit in a calendar year and 1.5% of users made four or more visits per calendar year. The annual increase of visits to the ED was 7% to 14% depending on the age group, with the highest increase among older men. The most frequent diagnostic category was non-causative diagnoses (R00-R99), accounting for 20% average, and increasing over the period. SMR for all causes of death was 1.81 (95% CI, 1.71 to 1.92) for men and 1.93 (95% CI, 1.81.to 2.05) for women. For patients with non-causative diagnoses, SMR for all causes of death was 1.57 (95% CI, 1.39 to 1.77) for men and 1.83 (95% CI, 1.61 to 2.08) for women; furthermore, for those diagnosed with mental disorders, SMR was 3.72 (95% CI, 2.72 to 4.98) for men and 2.45 (95% CI, 1.76 to 3.36) for women. The most common causes of death were malignant neoplasm, ischemic heart diseases, cerebrovascular disease, and the category of chronic lower respiratory diseases; by adding the category of external causes, these accounted for over 73% of the overall deaths, a total of 2,105. HR for all causes of death was 1.4 (95% CI, 1.2 to 1.5) among patients with two visits in a calendar year and 1.7 (95% CI, 1.4 to 2.0) among those with three or more visits in a calendar year. Comparing those with non-causative diagnoses to those having causative physical diagnoses, the HR for all causes of death was 0.84 (95% CI, 0.76 to 0.93). On the other hand, the HR for the category of external causes was 1.64 (95% CI, 1.07 to 2.52); HR for accidental poisoning was 1.51 (95% CI, 0.56 to 4.08); and the HR for suicide was 2.08 (95% CI, 1.02 to 4.24), all adjusted for age and gender. The OR for suicide among cases and controls was 7.84 (95% CI, 1.66 to 37.06) for patients with mental disorders, 96.89 (95% CI, 11.14 to 843) for those with use of alcohol, 24.51 (95% CI, 6.11 to 98.25) for those with drug intoxications and 2.69 (95% CI, 1.04 to 6.95) for those with non-causative diagnoses. The OR for fatal drug poisoning among cases and controls was 12.26 (95% CI, 2.10 to 71.76) for patients with use of alcohol, 37.22 (95% CI, 3.57 to 388.29) for those with drug intoxications, 5.76 (95% CI, 1.23 to 26.95), for those with factors influencing health status. The HR for non-causative diagnoses was 0.44 (95% CI, 0.20 to 0.96) for death within eight days when compared to causative diagnoses, adjusted for gender and age. Conclusion: There was an increase in visits to the ED in relation to the population of the Reykjavik capital area and this increase contributed to an increased burden at the ED. The most frequent diagnoses were non-causative diagnoses. Number of visits predicted higher mortality. The most common causes of death were due to malignant neoplasm, ischemic heart diseases, cerebrovascular diseases, chronic lower respiratory diseases, and external causes. Mortality was higher among ED users than in the general population. Users with non-causative diagnoses had higher mortality due to external causes, accidental poisoning, and suicide. Frequent visits to the ED were a strong risk factor for suicide and fatal drug poisoning . The discharged diagnoses of mental disorders, alcohol use, drug intoxication and non-causative diagnoses were independent risk factors for suicide. The discharge diagnoses of alcohol use, drug intoxication and factors influencing health status were independent risk factors for fatal drug poisoning. Health professionals at EDs should be careful when users have a number of discharged visits and they need to be aware that patients who have been discharged home present with new risk factors for suicide and fatal drug poisoning. The association of non-causative diagnoses with death within eight days after discharge can be used to evaluate the performance of the ED.