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- Duberg, Ann-Sofi, 1957-
(författare)
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Hepatitis C virus infection : a nationwide study of associated morbidity and mortality
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The hepatitis C virus (HCV) was characterised in 1989. HCV was transmitted through transfusion of blood/blood products, but injection drug use is now the most common route of transmission. The infection is usually asymptomatic but becomes chronic in about 75%, and in 20 years 15-25% develops liver cirrhosis, with a risk for liver failure and liver cancer. HCV has also been associated with lymphoproliferative disorders. The aim of this thesis was to study morbidity and mortality in a national, population-based cohort of HCV-infected individuals. The study population consisted of all persons with a diagnosed HCV-infection recorded in the national surveillance database. This file was linked to other national registers to obtain information of emigration, deaths, cancers, and inpatient care. All personal identifiers were removed before analysis. In Paper I the standardized incidence ratios (SIR) for Hodgkin’s and non-Hodgkin’s lymphoma (NHL), multiple myeloma, acute and chronic lymphatic leukaemia, and thyroid cancer were studied. In the HCV-cohort (n: 27,150) there was a doubled risk for NHL and multiple myeloma in patients infected for more than 15 years, compared with the general population (age-, sex- and calendar-year specific incidence rates). The results strengthened these earlier controversial associations. The SIR and also the absolute risk for primary liver cancer were estimated in Paper II. In the HCV-cohort (n: 36,126) the individuals infected for more than 25 years had a more than 40 times increased risk for liver cancer compared with the general population. The absolute risk of primary liver cancer was 7% within 40 years of HCV-infection. Mortality and cause of death were studied in Paper III. The standardized mortality ratio (SMR) demonstrated a 5.8 times excess mortality in the HCV-cohort (n: 34,235) compared with the general population, and a 35.5 times excess mortality from liver disease. Deaths from illicit drugs and external reasons were common in young adults. Paper IV presents a study of inpatient care. The HCV-cohort (n: 43,000) was compared with a matched reference population (n: 215,000). Cox regression was used to estimate the likelihood, a hazard ratio, for admission to hospital, and frequencies and rates to estimate the total burden. In the HCV-cohort inpatient care was high and about 50% was psychiatric, often drug-related care. The likelihood for liver-related admissions was very high, and serious liver complications increased in the 2000s, indicating that HCV-associated liver disease will increase the next decade. In the 2000s, about 1000 individuals per year were treated with HCV-combination therapy. To conclude, the risk for NHL and multiple myeloma was doubled, and liver- and drug-related morbidity and mortality was very high in the HCV-cohort. Serious liver complications increased in the 2000s and will probably increase the coming decade.
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| 2. |
- Geli Rolfhamre, Patricia, 1979-
(författare)
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From Penicillin Binding Proteins to Community Interventions : Mathematical and Statistical Models Related to Antibiotic Resistance
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antibiotic resistance has become a major public health concern and mathematical models are important analytical tools for the understanding, evaluation and prediction of the resistance problem and related control strategies.The risk of emerging antibiotic resistance and selection has rarely been a concern in the design of antibiotic drug dosing regimens. In the first paper, a selection of antibiotic resistant subpopulations for different antibiotic dosing regimens was studied in vitro. The demonstrated complex relationship was influenced by both the rise of new mutants and a postantibiotic effect (PAE) (continued inhibition of bacterial growth after removal of the antibiotic drug). By constructing a mathematical model that incorporated biologically relevant parameters, we were able to assess the risks of resistance development under different dosing strategies.In the second paper, the model for PAEs is further developed to determine the implications for different dosing regimens. The result challenges the conventional notion that long PAEs promote extended drug dosing intervals and it allows new hypotheses to be tested experimentally based on the findings from the theoretical framework.Since PAE experiments often are time-consuming and laborious, very few studies have been reporting variation for this phenomenon. In the third paper, an extension to capture the stochastic behavior of bacterial population growth under drug exposure is made. The stochastic nature of the model is also an important complement to the existing deterministic models on drug dose drug effect relationships.The last paper describes a controlled clinical intervention study aiming at determining whether the frequency of trimethoprim resistance in E. coli can be decreased by a sudden and drastic reduction in trimethoprim use. In addition to evaluating the intervention effect, the model, given estimated parameters, is also used for predicting other interesting outcomes.
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