Case-cohort Methods for Survival Data on Families from Routine Registers

In the Nordic countries, there exist several registers containing information on diseases and risk factors for millions of individuals. This information can be linked into families by use of personal identification numbers, and represent a great opportunity for studying diseases that show familial aggregation. Due to the size of the registers, it is difficult to analyze the data by using traditional methods for multivariate survival analysis, such as frailty or copula models. Since the size of the cohort is known, case-cohort methods based on pseudo-likelihoods are suitable for analyzing the data. We present methods for sampling control families both with and without replacement, and with or without stratification. The data are stratified according to family size and covariate values. Depending on the sampling method, results from simulations indicate that one only needs to sample 1%-5% of the control families in order to get good efficiency compared to a traditional cohort analysis. We also provide an application to survival data from the Medical Birth Registry of Norway

Trenger vi flere kliniske studier? Om verdien av mer informasjon i evaluering av helsetiltak

I denne artikkelen viser forfatterne Guttormsen, Moger og Kristiansen hvordan vi kan analysere verdien av informasjon i helseøkonomisk evaluering. I de fleste analyser er det usikkerhet knyttet til både helseeffekter og kostnader, i noen tilfeller kan denne usikkerheten reduseres ved å utføre flere kliniske studier. Ved hjelp av to eksempler viser de hvordan vi kan regne ut verdien av å utføre flere studier. I det ene eksempelet bruker de realopsjonsteori hentet fra tradisjonell investeringsanalyse, mens de i det andre eksempelet bygger videre på stoff presentert i: Moger, T.A., Guttormsen, A.G., Kristiansen, I.S., 2010. Nyere metoder – Hvordan prioritere helsetiltak når både effekter og kostnader er usikre. Helseøkonomisk forskningsprogram ved UiO - Volum 2010:5. HERO skriftserie/Working paper.verdi av informasjon; helseøkonomisk evaluering; usikkerhet; kliniske studier; relapsjonsteori

Nyere metoder: Hvordan prioritere helsetiltak bår både effekter og kostnader er usikre?

I denne artikkelen drøfter forfatterne bruk av nyere metoder innen økonomisk evaluering som samfunnet kan bruke for å prioritere mellom ulike behandlinger der både effektene og kostnadene er usikre. Tradisjonelt har man brukt p-verdier når man skal vurdere om én behandling er bedre enn en annen. I et eksempel som benytter metoder fra moderne cost-effectiveness analyser, viser vi at dette ikke alltid er en god metode for prioritering mellom helsetiltak. Fokus på p-verdier kan medføre at samfunnet tar beslutninger som med stor sannsynlighet er i strid med samfunnets målsetting med helsetjenesten.økonomisk evaluering; p-verdi; behandlingskostnader; cost-effectiveness; simulering; verdi av liv; legemiddel

Geographical variation in cardiovascular disease mortality in Norway: The role of life course socioeconomic position and parental health

Despite substantial geographical variation in cardiovascular (CVD) mortality within countries, little is known about whether this variation can be explained by individuals' life course socioeconomic position (SEP) or differences in family history of premature CVD deaths. Cox proportional hazards models were used to investigate the association between the county of residence at ages 50–59 and CVD death in Norwegians born between 1940 and 1959 and survived to at least age 60, using national data. Individual life course SEP and family history of premature CVD death reduced the geographical variation in CVD mortality across Norwegian counties, but some significant differences remained. Furthermore, CVD risk varied by residents' migration histories between two counties with distinct CVD and socioeconomic profiles.Geographical variation in cardiovascular disease mortality in Norway: The role of life course socioeconomic position and parental healthpublishedVersio

Hierarchical Lévy Frailty Models and a Frailty Analysis of Data on Infant Mortality in Norwegian Siblings

Distributions determined by non-negative Lévy processes, which include the power variance function (PVF) distributions among others, are commonly used as frailty distributions to model dependent survival times in family data. We present a hierarchical frailty model constructed by randomizing scale parameters, corresponding to time parameters of Lévy processes, in the Lévy frailty distributions. In its simplest form, this yields a two-model with heterogeneity the individual and family level. The family level frailty is shared within families, creating dependence. In the more complex models, it is extended to allow for several levels of dependence. This yields models with nested dependence structures (all individuals in a family are dependent, but some more than others), or genetic models for two-generation families (parents-children, where the parents are independent). The model allows for several different options on where to include covariates, and each alternative gives different interpretations of the regression coefficients. An application to dependent data on post-perinatal (7-364 days) infant mortality in siblings from the Medical Birth Registry of Norway is included. We compare the results for some of the different covariate modeling options from a case-cohort analysis of the data by using a two-level Lévy model

Performance comparison of hip fracture pathways in two capital cities: Associations with level and change of integration

Finland and Norway have health care systems that have a varying degree of vertical integration. In Finland the financial responsibility for all patient treatment is placed at the municipal level, while in Norway the responsibility for patients is divided between the municipalities (primary and long-term care) and state-owned hospitals. From 2012, the Norwegian system became more vertically integrated following the introduction of the Coordination Reform. The aim of the paper is to analyse the associations between different modes of integration and performance indicators. The data included operated hip fracture patients from the years 2009–2014 residing in the cities of Oslo and Helsinki. Data from routinely collected national registers, also including data from primary health and long-term-care services, were linked. Performance indicators were compared at baseline (before the Coordination Reform, i.e., 2009–2011), and trends were described and analysed by difference-in-difference methods. The baseline study indicated that hip fracture patients in Oslo, compared with those in Helsinki, had longer stays in acute hospitals. They used less institutional care outside of hospitals as well as more GP services and fewer other outpatient services. Mortality was lower, and the probability of being discharged to home within 90 days from the index day was higher. After the Coordination Reform, the length of stay in hospital was shorter and the length of the first institutional episode in Oslo was longer than before the Reform, demonstrating that the shorter hospital stays were more than compensated for by longer stays in long-term-care institutions. The number of patients institutionalised 90 days from the index day increased and the number of patients discharged to home within 90 days from the index day decreased in Oslo after the Reform while the opposite trends were observed in Helsinki. After the Reform, the performance differences between the two regions had decreased. Published: Online December 2018. In print January 2019.

Does the primary screening test influence women's anxiety and intention to screen for cervical cancer? A randomized survey of Norwegian women

Background Countries must decide whether or not to replace primary cytology-based screening with primary human papillomavirus (HPV)-based screening. We aimed to assess how primary screening for an HPV infection, a sexually transmitted infection (STI), and the type of information included in the invitation letter, will affect screening intention. Methods We randomized a representative sample of Norwegian women to one of three invitation letters: 1) Pap smear, 2) HPV testing or 3) HPV testing with additional information about the nature of the infection. Intention to participate, anxiety level and whether women intend to follow-up abnormal results were measured between groups using chi-squared and nonparametric Kruskal-Wallis tests. Determinants of intention were explored using logistic regression. Results Responses from 3540 women were representative of the Norwegian population with respect to age, civil status and geographic location. No significant difference across invitation letters was found in women’s stated intention to participate (range: 91.8-92.3%), anxiety (39-42% were either quite or very worried) or to follow-up after an abnormal result (range: 97.1-97.6%). Strength of intention to participate was only marginally lower for HPV-based invitation letters, albeit significant (p-value?=?0.008), when measured on a scale. Only 36–40% of respondents given the HPV invitations correctly understood that they likely had an STI. Conclusions We found that switching to primary HPV screening, independent of additional information about HPV infections, is not likely to reduce screening participation rates or increase anxiety; however, women lacked the ability to interpret the meaning of an HPV-test result