| 1. |
- Södergren, Anna, 1977-, et al.
(författare)
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Increased incidence of and impaired prognosis after acute myocardial infarction among patients with seropositive rheumatoid arthritis.
- 2007
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd & European League Against Rheumatism. - 0003-4967 .- 1468-2060. ; 66:2, s. 263-266
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the incidence and outcome of acute myocardial infarction (AMI) in patients with rheumatoid arthritis compared with the general population, and to examine whether care and treatment of an AMI differs between patients and controls. Methods: The Multinational Monitoring of Trends and Determinants of Cardiovascular Disease register for northern Sweden was used to compare those incidences of AMI in a cohort of patients with rheumatoid arthritis with that in the general population. 35 patients with rheumatoid arthritis who had also experienced an AMI were identified. For each patient with rheumatoid arthritis, three controls with a history of AMI but without rheumatoid arthritis were randomly selected from the same register, and matched for age, sex and year of the AMI for evaluation of case fatality and potential differences in treatment of AMI. Results: The standardised incidence ratio for AMI was 2.9 in patients with rheumatoid arthritis compared with the general population (p<0.05). During the first 10 years after an AMI, patients with rheumatoid arthritis had a higher overall case fatality compared with controls (hazard ratio (HR) 1.67, 95% confidence interval (CI) 1.02 to 2.71). Survival time was decreased in the rheumatoid arthritis group compared with controls despite the same care and treatment. Conclusion: Both the incidence of and case fatality after an AMI were higher among patients with rheumatoid arthritis than among the general population. The results emphasise the necessity of optimising the preventive, diagnostic and caring strategies for AMI in rheumatoid arthritis.
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| 2. |
- Wållberg-Jonsson, Solveig, 1953-, et al.
(författare)
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Cardiovascular morbidity and mortality in patients with seropositive rheumatoid arthritis in Northern Sweden.
- 1997
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Ingår i: Journal of Rheumatology. - : ?. - 0315-162X .- 1499-2752. ; 24:3, s. 445-451
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the overall and the cardiovascular mortality in rheumatoid arthritis (RA) in Northern Sweden. To analyze the effect of traditional risk factors and factors associated with rheumatoid disease and its treatment on the progression of cardiovascular disease (CVD) and on mortality by all causes. METHODS: A cohort of 606 patients with seropositive RA were followed from 1979 to the end of 1994 or to the death of the patient. Standardized mortality ratio and survival curves were estimated with the population of Vasterbotten as reference. Sex, age at disease onset, treatment with corticosteroids, use of disease modifying antirheumatic drugs (DMARD) and hormone replacement therapy (HRT), hypertension, diabetes mellitus, HLA types, and cause of death were recorded from disease onset. Cox's proportional hazards regression was used to identify important predictors for death and cardiovascular event during followup. RESULTS: The standardized mortality ratio in both sexes was significantly higher (1.57) for all underlying causes together, for CVD (1.46) and for ischemic heart disease (IHD) (1.54) compared to the reference population. The death rate increased over time. In multiple Cox regression analyses, male sex, higher age at disease onset, and former cardiovascular event increased the death rate. Male sex, high age at disease onset, and hypertension increased the risk of cardiovascular event. Diabetes mellitus, treatment with corticosteroids, DMARD, or HRT did not influence the risks of death or first cardiovascular event. CONCLUSION: The overall mortality and death due to CVD and IHD were in both sexes increased in seropositive RA. Male sex and high age at disease onset predicted death and cardiovascular event. Except for hypertension, which increased the risk for cardiovascular event, neither of these traditional cardiovascular risk factors nor corticosteroid treatment influenced mortality by all causes or by cardiovascular event.
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| 3. |
- Wållberg-Jonsson, Solveig, 1953-, et al.
(författare)
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Extent of inflammation predicts cardiovascular disease and overall mortality in seropositive rheumatoid arthritis : A retrospective cohort study from disease onset
- 1999
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Ingår i: Journal of Rheumatology. - Toronto, Canada : University of Toronto Publishing. - 0315-162X .- 1499-2752. ; 26:12, s. 2562-2571
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To identify predictors for cardiovascular disease (CVD) and for overall survival in patients with rheumatoid arthritis (RA) followed from disease onset. METHODS: A retrospective cohort of patients with seropositive RA and disease onset between 1974 and 1978 (n = 211) was followed up at the end of 1995. Potential predictors for CVD, as measured by "the first cardiovascular event," and for overall survival were registered. The predictors were identified by extended Cox regression models. RESULTS: In simple Cox regression analysis, male sex, higher age at disease onset, HLA-B27, high disease activity, corticosteroid treatment early in disease, and hypertension significantly increased risk of cardiovascular event. Higher educational level, extensive disease modifying antirheumatic drug (DMARD) treatment, and corticosteroids > or =1 yr before event decreased the risk. In multiple Cox regression analysis, male sex, high age at disease onset, hypertension, higher haptoglobin level at disease onset, and corticosteroid treatment early in disease increased risk of CVD. In a multiple model comprising only patients with CVD, corticosteroids delayed the event. A high last registered erythrocyte sedimentation rate (ESR) value before event increased CVD risk, in particular when early in disease progression. Decreased life span was predicted by higher age at disease onset, male sex, low education level, high disease activity, hypertension, and CVD. HLA-B27 was associated with decreased life span, as was early, but not extensive corticosteroid treatment. DMARD treatment was associated with decreased mortality risk, as was the presence of joint prosthesis. In multiple regression, male sex, higher age at disease onset, atlantoaxial subluxation early in disease, hypertension, and cardiovascular event increased mortality. A high last registered ESR value before event or death added to that risk. CONCLUSION: The study emphasizes the importance of inflammation as an important risk indicator for CVD and mortality in RA. The positive impact of disease activity reducing treatment on CVD risk and survival is suggested.
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| 4. |
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| 5. |
- Öhman, Marie-Louise, 1945-
(författare)
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A Monte Carlo study of some censored data Wilcoxon rank tests
- 1990
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Ingår i: Biometrical Journal. - Weinheim, Germany : WILEY-VCH Verlag GmbH & Co. KGaA. - 0323-3847 .- 1521-4036. ; 32:6, s. 721-735
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Tidskriftsartikel (refereegranskat)abstract
- The variance estimators usually applied for the generalized censored data Wilcoxon rank tests by Gehan and Peto & Prentice, are heavily biased in unbalanced problems. This paper reports the results of a Monte Carlo simulation study, where jackknifing is used to construct estimators of variance. Size, power and variance properties are compared for five variance estimators, when using different combinations of group sizes, failure and censoring patterns. The variance estimators are the permutational, the conditional permutational and the jackknife variance estimators for the statistic of Gehan and the asymptotic and the jackknife variance estimators for the statistic of Peto & Prentice. It appears that observed size, power and variance properties may be improved by using the jackknife variance estimator, when comparing to the variance estimators usually applied.
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| 6. |
- Öhman, Marie-Louise, 1945-
(författare)
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Aspects of analysis of small-sample right censored data using generalized Wilcoxon rank tests
- 1994
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The estimated bias and variance of commonly applied and jackknife variance estimators and observed significance level and power of standardised generalized Wilcoxon linear rank sum test statistics and tests, respectively, of Gehan and Prentice are compared in a Monte Carlo simulation study. The variance estimators are the permutational-, the conditional permutational- and the jackknife variance estimators of the test statistic of Gehan, and the asymptotic- and the jackknife variance estimators of the test statistic of Prentice. In unbalanced small sample size problems with right censoring, the commonly applied variance estimators for the generalized Wilcoxon rank test statistics of Gehan and Prentice may be biased. In the simulation study it appears that variance properties and observed level and power may be improved by using the jackknife variance estimator.To establish the sensitivity to gross errors and misclassifications for standardised generalized Wilcoxon linear rank sum statistics in small samples with right censoring, the sensitivity curves of Tukey are used. For a certain combined sample, which might contain gross errors, a relatively simple method is needed to establish the applicability of the inference drawn from the selected rank test. One way is to use the change of decision point, which in this thesis is defined as the smallest proportion of altered positions resulting in an opposite decision.When little is known about the shape of a distribution function, non-parametric estimates for the location parameter are found by making use of censored one-sample- and two-sample rank statistics. Methods for constructing censored small sample confidence intervals and asymptotic confidence intervals for a location parameter are also considered. Generalisations of the solutions from uncensored one-sample and two-sample rank tests are utilised. A Monte-Carlo simulation study indicates that rank estimators may have smaller absolute estimated bias and smaller estimated mean squared error than a location estimator derived from the Product-Limit estimator of the survival distribution function.The ideas described and discussed are illustrated with data from a clinical trial of Head and Neck cancer.
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| 7. |
- Öhman, Marie-Louise, 1945-
(författare)
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Contributions to generalized Wilcoxon rank tests
- 1992
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In unbalanced small sample size problems with right censorings, the variance estmators of linear rank statistics, may be biased. This is the case with the commonly applied variance estimators for the generalized Wilcoxon rank test statistics of Gehan and Prentice. The bias and variance of different variance estimators and observed significance level and power for standardized tests are compared in a Monte Carlo simulation study. The variance estimators are the permutational-, the conditional permutational- and the jackknife variance estimators for the statistic Gehan, and the asymptotic- and the jackknife variance estimators for the statistic of Prentice. It appears that observed level and power and variance properties may be improved by using the jackknife variance estimator. Further, The sensitivity curves of Turkey are used to establish the sensitivity to gross errors and misclassifications for standardized generalized Wilcoxon rank sum statistics in small samples with right censorings. For a certain combined sample, which might contain gross errors, a relatively fast method is needed to establish the applicability of the inference drawn from the selected ranktest. Ome way is to use the "change of decision point" (cdp), which in this thesis is defined as the smallest proportion of altered positions resulting in an opposite decision.
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| 8. |
- Öhman, Marie-Louise, 1945-
(författare)
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Estimating location parameters using censored rank statistics
- 1995
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Ingår i: Biometrical Journal. - Weinheim, Germany : WILEY-VCH Verlag GmbH & Co. KGaA. - 0323-3847 .- 1521-4036. ; 37:7, s. 767-782
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Tidskriftsartikel (refereegranskat)abstract
- In this paper censored data rank location estimators are obtained by using censored one-sample rank test statistics of the location parameter and censored two-sample rank test statistics of the shift of location parameter. Also, methods for constructing censored small sample confidence intervals and asymptotic confidence intervals for the location are considered. Generalizations of the solutions from uncensored one-sample and two-sample rank tests are utilized.
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| 9. |
- Öhman, Marie-Louise, 1945-
(författare)
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Generalized Wilcoxon rank tests and sensitivity curves
- 1991
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Ingår i: Biometrical Journal. - Weinheim, Germany : WILEY-VCH Verlag GmbH & Co. KGaA. - 0323-3847 .- 1521-4036. ; 33:7, s. 789-806
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we use the sensitivity curves of TUKEY (1977) and the change of decision point (cdp) (a modified version of the breakdown point of YLVISAKER, 1977), supplemented by simulation studies to acquire knowledge about sensitivity in generalized Wilcoxon rank test statistics. Sensitivity depends on balanced or unbalanced sample size cases, censoring, combinations of failure distributions and sources of errors in the data. It is important to consider the quality of the data, and the results show that cdp and some properties of the sensitivity curves may serve as a hint when selecting a test statistic and when making a decision for a given test statistic.
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