Knut Stavem

Akershus universitetssykehus, Kristiania (historical), Oslo County, Norway

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Publications (102)248.56 Total impact

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    ABSTRACT: Early identification of patients with a prolonged stay due to acute exacerbation of chronic obstructive pulmonary disease (COPD) may reduce risk of adverse event and treatment costs. This study aimed to identify predictors of prolonged stay after acute exacerbation of COPD based on variables on admission; the study also looked to establish a prediction model for length of stay (LOS). We extracted demographic and clinical data from the medical records of 599 patients discharged after an acute exacerbation of COPD between March 2006 and December 2008 at Oslo University Hospital, Aker. We used logistic regression analyses to assess predictors of a length of stay above the 75th percentile and assessed the area under the receiving operating characteristic curve to evaluate the model's performance. We included 590 patients (54% women) aged 73.2±10.8 years (mean ± standard deviation) in the analyses. Median LOS was 6.0 days (interquartile range [IQR] 3.5-11.0). In multivariate analysis, admission between Thursday and Saturday (odds ratio [OR] 2.24 [95% CI 1.60-3.51], P<0.001), heart failure (OR 2.26, 95% CI 1.34-3.80), diabetes (OR 1.90, 95% CI 1.07-3.37), stroke (OR 1.83, 95% CI 1.04-3.21), high arterial PCO2 (OR 1.26 [95% CI 1.13-1.41], P<0.001), and low serum albumin level (OR 0.92 [95% CI 0.87-0.97], P=0.001) were associated with a LOS >11 days. The statistical model had an area under the receiver operating characteristic curve of 0.73. Admission between Thursday and Saturday, heart failure, diabetes, stroke, high arterial PCO2, and low serum albumin level were associated with a prolonged LOS. These findings may help physicians to identify patients that will need a prolonged LOS in the early stages of admission. However, the predictive model exhibited suboptimal performance and hence is not ready for clinical use.
    International Journal of COPD 01/2014; 9:99-105.
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    ABSTRACT: Bakground: The objectives of this study were; (1) to assess the prevalence and frequency of headache in patients referred to polysomnography (PSG) due to a clinical suspicion of obstructive sleep apnea (OSA) or another sleep disturbance and compare with a reference population, and (2) to assess the association of OSA severity with headache and headache frequency. A total of 784 participants filled in a headache questionnaire between 2003 and 2009 at the Department of Clinical Neurophysiology, Akershus University Hospital. Of these patients 477 were suspected to have OSA, and 307 had other sleep complaints. We assessed the prevalence of headache and monthly headache frequencies, as well as sleep apnea severity using an apnea-hypopnea index (AHI). The association of headache and monthly headache frequencies with PSG subgroups was assessed using multivariate logistic and ordered logistic regression analysis. The frequency of headache was not associated with the severity of OSA. Patients referred to a sleep study for any reason had higher odds ratio (OR) for having experienced headache during the past year than population controls after adjustment for age, gender and education, i.e. patients with normal AHI had OR of 3.56, patients with OSA had OR of 3.51, and patients with other sleep disturbances had OR of 3.33. Similarly, the adjusted OR of being in a higher category of monthly headache frequency compared to controls was higher in those with normal AHI (OR 3.42), OSA (OR 3.29), and other sleep disturbances (OR 3.00). The odds of headache and headache frequency were higher in subjects referred to a PSG for any sleep disturbance independently of OSA, compared to general population controls. However, there was no association between experiencing headache during the past year or headache frequency with OSA severity.
    The Journal of Headache and Pain 11/2013; 14(1):90. · 2.78 Impact Factor
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    ABSTRACT: For clinical trial design and for clinical practice, it is of importance to assess factors associated with placebo response in patients with refractory epilepsy. We determined factors associated with placebo response in 359 adult patients with refractory focal epilepsy participating in three randomized placebo-controlled trials of the new antiepileptic drug lacosamide. At the end of the randomized 12-week maintenance period, 81 (23%) of the 359 patients randomized to placebo achieved at least a 50% seizure reduction (responders) compared to baseline. In contrast, 278 (77%) patients did not achieve a 50% seizure reduction (non-responders) compared to baseline. In multivariate analysis, five factors, which were present prior to the exposure to placebo, were found to be associated with placebo response. Higher age at study entry improved the chances of placebo response for each year [p=0.023, odds ratio (OR) 1.034 (95% confidence interval (95% CI): 1.005-1.063)]. In contrast, a lower chance of placebo response was seen with age at diagnosis of epilepsy of 6-20years compared to ≤5years [p=0.041, OR 0.475 (95% CI: 0.232-0.971)]. A history of 7 or more prior lifetime AEDs lowered the chance of achieving placebo response compared to 1-3 prior lifetime AEDs [p<0.001, OR 0.224 (95% CI: 0.101-0.493)] as did a baseline seizure frequency >10 seizures per 28days compared to ≤5 seizures per 28days [p=0.026, OR 0.431 (95% CI: 0.205-0.904)]. Prior epilepsy surgery lowered the likelihood of placebo response [p=0.02, OR 0.22 (95% CI: 0.062-0.785)]. We suggest that age at exposure to placebo, age at diagnosis of epilepsy, the number of prior lifetime AEDs, baseline seizure frequency and a history of epilepsy surgery appear to be associated with placebo response in adults with refractory focal epilepsy.
    Epilepsy & Behavior 03/2013; · 1.84 Impact Factor
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    ABSTRACT: INTRODUCTION: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a common cause of hospitalization, and the readmission rate is high. We aimed to determine whether patients discharged from a pulmonary department (PD) after an AECOPD episode had a lower COPD-related readmission rate during the next 12 months than comparable patients discharged from other internal medicine departments (ODs). METHODS: The medical records of 566 patients discharged after an episode of AECOPD between March 2006 and December 2008 at Oslo University Hospital, Aker were reviewed retrospectively. Demographic and medical data, together with number of readmissions due to AECOPD during 12 months following the index admission were extracted. We matched patients discharged from the PD and the ODs using a propensity score and used the paired t-test to compare COPD-related readmission rates between the matched patients. RESULTS: In total 481 patients were included in the analysis, 247 patients discharged from the PD and 234 from ODs. The propensity score matching process resulted in 155 well-matched pairs. The mean (standard deviation) number of readmissions within one year was 0.8 (1.3) for the PD versus 1.1 (1.9) for ODs (p=0.09). After adjusting for exposure time, the corresponding readmission rates were 1.1 (2.3) and 1.6 (4.0) per year, respectively (p=0.17). CONCLUSION: There was little difference in COPD-related readmission rates between comparable patients discharged from the PD and the ODs after an AECOPD during one year following the index admission.
    The Clinical Respiratory Journal 01/2013; · 1.66 Impact Factor
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    ABSTRACT: Background: National EQ-5D value sets are developed because preferences for health may vary in different populations. UK values are lower than US values for most of the 243 possible EQ-5D health states. Although similar protocols were used for data collection, analytic choices regarding how to model values from the collected data may also influence national value sets. Participants in the UK and US studies assessed the same subset of 42 EQ-5D health states using the time trade-off (TTO) method. However, different methods were used to transform negative values to a range bounded by 0 and -1, and values for all 243 health states were estimated using two different regression models. The transformation of negative values is inconsistent with expected utility theory, and the choice of which transformation method to use lacks a theoretical foundation. Objectives: Our objectives were to assess how much of the observed difference between the UK and US EQ-5D value sets may be explained by the choice of transformation method for negative values relative to the choice of regression model and the differences between elicited TTO values in the respective national studies (datasets). Methods: We applied both transformation methods and both regression models to each of the two datasets, resulting in eight comparable value sets. We arranged these value sets in pairs in which one source of difference (transformation method, regression model or dataset) was varied. For each of these paired value sets, we calculated the mean difference between the two matching values for each of the 243 health states. Finally, we calculated the mean utility gain for all possible transitions between pairs of EQ-5D health states within each value set and used the difference in transition scores as a measure of impact from changing transformation method, regression model or dataset. Results: The mean absolute difference in values was 1.5 times larger when changing the transformation method than when using different datasets. The choice of transformation method had a 3.2 times larger effect on the mean health gain (transition score) than the choice of dataset. The mean health gain in the UK value set was 0.09 higher than in the US value set. Using the UK transformation method on the US dataset reduced this absolute difference to 0.02. The choice of regression model had little overall impact on the differences between the value sets. Conclusions: Most of the observed differences between the UK and US value sets were caused by the use of different transformation methods for negative values, rather than differences between the two study populations as reflected in the datasets. Changing the regression model had little impact on the differences between the value sets.
    PharmacoEconomics 11/2012; · 2.86 Impact Factor
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    ABSTRACT: Background: Several countries have now passed laws that place limitations on where smokers may smoke. A range of smoking-cessation treatments have become available, many of which have documented increased quit rates. Population surveys show that most smokers wish to quit, and most non-smokers would prefer to reduce the prevalence of smoking in society. The strengths of these preferences, however, as measured by their willingness to pay (WTP), have not yet been investigated. Objective: This study aims to identify variables that explain variations in people's answers to WTP questions on smoking-cessation treatments. Methods: A representative sample of the Norwegian population was asked their WTP in terms of an earmarked contribution to a public smoking-cessation programme. A sub-group of daily smokers was, in addition, asked about their WTP for a hypothetical treatment that would remove their urge to smoke. The impact of variation in the question format (different opening bids) on stated WTP was compared with that of factors suggested by economic theory, such as quit-rate effectiveness, degree of addiction as measured by the 12-item Cigarette Dependence Scale (CDS-12), and degree of peer group influence as measured by the proportion of one's friends who smoke. Results: In both programmes, the most important determinant for explaining variations in WTP was the size of the opening bid. Differences in quit-rate effectiveness did not matter for people's WTP for the smoking-cessation programme. Addiction, and having a small proportion of friends who smoke, were positively associated with smokers' WTP to quit smoking. Conclusion: Variations in WTP were influenced more by how the question was framed in terms of differences in opening bids, than by variables reflecting the quality (effectiveness) and need (addiction level) for the good in question. While the WTP method is theoretically attractive, the findings that outcomes in terms of different quit rates did not affect WTP, and that WTP answers can be manipulated by the chosen opening bid, should raise further doubts on the ability of this method to provide valid and reliable answers that reflect true preferences for health and healthcare.
    Applied Health Economics and Health Policy 09/2012;
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    ABSTRACT: PURPOSE: Health state values are by convention anchored to 'perfect health' and 'death.' Attitudes toward death may consequently influence the valuations. We used attitudes toward euthanasia (ATE) as a sub-construct for attitudes toward death. We compared the influence on values elicited with time trade-off (TTO), lead-time TTO (LT-TTO) and visual analogue scale (VAS).Since the 'death' anchor is most explicit in TTO, we hypothesized that TTO values would be most influenced by ATE. METHODS: Respondents valued eight EQ-5D health states with VAS, then TTO (n = 328) or LT-TTO (n = 484). We measured ATE on a scale from -2 (fully disagree) to 2 (fully agree) and used multiple linear regressions to predict VAS, TTO, and LT-TTO values by ATE, sex, age, and education. RESULTS: A one-point increase on the ATE scale predicted a mean TTO value change of -.113 and LT-TTO change of -.072. Demographic variables, but not ATE, predicted VAS values. CONCLUSIONS: TTO appears to measure ATE in addition to preferences for health states. Different ways of incorporating death in the valuation may impact substantially on the resulting values. 'Death' is a metaphysically unknown concept, and implications of attitudes toward death should be investigated further to evaluate the appropriateness of using 'death' as an anchor.
    Quality of Life Research 06/2012; · 2.41 Impact Factor
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    ABSTRACT: In EuroQol five-dimensional questionnaire valuation studies, each participant typically assesses more than 10 hypothetical health states by using the time trade-off (TTO) method. We wanted to explore potential learning effects when using the TTO method, that is, whether the valuations were affected by the number of previously rated health states (the sequence number). We included 3773 respondents from the US EQ-5D valuation study, each of whom valued 12 health states (plus unconscious) in random order. With linear regression, we used sequence number to predict mean and standard deviations across all health states. We repeated the analysis separately for TTO responses indicating a state better than death and a state worse than death. Each TTO value requires a specific number of choice iterations. To test whether respondents used fewer iterations with experience, we used linear regression with sequence number as the independent variable and number of iterations as the dependent variable. Mean TTO values were fairly stable across the sequence number, but analyzing state better than death and state worse than death values separately revealed a tendency toward more extreme values: state better than death values increased by 0.02, while state worse than death values decreased by 0.21 (P < 0.0001) over the full sequence. The standard deviations increased slightly, while the number of choice iterations was the same over the sequence number. The findings were stable across the levels of health state severity, age, and sex. TTO values become more extreme with increasing experience. Because of the randomized valuation order, these effects do not bias specific health states; however, they reduce the overall validity and reliability of TTO values.
    Value in Health 03/2012; 15(2):340-5. · 2.19 Impact Factor
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    ABSTRACT: Given serious concerns over the adverse effects of enzyme induction, modern nonenzyme-inducing antiepileptic drugs (AEDs) may be preferable, provided they have similar efficacy as enzyme-inducing AEDs. This is currently unclear. Therefore, we performed a meta-analysis of the evidence to determine the placebo-corrected efficacy of adjunctive treatment with modern nonenzyme-inducing AEDs versus modern enzyme-inducing AEDs that are on the market for refractory focal epilepsy. Of 322 potentially eligible articles reviewed in full text, 129 (40%) fulfilled eligibility criteria. After excluding 92 publications, 37 studies dealing with a total of 9,860 patients with refractory focal epilepsy form the basis for the evidence. The overall weighted pooled-risk ratio (RR) in favor of enzyme-inducing AEDs over placebo was 2.37 (95% confidence interval [CI] 1.77-3.18, p < 0.001) for at least 50% seizure reduction and 4.45 (2.26-8.76, p < 0.001) for seizure freedom. The corresponding weighted pooled RR in favor of nonenzyme-inducing AEDs over placebo was 2.28 (95% CI 2.03-2.57, p < 0.001) for at least 50% seizure reduction and 3.23 (95% CI 2.23-4.67, p < 0.001) for seizure freedom. In a meta-regression analysis in the same sample with at least 50% seizure reduction as outcome, the ratio of RRs for enzyme-inducing AEDs (eight studies) versus nonenzyme-inducing AEDs (29 studies) was 1.01 (95% CI 0.77-1.34, p = 0.92)). Similarly, the ratio of RRs for a seizure-free outcome for enzyme-inducing AEDs (six studies) versus nonenzyme-inducing AEDs (19 studies) was 1.38 (95% CI 0.60-3.16, p = 0.43). Although the presence of moderate heterogeneity may reduce the validity of the results and limit generalizations from the findings, we conclude that the efficacy of adjunctive treatment with modern nonenzyme-inducing AEDs is similar to that of enzyme-inducing AEDs. Given the negative consequences of enzyme induction, our data suggest that nonenzyme-inducing AEDs may be useful alternatives to enzyme-inducing AEDs for treatment of refractory focal epilepsy.
    Epilepsia 03/2012; 53(3):512-20. · 3.96 Impact Factor
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    ABSTRACT: EQ-5D valuation studies are usually performed using the time tradeoff (TTO) method, which is costly and time consuming. We focused on 2 properties that particularly characterize TTO: the initial choice task categorizing health states as better than death (BTD), worse than death (WTD), or equal to death (ETD), and unwillingness to trade (UTT) lifetime to improve health. The aim of this study was to estimate the value of the information to be gained from continuing the conventional TTO tasks beyond the initial question and the extent to which mean-based EQ-5D tariff values could be predicted through a simplified method of categorizing health states into BTD, WTD, ETD, and UTT. We used data from the UK EQ-5D valuation study (n = 2997). We designed an abbreviated system with only 4 values (collapsed TTO [cTTO]) based on the 4 response categories and assigned values as follows: WTD = -.5, ETD = 0, BTD = .5, and UTT = 1. Based on the mean cTTO scores for the valued health states, we created a regression-based cTTO tariff, which was compared with the conventional (full) TTO tariff (fTTO) by regressing 1) the fTTO means on cTTO means and 2) the fTTO tariff on the cTTO tariff. WTD values were unrelated to health state severity. Correlation between the means of fTTO and means of cTTO was >.999, and tariff values from fTTO correlated with tariff values from cTTO at r > .999. Once respondents have classified health states as UTT, BTD, ETD, or WTD, the TTO procedure adds little further information to the tariff values. The WTD task fails to discriminate between good and bad health states. TTO valuation could likely be simplified using cTTO.
    Medical Decision Making 01/2012; 32(4):569-77. · 2.89 Impact Factor
  • K Stavem, O M Rønning
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    ABSTRACT: Few studies have assessed the influence of the organization of stroke care on long-term survival. To compare survival over 12 years after stroke between subjects treated in an acute stroke unit (SU) and those treated in general medical wards (GMW). In total, 550 subjects ≥60 years of age with acute stroke were prospectively allocated according to date of birth (day of the month) to treatment in a SU with relatively short length of stay or GMWs. We assessed survival through a link to the register of Statistics Norway. Groups were compared using Kaplan-Meier analysis on an intention-to-treat basis. Of the 550 eligible subjects, 271 were allocated to a SU and 279 to GMWs. There still was no difference in mortality over 12 years between the groups (P = 0.15, log-rank test) An acute SU offering early treatment and rehabilitation did not offer better long-term mortality after stroke in patients ≥60 years old than initial treatment in GMWs.
    Acta Neurologica Scandinavica 12/2011; 124(6):429-33. · 2.47 Impact Factor
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    ABSTRACT: EQ-5D tariffs are typically based on general population valuations studies, but whether valuations of experienced health (EH) or hypothetical health (HH) are more appropriate is disputed. Previous comparisons of valuations of EH and HH have focused on absolute differences in dimension-specific regression coefficients. We examined differences in the relative importance attributed to the EQ-5D dimensions between EH and HH valuations of EQ-5D states in the United States. We used the regression model from the US EQ-5D valuation study on EH ratings from the 2000-2003 Medical Expenditure Panel Survey and on HH ratings from the US EQ-5D valuation study conducted in 2001. We then compared patterns in the relative magnitudes of coefficients that corresponded to the five dimensions. In the HH model, self-care and pain/discomfort were the most important dimensions, while usual activities were the least important. In the EH model, usual activities were the most important dimension, while self-care was one of the least important. The findings reveal considerable differences between stated preferences for HH and ratings of EH, particularly for self-care and usual activities. The findings accentuate the importance of the debate about which groups' values should be used in medical priority setting.
    Quality of Life Research 09/2011; 21(6):1005-12. · 2.41 Impact Factor
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    ABSTRACT: Traumatic brain injury (TBI) is a major cause of lost disability-adjusted life years, and a valid model allowing prediction of outcome would be welcome. For a clinical prediction model to be valid, generalization to other populations must be possible. The aim of this study was to externally validate a model for in-hospital mortality in patients with TBI, which was recently development at the University of Southern California (USC). The validation cohort was derived from a hospital-based, prospectively collected trauma registry in Oslo, Norway. We included patients admitted with a head injury without hypotension, severe thoracic, or abdominal injury (n = 3,136). We calculated the probability of death according to the USC model. The performance of the model was evaluated using measures of calibration and discrimination in the total sample and subgroups according to initial Glasgow Coma Scale (GCS) score. The USC model provided excellent discrimination (area under the receiver operating characteristic curve, AUC = 0.93), but unsatisfactory calibration (p < 0.001) for the total sample (GCS 3-15). In the GCS 4-8 subgroup we found good discrimination (AUC = 0.89) but poor calibration (Hosmer-Lemeshow test, p < 0.001). The findings question the external validity of the USC model, suggesting that it should not be implemented as a tool for short-term mortality prediction in our TBI population.
    The Journal of trauma 04/2011; 70(4):E56-61. · 2.35 Impact Factor
  • Ole Morten Rønning, Knut Stavem
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    ABSTRACT: In this study, we investigated predictors for long-term all-cause mortality in a cohort of patients hospitalized for acute stroke. We prospectively followed 550 patients aged ≥ 60 years who were consecutively admitted within 24 hours of sustaining acute stroke. The patients were followed for 12 years or until death, whichever came first. Multivariate Cox regression models were used to analyze predictors of all-cause mortality, with the following independent variables: age, sex, living alone, previous stroke, ischemic heart disease, atrial fibrillation, hypertension, diabetes, cancer, current smoker, hemorrhagic stroke, treatment in an acute stroke unit, and stroke severity (measured with the Scandinavian Stroke Scale). The 12-year mortality rate was 86.5%. In a multivariate model, all-cause mortality was associated with the following variables: age (hazard ratio, 1.08; 95% confidence interval, 1.07-1.10), male sex (1.69, 1.40-2.05), previous stroke (1.34, 1.08-1.65), ischemic heart disease (1.30, 1.02-1.64), diabetes (1.74, 1.36-2.23), hemorrhagic stroke (1.58, 1.20-2.08), and stroke severity (1.03, 1.03-1.04); Age, male sex, stroke severity, ischemic heart disease, diabetes, and hemorrhagic stroke were all independently associated with an increased risk of all-cause mortality over the 12-year period after stroke.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 11/2010; 21(5):369-72.
  • Epilepsia 08/2010; 51(8):1645. · 3.96 Impact Factor
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    ABSTRACT: The organization of nursing services could be important to the quality of patient care and staff satisfaction. However, there is no universally accepted nomenclature for this organization. The objective of the current study was to classify general hospital wards based on data describing organizational practice reported by the ward nurse managers, and then to compare this classification with the name used in the wards to identify the organizational model (self-identification). In a cross-sectional postal survey, 93 ward nurse managers in Norwegian hospitals responded to questions about nursing organization in their wards, and what they called their organizational models. K-means cluster analysis was used to classify the wards according to the pattern of activities attributed to the different nursing roles and discriminant analysis was used to interpret the solutions. Cross-tabulation was used to validate the solutions and to compare the classification obtained from the cluster analysis with that obtained by self-identification. The bootstrapping technique was used to assess the generalizability of the cluster solution. The cluster analyses produced two alternative solutions using two and three clusters, respectively. The three-cluster solution was considered to be the best representation of the organizational models: 32 team leader-dominated wards, 23 primary nurse-dominated wards and 38 wards with a hybrid or mixed organization. There was moderate correspondence between the three-cluster solution and the models obtained by self-identification. Cross-tabulation supported the empirical classification as being representative for variations in nursing service organization. Ninety-four per cent of the bootstrap replications showed the same pattern as the cluster solution in the study sample. A meaningful classification of wards was achieved through an empirical cluster solution; this was, however, only moderately consistent with the self-identification. This empirical classification is an objective approach to variable construction and can be generally applied across Norwegian hospitals. The classification procedure used in the study could be developed into a standardized method for classifying hospital wards across health systems and over time.
    BMC Nursing 02/2010; 9:3.
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    ABSTRACT: The aim of this study was to describe how diabetes complications influence the health-related quality of life of individuals with diabetes using the individual EQ-5D dimensions and the EQ-5D index. We mailed a questionnaire to 1,000 individuals with diabetes type 1 and 2 in Norway. The questionnaire had questions about socio-demographic characteristics, use of health care, diabetes complications and finally the EQ-5D descriptive system. Logistic regressions were used to explore determinants of responses in the EQ-5D dimensions, and robust linear regression was used to explore determinants of the EQ-5D index. In multivariate analyses the strongest determinants of reduced MOBILITY were neuropathy and ischemic heart disease. In the ANXIETY/DEPRESSION dimension of the EQ-5D, "fear of hypoglycaemia" was a strong determinant. For those without complications, the EQ-5D index was 0.90 (type 1 diabetes) and 0.85 (type 2 diabetes). For those with complications, the EQ-5D index was 0.68 (type 1 diabetes) and 0.73 (type 2 diabetes). In the linear regression the factors with the greatest negative impact on the EQ-5D index were ischemic heart disease (type 1 diabetes), stroke (both diabetes types), neuropathy (both diabetes types), and fear of hypoglycaemia (type 2 diabetes). The EQ-5D dimensions and the EQ-5D seem capable of capturing the consequences of diabetes-related complications, and such complications may have substantial impact on several dimensions of health-related quality of life (HRQoL). The strongest determinants of reduced HRQoL in people with diabetes were ischemic heart disease, stroke and neuropathy.
    Health and Quality of Life Outcomes 01/2010; 8:18. · 2.27 Impact Factor
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    Heidi Kapstad, Berit Rokne, Knut Stavem
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    ABSTRACT: Pain is a cardinal symptom of osteoarthritis (OA) of the hip and important for deciding when to operate. This study assessed the internal consistency reliability, validity and responsiveness of the Brief Pain Inventory (BPI) among patients with OA undergoing total hip replacement (THR). We prospectively included 250 of 356 patients who were accepted to the waiting list for primary THR surgery. All participants responded to the BPI, WOMAC and SF-36 at baseline and 1 year after surgery. Internal consistency reliability (Cronbach's α) was >0.80 for the BPI, the WOMAC and five of the eight SF-36 scales The pattern of associations of the two BPI scales with corresponding and non-corresponding scales of the WOMAC and SF-36 largely supported the construct validity of the BPI. The responsiveness indices for change from baseline to 1 year after THR ranged from 1.52 to 2.05 for the BPI scales, from 1.69 to 2.84 for the WOMAC scales, and from 0.25 (general health) to 2.77 (bodily pain) for the SF-36 scales. The BPI showed acceptable reliability, construct validity and responsiveness in patients with OA undergoing THR. BPI is short and therefore is easy to use and score, though the instrument offers few advantages over and duplicates scales of more comprehensive instruments, such as the WOMAC and SF-36.
    Health and Quality of Life Outcomes 01/2010; 8:148. · 2.27 Impact Factor
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    ABSTRACT: Although adjunctive treatment with modern antiepileptic drugs (AEDs) is standard care in refractory epilepsy, it is unclear how much of the effect can be attributed directly to the AEDs and how much to the beneficial changes seen with placebo. Therefore, we performed a systematic review and meta-analysis of the evidence to determine the placebo-corrected net efficacy of adjunctive treatment with modern AEDs on the market for refractory epilepsy. Of 317 potentially eligible articles reviewed in full text, 124 (39%) fulfilled eligibility criteria. After excluding 69 publications, 55 publications of 54 studies in 11,106 adults and children with refractory epilepsy form the basis of evidence. The overall weighted pooled-risk difference in favor of AEDs over placebo for seizure-freedom in the total sample of adults and children was 6% [95% confidence interval (CI) 4-8, z = 6.47, p < 0.001] and 21% (95% CI 19-24, z = 17.13, p < 0.001) for 50% seizure reduction. Although the presence of moderate heterogeneity may reduce the validity of the results and limit generalizations from the findings, we conclude that the placebo-corrected efficacy of adjunctive treatment with modern AEDs is disappointingly small and suggest that better strategies of finding drugs are needed for refractory epilepsy, which is a major public health problem.
    Epilepsia 09/2009; 51(1):7-26. · 3.96 Impact Factor
  • Dieter Schmidt, Knut Stavem
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    ABSTRACT: A majority of patients with formerly drug-resistant temporal lobe epilepsy become seizure-free after surgery. However, apart from one 12-month randomized trial, it is unclear how many become seizure-free because of surgery. To determine the net benefit of surgery, we performed a systematic review and meta-analysis of the published evidence of how many patients in similar studies become seizure-free without surgery. Of 155 potentially eligible articles reviewed in full text, 29 (19%) fulfilled eligibility criteria. After excluding 9 publications, 20 studies form the base of evidence. Overall, 719 of 1,621 (44%) of patients with mostly temporal lobe surgery were seizure-free compared to 139 of 1113 (12%) of nonoperated controls [pooled random effects relative risk (RR) 4.26, 95% confidence interval (CI) 3.03-5.98]. The pooled risk difference in favor of surgery was 42% (95% CI 32-51%). We found no comparative outcome data in patients with extratemporal lobe epilepsy only. The available evidence from mostly nonrandomized observational studies indicates that in appropriately selected patients with drug-resistant temporal lobe epilepsy, the combination of surgery with medical treatment is 4 times as likely as medical treatment alone to achieve freedom from seizures.
    Epilepsia 03/2009; 50(6):1301-9. · 3.96 Impact Factor

Publication Stats

1k Citations
248.56 Total Impact Points


  • 2002–2013
    • Akershus universitetssykehus
      Kristiania (historical), Oslo County, Norway
  • 1999–2013
    • University of Oslo
      • • Institute of Clinical Medicine
      • • Department of Behavioural Sciences in Medicine
      • • Division of Medicine
      • • Department of Radiology and Nuclear Medicine (ARN)
      Kristiania (historical), Oslo County, Norway
  • 2009–2012
    • Centre Hospitalier de Luxembourg
      Letzeburg, Luxembourg, Luxembourg
  • 1999–2011
    • Oslo University Hospital
      • Department of Neurosurgery
      Oslo, Oslo, Norway
  • 2004–2010
    • Norwegian Knowledge Centre for the Health Services
      Kristiania (historical), Oslo County, Norway
  • 2005
    • Akershus universitetssykehus HF
      Kristiania (historical), Oslo County, Norway