Biomedical subjects

S Kreiner

Publications and source records attributed to S Kreiner.

At least 19 recordsLinked to original sources

PubMed2001

[Can readmission after apoplexy be prevented? Post-hospital follow-up intervention for apoplexy patients].

INTRODUCTION: The aim of this study was to evaluate two models of an organised postdischarge follow-up service for stroke survivors in comparison with standard aftercare. METHODS: One hundred and fifty-five stroke patients discharged to their homes with lasting impairment were randomised as follows: 54 to follow-up home visits by a physician (INT1-HVP), 53 to instruction by a physiotherapist in their home (INT2-PI), and 48 to standard aftercare (control). Six months after discharge, data on readmission were collected. RESULTS: The readmission rate over the six-month period was 26% in the INT1-HVP group, 34% in the INT2-PI group, and 44% for the controls (p = 0.028). Multivariate analysis of the readmission risk showed a significant, favourable effect of intervention in interaction with the length of hospital stay (p = 0.0332), which indicates that the effect of intervention was strongest for patients with a long inpatient rehabilitation. DISCUSSION: Follow-up intervention after discharge seems to be a way of preventing readmission, especially for patients with a long inpatient rehabilitation.

Activities of Daily Living↗

PubMed2001

A critical appraisal of the use of umbilical artery Doppler ultrasound in high-risk pregnancies: use of meta-analyses in evidence-based obstetrics.

OBJECTIVES: To reanalyze randomized controlled trials on the use of umbilical artery Doppler velocimetry in high-risk pregnancies and determine which high-risk pregnancies benefit from the use of Doppler velocimetry. METHODS: Searching Medline, the Cochrane Library and Embase we found 13 randomized controlled trials on the use of Doppler velocimetry in high-risk pregnancies. Of these, six included pregnancies with strictly defined suspected intrauterine growth restriction and/or hypertensive disease of pregnancy ('well-defined studies'); the rest included a great variety of high-risk pregnancies ('general risk studies'). The studies were analyzed with particular regard to the heterogeneity and to outcome. Audits of the perinatal deaths reported in the randomized controlled trials were performed by a panel of 32 international experts. RESULTS: The 'well-defined studies' had a more uniform study design as compared to the 'general risk studies' and they showed a significant reduction in antenatal admissions (odds ratio, 0.56; 95% confidence interval, 0.43-0.72), inductions of labor (0.78; 0.63-0.96), elective deliveries (inductions of labor and elective Cesarean sections) (0.73; 0.61-0.88) and Cesarean sections (0.78; 0.65-0.94). By perinatal audit it was found that more perinatal deaths in the 'well-defined studies' were potentially avoidable by use of Doppler velocimetry ( P < 0.0005) and the rate of avoidable perinatal deaths was higher among controls (50%) than cases (20%) in this group. CONCLUSION: The randomized controlled trials on umbilical artery Doppler velocimetry show major differences regarding study design and technical and clinical issues and, therefore, they should not be pooled in a simple meta-analysis. By stratification it was found that only in pregnancies with suspected intrauterine growth restriction and/or hypertensive disease of pregnancy will the use of umbilical artery Doppler velocimetry reduce the number of perinatal deaths and unnecessary obstetric interventions.

Confidence Intervals↗

PubMed2000

Prognostic factors in metastatic spinal cord compression: a prospective study using multivariate analysis of variables influencing survival and gait function in 153 patients.

PURPOSE: Based on a very large patient cohort followed prospectively for at least a year or until death, we analyzed the prognostic significance of various clinical and radiological variables on posttreatment ambulatory function and survival. METHODS AND MATERIALS: During a 312-year period we prospectively included 153 consecutive patients with a diagnosis of spinal cord compression due to metastatic disease. The patients were followed with regular neurological examinations by the same neurologist for a minimum period of 11 months or until death. The prognostic significance of five variables on gait function and survival time after treatment was analyzed. RESULTS: The type of the primary tumor had a direct influence on the interval between the diagnosis of the primary malignancy and the occurrence of spinal cord compression (p < 0. 0005), and on the ambulatory function at time of diagnosis (p = 0. 016). There was a clear correlation between the degree of myelographic blockage and gait function (p = 0.000) and between gait function and sensory disturbances (p = 0.000). The final gait was dependent on the gait function at time of diagnosis (p < 0.0005). Survival time after diagnosis depended directly on the time from primary tumor diagnosis until spinal cord compression (p = 0.002), on the ambulatory function at the time of diagnosis (p = 0.018), and on the ambulatory function after treatment. CONCLUSIONS: The pretreatment ambulatory function is the main determinant for posttreatment gait function. Survival time is rather short, especially in nonambulatory patients, and can only be improved by restoration of gait function in nonambulatory patients by immediate treatment.

Adult↗

PubMed2000

Can readmission after stroke be prevented? Results of a randomized clinical study: a postdischarge follow-up service for stroke survivors.

BACKGROUND AND PURPOSE: About 50% of stroke survivors are discharged to their homes with lasting disability. Knowledge, however, of the importance of follow-up services that targets these patients is sparse. The purpose of the present study was to evaluate 2 models of follow-up intervention after discharge. The study hypothesis was that intervention could reduce readmission rates and institutionalization and prevent functional decline. We report the results regarding readmission. METHODS: This randomized study included 155 stroke patients with persistent impairment and disability who, after the completion of inpatient rehabilitation, were discharged to their homes. The patients were randomized to 1 of 2 follow-up interventions provided in addition to standard care or to standard aftercare. Fifty-four received follow-up home visits by a physician (INT1-HVP), 53 were provided instructions by a physiotherapist in their home (INT2-PI), and 48 received standard aftercare only (controls). Baseline characteristics for the 3 groups were comparable. Six months after discharge, data were obtained on readmission and institutionalization. RESULTS: The readmission rates within 6 months after discharge were significantly lower in the intervention groups than in the control group (INT1-HVP 26%, INT2-PI 34%, controls 44%; P=0.028). Multivariate analysis of readmission risk showed a significant favorable effect of intervention (INT1-HVP or INT2-PI) in interaction with length of hospital stay (P=0.0332), indicating that the effect of intervention was strongest for patients with a prolonged inpatient rehabilitation. CONCLUSIONS: Readmission is common among disabled stroke survivors. Follow-up intervention after discharge seems to be a way of preventing readmission, especially for patients with long inpatient rehabilitation.

Aged↗

PubMed2000

Item bias in indices measuring psychosocial work environment and health.

OBJECTIVES: The main purpose of this study was to demonstrate the relevance of testing indices concerning the psychosocial work environment by item bias or differential item functioning (DIF) analysis. Especially when the work environment for different groups is compared, this kind of construct validation is important. As exogenous variables gender, age, and occupational group were selected. METHODS: Data were taken from a cross-sectional study of Danish employees aged 19-59 years (N=5940). The study was carried out in 1990 and followed-up in 1995. RESULTS: Item bias was demonstrated in all indices when analyzed in relation to gender, age, and occupational groups of the total population. Item bias was much weaker or disappeared as the population was divided into main occupational groups and analyzed in relation to the same exogenous variables. CONCLUSIONS: For a heterogeneous group of employees, gender, age, and occupational status are significant determinants of the response pattern in relation to indices of the psychosocial work environment. It was concluded that, if the psychosocial work environment for different groups is to be compared, indices should always be tested for item bias in relation to the exogenous variables included in the final analyses. Indices should only be used if there is no item bias. If such indices cannot be constructed, it is suggested that researchers either concentrate on constructing indices that are valid in subgroups or report results based on single-item analyses.

Adult↗

PubMed1998

Cerebral thrombosis and oral contraceptives. A case-control study.

To assess the influence of oral contraceptives (OC) on the risk of cerebral thrombosis and transient cerebral ischemic attacks, a 5-year case-control study including all Danish hospitals was conducted. All women 15-44 years old who suffered a cerebral thromboembolic attack (CTA) during the period 1994-95 and 1200 age matched control subjects were included. Of 309 patients and 1200 control subjects questionnaires sent out, 271 patients (87.7%) and 1074 control subjects (89.5%) responded and agreed to participate. After exclusion of women with nonvalid diagnoses, previous thromboembolic diseases, or current pregnancy, 219 patients and 1041 control subjects were available for analysis. After confounder control and with nonusers as reference, current users of first generation OC (50 micrograms of ethinyl estradiol [EE] or estrans) had an odds ratio (OR) of CTA of 1.86 (95% confidence interval [CI] 0.88-3.92); users of second generation OC (levonorgestrel or norgestimate) had an OR of 2.37 (1.35-4.16); and users of third generation OC (desogestrel or gestodene) had an OR of 1.32 (0.78-2.22). Users of OC with 50, 30-40, or 20 micrograms EE had OR of 2.65 (1.11-6.34), 1.60 (1.05-2.43), and 1.59 (0.57-4.58), respectively. Odds ratios for specific progestin types were as follows: estrans 1.37 (0.60-3.13), levonorgestrel 2.43 (1.40-4.21), norgestimate 7.09 (1.87-26.8), desogestrel 1.62 (0.72-3.63), and gestodene 1.24 (0.67-2.30). Duration of use was without significant influence on the risk and the OR were constant across the age bands. Compared with women who had never used OC, former users had an OR of CTA of 0.95 (0.66-1.51). In conclusion, use of OC with 50 micrograms of EE and OC with second generation progestins increased the risk of CTA significantly. OC with third generation progestins did not have any significant influence on the risk of CTA. The risk of CTA among former users of OC was not increased.

Adolescent↗

PubMed1998

Oral contraceptives and venous thromboembolism. A case-control study.

To assess the influence of oral contraceptives (OC) on the risk for venous thromboembolism (VTE) in young women, a 5-year case-control study including all women 15-44 years old suffering a first deep venous thrombosis or a first pulmonary embolism from all Danish hospitals, along with 1200 control subjects during the period 1994-1995, was conducted. Of 586 patient and 1200 control subject questionnaires sent out, 523 patient (89.2%) and 1074 control (89.5%) questionnaires were returned with an agreement to participate. After exclusion of women with nonvalid diagnoses, women who were pregnant, and women with previous VTE or acute myocardial infarction (AMI), 375 patients and 1041 control subjects were available for analysis. Potential tested confounders included: body mass index, length of OC use, family history of VTE, AMI, or stroke, smoking habits, coagulopathies, diabetes, years of schooling, certainty of diagnosis, previous births, and treated hypertension during any pregnancy. A multivariate analysis was performed. Estrogen dose had no influence on the risk for VTE. The risk for VTE among current users of OC was primarily influenced by duration of use, with significantly decreasing odds ratios (OR) over time: < 1 year; 5.1 (3.1-8.5); 1-5 years; 2.5 (1.6-4.1); and > 5 years; 2.1 (1.5-3.1), all compared with those for nonusers of OC. This trend was still significant after adjustment for progestin types. Without adjustment for duration of use, current users of OC with second generation (levonorgestrel or norgestimate) and third generation (desogestrel or gestodene) progestins had OR of 1.8 (1.1-2.9) and 3.2 (2.3-4.4), respectively. After correction for duration of use, however, no significant differences were found between users of OC with different types of progestins. In conclusion, OC increase the risk for VTE significantly. The risk among current users of OC is primarily influenced by duration of use. No difference in risk was found according to estrogen dose, and the difference in risk between different types of progestins was not statistically significant after adjustment for duration of use.

Adolescent↗

PubMed1998

Differential item functioning in the Danish translation of the SF-36.

Statistical analyses of Differential Item Functioning (DIF) can be used for rigorous translation evaluations. DIF techniques test whether each item functions in the same way, irrespective of the country, language, or culture of the respondents. For a given level of health, the score on any item should be independent of nationality. This requirement can be tested through contingency-table methods, which are efficient for analyzing all types of items. We investigated DIF in the Danish translation of the SF-36 Health Survey, using two general population samples (USA, n = 1,506; Denmark, n = 3,950). DIF was identified for 12 out of 35 items. These results agreed with independent ratings of translation quality, but the statistical techniques were more sensitive. When included in scales, the items exhibiting DIF had only a little impact on conclusions about cross-national differences in health in the general population. However, if used as single items, the DIF items could seriously bias results from cross-national comparisons. Also, the DIF items might have larger impact on cross-national comparison of groups with poorer health status. We conclude that analysis of DIF is useful for evaluating questionnaire translations.

Adolescent↗

PubMed1997

Hormone replacement therapy and risk of non-fatal stroke.

BACKGROUND: The effect of postmenopausal hormone replacement therapy (HRT) on the risk of subtypes of stroke is as yet unclear. To investigate the effect of oestrogen and combined oestrogen-progestagen therapy on the risk of non-fatal haemorrhagic and thromboembolic stroke, we carried out a case-control study. METHODS: From the Danish National Patient Register we identified all Danish women aged 45-64 years who had a non-fatal, first-ever cerebrovascular attack during 1990-92. Two age-matched controls were randomly selected for each case from the Danish National Person Register. Important correlates of hormone use and stroke, on which information was obtained from postal questionnaires, were controlled for by multivariate analyses based on log-linear graphical models. The analyses included data on 1422 cases classified in four subtypes of stroke (160 subarachnoid haemorrhage, 95 intracerebral haemorrhage, 846 thromboembolic infarction, 321 transient ischaemic attack) and 3171 controls. FINDINGS: After adjustment for confounding variables and correction for the trend in sales of HRT preparations, no significant associations were detected between current use of unopposed oestrogen replacement therapy and non-fatal subarachnoid haemorrhage (odds ratio 0.52 [95% CI 0.23-1.22]), intracerebral haemorrhage (0.15 [0.02-1.09]), or thromboembolic infarction (1.16 [0.86-1.58]), respectively, compared with never use. Current use of combined oestrogen-progestagen replacement therapy had no significant influence on the risk of subarachnoid haemorrhage (1.22 [0.79-1.89]), intracerebral haemorrhage (1.17 [0.64-2.13]), or thromboembolic infarction (1.17 [0.92-1.47]). A significantly increased incidence of transient ischaemic attacks among former users of HRT and among current users of unopposed oestrogen may to some extent be explained by selection--HRT users being more aware of symptoms than non-users. INTERPRETATION: Unopposed oestrogen and combined oestrogen-progestagen replacement therapy have no influence on the risk of non-fatal thromboembolic or haemorrhagic stroke in women aged 45-64 years.

Case-Control Studies↗

PubMed1995

Graphical models for panel studies, illustrated on data from the Framingham Heart Study.

Recursive graphical models allow description of the simultaneous development of several (discrete) characteristics such as are recorded in a panel study. Irreversible events (death, irreversible disease occurrence) between exams are naturally included. This paper reviews these models and gives a detailed discussion of an example consisting of 49-50 year old males from the Framingham Heart study. The program DIGRAM is used throughout and the present paper may also serve as an introduction to this software.

Cause of Death↗

PubMed1995

Test for item bias in a quality of life questionnaire.

Item bias (differential item functioning) analysis examines whether the construction of an index from two or more variables results in bias in relation to sex, age, or other criteria. Item bias may lead to erroneous conclusions because of distortion or dilution of the effects measured. In comparing groups, item bias analysis, tests whether the information about possible differences between groups, obtained by the variables constituting an index, are correctly passed on by the index score. We examined a quality of life questionnaire answered by 1189 breast cancer patients. We found age-bias or bias in the comparison of groups receiving different treatments in three out of nine indexes. Recommendations for the interpretation of these indexes are made. Item bias analysis is a useful method examining an issue not covered by traditional psychometric tests.

Adult↗

PubMed1995

Rasch analysis in the development of a rating scale for assessment of mobility after stroke.

The study describes the development of a rating scale for assessment of mobility after stroke. It was based on 74 first-stroke patients, 40 men and 34 women, each assessed three times during rehabilitation. Their median age was 69 years, and they represented all degrees of severity of paresis. Content, construct, criterion and convergent validity were examined, as well as the inter-rater reliability. The final rating scale has three special characteristics: 1) it reflects the regularity in the recovery of mobility after stroke; 2) the sum of item scores comprises the information contained in the 10-item subscores; 3) the score sum is independent of age, side of hemiparesis, and gender of the patient. Latent trait analysis (Rasch) was found to be an ideal model for statistical investigation of these properties.

Activities of Daily Living↗

PubMed1994

[Reproducibility of electrocardiographic interpretation in patients with suspected myocardial infarction. A controlled study of the effect of a training trial].

We examined the effect of a training programme to reduce interobserver variation in interpretation of electrocardiography in suspected myocardial infarction. Sixteen doctors with 6-24 months of clinical training in internal medicine read serial electrocardiographic recordings in 107 patients and assessed whether signs indicative of acute myocardial infarction were present. There was disagreement in approximately 70% of cases. Eight of the doctors were randomly allocated to attend an eight hour long intensive course on interpretation of electrocardiography in myocardial infarction. The remaining eight participants were allocated to a control group, received no training, and were not told about the subject of the study. All the doctors then reviewed another series of electrocardiographic recordings. No difference was found in the level of agreement within the two groups before and after the training programme, or between the two groups before and after the training. The raters' ability to discriminate between electrocardiograms with a high and low indication of infarction remained unaffected. We conclude that the training programme did not increase agreement regarding the interpretation of electrocardiographic data in suspected myocardial infarction. Our results suggest that the diagnostic approach of physicians is established at a very early stage in their clinical training. The effect of training programmes should be evaluated by the use of randomized clinical studies.

Clinical Competence↗

PubMed1994

Measurement issues in research on social support and health.

STUDY OBJECTIVE: The aims were: (1) to identify methodological problems that may explain the inconsistencies and contradictions in the research evidence on social support and health, and (2) to validate a frequently used measure of social support in order to determine whether or not it could be used in multivariate analyses of population data in research on social support and health. DESIGN AND METHODS: Secondary analysis of data collected in a cross sectional survey of a multistage cluster sample of the population of the United States, designed to study relationships in behavioural, social support and health variables. Statistical models based on item response theory and graph theory were used to validate the measure of social support to be used in subsequent analyses. PARTICIPANTS: Data on 1755 men and women aged 20 to 64 years were available for the scale validation. RESULTS: Massive evidence of item bias was found for all items of a group membership subscale. The most serious problems were found in relationship to an item measuring membership in work related groups. Using that item in the social network scale in multivariate analyses would distort findings on the statistical effects of education, employment status, and household income. Evidence of item bias was also found for a sociability subscale. When marital status was included to create what is called an intimate contacts subscale, the confounding grew worse. CONCLUSIONS: The composite measure of social network is not valid and would seriously distort the findings of analyses attempting to study relationships between the index and other variables. The findings show that valid measurement is a methodological issue that must be addressed in scientific research on population health.

Adult↗

PubMed1993

[Increased incidence of Crohn disease in the county of Copenhagen].

The incidence of Crohn's disease was assessed in a population based study in Copenhagen County from 1962-1987. The incidence increased six fold during the study period from 0.62/10(5) in 1962 to a mean of 4.1/10(5) from 1979-1987, equally in both sexes. The highest incidence was found in the age group 15-24 years: 12.8/10(5) for women and 6.0/10(5) for men (as mean of the period 1979-1987). The prevalence at the end of the study was 54/10(5). The clinical symptoms and extent of disease at diagnosis did not change over the time, but a significantly higher disease activity was found in the 1980's, 74% (1962-1979) vs 84% (1980-1987), p = 0.04. The increase in incidence of Crohn's disease is well established in most parts of the industrialized world. The analysis shows that it is not due to a new disease entity, since the extent of disease, the age and sex distribution, and the symptoms remained unchanged during the 26 year study period.

Adolescent↗

PubMed1993

The measurement of instrumental ADL: content validity and construct validity.

A new measure of Instrumental Activities of Daily Living (IADL), which is able to discriminate among the large group of elderly who do not depend on help, was tested for content validity and construct validity. Most assessments of functional ability include Physical ADL (PADL) and Instrumental ADL (IADL). PADL-scales assess the basic capacity of persons to care for themselves. IADL-scales are used to assess somewhat higher levels of performance, such as the ability to perform household chores or go shopping. Data were collected from 734 70-year-old people in Denmark in the county of Copenhagen. The measure of Instrumental ADL included 30 activities in relation to tiredness and reduced speed. Construct validity was tested by the Rasch model for item analysis; internal validity was specifically addressed by assessing the homogeneity of items under different conditions. The Rasch item analysis of IADL showed that 14 items could be combined into two qualitatively different additive scales. The IADL-measure complies with demands for content validity, distinguishes between what the elderly actually do, and what they are capable of doing, and is a good discriminator among the group of elderly persons who do not depend on help. It is also possible to add the items in a valid way. However, to obtain valid IADL-scales, we omitted items that were highly relevant to especially elderly women, such as house-work items. We conclude that the criteria employed for this IADL-measure are somewhat contradictory.

Activities of Daily Living↗

PubMed1993

Construct validation and the Rasch model: functional ability of healthy elderly people.

The purpose of this study was to test the construct validity of a measure of functional ability, developed with the intention of achieving a high degree of variability and capacity for discriminating among a group of healthy elderly people. Data were collected from 734 70-year-old people in Denmark in the county of Copenhagen. Functional ability was measured with the traditional activities of daily living and with a classification system developed specially for healthy elderly people. Construct validity was tested by the Rasch model for item analysis, addressing specifically the internal validity by assessing the homogeneity of items under different conditions. The results show that the proposed measure of functional ability is a combination of six different dimensions, divided into 3 types: mobility function, lower limb function and upper limb function. With regard to these three types decreased functional ability can appear by either tiredness or reduced speed.

Activities of Daily Living↗

PubMed1992

Sexual behaviour related to psycho-social factors in a population of Danish homosexual and bisexual men.

An anonymous self-administered questionnaire was distributed to (1) male members of the Danish Gay and Lesbian Association (2) through a gay magazine and (3) to readers of a gay pornographic magazine. For the purpose of this study sexual practices were classified into three categories taking into account the HIV-status of the respondent and his partner(s): safe sex (mutual masturbation, sex with condoms, sex without condoms between two HIV-positives), potentially safe sex (oral-genital sex without condoms irrespective of HIV-status, anal-genital sex without condoms between two HIV-negatives), unsafe sex (anal-genital sex without condoms between discordant partners or partners of unknown HIV status). Of the 2058 respondents 29.7% had had unsafe sex in the last 12 months. Multivariate analysis by recursive graphical models showed that sexual practice was directly related (that is conditionally dependent given the rest of the variables) to having a steady partner. Among men without a steady partner sexual practice was also directly related to age and number of partners showing an increase in unsafe sex with number of partners and a decrease with age. Thus of the men 16-19 years of age 43.5% had had unsafe sex irrespective of number of partners vs 5.7% of men older than 44 years and with one to two partners. Sexual practice was not directly related to any other demographic or psychosocial factor in the study. The adopted classification of sexual practice preclude that the high occurrence of unsafe sex could be explained by unsafe sex taking place among partners of concordant HIV status. The results emphasize the need for further preventive efforts to reduce transmission of HIV among homosexual men.

Adolescent↗