Biomedical subjects
A J Boeke
Publications and source records attributed to A J Boeke.
Cost effectiveness analysis of a population based screening programme for asymptomatic Chlamydia trachomatis infections in women by means of home obtained urine specimens.
OBJECTIVES: To evaluate the cost effectiveness of a systematic screening programme for asymptomatic Chlamydia trachomatis infections in a female inner city population. To determine the sensitivity of the cost effectiveness analysis to variation in the probability of developing sequelae. METHODS: A decision tree was constructed to evaluate health effects of the programme, such as averted sequelae of chlamydial infection. Cost effectiveness from a societal perspective was estimated for screening by means of a ligase chain reaction on mailed, home obtained urine specimens, in a population with a C trachomatis test prevalence of 2.9%. An extensive sensitivity analysis was performed for the probability of sequelae, the percentage of preventable pelvic inflammatory disease (PID), and the discount rate. RESULTS: The estimated net cost of curing one woman, aged 15-40 years, of a C trachomatis infection is US$1210. To prevent one major outcome (PID, tubal factor infertility, ectopic pregnancy, chronic pelvic pain, or neonatal pneumonia), 479 women would have to be screened. The net cost of preventing one major outcome is $15 800. Changing the probability of PID after chlamydial infection from 5% to 25% decreases the net cost per major outcome averted from $28 300 to $6380, a reduction of 78%. Results were less sensitive to variations in estimates for other sequelae. The breakeven prevalence of the programme ranges from 6.4% for the scenario with all probabilities for complications set at the maximum value to a prevalence of 100% for probabilities set at the minimum value. CONCLUSIONS: Systematic screening of all women aged 15-40 years for asymptomatic C trachomatis infections is not cost effective. Although the results of the analyses are sensitive to variation in the assumptions, the costs exceed the benefits, even in the most optimistic scenario.
Clinimetric properties of a parent report on their offspring's quality of life.
The objective of this study was to assess the reproducibility, construct validity, and responsiveness of the parent report version of the "How are you" (HAY), a quality of life questionnaire for children with a chronic disease. The reproducibility of the HAY was assessed by comparing the scores of two measurement cycles of children with stable asthma. Construct validity was evaluated by testing the differences between scores of the HAY of parents of children with and without asthma and by investigating the correlations between the HAY and instruments supposed to correlate with the HAY. Responsiveness was investigated in parents of children whose clinical status changed clinically relevant between two measurements. The HAY showed acceptable reproducibility. Also the HAY detected anticipated differences in quality of life between parents of asthmatic and healthy children. It furthermore showed acceptable ability to measure change in health status of children with asthma. The parent report version of the HAY shows acceptable reproducibility, supportive evidence for construct validity, and good responsiveness. The measurement of quality of life of asthmatic children and changes therein can truly rely on parental report.
Which source should we use to measure quality of life in children with asthma: the children themselves or their parents?
This study compares the reproducibility, construct validity and responsiveness of self-report and parent-report quality of life questionnaires How Are You (HAY) for 8-12-year-old children with asthma. A total of 228 Dutch children with asthma and their parents completed the HAY and daily recorded the child's asthma symptoms in a diary. Additionally 296 age- and -gender matched healthy children and their parents completed the generic part of the HAY. Reproducibility and responsiveness were examined in a sub-group of 80 children with asthma. In this group, three measurements were carried out, at baseline, after one week and once during the following 6 month when the clinical asthma status had changed. The within-subject standard deviations (SD) of three dimensions (physical activities, social activities, self-management) differed significantly (p < 0.05) in favour of the parent-version, indicating that the reproducibility of the parent version was better than that of the child version. The mean score-differences between children with asthma and healthy children as reported by parents did not significantly differ from those reported by children, except for cognitive activities (e.g. be able to concentrate on school work). The mean differences with regard to children with a different actual asthma status (symptom analysis), as reported by both informants, did not differ. Compared to the child-version, the parent-version showed greater ability to detect changes in children's quality of life over time for all but one dimension, indicating better responsiveness. The results indicate that in discriminative studies child and parents reports can be substituted on a group-level. In longitudinal studies data have to be obtained from parents. Consequently, caregivers collecting quality of life data for longitudinal purposes in daily practice should collect these data simply from parents.
Disappointing performance of literature-derived selective screening criteria for asymptomatic Chlamydia trachomatis infection in an inner-city population.
BACKGROUND: In an inner-city population with a low prevalence of Chlamydia trachomatis infection, selective screening may be indicated to increase the efficiency of screening. GOAL: To evaluate the performance of sets of selective screening criteria for asymptomatic Chlamydia trachomatis infection in an inner-city population. The criteria were derived from reports of studies carried out in various settings. STUDY DESIGN: A total of 5714 women age 15 to 40 years living in Amsterdam were invited for a screening based on home-obtained urine specimens. Criteria identified from the literature were applied to the screening population. A calculated area under the receiver-operator characteristic curve (AUC) of greater than 0.75 was considered a good measure of diagnostic accuracy. RESULTS: Of the four sets of criteria, selection based on the following determinants showed the highest diagnostic accuracy: younger than 25 years, being unmarried, number of partners during the previous 6 months, Surinam or Antillean origin (black), and vaginal douching (AUC, 0.67; 95% CI, 0.65-0.69). Selection based on age alone showed an AUC of 0.57 (95% CI, 0.55-0.69). CONCLUSION: The performance of selective screening criteria for asymptomatic C trachomatis infection in an inner-city population in Amsterdam was insufficient to recommend its implementation in practice.
Urogenital Chlamydia trachomatis serovars in men and women with a symptomatic or asymptomatic infection: an association with clinical manifestations?
To determine whether certain Chlamydia trachomatis serovars are preferentially associated with a symptomatic or an asymptomatic course of infection, C. trachomatis serovar distributions were analyzed in symptomatically and asymptomatically infected persons. Furthermore, a possible association between C. trachomatis serovars and specific clinical symptoms was investigated. C. trachomatis-positive urine specimens from 219 asymptomatically infected men and women were obtained from population-based screening programs in Amsterdam. Two hundred twenty-one C. trachomatis-positive cervical and urethral swabs from symptomatically and asymptomatically infected men and women were obtained from several hospital-based departments. Serovars were determined using PCR-based genotyping, i.e., restriction fragment length polymorphism analysis of the nested-PCR-amplified omp1 gene. The most prevalent C. trachomatis serovars, D, E, and F, showed no association with either a symptomatic or asymptomatic course of infection. The most prominent differences found were (i) the association of serovar Ga with symptoms in men (P = 0.0027), specifically, dysuria (P < 0.0001), and (ii) detection of serovar Ia more often in asymptomatically infected people (men and women) (P = 0.035). Furthermore, in women, serovar K was associated with vaginal discharge (P = 0.002) and serovar variants were found only in women (P = 0.045).
Low diagnostic accuracy of selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population.
OBJECTIVES: To develop and validate selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population. METHODS: 11,505 people, aged 15-40 years, registered in 16 general practices in Amsterdam were invited to return by mail a home obtained first void urine sample and a questionnaire. Participants were randomly allocated into a development group (75%) or a validation group (25%). C trachomatis infection was determined by the ligase chain reaction. In the development group a set of criteria was identified by means of stepwise logistic regression analysis. The diagnostic accuracy (area under the ROC curve; AUC) and sensitivity, and the corresponding percentage of people selected for screening were calculated. The criteria developed in this study were applied to the validation group. RESULTS: The prevalence of asymptomatic C trachomatis infections among men was found to be 2.4% (1.7-3.0), and among women 2.8% (2.2-3.4). Screening men, based on Surinam/Antillean origin and painful micturition, yielded an AUC of 0.58 (0.55-0.60). Screening women, based on Surinam/Antillean origin, new sex partner in the previous 2 months, and unmarried/not cohabiting, yielded an AUC of 0.67 (0.65-0.69). Application of the criteria for men to the validation group yielded an AUC of 0.53 (0.48-0.57); by screening 10% of the men, 15% of the cases were detected. The AUC of the criteria for women in the validation group was 0.58 (0.54-0.61); by screening 51% of the women, 63% of the cases were detected. CONCLUSION: The prevalence of asymptomatic C trachomatis infections in Amsterdam is less than 3%. No suitable selective screening criteria for the general population could be identified.
Reproducibility, construct validity, and responsiveness of the "How Are You?" (HAY), a self-report quality of life questionnaire for children with asthma.
This study assesses the reproducibility, construct validity, and responsiveness of a new self-report quality of life questionnaire, the "How Are You?" (HAY), for 8-12-year-old children with asthma, which contains both a generic and a disease-specific part. Two hundred twenty-eight children with asthma completed the HAY and the Child Attitude Toward Illness Scale (CATIS), while their parents monitored the actual asthma status; 80 children were measured three times in order to assess reproducibility and responsiveness; 296 healthy children completed the generic section of the HAY. Significant differences were found between children with asthma and healthy children, and among asthmatic children differing in actual asthma status. Reproducibility was adequate and supportive evidence was found for construct validity. Responsiveness was demonstrated by significant score changes for most dimensions in clinically changed children. The HAY seems useful for both discriminative and evaluative research in children with asthma.
Are postal urine specimens a feasible method for genital chlamydial infection screening?
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[Chronic recurrent headache without neurological abnormalities. Practice guidelines of the Netherlands Society of Neurology].
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[Systematic home screening for Chlamydia trachomatis infections of asymptomatic men and women in family practice by means of mail-in urine samples].
OBJECTIVE: To determine the prevalence and determinants of Chlamydia trachomatis (CT) infections among asymptomatic men and women in general practice. To determine participation rates in a systematic screening programme in general practice, using home obtained mailed urine samples. DESIGN: Cross-sectional study. METHODS: In 15 general practices in Amsterdam, the Netherlands, a sample of 11,005 persons (5541 women and 5464 men), aged 15-40 were invited to send in a urine sample and a completed questionnaire by mail. The urine samples were tested using the ligase chain reaction for DNA amplification. Patients diagnosed with CT were treated and partner notification was performed. RESULTS: 33% of invited males (1809/5464) and 50% of females (2751/5541) sent in the study material. Older patients participated more frequently than younger patients. Participation rates among persons with a Dutch background were higher than rates among persons from other ethnic groups. In 42 men and 79 women a CT infection was identified (2.3% and 2.9% respectively). Infections were more prevalent in patients from Surinam and the Dutch Antilles and in the age category 21-25 years. Type of health insurance as a proxy measure of socioeconomic status was not an indicator of infection. CONCLUSION: The participation in this systematic screening using mail-sent urine samples was 33% in men and 50% in women. The CT prevalences among asymptomatic men and women were 2.3% and 2.9% respectively.
Determination of Chlamydia trachomatis prevalence in an asymptomatic screening population: performances of the LCx and COBAS Amplicor tests with urine specimens.
This study determined the performances of the LCx (Abbott) and COBAS Amplicor (Roche) tests with urine specimens for the detection of Chlamydia trachomatis in an asymptomatic screening population. Randomly selected women and men (age range, 15 to 40 years) registered in 20 general practices in Amsterdam, The Netherlands, were invited to participate in this study. Urine specimens (n = 2, 906; 1,138 specimens from men and 1,717 specimens from women) were tested for C. trachomatis by the COBAS Amplicor (Roche) and LCx (Abbott) tests. Samples which were positive by only one assay were subjected to discrepant analyses by a third assay (in-house plasmid PCR). By the LCx assay C. trachomatis DNA was detected in urine specimens from 46 of 1,717 women and 29 of 1,138 men, while the COBAS Amplicor detected C. trachomatis DNA in 52 and 35 specimens, respectively. When comparing the LCx and COBAS Amplicor tests, 32 test results (20 for women and 12 for men) were discrepant. After discrepant analyses the following sensitivities, specificities, and positive predictive values were found for the LCx and COBAS Amplicor tests: 78.6 versus 98.8%, 99.7 versus 99.9%, and 88.0 versus 95.4%, respectively. No prominent differences were found between men and women with regard to the test performances. After discrepant analyses the overall prevalences of C. trachomatis in women and men were 3.0 and 2.8%, respectively. For both women and men the prevalence in the younger age groups was higher than that in the older age groups. In conclusion, the COBAS Amplicor tests shows better diagnostic characteristics than the LCx assay for the detection of C. trachomatis in urine specimens from an asymptomatic screening population. In this asymptomatic population the overall prevalence of C. trachomatis was 2.9%.
Mailed, home-obtained urine specimens: a reliable screening approach for detecting asymptomatic Chlamydia trachomatis infections.
The use of mailed, home-obtained urine specimens could facilitate screening programs for the detection of asymptomatic Chlamydia trachomatis infections. Since transport time could have an adverse effect on the sensitivity of C. trachomatis detection by PCR, the influence of DNA degradation on amplification was monitored over the course of 1 week. Therefore, urine specimens were aliquoted on the day of collection or arrival. Two groups of urine specimens were investigated. Group I contains first-void C. trachomatis-positive and -negative urine samples. DNA degradation was monitored in group I samples for 7 days at room temperature (RT) and at 4 degrees C by amplifying different lengths of the human beta-globin gene and the C. trachomatis plasmid target. DNA degradation was observed only for the larger human beta-globin fragments at days 5 to 7 at RT. In contrast, at 4 degrees C all targets could be amplified. Urine specimens were also frozen and thawed before aliquoting to mimic freezing during transport. This resulted in a lower sensitivity for the detection of C. trachomatis after thawing and 3 to 4 days at RT. In addition, mailed, home-obtained C. trachomatis-positive urine specimens (group II) were analyzed for 7 days after arrival by two commercially available C. trachomatis detection systems (PCR and ligase chain reaction [LCR]). The C. trachomatis plasmid target in mailed, home-obtained urine specimens could be amplified by both PCR and LCR after 1 week of storage and/or transport at RT. In conclusion, our findings indicate that mailed, home-obtained urine specimens are suitable for the sensitive detection of asymptomatic C. trachomatis infections by amplification methods, even if the transport time is up to 1 week at RT. These findings support the feasibility and validity of screening programs based on mailed, home-obtained urine specimens. Larger studies should be initiated to confirm our results.
Social network, social support, and loneliness in older persons with different chronic diseases.
OBJECTIVES: This study examines whether patterns of social network size, functional social support, and loneliness are different for older persons with different types of chronic diseases. METHODS: In a community-based sample of 2,788 men and women age 55 to 85 years participating in the Longitudinal Aging Study Amsterdam, chronic diseases status, social network size, support exchanges, and loneliness were assessed. RESULTS: Social network size and emotional support exchanges were not associated with disease status. The only differences between healthy and chronically ill people were found for receipt of instrumental support and loneliness. Disease characteristics played a differential role: greater feelings of loneliness were mainly found for persons with lung disease or arthritis, and receiving more instrumental support was mainly found for persons with arthritis or stroke. DISCUSSION: The specifics of a disease appear to play a (small) role in the receipt of instrumental support and feelings of loneliness of chronically ill older persons.
Chlamydia trachomatis prevalence and sexual behaviour among female adolescents in Belgium.
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Effectiveness of corticosteroid injections versus physiotherapy for treatment of painful stiff shoulder in primary care: randomised trial.
OBJECTIVE: To compare the effectiveness of corticosteroid injections with physiotherapy for the treatment of painful stiff shoulder. DESIGN: Randomised trial. SETTING: 40 general practices. SUBJECTS: 109 patients consulting general practitioners for shoulder pain were enrolled in the trial. INTERVENTIONS: Patients were randomly allocated to 6 weeks of treatment either with corticosteroid injections (53) or physiotherapy (56). MAIN OUTCOME MEASURES: Outcome assessments were carried out 3, 7, 13, 26, and 52 weeks after randomisation; some of the assessments were done by an observer blind to treatment allocation. Primary outcome measures were the success of treatment as measured by scores on scales measuring improvement in the main complaint and pain, and improvement in scores on a scale measuring shoulder disability. RESULTS: At 7 weeks 40 (77%) out of 52 patients treated with injections were considered to be treatment successes compared with 26 (46%) out of 56 treated with physiotherapy (difference between groups 31%, 95% confidence interval 14% to 48%). The difference in improvement favoured those treated with corticosteroids in nearly all outcome measures; these differences were statistically significant. At 26 and 52 weeks differences between the groups were comparatively small. Adverse reactions were generally mild. However, among women receiving treatment with corticosteroids adverse reactions were more troublesome: facial flushing was reported by 9 women and irregular menstrual bleeding by 6, 2 of whom were postmenopausal. CONCLUSIONS: The beneficial effects of corticosteroid injections administered by general practitioners for treatment of painful stiff shoulder are superior to those of physiotherapy. The differences between the intervention groups were mainly the result of the comparatively faster relief of symptoms that occurred in patients treated with injections. Adverse reactions were generally mild but doctors should be aware of the potential side effects of injections of triamcinolone, particularly in women.
Effects of social support and personal coping resources on depressive symptoms: different for various chronic diseases?
Effects of psychosocial coping resources on depressive symptoms were examined and compared in older persons with no chronic disease or with recently symptomatic diabetes mellitus, lung disease, cardiac disease, arthritis, or cancer. The 719 persons without diseases reported less depressive symptoms than the chronically ill. Direct favorable effects on depressive symptoms were found for having a partner, having many close relationships, greater feelings of mastery, greater self-efficacy expectations, and high self-esteem. Buffer effects were observed for feelings of mastery, having many diffuse relationships, and receiving emotional support. Buffer effects were differential across diseases for emotional support (in cardiac disease and arthritis only) and for diffuse relationships (in lung disease). Receiving instrumental support was associated with more depressive symptoms, especially in diabetes patients.
Effects of social support and personal coping resources on mortality in older age: the Longitudinal Aging Study Amsterdam.
This study focuses on the role of social support and personal coping resources in relation to mortality among older persons in the Netherlands. Data are from a sample of 2,829 noninstitutionalized people aged between 55 and 85 years who took part in the Longitudinal Aging Study Amsterdam in 1992-1995. Social support was operationally defined by structural, functional, and perceived aspects, and personal coping resources included measures of mastery, self-efficacy, and self-esteem. Mortality data were obtained during a follow-up of 29 months, on average. Cox proportional hazards regression models revealed that having fewer feelings of loneliness and greater feelings of mastery are directly associated with a reduced mortality risk when age, sex, chronic diseases, use of alcohol, smoking, self-rated health, and functional limitations are controlled for. In addition, persons who received a moderate level of emotional support (odds ratio (OR) = 0.49, 95% confidence interval (CI) 0.33-0.72) and those who received a high level of support (OR = 0.68, 95% CI 0.47-0.98) had reduced mortality risks when compared with persons who received a low level of emotional support. Receipt of a high level of instrumental support was related to a higher risk of death (OR = 1.74, 95% CI 1.12-2.69). Interaction between disease status and social support or personal coping resources on mortality could not be demonstrated.