Biomedical subjects

Lidia R Arends

Publications and source records attributed to Lidia R Arends.

6 recordsLinked to original sources

PubMed2005

Dietary fiber and blood pressure: a meta-analysis of randomized placebo-controlled trials.

BACKGROUND: Dietary fiber is part of a healthy diet and may exert a protective effect in the cardiovascular system. The effect of fiber intake on blood pressure (BP) has not yet been established. METHODS: We performed a meta-analysis of randomized placebo-controlled trials to estimate the effect of fiber supplementation on BP overall and in population subgroups. Original articles published between January 1, 1966, and January 1, 2003, were retrieved for 24 trials that fulfilled criteria for meta-analysis. Data were abstracted on fiber dose, fiber type, BP changes, study design features, and study population characteristics. A random-effects model was used for meta-analysis. RESULTS: Fiber supplementation (average dose, 11.5 g/d) changed systolic BP by -1.13 mm Hg (95% confidence interval: -2.49 to 0.23) and diastolic BP by -1.26 mm Hg (-2.04 to -0.48). Reductions in BP tended to be larger in older (>40 years) and in hypertensive populations than in younger and in normotensive ones. CONCLUSION: Increasing the intake of fiber in Western populations, where intake is far below recommended levels, may contribute to the prevention of hypertension.

Adult↗

PubMed2005

Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis of randomized controlled trials.

PURPOSE: Coffee is a widely consumed beverage and small health effects of substances in coffee may have large public health consequences. It has been suggested that caffeine in coffee increases the risk of hypertension. We performed a meta-analysis of randomized controlled trials of coffee or caffeine and blood pressure (BP). DATA IDENTIFICATION: BP trials of coffee or caffeine published between January 1966 and January 2003 were identified through literature databases and manual search. STUDY SELECTION: A total of 16 studies with a randomized, controlled design and at least 7 days of intervention was selected, comprising 25 strata and 1010 subjects. DATA EXTRACTION: Two persons independently obtained data on sample size, type and duration of intervention, changes in BP and heart rate (HR), and subjects' characteristics for each trial. Meta-analysis was performed using a random-effects model. RESULTS: A significant rise of 2.04 mmHg [95% confidence interval (CI), 1.10-2.99] in systolic BP and 0.73 mmHg (95% CI, 0.14-1.31) in diastolic BP was found after pooling of coffee and caffeine trials. When coffee trials (n = 18, median intake: 725 ml/day) and caffeine trials (n = 7, median dose: 410 mg/day) were analysed separately, BP elevations appeared to be larger for caffeine [systolic: 4.16 mmHg (2.13-6.20); diastolic: 2.41 mmHg (0.98-3.84)] than for coffee [systolic: 1.22 mmHg (0.52-1.92) and diastolic: 0.49 mmHg (-0.06-1.04)]. Effects on HR were negligible. CONCLUSIONS: Regular caffeine intake increases BP. When ingested through coffee, however, the blood pressure effect of caffeine is small.

Adult↗

PubMed2004

Temporomandibular involvement in juvenile idiopathic arthritis.

OBJECTIVE: To study occurrence as well as clinical signs and symptoms of temporomandibular joint (TMJ) involvement in juvenile idiopathic arthritis (JIA) in a population representing all subtypes of JIA. METHODS: Ninety-seven consecutive children with JIA underwent orthodontic evaluation including an orthopantomogram (OPG). Further evaluation included patient characteristics, disease onset, course, and medical treatment. RESULTS: Forty-five percent of all children had TMJ involvement. Frequencies according to JIA subtypes: systemic 67%, oligoarticular (persistent and extended) 39%, rheumatoid factor (RF) negative polyarticular 59%, RF positive polyarticular 33%, enthesitis related arthritis 13%, psoriatic arthritis 33%, and other arthritis 50%. In children with a polyarticular course, irrespective of their disease onset, TMJ involvement was more frequent (55% vs 31% in oligoarticular course). In children with disease onset at a young age and/or an extended course of the disease, TMJ involvement was also more frequent. Pain during jaw excursion, absence of translation, asymmetry during maximal opening and protrusion, as well as crepitation during evaluation are predictors for TMJ involvement with a good specificity but a low sensitivity. Not all patients with TMJ involvement have clinical signs. CONCLUSION: Because of the high prevalence and discrepancy between clinical signs and presence of arthritis of the TMJ, regular orthodontic evaluation and OPG is recommended to recognize TMJ involvement and enable early intervention.

Adolescent↗

PubMed2003

Endoscopic sclerotherapy compared with no specific treatment for the primary prevention of bleeding from esophageal varices. A randomized controlled multicentre trial [ISRCTN03215899].

BACKGROUND: Since esophageal variceal bleeding is associated with a high mortality rate, prevention of bleeding might be expected to result in improved survival. The first trials to evaluate prophylactic sclerotherapy found a marked beneficial effect of prophylactic treatment. These results, however, were not generally accepted because of methodological aspects and because the reported incidence of bleeding in control subjects was considered unusually high. The objective of this study was to compare endoscopic sclerotherapy (ES) with nonactive treatment for the primary prophylaxis of esophageal variceal bleeding in patients with cirrhosis. METHODS: 166 patients with esophageal varices grade II, III of IV according to Paquet's classification, with evidence of active or progressive liver disease and without prior variceal bleeding, were randomized to groups receiving ES (n = 84) or no specific treatment (n = 82). Primary end-points were incidence of bleeding and mortality; secondary end-points were complications and costs. RESULTS: During a mean follow-up of 32 months variceal bleeding occurred in 25% of the patients of the ES group and in 28% of the control group. The incidence of variceal bleeding for the ES and control group was 16% and 16% at 1 year and 33% and 29% at 3 years, respectively. The 1-year survival rate was 87% for the ES group and 84% for the control group; the 3-year survival rate was 62% for each group. In the ES group one death occurred as a direct consequence of variceal bleeding compared to 9 in the other group (p = 0.01, log-rank test). Complications were comparable for the two groups. Health care costs for patients assigned to ES were estimated to be higher. Meta-analysis of a large number of trials showed that the effect of prophylactic sclerotherapy is significantly related to the baseline bleeding risk. CONCLUSION: In the present trial, prophylactic sclerotherapy did not reduce the incidence of bleeding from varices in patients with liver cirrhosis and a low to moderate bleeding risk. Although sclerotherapy lowered mortality attributable to variceal bleeding, overall survival was not affected. The effect of prophylactic sclerotherapy seems dependent on the underlying bleeding risk. A beneficial effect can only be expected for patients with a high risk for bleeding.

Adult↗

PubMed2003

Combining multiple outcome measures in a meta-analysis: an application.

In meta-analysis of clinical trials published in the medical literature it is customary to restrict oneself to standard univariate fixed or random effects models. If multiple endpoints are present, each endpoint is analysed separately. A few articles have been written in the statistical literature on multivariate methods for multiple outcome measures. However, these methods were not easy to apply in practice, because self-written programs had to be used, and the examples were only two-dimensional. In this paper we consider a meta-analysis on the effect on stroke-free survival of surgery compared to conservative treatment in patients with increased risk of stroke. Three summary measures per trial are available: short-term post-operative morbidity/mortality in the surgical group; long-term event rate in the surgical group, and the event rate in the conservative group. We analyse the three outcomes jointly with a general linear MIXED model, compare the results with the standard univariate approaches and discuss the many advantages of multivariate modelling. It turns out that the general linear MIXED model is a very convenient framework for multivariate meta-analysis. All analyses could be carried out in standard general linear MIXED model software.

Disease-Free Survival↗

PubMed2002

Advanced methods in meta-analysis: multivariate approach and meta-regression.

This tutorial on advanced statistical methods for meta-analysis can be seen as a sequel to the recent Tutorial in Biostatistics on meta-analysis by Normand, which focused on elementary methods. Within the framework of the general linear mixed model using approximate likelihood, we discuss methods to analyse univariate as well as bivariate treatment effects in meta-analyses as well as meta-regression methods. Several extensions of the models are discussed, like exact likelihood, non-normal mixtures and multiple endpoints. We end with a discussion about the use of Bayesian methods in meta-analysis. All methods are illustrated by a meta-analysis concerning the efficacy of BCG vaccine against tuberculosis. All analyses that use approximate likelihood can be carried out by standard software. We demonstrate how the models can be fitted using SAS Proc Mixed.

BCG Vaccine↗