Browsing by Subject "Randomised controlled trials"

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  • Stassen, Willem; Wallis, Lee; Castren, Maaret; Vincent-Lambert, Craig; Kurland, Lisa (2019)
    The incidence of cardiovascular disease and STEMI is on the rise in sub-Saharan Africa. Timely treatment is essential to reduce mortality. Internationally, prehospital 12 lead ECG telemetry has been proposed to reduce time to reperfusion. Its value in South Africa has not been established. The aim of this study was to determine the effect of prehospital 12 lead ECG telemetry on the PCI-times of STEMI patients in South Africa. A multicentre randomised controlled trial was attempted among adult patients with prehospital 12 lead ECG evidence of STEMI. Due to poor enrolment and small sample sizes, meaningful analyses could not be made. The challenges and lessons learnt from this attempt at Africa's first prehospital RCT are discussed. Challenges associated with conducting this RCT related to the healthcare landscape, resources, training of paramedics, rollout and rando-misation, technology, consent and research culture. High quality evidence to guide prehospital emergency care practice is lacking both in Africa and the rest of the world. This is likely due to the difficulties with performing prehospital clinical trials. Every trial will be unique to the test intervention and setting of each study, but by considering some of the challenges and lessons learnt in the attempt at this trial, future studies might experience less difficulty. This may lead to a stronger evidence-base for prehospital emergency
  • Strain, William David; Paldánius, Päivi Maria (2020)
    Aim: Clinical inertia is a multifactorial phenomenon, with contributing factors from people with diabetes and their healthcare team. It is widely cited that clinical inertia is minimised by participation in clinical trials. We assessed whether trial participation per se improves metabolic parameters in people with diabetes, or a specific focus on glycaemia is required. Methods: We compared improvement in glycaemic control in a pooled set of people assigned to the "placebo" arm from 25 glycaemia-focused trials with a pooled group of people with diabetes allocated to sham or non-pharmacological intervention for the treatment of diabetic retinal disease. Mean change in HbA1c (ANCOVA) was evaluated. Results: The overall placebo effect in studies focused on glucose control (N = 3081) was comparable between strata groups with and without complications. Adjusted least square mean change in HbA1c at 24 weeks was between-0.23% (-2.50 mmol/mol) and -0.32% (-3.50 mmol/mol). In studies focused on retinal disease (N = 288), the change from baseline in HbA1c was +0.10% (1.10 mmol/mol) and fasting plasma glucose was +0.50 mmol/L showing no improvement in metabolic parameters at 12 months. Conclusions: Clinical trial participation alone does not seem to improve metabolic parameters in people living with diabetes. The benefits observed in glycaemia-focused studies were independent of age and comorbidities. (C) 2020 Elsevier B.V. All rights reserved.
  • Nichol, Alistair; French, Craig; Little, Lorraine; Presneill, Jeffrey; Cooper, D. James; Haddad, Samir; Duranteau, Jacques; Huet, Olivier; Skrifvars, Markus; Arabi, Yaseen; Bellomo, Rinaldo; EPO-TBI Investigators; New Zealand Intensive Care Soc (2015)
  • DISCO Study Grp; Kasenda, Benjamin; Schandelmaier, Stefan; Sun, Xin; Tikkinen, Kari; Briel, Matthias (2014)
    OBJECTIVE: To investigate the planning of subgroup analyses in protocols of randomised controlled trials and the agreement with corresponding full journal publications. DESIGN: Cohort of protocols of randomised controlled trial and subsequent full journal publications. SETTING: Six research ethics committees in Switzerland, Germany, and Canada. DATA SOURCES: 894 protocols of randomised controlled trial involving patients approved by participating research ethics committees between 2000 and 2003 and 515 subsequent full journal publications. RESULTS: Of 894 protocols of randomised controlled trials, 252 (28.2%) included one or more planned subgroup analyses. Of those, 17 (6.7%) provided a clear hypothesis for at least one subgroup analysis, 10 (4.0%) anticipated the direction of a subgroup effect, and 87 (34.5%) planned a statistical test for interaction. Industry sponsored trials more often planned subgroup analyses compared with investigator sponsored trials (195/551 (35.4%) v 57/343 (16.6%), P<0.001). Of 515 identified journal publications, 246 (47.8%) reported at least one subgroup analysis. In 81 (32.9%) of the 246 publications reporting subgroup analyses, authors stated that subgroup analyses were prespecified, but this was not supported by 28 (34.6%) corresponding protocols. In 86 publications, authors claimed a subgroup effect, but only 36 (41.9%) corresponding protocols reported a planned subgroup analysis. CONCLUSIONS: Subgroup analyses are insufficiently described in the protocols of randomised controlled trials submitted to research ethics committees, and investigators rarely specify the anticipated direction of subgroup effects. More than one third of statements in publications of randomised controlled trials about subgroup prespecification had no documentation in the corresponding protocols. Definitive judgments regarding credibility of claimed subgroup effects are not possible without access to protocols and analysis plans of randomised controlled trials.
  • Hemilä, Harri (2020)
    A previous analysis of the Alpha-Tocopherol Beta-Carotene (ATBC) Study on male smokers found that beta-carotene supplementation increased the risk of pneumonia 4-fold in those who started smoking at the age of >= 21 years and smoked >= 21 cigarettes/d (a subgroup of 7 % of the study population). The present study hypothesised that beta-carotene increases mortality in the same subgroup. The ATBC Study (1985-1993) recruited 29 133 Finnish male smokers (>= 5 cigarettes/d) aged 50-69 years. Cox regression models were constructed to estimate the effect of beta-carotene supplementation in subgroups. beta-Carotene increased mortality (risk ratio 1 center dot 56; 95 % CI 1 center dot 06, 2 center dot 3) in those who started to smoke at >= 21 years and smoked >= 21 cigarettes/d. Within this subgroup, there was strong evidence of further heterogeneity. The effect of beta-carotene supplementation was further modified by dietary vitamin C intake, fruit and vegetable intake (P = 0 center dot 0004), and by vitamin E supplementation (P = 0 center dot 011). Thus, harm from beta-carotene was not uniform within the study population. Interactions between beta-carotene and vitamins C and E were seen only within a subgroup of 7 % of the ATBC participants, and therefore should not be extrapolated to the general population. Heterogeneity of the beta-carotene effect on mortality challenges the validity of previous meta-analyses that have pooled many diverse antioxidants for one single estimate of effect using the assumption that a single estimate equally applies to all antioxidants and all people. Trial registration: NCT00342992.
  • Adebayo, Folasade Abiola; Itkonen, Suvi Tuulikki; Öhman, Taina; Skaffari, Essi; Saarnio, Elisa Maria; Erkkola, Maijaliisa; Cashman, Kevin; Lamberg-Allardt, Christel Johanna Emilia (2018)
    Insufficient vitamin D status (serum 25-hydroxyvitamin D (S-25(OH)D)<50 nmol/l) is common among immigrants living at the northern latitudes. We investigated ethnic differences in response of S-25(OH)D to vitamin D3 supplementation, through a 5-month randomised controlled trial, in East African and Finnish women in Southern Finland (60°N) from December 2014 to May 2015. Vitamin D intakes (dietary and supplemental) were also examined. Altogether, 191 subjects were screened and 147 women (East Africans n 72, Finns n 75) aged 21–64 years were randomised to receive placebo or 10 or 20 µg of vitamin D3/d. S-25(OH)D concentrations were assessed by liquid chromatography–tandem MS. At screening, 56 % of East Africans and 9 % of Finns had S-25(OH)D<50 nmol/l. Total vitamin D intake was higher in East Africans than in Finns (24·2 (sd 14·3) v. 15·2 (sd 13·4) µg/d, P<0·001). Baseline mean S-25(OH)D concentrations were higher in Finns (60·5 (sd=16·3) nmol/l) than in East Africans (51·5 (sd 15·4) nmol/l) (P=0·001). In repeated-measures ANCOVA (adjusted for baseline S-25(OH)D), mean S-25(OH)D increased by 8·5 and 10·0 nmol/l with a 10-µg dose and by 10·7 and 17·1 nmol/l with a 20-µg dose for Finns and East Africans, respectively (P>0·05 for differences between ethnic groups). In conclusion, high prevalence of vitamin D insufficiency existed among East African women living in Finland, despite higher vitamin D intake than their Finnish peers. Moderate vitamin D3 supplementation was effective in increasing S-25(OH)D in both groups of women, and no ethnic differences existed in the response to supplementation.