ABSTRACT
BACKGROUND: Randomized trials are generally performed from a frequentist perspective, which can conflate absence of evidence with evidence of absence. The RECOVERY trial evaluated convalescent plasma for patients hospitalized with coronavirus disease 2019 (COVID-19) and concluded that there was no evidence of an effect. Re-analysis from a Bayesian perspective is warranted. METHODS: Outcome data were extracted from the RECOVERY trial by serostatus and time of presentation. A Bayesian re-analysis with a wide variety of priors (vague, optimistic, sceptical, and pessimistic) was performed, calculating the posterior probability for: any benefit, an absolute risk difference of 0.5% (small benefit, number needed to treat 200), and an absolute risk difference of one percentage point (modest benefit, number needed to treat 100). RESULTS: Across all patients, when analysed with a vague prior, the likelihood of any benefit or a modest benefit with convalescent plasma was estimated to be 64% and 18%, respectively. The estimated chance of any benefit was 95% if presenting within 7 days of symptoms, or 17% if presenting after this. In patients without a detectable antibody response at presentation, the chance of any benefit was 85%. However, it was only 20% in patients with a detectable antibody response at presentation. CONCLUSIONS: Bayesian re-analysis suggests that convalescent plasma reduces mortality by at least one percentage point among the 39% of patients who present within 7 days of symptoms, and that there is a 67% chance of the same mortality reduction in the 38% who are seronegative at the time of presentation. This is in contrast to the results in people who already have antibodies when they present. This biologically plausible finding bears witness to the advantage of Bayesian analyses over misuse of hypothesis tests to inform decisions.
Subject(s)
COVID-19 , Bayes Theorem , COVID-19/therapy , Humans , Immunization, Passive , SARS-CoV-2 , Treatment Outcome , COVID-19 SerotherapyABSTRACT
Introduction There has recently been a rapid increase in the number of health and social care organisations offering remote consultations in order to minimise the spread of disease following the outbreak of COVID-19, but their effectiveness is unclear. The majority of studies focusing on remote consultations to date have evaluated telephone appointments. Although some studies have used video conferencing technology in the secondary care sector, the sample sizes have been small and they differ in their findings. This study evaluated the feasibility of implementing video clinics at a large hospital trust in the UK and assessed whether the intervention improved patient satisfaction compared to standard face-toface appointments for liver transplant patients. Methods Clinically stable liver transplant patients were randomised to video clinic appointments (intervention) or standard face-to-face appointments (usual care). The intervention group had routine follow-up appointments via secure video link. Participants were asked to complete post-appointment questionnaires over 12 months. The primary outcome was the difference in scores between baseline and study end by patient group for three domains of patient satisfaction using the Visit-Specific Satisfaction Instrument (VSQ-9). An embedded qualitative process evaluation used interviews to assess patient and staff experiences. Results Fifty four patients were randomised: 29 to receive video clinics and 25 to usual care (recruitment rate 26.6%). Crossover from intervention to usual care was high (44.8%). 129 appointments were completed with 64% of questionnaires returned. Patient satisfaction (intention-to-treat analysis) increased in both intervention and usual care groups but the between-group difference was not significant after controlling for baseline scores. Video appointments were perceived to save patients time and money, and patients found video clinics to be less burdensome, with fewer negative impacts on their health. Technical problems with the software were common, however, the software is constantly evolving and as time goes on these types of problems should ease. Both clinicians and patients saw video clinic appointments as positive and beneficial. Discussion The UK National Health Service is facing huge challenges with regards to staffing, budgets and space due to increasing patient numbers. Being innovative by using available technology to offer routine follow-up appointments via secure video link may help ease some of the burdens and free up clinic space for those patients who need to be seen face-to-face. This study outlines our experiences of using a remote video consultation system and the associated advantages and pitfalls.