Research strategies in treatment of hypertension: value of retrospective real-life data.

This review will discuss the limitations of data collected by RCTs in relation to their applicability to daily life clinical management. It will then argue that these limitations are only partially overcome by modifications of RCT design and conduction (e.g. 'pragmatic trials') while being substantially attenuated by real-life-derived research, which can fill many gaps left by trial-collected evidence and have thus an important complementary value. The focus will be on the real-life research approach based on the retrospective analysis of the now widely available healthcare utilization databases (formerly known as administrative databases), which will be discussed in detail for their multiple advantages as well as challenges. Emphasis will be given to the potential of these databases to provide low-cost information over long periods on many different healthcare issues, drug therapies in particular, from the general population to clinically important subgroups, including (i) prognostic aspects of treatments implemented at the medical practice level via hospitalization and fatality data and (ii) medical practice-related phenomena such as low treatment adherence and therapeutic inertia (unsatisfactorily evaluated by RCTs). It will also be mentioned that thanks to the current availability of these data in electronic format, results can be obtained quickly, helping timely decisions under emergencies. The potential shortcomings of this approach (confounding by indication, misclassification, and selection bias) will also be discussed along with their possible minimization by suitable analytic means. Finally, examples of the contributions of studies on hypertension and other cardiovascular risk factors will be offered based on retrospective healthcare utilization databases that have provided information on real-life cardiovascular treatments unavailable via RCTs.

Comparative effectiveness of different primary vaccination courses on mRNA-based booster vaccines against SARs-COV-2 infections: a time-varying cohort analysis using trial emulation in the Virus Watch community cohort.

BACKGROUND: The Omicron B.1.1.529 variant increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in doubly vaccinated individuals, particularly in the Oxford-AstraZeneca COVID-19 vaccine (ChAdOx1) recipients. To tackle infections, the UK's booster vaccination programmes used messenger ribonucleic acid (mRNA) vaccines irrespective of an individual's primary course vaccine type, and prioritized the clinically vulnerable. These mRNA vaccines included the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) the Moderna COVID-19 vaccine (mRNA-1273). There is limited understanding of the effectiveness of different primary vaccination courses on mRNA booster vaccines against SARs-COV-2 infections and how time-varying confounders affect these evaluations. METHODS: Trial emulation was applied to a prospective community observational cohort in England and Wales to reduce time-varying confounding-by-indication driven by prioritizing vaccination based upon age, vulnerability and exposure. Trial emulation was conducted by meta-analysing eight adult cohort results whose booster vaccinations were staggered between 16 September 2021 and 05 January 2022 and followed until 23 January 2022. Time from booster vaccination until SARS-CoV-2 infection, loss of follow-up or end of study was modelled using Cox proportional hazard models and adjusted for age, sex, minority ethnic status, clinically vulnerability and deprivation. RESULTS: A total of 19 159 participants were analysed, with 11 709 ChAdOx1 primary courses and 7450 BNT162b2 primary courses. Median age, clinical vulnerability status and infection rates fluctuate through time. In mRNA-boosted adults, 7.4% (n = 863) of boosted adults with a ChAdOx1 primary course experienced a SARS-CoV-2 infection compared with 7.7% (n = 571) of those who had BNT162b2 as a primary course. The pooled adjusted hazard ratio (aHR) was 1.01 with a 95% confidence interval (CI) of: 0.90 to 1.13. CONCLUSION: After an mRNA booster dose, we found no difference in protection comparing those with a primary course of BNT162b2 with those with a ChAdOx1 primary course. This contrasts with pre-booster findings where previous research shows greater effectiveness of BNT162b2 than ChAdOx1 in preventing infection.