Comparison of treatment effect estimates for pharmacological randomized controlled trials enrolling older adults only and those including adults: a meta-epidemiological study

Preferred study designs to support a comparative therapeutic strategy question in oncology: a vignette study

OBJECTIVES

Some therapeutic strategy questions in oncology could be answered with studies using observational data. Target trial emulation is the application of design principles from randomized controlled trials (RCTs) to the analysis of observational data, to reduce design-induced biases. Our objective was to determine which type of study physicians would preferably plan to answer a comparative effectiveness question lacking evidence in oncology.

METHODS

We launched an online survey among physicians specialized in oncology. We constructed a vignette-based inquiry where vignettes described study scenarios which could be conducted to answer the predefined question. We designed six vignettes described by study design (RCT or observational study with a trial emulation framework), main study characteristics, probability of the study succeeding and anticipated delay before results availability. Participants randomly assessed five pair-wise comparisons of the vignettes and were asked which study they would preferably plan by using a Likert scale ranging from -5 to 5. The main outcome was the evaluation of clinicians' preferences for each pairwise comparison. Mean and median preference scores were calculated.

RESULTS

Two hundred thirteen participants, specialized in many tumor types, assessed at least one comparison with 82% reporting France as their country of affiliation. The interquartile range was -4 to 4 across pairwise comparisons. The median preference score was in disfavor of the monocentric RCT for the five comparisons where it appeared. The median preference score was strongly in favor of the multicentric national emulated trial when compared to the monocentric emulated trial 4 [IQR 2.5-4]. The mean preference score was the highest for the large European observational study 1.14 (SD 3.33), while the mean preference score was the lowest for the monocentric RCT -1.86 (SD 2.93).

CONCLUSION

No study design was strongly preferred, but the monocentric RCT was the least favored study in pair-wise comparisons. The planification of the new research is a compromise between scientific soundness, feasibility, cost, and time before obtaining results. We need to have the right answers to the right questions at the right time.

Population characteristics as important contextual factors in rheumatological trials: an exploratory meta-epidemiological study from an OMERACT Working Group

OBJECTIVES

To explore whether trial population characteristics modify treatment responses across various interventions, comparators and rheumatic conditions.

METHODS

In this meta-epidemiological study, we included trials from systematic reviews available from the Cochrane Musculoskeletal Group published up to 23 April 2019 in Cochrane Library with meta-analyses of five or more randomised controlled trials (RCTs) published from year 2000. From trial reports, we extracted data on 20 population characteristics. For characteristics with sufficient data (ie, available for ≥2/3 of the trials), we performed multilevel meta-epidemiological analyses.

RESULTS

We identified 19 eligible systematic reviews contributing 187 RCTs (212 comparisons). Only age and sex were explicitly reported in ≥2/3 of the trials. Using information about the country of the trials led to sufficient data for five further characteristics, that is, 7 out of 20 (35%) protocolised characteristics were analysed. The meta-regressions showed effect modification by economic status, place of residence, and, nearly, from healthcare system (explaining 4.8%, 0.9% and 1.5% of the between-trial variation, respectively). No effect modification was demonstrated from age, sex, patient education/health literacy or predominant religion.

CONCLUSIONS

This study demonstrates the scarce reporting of most population characteristics, hampering investigation of their impact with meta-research. Our sparse results suggest that place of residence (ie, continent of the trial), economic status (based on World Bank classifications) and healthcare system (based on WHO index for health system performance) may be important in explaining the variation in treatment response across trials. There is an urgent need for consistent reporting of important population characteristics in trials.

PROSPERO REGISTRATION NUMBER

CRD42019127642.

Evolution of Age and Female Representation in the Most-Cited Randomized Controlled Trials of Cardiology of the Last 20 Years

BACKGROUND

Older adults and women have historically been underrepresented in randomized controlled trials of cardiology. Recent temporal evolution and factors influencing representation are incompletely investigated. We aimed to contrast age and female representation in the most influential randomized controlled trials in cardiology of the last 20 years to population prevalence and to assess the study factors affecting representation.

METHODS AND RESULTS

Using Web of Science, we selected the 25 most-cited cardiology articles each year between 1996 and 2015, and extracted mean age, percentage of women, funding source, sample size, disease condition, intervention type, and exclusion criteria. The outcomes were the evolution of the mean age and the percentage of women over time. Protocol design elements and year of publication were assessed as predictors of outcomes in multivariable regressions. A total of 500 studies were analyzed, where the mean age was 62.6±7.4 years and the median percentage of women was 28.6% (22.2-40.5). Compared with population prevalence derived from National Health and Nutrition Examination Survey 2015-2016, gaps in representation were apparent and more pronounced for coronary artery disease (-5.0 years; -27.2% women) and heart failure (-6.0 years; -25.4% women). The mean age (0.15 year per year; 95% confidence interval, 0.04-0.26) and percentage of women (+0.29% per year; 95% confidence interval, 0.07-0.50), slightly but significantly increased over time. Private funding, small sample size, and exclusions pertaining to maximal age, atrial fibrillation, and diabetes mellitus were associated with a decreased mean age in multivariable linear regressions. Age and life expectancy exclusions were associated with lower female percentage.

CONCLUSIONS

Although age and female representation increased over time, the modest trends are unlikely to resolve the persistently wide gaps with actual populational prevalence, especially for coronary artery disease and HF. Representation is modulated by the cardiovascular condition studied and some modifiable protocol elements.

Diverse criteria and methods are used to compare treatment effect estimates: a scoping review

OBJECTIVES

To determine what criteria researchers use to assess whether the estimates of effect of an intervention on a dichotomous outcome are different when obtained using different study designs.

STUDY DESIGN AND SETTING

Scoping review of the literature. We included studies of dichotomous outcomes in which authors compared the estimates of effects from different study designs. We performed searches in electronic databases and in the list of references of relevant studies. Two reviewers independently selected studies and abstracted data. We created a list of the criteria used to compare estimates of effects between study designs, described their main features, and classified them using a clinical perspective.

RESULTS

We included 26 studies, from which we identified 24 criteria. Most of the studies focused on comparing estimates from observational studies and randomized controlled trials (n = 19). The most common criteria aimed to determine whether there was a difference or not (n = 18), provided guidance for such a judgment (n = 16), and were based on the point estimates (n = 11). We judged 14 criteria to be appropriate and classified them as either statistically related or clinically related.

CONCLUSION

We found that diverse criteria are used to compare effect estimates between study designs. Familiarity with these would aid in the interpretation of results from different studies regarding the same question.

Drug therapies in older adults (part 1)

Prescribing for older adults represents a significant challenge as the UK population ages. Physiological decline and the rising prevalence of frailty increase the likelihood of altered pharmacodynamics and pharmacokinetics, suboptimal prescribing and adverse effects among this growing cohort of the population. In the first of two articles, we begin by considering these issues and posit four key questions which should be considered when prescribing for older adults. Does this agent reflect the priorities of the patient? Are there alternatives - with greater efficacy, effectiveness or tolerability - that might be considered? Are the dose, frequency and formulation appropriate? How does this prescription relate to concurrent medication? We also describe current drug therapies in two disease states with a predilection for older adults: Alzheimer's disease (AD) and osteoporosis. Using these examples we highlight the limitations of evidence-based medicine and guidelines in this cohort of the population, illustrating the reliance on sub-group analysis to demonstrate the efficacy of drug therapies for older adults in osteoporosis and the underutilisation of appropriate treatments for patients with AD as a result of flawed guidelines.