Johann Castañeda-Sanabria

BACKGROUND: Observational studies are widely used in pharmacoepidemiology. Several designs can be used, in particular self-controlled designs (case-crossover and self-controlled case series). These designs offer the advantage of controlling for time-invariant confounders, which may not be collected in electronic healthcare databases. They are particularly useful in pharmacoepidemiology involving healthcare database. To be valid, they require the presence of some characteristics (key validity assumptions), and in such situations, these designs should be preferred. We aimed at describing the appropriate use and reporting of the key validity assumptions in self-controlled design studies. METHODS: Articles published between January 2011 and December 2014, and describing a self-controlled study design involving electronic healthcare databases were retrieved. The appropriate use (fulfilment of key assumptions) was studied in terms of major (abrupt onset event, rare or recurrent event, and intermittent exposure) and minor assumptions (those for which the design can be adapted). RESULTS: Among the 107 articles describing a self-controlled design, 35/53 (66%) case-crossover studies, and 48/55 (87%) self-controlled case series fulfilled the major validity assumptions for use of the design; 4/35 and 14/48 respectively did not fulfill the minor assumptions. Overall, 31/53 (58%) case-crossover studies and 34/55 (62%) self-controlled case series fulfilled both major and minor assumptions. The reporting of the methodology or the results was appropriate, except for power calculation. CONCLUSIONS: Self-controlled designs were not appropriately used in34% and 13% of the articles we reviewed that described a case-crossover or a self-controlled case series design, respectively. We encourage better use of these designs in situations in which major validity assumptions are fulfilled (i.e., for which they are recommended), accounting for situations for which the design can be adapted.

BACKGROUND: Numerous inclusion and exclusion criteria are involved in phase III moderate to severe psoriasis trials investigating the safety and efficacy of biologics. This questions the generalization of results. METHODS: In this cohort study, we applied inclusion/exclusion criteria for phase III trials from original protocols (adalimumab - REVEAL, ustekinumab - PHOENIX, brodalumab - AMAGINE, secukinumab FIXTURE) to all patients enrolled in the PsoBioTeq prospective registry who received a biological agent for the first time between July 2012 and November 2017. We then compared the efficacy, drug survival and occurrence of adverse events between patients who satisfied/did not satisfy the eligibility criteria for these phase III trials. RESULTS: A total of 1267 patients were enrolled, of whom 993 (78.4%) were not eligible for at least one RCT (randomized controlled trial) and 251 (19.1%) did not meet the PASI/PGA severity requirements. Apart from disease severity, the most frequent criteria resulting in exclusion were as follows: non-plaque psoriasis (12.6%), significant cardiac disease (8.4%), significant liver disease (7.3%), elevated liver enzymes (4.9-9.6%) and personal history of diabetes (9.2%). There was no difference in drug survival between the two groups. The incidence ratio of adverse events was significantly lower in eligible versus non-eligible patients [0.78 (95% CI 0.62-0.97) (P = 0.03)]. CONCLUSION: The majority of patients treated with biologics in the PsoBioTeq real-life registry would not have been eligible for phase III moderate to severe psoriasis trials. Patients not eligible for psoriasis phase III clinical trials have a higher incidence of adverse events.

PURPOSE: The self-controlled (SC) designs offer the advantage of inherently controlling for time-invariant confounders, which may not be collected in electronic healthcare databases. To be valid, the design requires that some characteristics must be present. Recommendations for their use have been published in 2012, which encourage their implementation when these key characteristics are valid. We aimed at describing the potentially missed opportunities for the use of SC in pharmacoepidemiological studies on electronic healthcare databases. METHODS: We searched Medline for the articles published in two different 6-month periods before and after the 2012 recommendations. The potentially opportunity for the use of SC design is based on major required characteristics (abrupt onset event, rare or recurrent event, and acute or intermittent exposure). RESULTS: In total, 94 papers in 2011 were analysed and 106 in 2014. SC designs were rarely used (2% in 2011 and 1% in 2014). A potentially missed opportunity for SC use was found in 16% of papers in 2011 and 15% in 2014. CONCLUSIONS: We found that SC designs were underused and identified situations in which they could have been applied, but were not. Their use should be encouraged.