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The CONGA project obtaind funding from AOI CHU Nantes + ANR résilience COVID

Both in France and Sweden, global changes in online gambling activities due to the COVID-19 pandemic, and their potential for gambling problems, are a source of concerns for public health authorities. The CONGA project aims to measuring the impact of the COVID-19 pandemic on the online gambling activity, both in France and Sweden. The use of gambling tracking data, widely acclaimed in recent years in research on online gambling given its ecological nature, could allow observing longitudinally changes in online gambling activities due to the pandemic. Moreover, the combination of French and Swedish data will allow comparing two countries with very distinct politics regarding the pandemics, i.e. a lockdown in France compared to no lockdown in Sweden. The CONGA study will provide a better understanding of the impact of restriction measures in the context of the health crisis on online gambling activities. Moreover, the identification of sub-populations particularly at risk of increasing their gambling activity in response to the health crisis will have both clinical and epidemiological perspectives, even beyond the current period of crisis.

Principal investigator: Gaëlle Challet-Bouju


The project NABAB recently obtained a national PHRC funding

Behavioural addictions (BAs) [gambling disorder (GD), food addiction (FA), sexual addiction (SA)] may lead to disastrous consequences. They are often associated with other addictive or psychiatric disorders, and high rates of suicide attempts. Epidemiological studies report prevalence reaching 2.7% for GD, 5% for SA, and up to 7.9% for FA.
Many similarities have been highlighted between BAs, as well as with substance use disorders. One core clinical similarity between those disorders is craving (uncontrollable urge to engage in rewarding behaviours), which has been consistently associated with diminished control over the behaviour and relapse.
Whereas cognitive behavioural therapies have demonstrated their efficacy for the management of BAs in the short-term, the extent and durability of their effects are still unknown. Drop-outs are frequent, as well as relapses, with for example more than 70% of patients presenting recurrence of gambling behaviour at 12-months follow-up.
At present, no pharmacological treatment has been approved for BAs, but several medications have been tested. Among them, two opioid receptor antagonists - naltrexone and nalmefene - appear the most promising. By decreasing dopamine neurotransmission in the reward circuitry, they reduce both excitement for rewarding behaviours and craving.
Compared to naltrexone, nalmefene seems to have a better safety. To date, no study investigated the efficacy of nalmefene as a pan-addiction treatment for BAs. Two clinical trials have demonstrated its efficacy for the treatment of GD, but no clinical trial was conducted for FA and SA.
We hypothesise that nalmefene (36 mg/d), compared to a placebo, can have a therapeutic effect as an add-on to usual treatment for decreasing craving in several BAs. The NABAB study could therefore lead to the development of guidelines incorporating a drug option for treating BAs. The project will also investigate the genetic predictors of therapeutic success, which may improve knowledge on the genetic determinants of the nalmefene action.
Nalmefene holds a marketing authorization at the dosage of 18 mg/d in France for alcohol use disorder only. The choice of the dosage tested in this study (36 mg/d) results of a balanced decision between efficacy (demonstrated at 40 mg/d) and safety (poor from 50 mg/d), as observed in the two trials on GD. Moreover, our study will comprise “real-life” conditions: (i) patients who are often excluded from clinical trials on addiction, i.e. females, patients with psychiatric/addictive comorbidities and concomitant substance consumption, or treated with concomitant psychotropic medications, provided that nalmefene is not contraindicated; (ii) all therapeutic goals, either regaining control over the addictive behaviour or achieving abstinence. This may favour the applicability of the treatment in real-life and the generalizability for all patients that could benefit from it.
The provision of well-tolerated and inexpensive drug treatment would allow easier accessibility to care, for example in primary care such as general practice, and in the management of patients who have difficulty engaging in specialized care.

Principal investigator: Marie Grall-Bronnec


Bruno Giraudeau obtained a new ANR project: ESCIENT !

Complex interventions include several components that may interact with one another. In health service and public healthresearches they are often assessed with cluster randomized trials, which randomize intact social units. In these trials, whichpopulation is to be analyzed is a challenging issue. The boundary between lack of compliance and adaptation of the intervention tothe context is tenuous; participants may lack compliance because of their own willingness, or because of external events; becausethe intervention may be adapted to the context, an “as treated” population is also of interest. We definitely need guidelines on thisissue. On a statistical point of view, such trials are also challenging. While an adjusted risk difference is the preferred way ofexpressing results, classical statistical analyses usually return odds ratios. We presently lack clear recommendations on the optimalstatistical method to be used. The ESCIENT project aims to close these two gaps.

A revised model of response shift phenomenon
04/05/2021 04/2021

Response shift in patient‑reported outcomes: definition, theory, and a revised model

Author(s) of the publication: Antoine Vanier, Frans J Oort, Leah McClimans, Nikki Ow, Bernice G Gulek, Jan R Böhnke, Mirjam Sprangers, Véronique Sébille, Nancy Mayo, the Response Shift - in Sync Working Group

This work is part of an international initiative: the Response Shift - in Sync Working Group.

Purpose The extant response shift definitions and theoretical response shift models, while helpful, also introduce predicaments
and theoretical debates continue. To address these predicaments and stimulate empirical research, we propose a more
specific formal definition of response shift and a revised theoretical model.
Methods This work is an international collaborative effort and involved a critical assessment of the literature.
Results Three main predicaments were identified. First, the formal definitions of response shift need further specification
and clarification. Second, previous models were focused on explaining change in the construct intended to be measured
rather than explaining the construct at multiple time points and neglected the importance of using at least two time points
to investigate response shift. Third, extant models do not explicitly distinguish the measure from the construct. Here we
define response shift as an effect occurring whenever observed change (e.g., change in patient-reported outcome measures
(PROM) scores) is not fully explained by target change (i.e., change in the construct intended to be measured). The revised
model distinguishes the measure (e.g., PROM) from the underlying target construct (e.g., quality of life) at two time points.
The major plausible paths are delineated, and the underlying assumptions of this model are explicated.
Conclusion It is our hope that this refined definition and model are useful in the further development of response shift theory.
The model with its explicit list of assumptions and hypothesized relationships lends itself for critical, empirical examination.
Future studies are needed to empirically test the assumptions and hypothesized relationships.

Response Shift, Theory
Quality of Life Resarch
Critical examination of current response shift methods and proposal for advancing new methods
04/05/2021 02/01/20

Critical examination of current response shift methods and proposal for advancing new methods

Author(s) of the publication: Véronique Sébille, Lisa M Lix, Olawale F Ayilara, Tolulope T Sajobi, A.Cecile JW Janssens, Richard Sawatzky, Mirjam AG Sprangers, Mathilde GE Verdam - the Response Shift - in Sync Working Group

This work is part of an international initiative : The Response Shift - in Sync Working Group.

Purpose This work is part of an international, interdisciplinary initiative to synthesize research on response shift in results
of patient-reported outcome measures. The objective is to critically examine current response shift methods. We additionally
propose advancing new methods that address the limitations of extant methods.
Methods Based on literature reviews, this critical examination comprises design-based, qualitative, individualized, and
preference-based methods, latent variable models, and other statistical methods. We critically appraised their definition,
operationalization, the type of response shift they can detect, whether they can adjust for and explain response shift, their
assumptions, and alternative explanations. Overall limitations requiring new methods were identified.
Results We examined 11 methods that aim to operationalize response shift, by assessing change in the meaning of one’s
self-evaluation. Six of these methods distinguish between change in observed measurements (observed change) and change in
the construct that was intended to be measured (target change). The methods use either (sub)group-based or individual-level
analysis, or a combination. All methods have underlying assumptions to be met and alternative explanations for the inferred
response shift effects. We highlighted the need to address the interpretation of the results as response shift and proposed
advancing new methods handling individual variation in change over time and multiple time points.
Conclusion No single response shift method is optimal; each method has strengths and limitations. Additionally, extra steps
need to be taken to correctly interpret the results. Advancing new methods and conducting computer simulation studies that
compare methods are recommended to move response shift research forward.

Patient-Reported Outcomes, Response shift
Quality of Life Resarch
logo Inserm

Two pages on SPHERE in the latest issue of Inserm, Le magazine!

Public Health: Consider the entire patient sphere

pages 12-13


Methodological review showed that time-to-event outcomes are often inadequately handled in cluster randomized trials

Author(s) of the publication: Agnès Caille, Elsa Tavernier, Monica Taljaard, Solène Desmée

Objectives: To estimate the prevalence of time-to-event (TTE) outcomes in cluster randomized trials (CRTs) and to examine their
statistical management.
Study design and setting: We searched PubMed to identify primary reports of CRTs published in six major general medical journals
(2013–2018). Nature of outcomes and, for TTE outcomes, statistical methods for sample size, analysis, and measures of intracluster
correlation were extracted.
Results: A TTE analysis was used in 17% of the CRTs (32/184) either as a primary or secondary outcome analysis, or in a sensitivity
analysis. Among the five CRTs with a TTE primary outcome, two accounted for both intracluster correlation and the TTE nature of the
outcome in sample size calculation; one reported a measure of intracluster correlation in the analysis. Among the 32 CRTs with a least
one TTE analysis, 44% (14/32) accounted for clustering in all TTE analyses. We identified 12 additional CRTs in which there was at
least one outcome not analyzed as TTE for which a TTE analysis might have been preferred.
Conclusion: TTE outcomes are not uncommon in CRTs but appropriate statistical methods are infrequently used. Our results suggest
that further methodological development and explicit recommendations for TTE outcomes in CRTs are needed.

Journal of Clinical Epidemiology
seminar 27 may 2021
SPHERE seminar
27/05/2021 12h30

Using pooling for RT-qPCR tests

Presenter(s) : Vincent Brault (associate professor in statistics in Grenoble)

One of the challenges of the current COVID-19 pandemic is the need to test populations as widely as possible to better detect spread and evolution. However, technical problems were highlighted, such as the tension on the availability of reagents. To limit this problem, pooling methods (mixing multiple samples before testing) are regularly considered in RT-qPCR (see, for example, Gollier et Gossner (2020)).

In this talk, we will begin by explaining the principle of an RT-qPCR test and recall the definition of the false positives and negatives. We will then look at the pooling principle and how this procedure influences the results on the rate of false negatives. In particular, we will highlight the importance of knowing the distribution of viral load concentration. Therefore, we will continue on the difficulty of estimating this concentration and conclude with a few procedures that could be applied to help in this time of crisis.

Location: Tours + zoom

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