Aims of the study:
Evaluate the relative efficacy of an individually delivered versus group-based
CBTgrief.
Evaluate the relative cost-effectiveness of an individually delivered versus
group-based CBTgrief.
Examine the theoretically proposed treatment mediators of CBTgrief.
Explore loss-related and sociodemographic characteristics as possible moderators of
intervention effects.
Primary hypothesis:
Group-based CBTgrief will show non-inferiority (i.e., equal efficacy) in reducing
symptoms of PGD compared to individually delivered CBTgrief at six months follow-up.
Secondary hypotheses:
Group-based CBTgrief will show non-inferiority (i.e., equal efficacy) in reducing
symptoms of posttraumatic stress, depression, and anxiety compared to individually
delivered CBTgrief at six months follow-up.
Group-based CBTgrief will be more cost-effective than individually delivered
CBTgrief.
The observed effect of CBTgrief is mediated by changes in theoretically proposed
maintaining mechanisms of complicated grief reactions (i.e. insufficient integration
of the loss; negative loss-related cognitions; depressive and anxious avoidance).
Gender, level of education, age, baseline grief symptom level, type of loss,
circumstances of the loss, time since loss, and number of additional losses will
moderate the observed effects of CBTgrief.
Additional exploratory analyses include an additional matched comparison group, who
have not received treatment in order to compare the effect of individual and
group-based CBTgrief to a non-treatment group. This group will be extracted from a
large-scale survey study: The Aarhus Bereavement Study (NCT03049007). Here, it is
hypothesized that CBTgrief will have a statistically significant medium size effect
on symptoms of PGD at six months follow-up compared to a matched comparison group,
who did not receive treatment.
Design: The present study is conducted as a randomized non-inferiority trial of
individually delivered versus group-based CBTgrief using block randomization.
Participants: Participants are recruited from the Danish National Center for Grief
(DNCG), which is a Danish national organization that provide specialized psychological
therapy to bereaved individuals who have lost a loved one. The therapists at the DNCG
will screen and treat bereaved elderly people for complicated grief reactions with
CBTgrief at their clinics in Odense and Copenhagen, Denmark. DNCG identifies participants
through consultants, local practitioners, self-referral, and the DNCG grief support line.
Assessment points: Participants will be assessed at pre-, mid-, and post-intervention as
well as at three and six months follow-up (T1-T5). Additionally, data on healthcare
utilization will be retrieved from the Danish national registers concerning use of health
care services such as visits to general practitioners, psychologists etc.
Sample size: A group sample size of 2x64 will enable us to detect non-inferiority between
individually delivered and group-based CBTgrief with a non-inferiority of -0.5 SD on the
primary outcome, i.e. symptoms of PGD, and a statistical power of 0.80. The true
difference is assumed to be 0.0 and the one-sided significance level (alpha) of the test
is 0.025. Based on an estimated dropout rate of 20% the total number of participants
needed to recruit is N=160 participants.