Abstract
Background:
Placebo or contextual effect is an integral part of the treatment effect (1). The factors related to this effect are “contextual factors” (CFs) (2). CFs may be categorised into five groups as factors related to practitioner, patient, practitioner-patient interaction, treatment and therapeutic environment (3). Several CFs have demonstrated their therapeutic effect, whereas others not (4). The majority of musculoskeletal pain relief result from CFs (5). Identifying the key CFs may encourage health practitioners to optimize the contextual aspects of care.
Objectives:
To identify the modifiable CFs that can improve clinical outcomes in published randomised controlled trials (RCTs).
Methods:
A systematic search was carried out, up until April 18th 2019, on the following databases: MEDLINE via Ovid, EMBASE, AMED, PsycINFO and Cochrane library. RCTs comparing contextual enhanced interventions versus non-enhanced control in adults for any health conditions were searched. The outcomes included both self-reported outcomes and objectively measured outcomes. The effect size and 95%confidence interval were calculated using the standard mean difference. Risk of bias was evaluated using the modified Cochrane tool. The random effects model was used to pool the results.
Results:
Of 3900 records generated from the systematic search, 15 trials (4615 participants) met the inclusion criteria, and 13 were included in this meta-analysis (Figure 1). Conditions studied included musculoskeletal [4], cardiovascular [2], irritable bowel syndrome [1], diabetes [1], asthma [1], GP or hospital patients [6]. Three CFs have been identified from these trials, including empathy, patient involvement and positive communication. All were found to be effective for patient experience i.e. satisfaction. Positive communication was also effective for symptoms but not objective outcomes (Table 1).
Table 1.
Summary of results.
Outcome
Intervention
Number of studies (Number of participants)
SMD (95% CI)
I
2
Patient experience outcomes,
e.g. satisfaction
Empathy
2 (137)
0.45 (0.11, 0.79)
42.2 %
Patient involvement
4 (1596)
0.31 (0.21, 0.41)
93.0 %
Positive communication
3 (793)
0.38 (0.24, 0.52)
93.9 %
Symptomatic outcomes,
e.g. pain
Empathy
1 (221)
-0.18 (-0.45, 0.08)
0.0 %
Patient involvement
1 (314)
-0.05 (-0.27, 0.17)
0.0 %
Positive communication
3 (658)
0.20 (0.05, 0.35)
64.8 %
Objective outcomes,
e.g. peak expiratory flow
Positive communication
2 (266)
0.10 (-0.14, 0.34)
66.6 %
Positive SMD favours intervention group. SMD= Standard mean difference, CI= Confidence interval, I
2
= heterogeneity.
Figure 1.
Summary of screening process.
Conclusion:
This systematic review has identified three CFs (empathy, patient involvement and positive communication) that have therapeutic effects for different conditions in trials, especially for self-reported outcomes. More research is needed to examine the clinical outcomes of CFs and to understand the influence of health practitioners on disease processes.
References:
[1]Zou K, Wong J, Abdullah N, Chen X, Smith T, Doherty M et al. Examination of overall treatment effect and the proportion attributable to contextual effect in osteoarthritis: meta-analysis of randomised controlled trials. Annals of the Rheumatic Diseases. 2016;75(11):1964-1970.
[2]Miller F, Kaptchuk T. The power of context: reconceptualizing the placebo effect. Journal of the Royal Society of Medicine. 2008;101(5):222-225.
[3]Di Blasi Z, Harkness E, Ernst E, Georgiou A, Kleijnen J. Influence of context effects on health outcomes: a systematic review. The Lancet. 2001;357(9258):757-762.
[4]Howick J, Moscrop A, Mebius A, R Fanshawe T, Lewith G, L Bishop F et al. Effects of empathic and positive communication in healthcare consultations: a systematic review and meta-analysis. Journal of the Royal Society of Medicine. 2018;111(7):240–252.
[5]Rossettini G, Carlino E, Testa M. Clinical relevance of contextual factors as triggers of placebo and nocebo effects in musculoskeletal pain. BMC Musculoskeletal Disorders. 2018;19(1).
Disclosure of Interests:
None declared.