Componentes del efecto placebo: ensayo aleatorizado controlado en pacientes con síndrome de colon irritable

• Autores: Josef Hummelsberger
• Localización: Revista Internacional de Acupuntura, ISSN-e 1887-8369, Vol. 4, Nº. 3, 2010, págs. 149-150
• Idioma: español
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• Resumen

  • Objective: To investigate whether placebo effects can experimentally be separated into the response to three components � assessment and observation, a therapeutic ritual (placebo treatment), and a supportive patient-practitioner relationship � and then progressively combined to produce incremental clinical improvement in patients with irritable bowel syndrome. To assess the relative magnitude of these components.

    Design: A six week single blind three arm randomised controlled trial. Setting Academic medical centre. Participants 262 adults (76% women), mean (SD) age 39 (14), diagnosed by Rome II criteria for and with a score of = 150 on the symptom severity scale.

    Interventions: For three weeks either waiting list (observation), placebo acupuncture alone (�limited�), or placebo acupuncture with a patient-practitioner relationship augmented by warmth, attention, and confidence (�augmented�). At three weeks, half of the patients were randomly assigned to continue in their originally assigned group for an additional three weeks. Main outcome measures Global improvement scale (range 1�7), adequate relief of symptoms, symptom severity score, and quality of life.

    Results: At three weeks, scores on the global improvement scale were 3.8 (SD 1.0) v 4.3 (SD 1.4) v 5.0 (SD 1.3) for waiting list versus �limited� versus �augmented,� respectively (P < 0.001 for trend). The proportion of patients reporting adequate relief showed a similar pattern: 28% on waiting list, 44% in limited group, and 62% in augmented group (P < 0.001 for trend). The same trend in response existed in symptom severity score (30 (63) v 42 (67) v 82 (89), P < 0.001) and quality of life (3.6 (8.1) v 4.1 (9.4) v 9.3 (14.0), P < 0.001). All pairwise comparisons between augmented and limited patient-practitioner relationship were significant: global improvement scale (P < 0.001), adequate relief of symptoms (P < 0.001), symptom severity score (P = 0.007), quality of life (P = 0.01). Results were similar at six week follow-up.

    Conclusion: Factors contributing to the placebo effect can be progressively combined in a manner resembling a graded dose escalation of component parts. Non-specific effects can produce statistically and clinically significant outcomes and the patient-practitioner relationship is the most robust component. Trial registration Clinical Trials. NCT00065403.