1.
Change in forced expiratory volume in 1 second after sham bronchoconstrictor in suggestible but not suggestion-resistant asthmatic subjects: a pilot study.
Leigh, R, MacQueen, G, Tougas, G, Hargreave, FE, Bienenstock, J
Psychosomatic medicine. 2003;(5):791-5
Abstract
OBJECTIVE Randomized controlled trials in asthma often demonstrate a benefit from placebo interventions, although no study has yet characterized this group of placebo responders. Literature points to the importance of suggestion in asthma, and we reasoned that patients' level of suggestibility might influence their likelihood of responding to placebo-like suggestion. METHODS To determine whether suggestion differentially influenced airway tone in preselected suggestible compared with suggestion-resistant asthmatics, we performed a prospective, double-blind, crossover pilot study in which subjects were identified as being suggestible or suggestion-resistant using the Creative Imagination Scale. Responses to inhaled saline were assessed using FEV1 and a modified Borg scale after the suggestion that the saline was a bronchoconstrictor and subsequently a bronchodilator. RESULTS Five of eight suggestible subjects compared with one of nine suggestion-resistant subjects demonstrated a fall in FEV1 greater than 150 ml in response to inhaled saline and suggestion of bronchoconstriction (p =.027). Fourteen subjects experienced dyspnea in response to sham bronchoconstrictor, but none reported increased dyspnea after sham bronchodilator. CONCLUSIONS This is the first time that subjects with asthma have been categorized as suggestible or nonsuggestible with this distinction then used to predict response to an intervention. The results of this pilot study suggest that a subgroup of suggestible asthmatic patients is more likely to respond to a placebo-like sham bronchoconstriction challenge. The data support earlier observations that psychological factors may influence asthma, and provide insights into the placebo response.
2.
Antibiotic treatment and baseline severity of disease in acute exacerbations of chronic bronchitis: a re-evaluation of previously published data of a placebo-controlled randomized study.
Allegra, L, Blasi, F, de Bernardi, B, Cosentini, R, Tarsia, P
Pulmonary pharmacology & therapeutics. 2001;(2):149-55
Abstract
The study was designed to extend retrospectively the analysis of a previously reported study on chronic bronchitis patients with acute exacerbations treated with amoxicillin-clavulanic acid or matched placebo. We retrospectively re-clustered patients on the basis of severity of baseline lung function: Cluster 1 (104 patients) mean screening FEV(1)32.67+/-6.83 (SD); Cluster 2 (109 patients) mean screening FEV(1)54.12+/-5.56; Cluster 3 (122 patients) mean screening FEV(1)71.54+/-5.51. The success rate in the antibiotic group was significantly greater compared to the placebo group (P<0.001). When clinical improvement was analysed on the basis of patient re-clustering, 31.4% of Cluster 1 (severe COPD) patients treated with amoxicillin/clavulanate showed clinical improvement, whereas success was recorded in 58.8%. Conversely, 13.2% of Cluster 1 patients receiving placebo improved and 17% successfully recovered (P<0.001). Mild and moderate COPD patients (Clusters 2 and 3) were grouped together. In these two groups, 31.2% and 53.6% of patients receiving antibiotic treatment showed improvement or recovery, respectively, compared to 29.2% improvements and 30.2% successful recoveries among placebo-treated patients (P<0.001). In placebo-treated patients the improvement/success vs. failure rate was significantly different in Cluster 1 patients compared to Cluster 2+3 subjects (P<0.01, (2)test). The differences in final FEV(1)values in the treatment group and placebo group were significantly different (P<0.01) in favour of the active treatment group. Among more severe patients (Cluster 1), the comparison between screening and follow up FEV(1)values showed an improvement following antibiotic treatment and worsening after placebo (P<0.01). In Clusters 2 and 3 the difference between screening and follow up FEV(1)values was not significant for both treatment groups. Our patients with severe functional impairment and higher number of exacerbations per year are those who derive the greatest benefit from antibiotic treatment.