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When a placebo is not a ‘placebo’: a placebo effect on postprandial glycaemia
Author(s) -
Sievenpiper John L.,
Ezatagha Adish,
Dascalu Anamaria,
Vuksan Vladimir
Publication year - 2007
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.2007.02929.x
Subject(s) - postprandial , placebo , medicine , confidence interval , body mass index , endocrinology , insulin , alternative medicine , pathology
What is already known about this subject • Although placebo effects have been shown on subjective continuous variables such as pain, placebo effects on objective continuous variables remain uncertain. • The present, pilot, follow‐up investigation represents the first to assess a placebo effect on the objective continuous measurement of acute postprandial plasma glucose. What this study adds • Placebo effects may be operating on postprandial plasma glucose outcomes. • Cornstarch sources of placebo may decrease the plasma glucose response to a 75‐g oral glucose tolerance test, rendering them as positive controls when assessing postprandial outcomes. • Other carbohydrate sources used as placebos in research may show similar effects. Aims Placebo effects in clinical trials remain uncertain. To investigate a placebo effect on acute postprandial plasma glucose, we conducted a follow‐up investigation on a previous study. Methods The effect of placebo (9 g encapsulated cornstarch +500 ml water, taken at −40 min) on the plasma glucose response to a 75‐g oral glucose tolerance test (OGTT) was assessed in a previous study in 12 healthy subjects (gender, five male, seven female; age 27 ± 6 years; body mass index 24 ± 3.4 kg m −2 ). This was compared with the effect of a water control (500 ml water taken alone at −40 min) on the same outcome in the same subjects in a follow‐up study. Results Cornstarch placebo decreased plasma glucose area under the curve during the 75‐g OGTT by 28% [Δ (95% confidence interval) −63.3 min mmol −1 l −1 (−218.33, 91.66), P < 0.02] compared with the water control ( P < 0.05). Conclusions Postprandial plasma glucose outcomes may be vulnerable to placebo effects.