TY - JOUR
T1 - The impact of non-blinding in critical care medicine trials
AU - Baiardo Redaelli, M.
AU - Belletti, A.
AU - Monti, G.
AU - Lembo, R.
AU - Ortalda, A.
AU - Landoni, G.
AU - Bellomo, R.
PY - 2018/12
Y1 - 2018/12
N2 - Purpose: It is uncertain whether, in critical care medicine, non-blinded trials are associated with a bias toward a different effect size. The aim of our study was to assess if conducting non-blinded/open label studies leads to greater effect size than blinded studies, and to provide an estimate of the weight of this difference. Materials and methods: We systematically searched all papers published in peer-reviewed journals between January 2000 and December 2015, dealing with non surgical interventions in critically ill adults and reporting a statistically significant difference in mortality. We assessed the number needed to treat (NNT) of each trial to estimate the treatment effect size and we divided studies into non-blinded, single-blinded and double-blinded. We searched for correlation between the treatment effect size and blinding, and adjusted for the other trial variables. Results: We identified 119 critically ill randomized controlled trials. Of these, 69 studies were non-blinded and 50 were blinded. The median NNT in non-blinded studies was 5 [IQR 4–7] while it was 7 [IQR 5–7] in the blinded studies (p <.001). Conclusions: The NNT for blinded studies is 40% higher than for unblinded studies. This should be taken into account when planning and interpreting the findings of non-blinded studies performed in critically ill settings.
AB - Purpose: It is uncertain whether, in critical care medicine, non-blinded trials are associated with a bias toward a different effect size. The aim of our study was to assess if conducting non-blinded/open label studies leads to greater effect size than blinded studies, and to provide an estimate of the weight of this difference. Materials and methods: We systematically searched all papers published in peer-reviewed journals between January 2000 and December 2015, dealing with non surgical interventions in critically ill adults and reporting a statistically significant difference in mortality. We assessed the number needed to treat (NNT) of each trial to estimate the treatment effect size and we divided studies into non-blinded, single-blinded and double-blinded. We searched for correlation between the treatment effect size and blinding, and adjusted for the other trial variables. Results: We identified 119 critically ill randomized controlled trials. Of these, 69 studies were non-blinded and 50 were blinded. The median NNT in non-blinded studies was 5 [IQR 4–7] while it was 7 [IQR 5–7] in the blinded studies (p <.001). Conclusions: The NNT for blinded studies is 40% higher than for unblinded studies. This should be taken into account when planning and interpreting the findings of non-blinded studies performed in critically ill settings.
KW - Anesthesia
KW - Blind
KW - Critical care
KW - Intensive care
KW - Mortality
KW - Research methodology
UR - http://www.scopus.com/inward/record.url?scp=85054555611&partnerID=8YFLogxK
U2 - 10.1016/j.jcrc.2018.09.031
DO - 10.1016/j.jcrc.2018.09.031
M3 - Article
C2 - 30317050
AN - SCOPUS:85054555611
SN - 0883-9441
VL - 48
SP - 414
EP - 417
JO - Journal of Critical Care
JF - Journal of Critical Care
ER -