TY - JOUR
T1 - GRADE guidelines 6. Rating the quality of evidence - Imprecision
AU - Guyatt, Gordon H.
AU - Oxman, Andrew D.
AU - Kunz, Regina
AU - Brozek, Jan
AU - Alonso-Coello, Pablo
AU - Rind, David
AU - Devereaux, P. J.
AU - Montori, Victor M.
AU - Freyschuss, Bo
AU - Vist, Gunn
AU - Jaeschke, Roman
AU - Williams, John W.
AU - Murad, Mohammad Hassan
AU - Sinclair, David
AU - Falck-Ytter, Yngve
AU - Meerpohl, Joerg
AU - Whittington, Craig
AU - Thorlund, Kristian
AU - Andrews, Jeff
AU - Schünemann, Holger J.
PY - 2011/12
Y1 - 2011/12
N2 - GRADE suggests that examination of 95% confidence intervals (CIs) provides the optimal primary approach to decisions regarding imprecision. For practice guidelines, rating down the quality of evidence (i.e., confidence in estimates of effect) is required if clinical action would differ if the upper versus the lower boundary of the CI represented the truth. An exception to this rule occurs when an effect is large, and consideration of CIs alone suggests a robust effect, but the total sample size is not large and the number of events is small. Under these circumstances, one should consider rating down for imprecision. To inform this decision, one can calculate the number of patients required for an adequately powered individual trial (termed the "optimal information size" [OIS]). For continuous variables, we suggest a similar process, initially considering the upper and lower limits of the CI, and subsequently calculating an OIS. Systematic reviews require a somewhat different approach. If the 95% CI excludes a relative risk (RR) of 1.0, and the total number of events or patients exceeds the OIS criterion, precision is adequate. If the 95% CI includes appreciable benefit or harm (we suggest an RR of under 0.75 or over 1.25 as a rough guide) rating down for imprecision may be appropriate even if OIS criteria are met.
AB - GRADE suggests that examination of 95% confidence intervals (CIs) provides the optimal primary approach to decisions regarding imprecision. For practice guidelines, rating down the quality of evidence (i.e., confidence in estimates of effect) is required if clinical action would differ if the upper versus the lower boundary of the CI represented the truth. An exception to this rule occurs when an effect is large, and consideration of CIs alone suggests a robust effect, but the total sample size is not large and the number of events is small. Under these circumstances, one should consider rating down for imprecision. To inform this decision, one can calculate the number of patients required for an adequately powered individual trial (termed the "optimal information size" [OIS]). For continuous variables, we suggest a similar process, initially considering the upper and lower limits of the CI, and subsequently calculating an OIS. Systematic reviews require a somewhat different approach. If the 95% CI excludes a relative risk (RR) of 1.0, and the total number of events or patients exceeds the OIS criterion, precision is adequate. If the 95% CI includes appreciable benefit or harm (we suggest an RR of under 0.75 or over 1.25 as a rough guide) rating down for imprecision may be appropriate even if OIS criteria are met.
KW - Confidence in estimates
KW - Confidence intervals
KW - GRADE
KW - Imprecision
KW - Optimal information size
KW - Quality of evidence
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U2 - 10.1016/j.jclinepi.2011.01.012
DO - 10.1016/j.jclinepi.2011.01.012
M3 - Article
C2 - 21839614
AN - SCOPUS:80054997769
SN - 0895-4356
VL - 64
SP - 1283
EP - 1293
JO - Journal of Clinical Epidemiology
JF - Journal of Clinical Epidemiology
IS - 12
ER -