Confidence In Effect Estimates Research Articles

GRADE Leitlinien: 6. Einschätzung der Qualität der Evidenz – Unzureichende Präzision

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 when 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" or 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 a 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.

Diagnostik und linked evidence – Wie robust muss die Kette sein?

In this article we describe the methodological underpinnings in assessing the confidence in estimates of effects (quality of evidence) for diagnostic questions and resulting recommendations in guidelines. In particular, we will describe current considerations and research regarding the link between data relating to diagnostic accuracy and patient important outcomes and how to move from evidence about diagnostic tests and strategies to recommendations. Our deliberations and suggestions, a result of an invited presentation at the annual fall conference of the German Institute for Quality and Efficiency in Healthcare (IQWiG), are based on our work with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group.

GRADE guidelines 6. Rating the quality of evidence—imprecision

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.

Crohn's disease in Nottingham: a search for time-space clustering.

All cases of Crohn's disease in the Nottingham area were ascertained and the date and place of domicile and work at the time of onset of symptoms noted. Applying the Knox and Pike and Smith tests for clustering of patients in time and space, no significant results were observed. Further analysis of differences in time-space clustering between a group of patients and matched controls is in hand.