![]() ![]() The OR for death in ligation group versus sclerotherapy group = 39/81 = 0.48. This implies that ligation decreases the risk of death by 37% (calculated as 100 minus 63%) as compared with sclerotherapy. This means that the risk of death after ligation is 63% of the risk of death after sclerotherapy. In the same example, the RR of death in ligation group versus sclerotherapy group = 0.28/0.44 = 0.63. As for other summary statistics, confidence intervals can be calculated for RR and OR. An RR (or OR) more than 1.0 indicates an increase in risk (or odds) among the exposed compared to the unexposed, whereas a RR (or OR) <1.0 indicates a decrease in risk (or odds) in the exposed group. The odds ratio (OR) is the ratio of odds of an event in one group versus the odds of the event in the other group.Īn RR (or OR) of 1.0 indicates that there is no difference in risk (or odds) between the groups being compared. The relative risk (also known as risk ratio ) is the ratio of risk of an event in one group (e.g., exposed group) versus the risk of the event in the other group (e.g., nonexposed group). By contrast, the odds of death in the two groups was 18/46 (0.39) and 29/36 (0.81), respectively. ![]() The risk of death in the ligation group was 18/64 (28% or 0.28), and the risk of death in the sclerotherapy group was 29/65 (44% or 0.44). Let us look at the hypothetical example of a randomized trial comparing endoscopic sclerotherapy ( n = 65) versus band ligation ( n = 64) for the treatment of bleeding esophageal varices. At first glance, though these two concepts seem similar and interchangeable, there are important differences that dictate where the use of either of these is appropriate. “Odds” refers to the probability of occurrence of an event/probability of the event not occurring. The term “odds” is often used instead of risk. Statistically, risk = chance of the outcome of interest/all possible outcomes. “Risk” refers to the probability of occurrence of an event or outcome. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |