Reply to Letter to the Editor

We would like to thank Lim et al. for their letter. Our study showed that endoscopy within 13 hours of presentation was associated with lower mortality in high-risk but not low-risk nonvariceal upper gastrointestinal bleeding (NVUGIB), as triaged by the Glasgow-Blatchford score (GBS) [1].

In view of the large sample size of the entire study cohort, the Student t test was performed in our study based on the central limit theorem, which states that the distribution of means will increasingly approximate a normal distribution as the sample size increases. Upon the suggestion by Lim et al., we re-analyzed the data of the smaller subgroup of patients in the high-risk group by evaluating the differences in continuous variables using a Gamma distribution with log link to account for the skewness of the variables. With this re-analysis, the presentation-to-endoscopy time, in-hospital NVUGIB, one or more significant co-morbidities, lower platelet count, prolonged prothrombin time and partial thromboplastin time remained significant variables associated with in-hospital mortality on univariate analysis, as per the results in our published paper [1]. Multivariate analysis showed that presentation-to-endoscopy time was the only variable significantly associated with mortality.

In their letter, Lim et al. noted that high-risk patients with one or more significant co-morbidities had an odds ratio of 10 for mortality, but this was not statistically significant, which could be due to the small sample size of the high-risk group in our cohort. We agree that with a larger sample size of this subgroup, co-morbidities might show a statistically significant association with mortality upon multivariate analysis. Correspondingly, with the larger sample size, our finding of presentation-to-endoscopy time being significantly associated with mortality in the high-risk group will still remain true.

In our study, the measured sensitivity for GBS in predicting mortality was only 40 % in the group with GBS of ≥ 12. This was because a specificity of 90 % was chosen for the GBS cut-off for determining the high-risk cohort; if we had chosen the usual cut-off based on optimal sensitivity and specificity, the population selected would be moderate-to-high risk rather than the high-risk group that we wanted to evaluate.

We divided patients into high risk (GBS ≥ 12) and low risk (GBS < 12) for simplicity. An alternative categorization could be low risk (GBS = 0), moderate risk (GBS 1 – 11), and high risk (GBS ≥ 12). Stanley et al. had shown that patients with GBS = 0 could be managed safely as outpatients [2]. Among patients in our study with a GBS of 0, none needed blood transfusion, re-bled, had surgery, or died, and only two patients needed endoscopic treatment, which was consistent with the findings of Stanley et al. In this case, the mortality is 0 % for low-risk patients and 4 % for moderate-risk patients. In addition, our study provided information on patients at the other end of the spectrum with severe upper gastrointestinal bleeding. Stratification with GBS to identify a subgroup of patients who may benefit from urgent endoscopy and those who may be managed as outpatients can be expected to help appropriate service delivery without unduly straining limited resources, as the majority will not need urgent endoscopy.

Finally, we would like to reiterate that no scoring system should completely replace human judgement in the management of NVUGIB. GBS can aid in the triaging of patients but should not be the sole determinant of the management decisions. In addition to endoscopy, prompt resuscitation, reversal of anticoagulation, frequent monitoring, timely action on deterioration of vital signs, and administration of proton-pump inhibitors are other important aspects in the management of patients with NVUGIB.

References

• 1 Lim L G, Ho K Y, Chan Y H et al. Urgent endoscopy is associated with lower mortality in high-risk but not low-risk nonvariceal upper gastrointestinal bleeding.  Endoscopy. 2011;  43 300-306
• 2 Stanley A J, Ashley D, Dalton H R et al. Outpatient management of patients with low-risk upper-gastrointestinal haemorrhage: multicentre validation and prospective evaluation.  Lancet. 2009;  373 42-47