The few key limitations to the present study were single hospital cohort, referral bias
and lack of long term follow up.
However, referral bias
may not have as much effect as would be expected, because most endoscopies are done in tertiary institutions like ours.
(1) In a multivariate model, even when accounting for referral bias
and patient comorbidity, all five procedures took significantly longer in academic hospitals when compared to non-teaching centres.
was the cause for the increase of the sensitivity and decrease of the specificity by decreasing the number of the true negatives and false negatives.
The high frequency of CD among patients undergoing colonoscopy in our unit is likely to be due to a referral bias
. Although this study was conducted in a tropical setting, we did not observe a high rate of infectious diseases.
Whether this finding is indicative of the fact that female patients have more severe symptoms from concussion in general, as suggested in several previous studies, or is due to referral bias
in which female individuals preferentially present to the ED when symptoms are more severe ...
(10) Furthermore, one rural academic center has pointed to referral bias
on the part of transferring physicians at outlying hospitals in explaining a disproportionately high referral rate of patients with intra-cerebral hemorrhage.
A meeting attendee suggested that referral bias
was behind their higher prevalence--in other words, more adolescent girls presented to their institution because of better awareness of endometriosis among providers.
Although limited by the use of single night polysomnography, a small study population, and possibly by referral bias
to a tertiary center, the findings suggest that periodic limb movements of sleep might be an important side effect of SSRIs that is frequently overlooked in children.
Because of Denmark's universal health care plan, this study also had no referral bias
or diagnostic bias.
These differences would be unlikely to introduce any referral bias
in our study because we adjusted for these factors.
The studies had multiple limitations, including location (potential population bias), patient symptoms, and setting (potential referral bias