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.
Files of patients with negative MPI reports were reviewed for possible subsequent referral to CAG 3 months after receiving a negative MPI to ensure that all the cases where patients took both tests were included in this study in hope to minimize the effect of the referral bias
Studies on the subject reveal conflicting observations by different investigators about the sensitivity and specificity of ETT and MPS perhaps because it is extremely difficult to eliminate referral bias
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.
These studies have been widely criticized for having insufficiently considered risk adjustment and possible referral bias
In summary, given the disparity in results published so far, more clinical research as provided by Chou and colleagues (7) is needed to better characterize the relationships between SDB and dyslipidaemia, particularly from epidemiologic cohorts enrolling community dwelling individuals that would have limited referral bias