The baseline characteristics of the 150 subjects, indications for the colonoscopies and findings are shown in Table 3.
While there are open questions in the generation of these maps (e.g., how many dimensions should they have?), they all have the virtue that their accuracy can be checked (e.g., by examining the correlation between subjects' indications of item pair dissimilarity and the distance between that pair on the map), and thus the maps can be improved.
Antibiotics are the most important risk factor for C. difficile, and inpatient drug use is not available in the Ontario administrative databases; therefore, our results may have been subject to indication bias.
Further, we have previously shown that the use of a 'contemporary' untreated control cohort that is, where patients are potentially eligible for a DMT in an era when the DMTs are readily available, but remain untreated is subject to indication bias and thus a historical control cohort, with data collected pre-DMT use, is likely to be more appropriate.
Observational studies which provide most of the available evidence on the topic are potentially subject to indications-for-treatment bias, because the conditions serving as the indication for immunosuppression are themselves often associated with an intrinsically higher risk of mortality or cancer, and the patients with more severe disease are more likely to receive the treatment.
In these subjects the indication for mechanical ventilation may be questionable.
Subjects with indication of inflammation (CRP >5 mg/l) were excluded from the analyses.
Finally, we performed eight intestinal biopsies of normal mucosa in control subjects (the indication for colonoscopies was no specific abdominal symptoms; endoscopy and histology were scored as normal, and the patients were subsequently diagnosed as having irritable bowel syndrome).
The significant variations in serum iron, transferrin saturation and total iron binding capacity (TIBC) obtained in HIV-1 infected subjects were indications of derangement in iron metabolism.
For this study, we did not include the control group for two reasons: at first, because patients were control of themselves; secondly, we preferred not exposing subjects without indications for ASA treatment to a possible bleeding risk.
For me it was a deliberate statement on the nature of the subject matter, an indication of what you could expect to get from the book.
