The lack of a direct comparator group (such as VKA-treated patients) could be regarded as a limitation.
For example, enoxaparin was considered as the direct comparator for rivaroxaban by all three agencies, and the PBAC evidence base included three RCTs for enoxaparin, whereas CDR included five and NICE included seven.
The lack of direct comparator studies led to an indirect comparison of the efficacy and tolerability of duloxetine with that of pregabalin and gabapentin in participants with painful DSPN, using placebo as a common comparator (78).
Clinical studies of CT screening have been published but, to date, none has had a comparator group, nor have mortality improvements as a direct consequence of screening been demonstrated.
There was no direct comparator from the baseline survey.
Therefore, the low number of comparator trials for fibrinogen concentrate still provided useful evidence and allowed valuable comparisons to be made between the intervention and a non blood control, as well as a direct comparison with FFP.
No direct comparators to this qualitative study, which examined telemonitoring provided in a usual care context, have been found.
For comparison, Apple generated $32.2bn revenue from the iPhone in the fourth quarter of 2015 alone – a figure that doesn't include its income from the App Store and iAd platforms, each the most direct comparators for Google's Android revenue.
There is only a limited evidence for a direct comparison, mainly comparing RCTs with non-randomised trials and observational studies that included comparator groups [ 7].
Adjusted indirect comparisons preserve the strength of randomization by comparing the (pooled) relative effect estimate of intervention A vs. X with the (pooled) relative effect estimate of intervention B vs. X (X as common comparator), as in Figure 1 with common comparator X. Placebo is often used as a common comparator [2]-[5].
