You can, and I notice that this practice was quite prevalent in the past. Consider the following points:

1. Making a single publication (your cohort study together with a systematic review & meta-analysis [SRMA]) will make your work more loaded with content. However, I foresee that aiming for a single publication will take more time compared to publishing first the cohort study.

2. An SRMA is not simply about pooling common outcomes and data across included studies - it is a distinct endeavor in itself, with rationale, methods, results, discussions (with limitations) and conclusions. I fear that in your attempt to generate a single work from the cohort study and the SRMA, you will inadvertently put more weight in the cohort study and "relegate" the SRMA as if it is just a minor part of the discussion. This is problematic. You have to be as detailed in your cohort study reporting as you did your subsequent SRMA. In doing so, it may be difficult for future readers to digest/understand your work as they are basically dealing with two studies in one paper.

3. If you are faculty member, it would be more advantageous for your promotion/tenure if you publish the cohort study and the SRMA separately - consider the weight of 2 publications versus 1 publication only. While in a lot of cases this will be considered "devious," I think that this will be acceptable in this context as an SRMA is a legitimate, standalone research endeavor on its own.

Aedrian Abrilla I am agree with you. It depends on personal interest.

I like the idea of combining the cohort and meta-analysis studies together. I would put the cohort study first followed by the meta-analysis and then use the meta-analysis to provide context for your cohort study. I am suggesting this as a former research journal editor (10 years). It would help separate your manuscript from others.

Good luck,

Jim McLean

This is a combination of two research techniques.In fact sometimes we find out the result of the same problem through two techniques and compare the results and present to the reader in a single research paper

Hi Fachreza Aryo Damara ,

The pros and cons of doing that have been exhaustively described above. I think it is possible and also a good idea to incorporate a meta if you want to calculate the combined effect of your particular treatment. I also think that having a set of data from an understudied demographic group would help to increase the diversity of the pool which is another strong point even if you decide to publish the cohort study only. Good luck.