Greetings to the respected ResearchGate community:

I wanted to know if it would be invalid to conduct a double-armed meta-analysis (DAMA) if a network meta-analysis (NMA) already exists in the literature?

I'll provide you with two examples below:

1. I am willing to compare the efficacy of two different drug classes in the treatment of migraines through a double-armed, comparative meta-analytic review. A NMA already exists and ranks the different medication classes through its direct and indirect comparisons.

Would it be non-feasible to conduct a DAMA in this case?

What if the relationship/the ranking of medications - which has already happened in the NMA - was done through an indirect comparison... Would this necessitate the need for a direct comparison through a DAMA?

2. I am willing to compare the efficacy of two flaps used in plastic surgery through a DAMA. A planned NMA on PROSPERO is already present which aims to compare three different flap types (including the ones I've had in mind). Does this invalidate the need for such a DAMA?

As a clinician/headache specialist, would you be interested in such findings - given the pre-existence of a NMA?

As a plastic surgeon, would you be interested in such findings - given the pre-existence of a NMA?

Please advise me - if possible.

Thank you very much in advance.