"most frequent topic" is correct and usable in written English.
It can be used to refer to a subject or topic which is discussed or written about often. For example: "Climate change is the most frequent topic of conversation these days."
The most frequent topic areas were 'Aesthetics and Upkeep' (18), 'Access to Resources/Facilities' (15), 'Security and Safety' (15), and 'Walkability' (14).
Further, more than half of boards now communicate directly with investors, with board oversight of long-term strategy the most frequent topic of investor dialogue.
But his most frequent topic is crimes most heinous, usually along the Mexican border of his state: "Nancy was shot in the back of the head.
RMI's Matt Lehrman describes in a blog post how the net metering debate, the most frequent topic into which multi-stakeholder conversations about DERs devolves, is a red herring.
Earlier today, I was debating as to whether to write about health care (my most frequent topic these days), or jobs, an incredibly urgent issue there's been some important articles about in the last 48 hours.
"Perceptions of poor management, and a lack of accountability for poor management, comprised five of the top 10 reasons why people leave or consider leaving CIA and were the most frequent topic of concern among those who volunteered comments," the inspector general's report says.
The long-term behavior of the stem cement interface is one of the most frequent topics of discussion in the design of cemented total hip replacements, especially with regards to the process of damage accumulation in the cement layer.
Among its most frequent topics are his wealth and copious free time — "Coffee, liquor, money, is that your life now?" his "Seinfeld" cast mate Michael Richards asks — and these seem to be reflected in the show's indolent, contented rhythms and (for short-format online video) high production values.
Among the most frequent topics were environmental contamination, toxicology, environmental processes, and method development.
The most frequent communication method patients used was approval, whereas the most frequent topics were about physiologic needs and information related to the surgery.
Their most frequent topics of conversation are how they get bathroom breaks, the pleasant temperature of the warehouses, the excellent benefits and suitable wages, friendly management and how the job isn't monotonous or tiring at all.
