Response to Zhou et al. regarding Cardiac injury prediction and lymphocyte immunity and inflammation analysis in hospitalized patients with coronavirus disease 2019 (COVID-19).

Dear Dr. Zhou and contributors,

We are grateful for the response to our letter and the insight which you have provided. We agree that more data will enable clinicians and researchers to establish the risk Covid-19 poses to cardiac tissue.

As you conclude in your response, when comparing baseline troponin readings in patients with diabetes hs-cTnT more commonly returns elevated than hs-cTnI. With research performed by Jain and Hedayati suggesting troponin assays in patients with diabetes return above the 99th centile in 82% and 6% respectively [2]. However, at the time of writing 105, 294, 765 confirmed cases of Covid-19 have been reported to the WHO [3]. Given the scale of the Covid-19 pandemic reliance on a single assay presents a risk of over-diagnosis of cardiac injury secondary to patient co-morbidity. We hope further work will include dynamic troponin results to exclude this possibility.

Additionally, we agree as Bhatia and Daniels have suggested that age-specific troponin cut-offs are more relevant clinically in younger patients [4]. Although, in your study patients under the age of 65 represented 43% of the included patients. Further insight into patient demographics would help clarify this [1].

Funding

None.

Declaration of competing interest

None.