Clinical characteristics, risk factors and complications of COVID-19 among critically ill older adults - A case control study

Reduce the number of references in the Introduction section.

Specify, what percentage or proportion of COVID-positive cases was taken for the sample size calculation?

This being a case control study, more likely to be of retrospective nature, how was written informed consent obtained? More so from patients - non-survivors?

Results: Authors mention systolic and diastolic blood pressure were higher in case group. The same should be deleted as it neither seems clinically significant nor statistically significant.

Which diseases were included in chronic neurologic disorders?

Though not statistically significant, presence of co-morbdities such as lung disease (COPD and asthma) and cardiac disease were higher in case group. This should be mentioned in Results and briefly highlighted in Discussion.

Likewise in symptoms, mention the common symptoms followed by symptoms which were noticed in higher percentage in case or control group. For example cough, anosmia, loss of taste, muscle aches and seizures.

Table 5, mention the units of cell count in cells/µL. Mention the units of HbA1c.

Provide platelet count in the two groups. Comment upon the thyroid function status of the two groups.

Mention about stroke rates in the two groups in Results section.

Discussion: Needs major revision. Avoid mentioning the sample size and exact rates. Avoid describing co-morbidities, age distribution again. This is mentioned in Results section. Write in terms of majority or most common observations. Discussion should be limited to important findings of the paper.

The present study did not find gender to be associated with severe COVID-19. The percentage of individuals with lung disease was higher (though not statistically significant) in cases. Likewise, wheezing was statistically more common in non-survivors. In this context, a larger study from North India by Kaur et al. (2022¹) should be discussed. The study highlighted male gender and presence of lung disease to be significant determinants of severe COVID-19.

Authors should briefly describe the common symptoms observed in their study with the ones reported in other studies. This should be followed by signs and laboratory findings or complications. Only the atypical ones need to be discussed.

A better way is to include the atypical findings of the present study and those of other studies in a separate Table. Seizure rates, anosmia, wheeze and complications need to be emphasized rather than the typical clinical features observed in other studies. Varying seizure rates in the two groups might be because of a higher percentage of neurological disorder in the Case group.

A larger section is attributed to co-morbidities, which is not necessary. The part needs to be shortened.

Authors should provide a Limitation section. A major limitation is the retrospective analysis of the present study. Failure to consider the Vaccination history. Authors have collected the data until September 2022 by which time a greater percentage of elderly, being the priority groups would have received the vaccine. Also no history of previous COVID-19 has been mentioned, which is another big limitation. If thyroid function status was not included, this is another limitation. Any vaccine received after recovery from COVID-19 and presence of thyroid abnormality have been proposed as major determinants of complications such as persistent health issues and long term adverse events which can be independent determinants of mortality in COVID-19 patients. Such studies need to be discussed in the Limitation section of the present paper (Kaur et al., 2022²).