Older age, lack of vaccination and infection with variants other than Omicron associated with severity of COVID-19 and in-hospital mortality in Pakistan

Objectives We investigated factors associated with COVID-19 disease severity and in-hospital mortality in a low-middle income setting. Methods Records of 197 adult COVID-19 patients admitted to the Aga Khan University Hospital, Karachi between April 2021 and February 2022 were reviewed. Clinical data including, that of SARS-CoV-2 variants was collected. Results The median age of the patients was 55 years and 51.8% were males. 48.2 % of patients had non-severe disease, while 52.8% had severe/critical disease. Hypertension (48%) and diabetes mellitus (41.3%) were most common comorbid conditions. Omicron (55.3%), Beta (14.7%), Alpha (13.7%), Delta (12.7%) and Gamma (3.6%) were identified in patients. The risk of severe disease was higher in those aged above 50 years (OR 5.73; 95%CI [2.45-13.7]) and in diabetics (OR 4.24; 95% CI[1.82-9.85]). Full vaccination (OR 0.25; 95%CI [0.11-0.58]) or infection with Omicron variants (OR 0.42; 95% CI[0.23-0.74]) reduced disease severity. Age > 50 (OR 5.07; 95%CI [1.92-13.42]) and presence of myocardial infarction (OR 5.11; 95% CI[1.45-17.93]) was associated with increased mortality, but infection with Omicron (OR 0.22 95% CI 0.10-0.53]) reduced risk. Conclusions Vaccination was found to protect against severe COVID-19 regardless of the infecting variant and is recommended especially, in those aged over 50 years and with co-morbid conditions. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement SARS-CoV-2 variant testing was supported by the World Health Organization, Pakistan and through a COVID-19 Research Rapid Grant from the Higher Education Commission, Pakistan. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The work received approval from the Ethical Review Committee of the Aga Khan University (study reference no. 2021-6232-19404). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors