Demographic and Laboratory Characteristics of COVID-19 Patients: A Three-Tier Severity Classification Study

This study aimed to investigate the demographic and laboratory characteristics of COVID-19 patients categorized into three severity groups: non-severe, severe, and critical, based on WHO guidelines. Unlike many studies that utilize a binary classification (non-severe vs. severe), this three-tier approach enhances the study's clinical applicability.

Our findings revealed significant differences in demographic characteristics and laboratory results across the severity groups. Notably, a significant age difference was observed between the critical and non-severe groups, aligning with previous research highlighting age as a crucial determinant of COVID-19 severity [10-12] and its association with mortality risk [13]. This association is likely attributable to increased comorbidities, age-related immune decline [14], and elevated pro-inflammatory cytokines in older adults [15].

Comorbidities also differed significantly across the groups. Cardiovascular disease was the most prevalent (55.6%), followed by underlying respiratory diseases (30.6%) and diabetes (23.6%). While our finding regarding cardiovascular disease being the most common comorbidity at all stages of COVID-19 infection aligns with existing literature [16], we observed a higher prevalence of cardiovascular disease and a lower prevalence of diabetes compared to some studies [17]. This discrepancy might stem from population differences, as suggested by studies showing higher mortality risk among Asian COVID-19 patients [18] and increased likelihood of severe cardiopulmonary complications in Asian patients compared to non-Spanish white patients [19].

Furthermore, the study underscores the complex interplay between COVID-19 and respiratory comorbidities. It remains unclear whether the increased mortality risk in such patients results from more severe COVID-19 manifestation or exacerbation of pre-existing respiratory conditions [20-23].

Finally, our study found a higher proportion of male patients than female patients, consistent with prior research indicating a higher COVID-19 infection risk in males. This could be attributed to sex-specific hormonal influences on inflammation, varying levels of angiotensin-converting enzyme receptors and transmembrane protease serine (which facilitate viral entry), and lifestyle factors like smoking prevalent among males [24].

In conclusion, our study underscores the importance of considering age, comorbidities, and sex when assessing COVID-19 severity. The three-tier classification system employed in this study provides valuable insights into the distinct characteristics of different patient subgroups, ultimately contributing to more tailored and effective clinical management strategies.