A total of 2820 patients hospitalized with COVID-19 pneumonia were included in this study.

The above Table 1 shows that maximum number of study subjects i.e., 22.98% were belonging to 19-30 years of age group, majority i.e., 62.9% study subjects were males. About 11.88% study subjects were alcoholic, 11.45% were smokers. Travel history was present in 20.14% study subjects. Majority i.e., 86.60% subjects were asymptomatic/mild/moderate COVID 19 positive cases while rest were severe COVID 19 positive cases Table 2.

Only 150 (5.31%) population was underweight (BMI- < 18.5 kg/m²) in which majority, 130 (86.67%) were asymptomatic, and only 20 (13.33%) patients had severe illness. Odds of having of severe COVID-19 illness was 1.18 times more as compared to patients with normal BMI but this association was found to be statistically not significant (p-value> 0.05).

About 647 (22.94%) of the total patients were in the overweight, in which 541 (83.62%) were asymptomatic, and 106 (16.38%) had severe COVID- 19 pneumonia. Odds ratio for this association was found as 1.51 which suggests that as compared to patients with normal BMI, overweight patients have one and half times more odds of having severe COVID- 19 disease and this association was also found to be statistically highly significant (p-value< 0.005).

Similarly, the patients who were obese, maximum 363 (84.03%) patients were asymptomatic and 69 (15.97%) had severe COVID- 19 pneumonia. Odds ratio for this association was found as 1.5, which indicates that patients who were obese had 1.5 times increased odds of severe COVID- 19 illness as compared to patients with normal BMI. This association was also found to be statistically significant (p-value < 0.05).

Global research efforts are being taken to identify individuals at a greater risk of developing critical illness, including death, due to COVID-19. In a previous study we have seen that old age and those having metabolic comorbidities are particularly vulnerable. ⁶⁹ In this study, we investigated the association of BMI with the severity of COVID-19 in 2820 patients aged more than 18 years. We observed that in our study overweight and obesity augmented the disease progression of COVID-19. Recently evidence have emerged regarding the association between a higher prevalence of obesity among COVID-19 patients and an increased risk of poor prognosis from SARS-CoV-2 infection.

We found that patients who were underweight had a slightly higher risk of severe COVID-19 illness (OR- 1.18, 95% CI- 0.721-1.942), but this association was statistically not significant. In a study done by Kim et al in 10,861 patients with COVID-19 infection, being underweight and obese was suggested to have a higher risk of death (OR = 1.44, 95% CI 1.08-1.92) respectively.10 It can be speculated that being underweight is often associated with malnutrition, impaired immune function, underlying frailty along with coexisting chronic conditions. Furthermore, being underweight is at an increased risk for pneumonia, and worse outcomes among older hospitalized patients.11

In our study, we found that patients who were overweight and obese had 1.5 times increased risk of severe COVID-19 illness as compared to patients with normal BMI. Data from Shenzhen, China with 383 COVID-19 patients revealed that overweight and obese were at 86% and 142% higher risk of developing severe pneumonia respectively as compared with patients with normal weight.12

Tartof et al. reported that a higher BMI (≥ 40 kg/m²) was associated with an increased risk of death from COVID-19,13 particularly in male patients and younger individuals (≤60 years), in both outpatients and inpatients. S. Hendren et al found that the association of BMI with death or mechanical ventilation was strongest in adults ≤50 years and severely obese individuals (BMI ≥40 kg/m²) had an increased risk of in-hospital death.9

Obesity and excess fat mass are commonly related to other comorbidities, such as hypertension, diabetes, cerebrovascular disease and renal disease indirectly. These comorbidities are considered to result in increased vulnerability to pneumonia-associated organ failures.14 For example, beta cell function is impaired in individuals with diabetes, obesity, and excess ectopic fat, resulting in insulin resistance. So, during an immunologic challenge, an appropriate metabolic response is limited. Because of this, some diabetic patients require substantial amounts of insulin during severe infections.15 In addition, alterations in respiratory mechanisms, increased airway resistance, impaired gas exchange, diminishing forced volume and forced vital capacity are some respiratory problems often seen in patients with obesity which could possibly leading to ARDS.11

In summary, underweight, overweight and obese patients are at a higher risk of developing severe COVID-19 disease as compared to the patients with normal BMI. As the COVID- 19 infection may continue to spread world- wide, clinicians should maintain a high level of attention towards BMI as well while treating the patient. Particularly, overweight and obese patients should be carefully monitored and managed with prompt and aggressive treatment.