Mortality in COVID-19 is related to the immune response of the host as well as the viral effect. The increase in COVID-19 deaths in cancer patients has yet to be fully explained. In this retrospective study, we analyzed the factors affecting the prognosis of COVID-19 in lung cancer patients.
In univariate analysis, thirty-four possible prognostic factors for survival were analyzed. Seven of thirty-four potential factors were identified as significant prognostic factors for survival: Receiving chemotherapy in the last 28 days, hemoglobin, uric acid, platelet count, hospitalization in the intensive care unit, mechanical ventilation requirement, COVID 19 corticosteroid treatment doses (≤ 1 mg/kg/ >1 mg/ kg).
Hemoglobin and uric acid were associated with mortality in the multivariate analysis. The adjusted odds ratios (95 CI) for hemoglobin and üric acid were 3.86 (1.1–14.6) and 28 (2.3–336).
In cancer patients, the proinflammatory state may be effective in increasing mortality. A recent study found that neutrophil-lymphocyte ratio, on Covid Inflammatory Score, prognostic index, prognostic index, modified Glasgow prognostic score were associated with survival . In our study, however, no statistically significant relationship was found between inflammatory parameters and survival. This result may be due to the small number of patients in our study.
Several previous studies have shown that chemotherapy and immunotherapy increase the severity of the disease in COVID-19 with cancer patients [4, 5]. A recent study showed that systemic cancer treatments do not increase mortality rates in patients with lung cancer . In our study, chemotherapy history in the last 28 days was statistically significant in the univariate analysis(p = 0.005), but not in the multivariate analysis(p = 0.249). We think that this result is due to the small number of patients.
Uric acid is one of the anti-oxidants in plasma that protects cells from oxidative damage. Viral invasion causes an immune response, induces the activation of inflammatory factors, and causes the production of a large number of free radicals. These free radicals produce oxidative stress, which can further activate the pathways of inflammatory factors. Oxidative stress plays a crucial role in viral invasion . These suggest that low uric acid levels may indicate a higher inflammatory status and death risk in patients with COVID-19. Previous studies have shown that serum uric acid levels are lower than normal in patients with COVID-19 [20–23]. In our analysis, blood uric acid level was found to be an independent prognostic factor on survival in patients lung cancer with COVID-19 patients (p = 0.008). In our patients, favipiravir, which increases the uric acid level, was used in the treatment. However, in our study, uric acid values before starting favipiravir treatment were used. Previous studies on uric acid levels in patients with COVID-19 included patients without cancer [21–22]. Our study was conducted in lung cancer patients, and there is no study on uric acid levels in lung cancer patients. Consumption of uric acid in response to oxidative stress and hyper inflammation may result in decreased uric acid levels in the blood. However, the mechanism was unclear.
Hemoglobin is the most important determinant of the oxygen-carrying capacity of the blood. Hemoglobin levels decrease in hospitalized patients with COVID-19. It is associated with hyper inflammation and cytokine-mediated changes . Huang C et al. study showed that suppression of erythropoiesis and lymphopenia were secondary to the increase in interleukin-10 and interleukin-4 in COVID-19 patients . Omrani-Nava V et al. reported that hemoglobin levels in COVID19 patients were lower than in the control group. However, there was no statistically significant difference .
A recent study showed that low hemoglobin level is associated with mortality in cancer patients with COVID-19 . In our study, the results were similar. In our analysis, hemoglobin level was found to be an independent prognostic factor on survival in patients with lung cancer and COVID-19 patients (p = 0.0047).
The present study has some limitations which need to be taken into account. Firstly, it is a retrospective study. Secondly, there was a small number of patients.
In conclusıon; serum uric acid and hemoglobin levels were identified as important prognostic factors in lung cancer patients with COVID-19. These findings may also facilitate pretreatment prediction of survival in lung cancer COVID-19 patients. In the literature, there is no previous study on the effect of uric acid on prognosis in patients with COVID-19 and lung cancer. Prospective studies with larger patient populations are needed to confirm this study.