Summary The disease course of COVID‐19 varies from asymptomatic infection to critical condition leading to mortality. Identification of prognostic factors is important for prevention and early treatment. We aimed to examine whether obesity is a risk factor for the critical condition in COVID‐19 patients by performing a meta‐analysis. The review protocol was registered onto PROSPERO (CRD42020185980). A systematic search was performed in five scientific databases between 1 January and 11 May 2020. After selection, 24 retrospective cohort studies were included in the qualitative and quantitative analyses. We calculated pooled odds ratios (OR) with 95% confidence intervals (CIs) in meta‐analysis. Obesity was a significant risk factor for intensive care unit (ICU) admission in a homogenous dataset (OR = 1.21, CI: 1.002‐1.46; I2 = 0.0%) as well as for invasive mechanical ventilation (IMV) (OR = 2.05, CI: 1.16‐3.64; I2 = 34.86%) in COVID‐19. Comparing body mass index (BMI) classes with each other, we found that a higher BMI always carries a higher risk. Obesity may serve as a clinical predictor for adverse outcomes; therefore, the inclusion of BMI in prognostic scores and improvement of guidelines for the intensive care of patients with elevated BMI are highly recommended.

Background: The prevalence of hyponatremia is highly variable among patients with lung cancer. However, its prevalence and prognostic significance in subgroups of patients with lung cancer have not yet been evaluated in a meta-analysis.Methods: We have registered our meta-analysis and review protocol to the PROSPERO International Prospective Register of Systematic Reviews, with the following registration number: CRD42020167013. A systematic search was done in the following sources: MEDLINE, Embase, CENTRAL, Web of Science, ClinicalTrials.gov, a WHO Global Health Library.Results: We identified a total of 8,962 potentially eligible studies, and we included 31 articles in our evaluation. The prevalence of hyponatremia in patients with lung cancer varied between 3 and 94.8% with an average of 25% without any significant differences between the following subgroups: histotype, gender, age, Eastern Cooperative Oncology Group (ECOG) state, and the extent of disease. The overall survival (OS) was significantly lower in hyponatremic compared to normonatremic patients at 10 months [RR.59 (95% CI.47–0.74), p < 0.001] and at 20 months [RR.44 (95% CI.33–0.59), p < 0.001], with worse survival rates in non-small cell lung cancer (NSCLC) [RR.27 (95% CI.12–0.44), p < 0.001] than in small cell lung cancer (SCLC) [RR.42 (95% CI.27–0.57), p < 0.001]. If hyponatremia was corrected, OS at 10 months was significantly higher than in the uncorrected hyponatremia group [RR 1.83 (95% CI 1.37–2.44), p < 0.001], but, at 20 months, no statistically significant difference could be found between these subgroups [RR 2.65 (95% CI.94–7.50), p = 0.067].Conclusions: Patients with lung cancer diagnosed with hyponatremia, especially patients with NSCLC, seem to have significantly lower survival rates than normonatremic patients. If hyponatremia remains uncorrected, the mortality rates might be even higher.

Background The prevalence of hyponatremia is highly variable among lung cancer patients. It is also an important predictive factor, according to numerous studies. However, its prevalence and prognostic significance in subgroups of lung cancer patients, e.g. in small cell and non-small cell lung cancers (SCLC and NSCLC, respectively), have not yet been evaluated in a meta-analysis.Methods We report this systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2009) Statement. We have registered our meta-analysis and review’s protocol to the PROSPERO International Prospective Register of Systematic Reviews, with the following registration number: CRD42020167013. A systematic search was done in the following sources: MEDLINE, Embase, CENTRAL, Web of Science, ClinicalTrials.gov, a WHO Global Health Library. We extracted the effect measure for each outcome as the relative risk (RR) with the related 95% confidence interval (CI). Results We identified a total of 8127 potentially eligible studies and we included 25 studies in our evaluation. The prevalence of hyponatremia in lung cancer patients varied between 3% and 56.1% with an average of 23% without any significant differences between the following subgroups: cancer type (p=0.780), gender (p=0.223), age (p=0.773), ECOG state (p=0.317) and the extent of disease (p=0.999). Hyponatremia was more consistently an independent prognostic factor in NSCLC than in SCLC. The overall survival (OS) was significantly lower in hyponatremic compared to normonatremic patients at 10 months (RR: 0.59, 95% CI, 0.47 to 0.74, p<0.001) and at 20 months (RR: 0.44, 95% CI, 0.33 to 0.59, p<0.001), with worse survival rates in NSCLC than in SCLC (27% vs 42%) (p<0.001). If hyponatremia was corrected, OS at 10 months was 1.83 times higher than in the uncorrected hyponatremia group (95% CI, 1.37 to 2.44, p<0.001), but at 20 months no statistically significant difference could be found between these subgroups (p=0.067).Conclusions Low serum sodium levels have a negative impact on mortality at 10 and 20 months, which is more pronounced among NSCLC patients. The correction of hyponatremia has a positive effect on OS rates at 10 months, but this advantage disappears by 20 months.