Relationship between ultra-short heart rate variability and short-term mortality in hospitalized COVID-19 patients.

OBJECTIVE: To assess the association between ultra-short heart rate variability (US-HRV) and short-term mortality in patients with COVID-19 and develop prognostic prediction models to identify high-risk patients as early as possible. METHODS: A retrospective cohort study was performed on 488 patients diagnosed with COVID-19 and hospitalized in the First Affiliated Hospital of Fujian Medical University from December 2022 to January 2023. 10-s electrocardiogram (ECG) data were available for these patients. The US-HRV parameters including standard deviation of all normal-to-normal R-R intervals (SDNN) and root mean square of successive differences between normal-to-normal R-R intervals (rMSSD) were calculated using Nalong ECG software. The endpoint was short-term mortality, including in-hospital mortality or mortality within 1 week after discharge. RESULTS: Of the 488 patients, 76 (15.6%) died. The SDNN and rMSSD in the death group were significantly lower than those in the survival group (P < 0.001). The area under the receiver operating characteristic (ROC) curve (AUC) for SDNN and rMSSD to predict mortality was 0.761 and 0.715, respectively. The combined use of SDNN and rMSSD had an AUC of 0.774. The mortality rate in the group with SDNN ≤7.5 ms was higher than that of SDNN >7.5 ms group (P < 0.05). With the decrease of SDNN, the mortality of patients showed an upward trend, and the mortality of patients with SDNN ≤2 ms was the highest (66.7%). Multivariate logistic regression analysis identified SDNN as an independent predictor of prognosis (odds ratio (OR) = 5.791, 95% confidential interval (CI) 1.615-20.765, P = 0.007). The AUC of Model 1 (simple model) was 0.866 (95% CI 0.826-0.905). The AUC of Model 2 (comprehensive model) was 0.914 (95% CI 0.881-0.947). CONCLUSION: SDNN was associated with short-term mortality and provided the additional discriminatory power of the risk stratification model for hospitalized COVID-19 patients.

Association between platelet distribution width and peripheral arterial disease in elderly patients.

Background: The prevalence of peripheral arterial disease (PAD) increases with age. Platelet activation has been linked to PAD. Platelet distribution width (PDW) is a measure of platelet function. This study aimed to investigate the relationship between PAD and PDW in elderly patients. Patients and methods: A total of 416 elderly patients in Fujian Provincial Hospital between January 1, 2018 and June 30, 2019 were enrolled. PAD was diagnosed when the ankle-brachial index (ABI) was below 0.9. Multivariate logistic regression analysis was used to examine the association between PDW and PAD. ROC curves and AUC were used to assess the diagnostic value. Results: Compared to patients without PAD, PDW was higher in patients with PAD (PAD vs. subjects without PAD, 13.19±2.24% vs. 11.52±1.39%, p<0.001). PDW was associated with an increased OR of PAD (OR: 1.667, 95% CI: 1.462-1.901, p<0.001). After adjusting for potential confounding factors, the OR changed to 1.821 (95% CI: 1.535-2.114, p<0.001). This association appeared to be more prominent in females than males (females vs. males, OR: 2.294, 95% CI: 1.556-3.381 vs. OR: 1.695, 95% CI: 1.404-2.047, p<0.001). The AUC area was 0.760 (95% CI: 0.682-0.837) for females and 0.689 (95% CI: 0.627-0.752) for males. Both cut-off values had high specificity (females vs. males, 95% vs. 100%). Conclusions: PDW was higher in elderly patients with PAD than in subjects without PAD, and the association between PDW and PAD persisted after adjusting for confounding factors.