Impact of oral health on COVID-19 outcomes in patients with pre-existing cardiovascular conditions: a questionnaire-based analysis of disease severity, recovery time, and C-reactive protein

Aim: This study aimed to assess oral health’s influence on COVID-19 outcomes in recovered individuals with pre-existing cardiovascular conditions. Methods: In the main study employing a cross-sectional design based on a questionnaire survey, 464 Egyptian patients who had recovered from COVID-19 were enrolled, with 86 individuals who had pre-existing cardiovascular conditions included in a subgroup analysis. Oral health was classified as poor and good based on scores from an 18-question survey with higher scores indicating better health. Severe COVID-19 was defined by criteria that included elevated respiratory and heart rates, severe dyspnea low oxygen saturation, high fever, and need for hospitalization or ICU care. Participants’ recovery duration was classified into three groups: fast (≤ 2 weeks), intermediate (4 weeks), and delayed (6 weeks), characterized by symptom-free status. Moreover, C-reactive protein (CRP) levels (> 18 mg/L) were considered elevated. Results: Our results revealed that cardiac patients with poor oral health showed a significant association with severe COVID-19 cases, elevated CRP levels (> 18 mg/L), and a prolonged recovery period (6 weeks) (p < 0.001). In contrast, participants demonstrating good oral health were associated with milder COVID-19 cases, lower CRP levels, and faster recovery (p < 0.001). Conclusions: Our findings indicate a significant link between the condition of oral health and the experienced severity of COVID-19 in cardiac patients. Poor oral health was associated with elevated CRP levels, delayed recovery, and more severe symptoms. These results highlight the importance of good oral hygiene as a modifiable factor in reducing infection severity, especially in vulnerable cardiac populations.