Evaluation of long-term follow-up of COVID-19 patients

Aim: COVID-19 infection, which has become a major public health issue, needs to be examined and monitored in all aspects as a clinical condition. The number of studies on post-COVID-19 persistent symptoms is increasing, and variations can be observed in the types and frequencies of these symptoms among different studies. In this context, we aimed to reveal our local patient profile by following COVID-19 patients in our clinic from the onset of the disease. In our study, by examining the long term mortality rates of patients and newly diagnosed diseases added to their pre existing health conditions, we aimed to contribute to the literature, which has limited studies in this field, in terms of their relationship with COVID-19. The findings of this study will provide significant contributions to clinical practices for the long-term follow-up and management of COVID-19 patients. Materials and method: Our study was conducted at Karadeniz Technical University Farabi Hospital and included COVID-19 patients who were hospitalized and followed up between March 1, 2020, and May 1, 2022. The study also included COVID-19 patients evaluated in the post-COVID-19 follow-up clinic. Retrospective evaluation was performed on the symptoms and findings during the 0-6 months, 6-12 months, 12-18 months, and 18-24 months periods after COVID-19, as well as the newly diagnosed diseases. Results: The study included a total of 975 COVID-19 patients, of which 53.23% (n=519) were male. The mean age of all participants was 59.87 ± 18.05 years (median=62.00, min=18.00, max=98.00). At least one comorbidity was present in 761 patients. The majority of patients belonged to the severe (33.84%) category. Prior to SARS-CoV-2 PCR positivity, at least one COVID-19 vaccination had been administered to 422 patients (43.28%). During the follow-up period, additional complications were observed in 275 patients (28.20%), with infection being the most common complication (6.66%). Among the hospitalized patients, 186 (19.07%) died. The age of the deceased patients was significantly higher than that of the survivors (OR 1.04, p<0.001). In males (OR 1.54, p=0.009), hospital-associated COVID-19 patients (OR 2.70, p<0.001), patients with comorbidities (OR 9.01, p<0.001), and patients with additional conditions such as hypertension (OR 1.54, p=0.008), cardiac disease (OR 1.96, p=0.002), oncologic disease (OR 2.96, p<0.001), asthma and/or COPD (OR 1.77, p=0.006), neuropsychiatric disease (OR 2.29, p=0.001), and autoimmune disease (OR 2.14, p=0.017), respiratory distress (OR 1.75, p=0.012), general condition deterioration (OR 3.40, p<0.001), confusion (OR 2.58, p=0.031), and diarrhea (OR 2.89, p=0.049) were more prevalent at the time of hospital admission. The severe and critical categories of disease severity, intensive care unit admission (OR 12.30, p<0.001), presence of lung imaging findings (OR 2.60, p<0.001), development of complications during the acute phase of COVID-19 (OR 2.10, p<0.001), and higher mortality rates were observed. Post-COVID-19 symptoms persisted for an average of 2.20 ± 1.60 months in 450 patients. Among the comorbidities, patients with cardiac disease (OR 1.58, p=0.014), asthma and/or COPD (OR 1.62, p=0.031), and thyroid disease (OR 3.26, p=0.007) had a higher frequency of post-acute COVID-19 symptoms. Additionally, patients with symptoms during the acute phase of COVID-19 (OR 2.55, p<0.001), those followed in the intensive care unit (OR 3.17, p<0.001), and those with lung involvement on imaging (OR 1.72, p=0.003) were more likely to experience post-COVID-19 symptoms. The frequency of post-acute symptoms was also higher in patients with complications during the acute phase of COVID-19 (OR 2.41, p<0.001). Among the survivors, 126 patients died during the follow-up period. Among the survivors, males (OR 1.55, p=0.026), those with at least one comorbidity (OR 13.46, p<0.001), and those with comorbidities such as cardiac disease (OR 2.79, p<0.001), oncologic disease (OR 5.21, p<0.001), neuropsychiatric disease (OR 2.10, p=0.015), hypertension (OR 2.04, p=0.016), and liver cirrhosis (OR 5.40, p=0.026) had a higher risk of mortality during the post COVID-19 period. Additionally, mortality rates were higher in patients with complications during the course of COVID-19 (OR 2.94, p<0.001) and those with post-acute symptoms such as dyspnea (OR 6.33, p<0.001) and fever (OR 2.40, p=0.022). Infectious disease (OR 2.48, p<0.001) and oncologic disease (OR 3.27, p=0.042) diagnoses in the post-COVID-19 period were also associated with higher mortality rates. The age of patients who died during the post-COVID-19 period was significantly higher than that of the survivors (OR 1.04, p<0.001). During long-term COVID-19 follow-up, 306 patients received a new diagnosis. Infectious diseases were the most common diagnoses. In the first 6 months of long-term COVID-19 follow-up, 85 patients died, while 186 new diagnoses were made. In the 6-12 month period, 20 patients died, and 101 new diagnoses were made. In the 12-18 month period, 16 patients died, and 57 new diagnoses were made. In the 18-24 month period, 5 patients died, and 17 new diagnoses were made. The frequency of receiving a new diagnosis was significantly higher in patients with hypertension (OR 1.68, p<0.001), those with complications during the acute phase of COVID-19 (OR 1.47, p=0.026), those with post-acute COVID-19 symptoms (OR 1.79, p<0.001), and older patients (OR 1.01, p=0.004). Conclusion: This study highlights the importance of long-term follow-up after COVID-19. Our findings demonstrate that mortality and new disease diagnoses are most commonly observed within the first 6 months. This underscores the need to monitor the long-term health status of COVID-19 survivors and intervene when necessary. Healthcare providers should ensure regular check-ups for patients during this period and include them in follow-up programs to facilitate early detection of potential complications. Key words: COVID-19, long-term follow-up, health status.