In the present study, we assessed the long-term COVID-19-related symptoms in hospitalized patients in the non-intensive COVID-19 wards of a tertiary referral center, 3 months after discharge, during the fifth pandemic wave in northern Iran. The analysis of the responses showed that 7.5% of participants were symptom-free 3 months after hospital discharge, and the only complaint in 23.2% of the cases was the hair loss. In a study performed on hospitalized COVID-19 survivors, 89.0% of patients had at least one symptom 3 months later (20). A new meta-analysis reported that 80% (95% CI: 65–92) of the patients with COVID-19 experienced at least one or more long-term symptoms (21).
Arnold DT et al., in a prospective follow-up study in the UK, demonstrated that about 74% of COVID-19 patients appeared symptomatic 3 months after hospitalization (22). In some reports assessing COVID-19 patients at 60 days post-discharge, the proportion of patients with at least one persistent COVID-19 symptom ranged from 66–87% (23–25). A longitudinal study in Wuhan, China illustrated that 49.6% of the hospitalized patients continue to suffer from at least one symptom including physical deterioration, fatigue, and myalgia, after 3 months of discharge (26).
Reports have shown that 1 in 5 patients, regardless of the severity of the initial infection, may complain of COVID-related persistent symptoms for 5 weeks or more, while 1 in 10 may have symptoms lasting 12 weeks or more (2).
The causes of considerable differences in long COVID proportion among studies seem to be the difference in the type of participants (inpatient or outpatient), follow-up time from the acute episode of infection, the severity of disease, geographical area, power of tests to confirm the COVID-19 diagnosis, and the inability to track and follow up all patients.
The five commonest long COVID complaints in our study were hair loss, fatigue, shortness of breath, altered smell, and aggression. The most prevalent symptoms reported in almost all studies were fatigue and dyspnea, ranging from 35 to 60% according to the follow-up time (2, 22, 24, 27, 28).
In this study, the most common sequelae presented after recovery from the acute phase was hair loss. In a symptom cluster analysis comparing long COVID symptoms 30 days and 90 days after discharge, alopecia was the main complaint at 90 days (23). In another study, 46.1% of hospitalized COVID survivors at 3 months experienced hair loss (20). The hair shedding which occurs 2 to 3 months following a stressful event, including severe infective episodes, is known as Telogen effluvium (TE) (29). Since COVID-19 is a febrile and infectious disease with high emotional and physiological stress, TE would be an expected manifestation. The medications administered during the acute phase can also play a role in the development of TE (30). In our study, hair loss has highly affected women. Women are more attentive to hair loss because of its effects on beauty and psychological consequences. Additionally, the long hair of women is more easily identified during hair loss. COVID-related alopecia has been probably under-reported among men (29, 31).
Among residual symptoms persisting from the time of acute infection, fatigue was the most prominent complaint. In the majority of previous research, fatigue appeared as the most common prevalent symptom after recovery from acute COVID-19 infection (9, 20, 21, 32).
Shortness of breath was the most prevalent respiratory symptom experienced by our patients. Other studies have reported the prevalence of dyspnea ranging from 5–81%, 1 to 12 months after hospitalization (33).
Among neurological symptoms, olfactory dysfunction was the most commonly reported complaint. Smell alteration is a frequent early symptom of COVID-19 infection, which is attributed to neuroinflammation of the olfactory bulb (34). It usually subsides over a period of 2–3 weeks, however, it persists in some patients beyond a month due to prolonged healing (35). In a systematic review on persistent symptoms after hospital discharge, the most neurological symptoms were headache, insomnia, and loss of smell or taste (27).
Another prominent complaint asserted by about one-third of our patients was aggression. However, in other studies, depression was frequently reported as the main psychiatric disorder (36). In another study in Mexico City, among mood disorders, sadness, desire to cry, anguish, anger, and anhedonia were the most common symptoms reported (23).
In the present study, there was a significant correlation between remained complaints and gender, and it was higher in women. This finding is in agreement with the previous studies (7, 37, 38). It is attributable to the fact that women pay more attention to their health, and are more expressive.
Similar to the preliminary studies, we found that underlying comorbidities were significantly associated with the presence of long-term symptoms, and those with pre-existing diseases reported more complaints (14, 15).
There was no association between age and remained symptoms in the current study. Conversely, in the Logue study (14), long-term complications were reported more frequently in the higher age groups. The age limits of our study (up to 60 years) can be the probable cause of different results.
Most infected patients with COVID-19 are asymptomatic or have mild symptoms. Therefore, measuring the exact prevalence of long COVID complications is not possible. The present study was performed only on hospitalized patients who had moderate to severe conditions and were expected to have a higher percentage of complications and complaints.
The current study did not assess the quality of life of patients. Their general health status was evaluated 6 months after COVID-19 infection, and the majority of the participants were in a good condition.
Our study had several limitations. It was a symptom-oriented assessment. We did not use objective evaluation, and the severity of reported symptoms was not assessed. However, symptoms were documented by a physician, and only reliable and significant symptoms were recorded after comprehensive history-taking. The relatively small sample size of the study may leave some associations undetected. Single-center design, the age limits, recall bias, and the exclusion of ICU-admitted patients and those with malignant comorbidities are other limitations. Moreover, this study was performed only on hospitalized patients and did not include outpatients. More extensive studies are required in order to better understand the epidemiology and clinical course of the long COVID condition.