The burden of persistent COVID-19 symptoms appeared to improve over time, but a higher percentage of former patients reported poor health, compared with the general population. This suggests that some patients need more time to completely recover from COVID-19, wrote the authors of the new study, which wasin The Lancet Respiratory Medicine. Previous research has shown that the health effects of COVID-19 last for up to a year, but data from longer-term studies are limited, said Lixue Huang, MD, of Capital Medical University, Beijing, one of the study authors, and colleagues.
Methods and results
In the new study, the researchers reviewed data from 1,192 adult patients who were discharged from the hospital after surviving COVID-19 between Jan. 7, 2020, and May 29, 2020. The researchers measured the participants’ health outcomes at 6 months, 12 months, and 2 years after their onset of symptoms. A community-based dataset of 3,383 adults with no history of COVID-19 served as controls to measure the recovery of the COVID-19 patients. The median age of the patients at the time of hospital discharge was 57 years, and 46% were women. The median follow-up time after the onset of symptoms was 185 days, 349 days, and 685 days for the 6-month, 12-month, and 2-year visits, respectively. The researchers measured health outcomes using a 6-min walking distance (6MWD) test, laboratory tests, and questionnaires about symptoms, mental health, health-related quality of life, returning to work, and health care use since leaving the hospital.
Overall, the proportion of COVID-19 survivors with at least one symptom decreased from 68% at 6 months to 55% at 2 years (P < .0001). The most frequent symptoms were fatigue and muscle weakness, reported by approximately one-third of the patients (31%); sleep problems also were reported by 31% of the patients.
The proportion of individuals with poor results on the 6MWD decreased continuously over time, not only in COVID-19 survivors overall, but also in three subgroups of varying initial disease severity. Of the 494 survivors who reported working before becoming ill, 438 (89%) had returned to their original jobs 2 years later. The most common reasons for not returning to work were decreased physical function, unwillingness to return, and unemployment, the researchers noted.
However, at 2 years, COVID-19 survivors reported more pain and discomfort, as well as more anxiety and depression, compared with the controls (23% vs. 5% and 12% vs. 5%, respectively).
In addition, significantly more survivors who needed high levels of respiratory support while hospitalized had lung diffusion impairment (65%), reduced residual volume (62%), and total lung capacity (39%), compared with matched controls (36%, 20%, and 6%, respectively) at 2 years.
Approximately half of the survivors had symptoms of long COVID at 2 years. These individuals were more likely to report pain or discomfort or anxiety or depression, as well as mobility problems, compared to survivors without long COVID. Participants with long-COVID symptoms were more than twice as likely to have an outpatient clinic visit (odds ratio, 2.82), and not quite twice as likely to be rehospitalized (OR, 1.64).