Research led by University College London (UCL) and the University of Exeter examined the impact of long Covid on the lives of 3,754 people who were referred to a clinic for the illness.
As part of the study, patients were asked to answer questions on an app about how long Covid affects their day-to-day lives, giving a score of between 0 and 40 to indicate severity.
It found that average fatigue scores were similar or worse than for patients with cancer-related anaemia or severe kidney disease, and quality of life scores were also lower than those with advanced cancers.
Researchers also suggested that the impact of long Covid on the daily activities of patients is worse than that for stroke patients and was comparable to that of patients with Parkinson’s disease.
To be referred to a long Covid clinic, people must have continued symptoms 12 weeks after an acute coronavirus infection.
According to the NHS, the main markers of long Covid include extreme tiredness, shortness of breath, a loss of smell, and muscle aches.
Dr Henry Goodfellow, of UCL’s Institute of Epidemiology and Health, who co-led the study, said the impact of the condition is still not fully understood.
“Our results have found that long Covid can have a devastating effect on the lives of patients – with fatigue having the biggest impact on everything from social activities to work, chores and maintaining close relationships,” he said.
Researchers also said that long Covid could have a “significant economic and social impact”.
Of those people involved in the study, 94% were of “working age” (between 18 and 65), with 51% reporting that they had been unable to work for at least one day in the previous month.
Dr Goodfellow said: “We hope that a greater understanding of the symptoms and impact of long Covid in these patients will help the NHS and policymakers to target limited resources by adapting existing services and designing new ones to better meet the needs of patients with long Covid.
“Our findings show that fatigue should be an important focus for clinical care and the design of rehabilitation services.
“Post-Covid assessment services should consider focusing on assessing and treating fatigue to maximise the recovery and return to work for sufferers of long Covid.”
Co-author Professor William Henley, of the University of Exeter Medical School, said: “We urgently need more research to enable the development of evidence-based services to support people trying to manage this debilitating new condition.”