12-month Respiratory Outcomes

Published in the Lancet "3-month, 6-month, 9-month, and 12-month respiratory outcomes in patients following COVID-19-related hospitalisation: a prospective study" by Wu et al looks lung events for patients admitted to hospital with Covid-19 who were not ventilated.


The consequences of COVID-19 in those who recover from acute infection requiring hospitalisation have yet to be clearly defined. We aimed to describe the temporal trends in respiratory outcomes over 12 months in patients hospitalised for severe COVID-19 and to investigate the associated risk factors.


In this prospective, longitudinal, cohort study, patients admitted to hospital for severe COVID-19 who did not require mechanical ventilation were prospectively followed up at 3 months, 6 months, 9 months, and 12 months after discharge from Renmin Hospital of Wuhan University, Wuhan, China. Patients with a history of hypertension; diabetes; cardiovascular disease; cancer; and chronic lung disease, including asthma or chronic obstructive pulmonary disease; or a history of smoking documented at time of hospital admission were excluded at time of electronic case-note review. Patients who required intubation and mechanical ventilation were excluded given the potential for the consequences of mechanical ventilation itself to influence the factors under investigation.

During the follow-up visits, patients were interviewed and underwent

  • physical examination

  • routine blood tests

  • pulmonary function tests (ie, diffusing capacity of the lungs for carbon monoxide [DLCO]; forced expiratory flow between 25% and 75% of forced vital capacity [FVC]; functional residual capacity; FVC; FEV1; residual volume; total lung capacity; and vital capacity) The DLCO measures the ability of the lungs to transfer gas from inhaled air to the red blood cells in pulmonary capillaries.

  • chest high-resolution CT (HRCT) - looks for long term lung damage

  • 6-min walk distance test - looks for desaturations on exertion

  • assessment using a modified Medical Research Council dyspnoea (shortness of breath) scale (mMRC).


Between Feb 1, and March 31, 2020, of 135 eligible patients, 83 (61%) patients participated in this study. The median age of participants was 60 years (IQR 52–66). Temporal improvement in pulmonary physiology and exercise capacity was observed in most patients however;

  1. Persistent physiological and radiographic abnormalities remained in some patients with COVID-19 at 12 months after discharge.

  2. A significant reduction in DLCO over the study period, with a median of 77% of predicted (IQR 67–87) at 3 months, 76% of predicted (68–90) at 6 months, and 88% of predicted (78–101) at 12 months after discharge.

  3. At 12 months after discharge, radiological changes persisted in 20 (24%) patients.

  4. The study showed increasing odds of impaired DLCO associated with female sex ( 8 times increased risk).


In most patients who recovered from severe COVID-19, dyspnoea scores and exercise capacity improved over time; however, in a subgroup of patients at 12 months we found evidence of persistent physiological and radiographic change. A unified pathway for the respiratory follow-up of patients with COVID-19 is required.

So these were the results for a group of patients hospitalised with severe Covid-19 and at 12 months there were still ongoing breathlessness. 20 % of them still had changes on their CT scan. Many had a reduction in the ability of their lungs to transport oxygen into the bloodstream and the risk of this occurring was 8 times greater in women.

Of course those with an acute Covid-19 infection during the first wave have been classed as mild cases if they were not admitted to hospital despite having similar findings to severe patients. I managed to find this classification from the NIH Covid-19 Treatment Guidelines:

Mild Illness: Individuals who have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell) but who do not have shortness of breath, dyspnea, or abnormal chest imaging.

Moderate Illness: Individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (SpO2) ≥94% on room air at sea level.

Severe Illness: Individuals who have SpO2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mm Hg, respiratory frequency >30 breaths/min, or lung infiltrates >50%.

I just wonder how many of us fell into the moderate to severe category? I myself had resting sats of 92 % and a CXR which showed a "pneumonia".

I also doubt very few of you, unless you have sought a private consultation, have managed to have the above respiratory investigations for your ongoing breathlessness despite your moderate/severe acute infection and have just been dismissed as having Long Covid or dysfunctional breathing with either no follow up at all or signposted towards breathing exercises.

The paper can be read here

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