Based on data published from China in 44, 672 patients [Wu Z et al. 2020]:
- 2.3% case fatality in all patients
- 14.8% case fatality in patients 80 years or older
- 14% of all patients had severe disease (hypoxemic, tachypneic)
- 5% were critical (respiratory failure, septic shock)
Based on recent data published from Italy [Onder G et al. 2020]:
- Case fatality rate: 7.2% [all comers].
- If age over 80: 20% case fatality.
- Approximately 12% of all cases are admitted to intensive care units.
Case fatality rate is a number in which it is very difficult to have significant confidence. Some of the reasons are discussed in this summary article. [Battegay M, et al. 2020]
Admissions to the ICU
- Patients are usually admitted to ICU due to respiratory failure, many of whom will progress to acute respiratory distress syndrome (ARDS).
- A subset of those patients will develop shock and multi-organ dysfunction syndrome.
- A smaller proportion of patients will also develop cardiomyopathy with severe impairment of cardiac function.
What is ARDS?
ARDS is a syndrome of diffuse lung inflammation causing hypoxia refractory to ward level support.
Generally accepted criteria
- Acute onset, meaning onset over 1 week or less, AND
- bilateral opacities consistent with pulmonary edema must be present and may be detected on CT or chest radiograph, AND
- PaO2/FiO2 ratio < 300 mmHg with a minimum of 5 cm H20 PEEP (or CPAP), AND
- must not be fully explained by cardiac failure or fluid overload, in the physician’s best estimation using available information.
The average time from the onset of initial symptoms to ARDS in COVID is about 8 days.
Prognosis in Critically Ill
Some patients are at significantly increased risk of respiratory failure and death. [Yang et al., 2020] This seems to be consistent across a number of studies:
- cardiovascular disease
- chronic lung disease
- chronic kidney disease)
Age seems to be especially important as patients get to be over 70 years of age with reported mortality exceeding 70% in this population [ICNARC Database].
- Once a patient is intubated, the mortality of that patient population is difficult to extrapolate from available data although several investigators are working on estimating this risk as we speak.
- If the patient is intubated, our best estimate of mortality is between 35 and 74%, with most studies reporting mortality rates in intubated patients in the higher end of that range.
- Typical ARDS (non-COVID) has a mortality rate of about 35-45%.
When information on prognosis is important for an individual patient to make decisions or the decision is challenging, we recommend seeking multidisciplinary input from the physician that knows the patient best and specialists in infectious diseases and critical care.