COVID Uncovered (part 5)
Lessons from an undisclosed NHS Trust
In part 3 of this miniseries I stumbled upon a most peculiar result - COVID patients who died in hospital within the NHS Trust under study over the period 1st Feb – 7th Dec 2020 were healthier than non-COVID cases! Modelling revealed incidence of chronic respiratory disease, pulmonary disease, acute myocardial infarction, cardiac arrhythmia, heart failure, other cardiac conditions, hypertension, organ failure, clotting, haemorrhage, sepsis and general inflammation to be less frequent in patients testing positive with COVID prior to death when we’d expect some of these to be more frequent. I thus went in search of an answer in part 4 using factor analysis, where a colourful but brain-bending table gave a possible clue – COVID deaths appeared to be inversely linked to cancer deaths.
This morning whilst my tea brewed I thought I’d run a simple crosstabulation to see if this assumption held true and indeed it does. Below is my audited COVID death indicator tabulated against an indicator for a cancer diagnosis and this plainly shows a marked difference between non-COVID death (31.8% are cancer-related), asymptomatic/mild+ COVID death (13.0% are cancer-related) and symptomatic/severe+ COVID death (14.1% are cancer-related)1. In terms of the crude odds ratio COVID deaths are around 2.3 – 2.4 times less likely to be cancer-related deaths and this may go a fair way to explaining why COVID deaths appear to be among a healthier cohort…
This is rather intriguing for we would assume cancer patients are more likely to be immunocompromised and more likely to visit hospital and thus at greater risk of nosocomial infection. Bizarrely, we observe the opposite! This calls for a fresh pot of tea and a search for a simple explanation.
Please note that the ‘+’ symbol in these variable names denotes presence of non-COVID respiratory diagnoses, so these should be viewed as multicausal deaths rather than pure COVID.