The PCR Test As A Predictor Of Acute Respiratory Conditions (part 1)
I utilise data from an unknown NHS Trust to determine the real-world value of a COVID-19 diagnosis in the EPR of in-hospital deaths
In part 11 of ‘Do COVID Vaccines Work?’ I promised to have a think how best to proceed given the ambiguity inherent in COVID designation prior to death. That’s a fancy way of saying that the COVID-Dx indicator variable I have been relying on is a pile of tripe without the benefit of onion sauce. I first looked at this issue in relation to my sample of in-hospital deaths in Catastrophic Health Collapse (part 7) back in April 2023 where we discovered a peculiar propensity for asymptomatic COVID death during the pandemic first wave, these being people who tested positive but never developed an acute respiratory phase. I had thought I’d undertaken a bit of modelling to investigate matters more deeply but it transpired that I hadn’t… hence today’s article and the beginning of a new mini-series.
Essentially what I am about to do is flip the logistic regression modelling process on its head and try to predict onset of acute respiratory conditions prior to death using a few basic demographics to level the playing field followed by the COVID-Dx indicator variable. We’ll then have a better idea of whether this variable is a plate of pure tripe or tripe served with boiled potatoes and some healthy green veg. I realise that not all acute respiratory conditions are going to be the result of SARS-COV-2 infection and thus the data will be peppered with true negatives but let’s just see how the analysis pans out…
Data Sample
A total of 19,857 in-hospital deaths aged 18 years and over were present in the EPR data dump for the period 2020/w10 - 2021/w38 and the weekly frequency of these is present in the following slide:
The dashed grey lines mark three periods that I elected to serve in split file analysis mode, these being 2020/w10 – 2020/w40 (n=7,420), 2020/w41 – 2021/w20 (n=8,980) and 2021/w21 – 2021/w36 (3,252). Deaths tail-off dramatically after week 36 owing to administrative delays hence the cut-off at 2021/w36.
We ought to pile straight in with a simple crosstabulation of acute respiratory conditions against COVID-19 diagnosis for all periods combined: