Potentially eligible patients will be:
- PCR or lateral flow COVID-19 positive SGSS (Second Generation Surveillance System) or NPEx (National Pathology Exchange). This will be confirmed by a Polymerase Chain Reaction (PCR) or Lateral Flow test within the therapeutic window in calendar days
- 12 years old minus the therapeutic window minus 1 calendar day (or older) for example if the therapeutic window is 3 days the patient will be 12 years old minus 2 days, or older
Detailing this, the principal output for the cohorts is that:
- patients are aged 12 minus the therapeutic window minus 1 calendar day or older, with one or more triggering comorbidity (see the lists below)
- each patient that goes into our process flow will be someone that has had a positive COVID-19 PCR or Lateral Flow test within the therapeutic window in calendar days
- this positive diagnosis will be indicated to us by SGSS Pillars 1, NPEX Pillar 2 COVID-19 testing data set, already present in Databricks
- the comparator days is based on NPEX's 'Specimen Processed Date' for Pillar 2. If 'Specimen Processed Date' is empty, then 'Test Start Date' will be used instead
- in Pillar 1 SGSS data, due to the increased potential for manual entry errors, the latest, non-future lab report date or specimen date will be used
As this piece of work relied heavily on linking data, the NHS Number was used as the main link, or index, key for the included datasets. In HES (Hospital Episode Statistics), if a patient’s NHS Number is not found in the GP data sets then it will be ignored to avoid false matching.
In addition, deceased patients were identified and removed from the final composite patient list by checking for the date of death in PDS (Personal Demographics Service). We accepted one or both informal and formal notification of death markers.
All cohorting is based on the run date of the process. For example, when we need to evaluate a patient's age, we will use their current age at the time of the process run. If we run the process and check the same patient the next day, their age may show up as one year older if it happens to be their birthday. The patient's age that we previously processed would still reflect the age they had on the day before.
We do not process based on time of day, except where it is necessary to establish determinism. For example, when we look at two competing items of data we should choose the same item on each run.
Patients will also:
- have positive PCR or Lateral Flow tests in either the NPEx (Pillar 2) or SGSS (Pillars 1) data sets
- need to be 12 years minus the therapeutic window minus 1 calendar day, or older
- have one or more qualifying condition
- have a positive test result within the therapeutic window in calendar days and the patient will not have had a previous positive test within the last 30 days
The rule logic for the last bullet point is to prevent a patient undergoing multiple triage assessments for the same illness due to positive results within one disease episode.
A patient will be included in the cohort if they have:
- a positive test yesterday, with no previous positive test - they would fall within the treatment window as the current period of infection started yesterday
- a positive test today, but also has a previous positive test 31 days before today - this is because the current period of infection started today, as the previous test is over 30 days before today
A patient will not be included in the cohort if they have:
- a positive test 10 days before today - they would be outside of the treatment window because the current period of infection started 10 days ago
- a positive test today, but also has positive test 14 days before today - they would be outside of the treatment window because the current period of infection started 14 days ago
- a positive test today, but also has a prior positive test 30 days before today - they would be outside of the treatment window because the current period of infection started 30 days before today
A patient will also not be included in the cohort if they have tested positive for COVID-19 today, as well as 14, 29, 43, and 50 days before today. We would identify the first period of infection as beginning 50 days ago and ending 20 days ago, thus disregarding the tests from 29 and 43 days ago. They would be outside of the treatment window because The start of the current period of infection would be identified as 14 days ago.
To determine if a patient is eligible for COVID-19 treatment, their test history is reviewed. For example, if a patient had positive tests today or 14 and 35 days before today, they would be considered for treatment as the current period of infection started today. Their prior positive tests show that they had a period of infection that started 35 days ago and ended 5 days ago. Today's positive test is seen as the start of a new period of infection.
Defining the highest risk clinical subgroups upon community infection with SARS-CoV-2 when considering the use of neutralising monoclonal antibodies (nMABs) and antiviral drugs (updated March 2023) - updated 5 April 2023