Table 1.

Description of variables (cohort identification, outcomes, covariates)

Variable	Data source	Description	Value
Cohort: COVID-19 status
Cause of admission	SMR01/RAPID	Suspected or confirmed	ICD10 codes: U07.1, U07.2
PCR test result	ECOSS	COVID-19 test result (within 28 days prior to admission)	Categorical: positive, negative, unavailable
Primary outcome: medication use
Drug name	HEPMA	Drugs of interest: Dexamethasone, remdesivir, tocilizumab*	Character (name, according to dm +d)
Drug dose	HEPMA	Prescribed and administered	Numeric (mg, ml)
Prescribed date	HEPMA	First prescribed date: index date	Date (yyyy-mm-dd)
Administered date	HEPMA	Dates of drug administration	Date (yyyy-mm-dd)
Duration of treatment†	HEPMA	(first—last administered date)‡	Numeric (days)
Treatment changes†	HEPMA	Changes in dosing and/or drug	Categorical: yes, no
Secondary outcomes
Hospital specialty	SMR01	At admission	Character (name)
Specialty changes†	SMR01	Internal transferals during stay	Categorical: yes, no
ICU/HDU	SICSAG	Admission to intensive care	Categorical: yes, no
Discharge: alive	SMR01	Outcome of hospital episode	Categorical: home, w/family, care facility, other hospital
Discharge: dead	SMR01, NRS	Outcome of hospital admission (In-hospital mortality)	Categorical: yes, no Cause: ICD-10 codes
Death	NRS	Overall mortality (after discharge)	Categorical: yes, no Cause: ICD-10 codes
Length of stay§	SMR01	Duration of in-hospital stay	Numeric (days)
Covariates: sociodemographic
Age†	GP extract	Patient age at index date	Numeric (years)
Sex	GP extract	Biological sex at birth	Categorical: male, female
Health board	GP extract	Patient place of residence at admission	Categorical: A&A, D&G, Forth Valley, Lanarkshire, Lothian;
Data zone	GP extract	Patient place of residence	Categorical
SIMD	GP extract	Level of deprivation, based on data zone of residence	Categorical: 1 (most) to 5 (least deprived)
Covariates: disease (severity) related
COVID-19 vaccination status	GP extract/ TVMT	Status at hospital admission	Categorical: unvaccinated, vaccinated once, twice
Level of care	SICSAG/ SMR01	Admission to ICU; level of care received while at ICU	Categorical: yes, no Categorical: ACP levels 0–3
Supporting medication	HEPMA	Therapeutics prescribed and administered during in-hospital stay	Character (name, according to dm +d)
Covariates: comorbidities and concomitant medication
Other causes of admission	SMR01	Conditions underlying or attributing to hospital admission	ICD-10 codes
Comorbidities	GP extract/ SMR01	Pre-existing conditions	READ codes, ICD-10 codes
Charlson score†41	SMR01	Estimated based on secondary care data (historic hospital episodes)	Numeric
Concomitant medication	PIS	Potential proxy for comorbidities; specific drugs of interest	Character (name, according to the BNF)
Polypharmacy †	PIS	Based on number of different drugs prescribed simultaneously	Categorical: yes, no

*Cut-off dates to exclude patients who have been treated as part of a clinical trial, if no trial flag participation available in the dataset: remdesivir 29 May 2020; dexamethasone 16 June 2020; tocilizumab 8 January 2021.

†Denotes derived variables.

‡Adding discharge/outpatient prescribing if patient discharged prior to end of treatment regimen (if available).

§Can be derived if variable not readily available in dataset (date of discharge—first date of admission).

A&A, Ayrshire & Arran; ACP, augmented care period; BNF, British National Formulary; D&G, Dumfries & Galloway; dm+d, dictionary of medicines and devices; ECOSS, Electronic Communication of Surveillance in Scotland; GP, General Practice; HDU, high-dependency unit; HEPMA, Hospital Electronic Prescribing and Medicines Administration; ICD-10, International Classification of Diseases, 10th Edition; ICU, intensive care unit; NRS, National Records of Scotland; PIS, prescribing information system; RAPID, rapid preliminary in-patient data; SICSAG, Scottish Intensive Care Society Audit Group; SIMD, Scottish Index of Multiple Deprivation; SMR01, Scottish Morbidity Records, in-patient dataset; TVMT, Tuas Vaccine Management Tool.