Table 2

Characteristics of the individuals with type 1 diabetes (T1D) and their controls for the three studies

VariableOriginal studyNational analysis 1National analysis 2
ControlsT1DControlsT1DControlsT1D
N2573 (100%)862 (100%)114 790 (100%)38 523 (100%)223 995 (100%)77 392 (100%)
Admission (within 28 days)120 (5%)86 (10%)3735 (3%)3422 (9%)8665 (4%)8263 (11%)
Age (years)39.0 (17.0)39.4 (17.4)40.3 (18.0)40.5 (18.2)38.6 (18.3)38.9 (18.4)
Sex (is male)1349 (52.4%)454 (52.7%)58 290 (50.8%)19 655 (51.0%)117 304 (52.4%)40 722 (52.6%)
Townsend score (higher is more deprived)0.9 (3.7)0.9 (3.6)−0.1 (3.6)−0.2 (3.5)0.0 (3.6)−0.1 (3.5)
Townsend quintile (higher is more deprived)
1 (least deprived)447 (17%)135 (16%)24 210 (21%)7889 (21%)46 237 (21%)15 612 (20%)
2364 (14%)126 (15%)23 891 (21%)8335 (22%)46 173 (21%)16 372 (21%)
3430 (17%)150 (17%)22 092 (19%)7686 (20%)42 955 (19%)15 548 (20%)
4564 (22%)202 (23%)21 294 (19%)7340 (19%)42 809 (19%)15 136 (20%)
5 (most deprived)768 (30%)249 (29%)23 303 (20%)7273 (19%)45 821 (21%)14 724 (19%)
Latest BMI value27.9 (6.2)27.2 (5.8)27.9 (6.7)27.4 (6.1)27.6 (6.8)27.0 (6.1)
Latest LDL cholesterol value2.9 (0.9)2.5 (1.0)2.9 (0.9)2.4 (0.9)2.9 (0.9)2.4 (0.9)
Latest HDL cholesterol value1.4 (0.4)1.4 (0.4)1.4 (0.4)1.5 (0.5)1.4 (0.4)1.5 (0.4)
Latest eGFR value82.3 (13.8)80.5 (18.1)81.1 (13.7)80.3 (19.4)80.6 (14.2)79.7 (20.3)
Latest HbA1c value34.5 (8.8)67.6 (22.7)36.5 (4.2)66.8 (18.8)36.4 (4.2)67.3 (19.2)
Latest total cholesterol value5.0 (1.0)4.6 (1.1)5.0 (1.1)4.5 (1.1)5.0 (1.1)4.5 (1.1)
Current smoking status
Non-smoker1800 (70%)593 (69%)98 551 (86%)32 924 (86%)191 091 (85%)65 661 (85%)
Smoker773 (30%)269 (31%)16 239 (14%)5599 (15%)32 904 (15%)11 731 (15%)
Patient has asthma430 (17%)149 (17%)19 453 (17%)6583 (17%)35 532 (16%)12 782 (17%)
Patient has COPD41 (2%)21 (2%)1659 (1%)599 (2%)2940 (1%)1112 (1%)
Patient has severe mental illness41 (2%)21 (2%)921 (1%)387 (1%)1757 (1%)761 (1%)
Patient has hypertension257 (10%)197 (23%)11 965 (10%)8580 (22%)20 990 (9%)15 869 (21%)
Patient is on ACEI178 (7%)210 (24%)5590 (5%)6805 (18%)9716 (4%)12 537 (16%)
Patient is on aspirin52 (2%)91 (11%)2417 (2%)3351 (9%)4098 (2%)6182 (8%)
Patient is on clopidogrel27 (1%)37 (4%)1038 (1%)1215 (3%)1922 (1%)2361 (3%)
Patient is on metformin9 (0%)117 (14%)224 (0%)4133 (11%)347 (0%)7418 (10%)
Hospital length of stay (days)3.8 (8.6)5.2 (8.2)2.8 (8.2)4.0 (9.2)2.6 (9.1)3.8 (10.3)
Ethnicity
White1731 (67%)650 (75%)95 942 (84%)34 755 (90%)185 136 (83%)69 364 (90%)
Asian334 (13%)73 (9%)8977 (8%)1701 (4%)17 233 (8%)3373 (4%)
Black54 (2%)26 (3%)3113 (3%)869 (2%)6649 (3%)1950 (3%)
Mixed46 (2%)10 (1%)2128 (2%)610 (2%)4524 (2%)1346 (2%)
Other91 (4%)33 (4%)2497 (2%)455 (1%)5325 (2%)969 (1%)
Unknown317 (12%)70 (8%)2133 (2%)133 (0%)5128 (2%)390 (1%)
  • ‘Original study’ is the original published study from Greater Manchester with data from 1 January 2020 up to 31 May 2021. ‘National analysis 1’ is the first replication analysis using COVID-19 test data from the primary care data feed. ‘National analysis 2’ is the second replication analysis using the Second-Generation Surveillance System for the COVID-19 test results. The national analysis was on data from 1 January 2020 to 31 December 2022. Values are presented as either ‘mean (SD)’ or ‘count (percentage)’.