| Characteristic | Nmissing values | Mean (SD) |
| Age, years | 6 | 68.3 (11.1) |
| | Categories | N(%) |
| Recruitment source | General practitioner | 64 (15.1) |
| Postal invite | 359 (84.9) |
| Sex | Male | 243 (57.5) |
| Female | 179 (42.3) |
| Missing | 1 (0.2) |
| Ethnicity | White | 385 (91.0) |
| South Asian | 21 (5.0) |
| Black | 8 (1.9) |
| Other | 6 (1.4) |
| Missing | 3 (0.7) |
| Time since type 2 diabetes diagnosis | < 12 months | 19 (4.5) |
| 1 to 3 years | 29 (6.9) |
| 4 to 10 years | 146 (34.5) |
| > 10 years | 220 (52.0) |
| Missing | 9 (2.1) |
| HbA1c measured in the last 12 months | Yes | 392 (92.7) |
| No | 13 (3.1) |
| Do not know | 16 (3.8) |
| Missing | 2 (0.5) |
| HbA1c result, mmol/mol | ≤ 53 (≤ 7%) | 136 (32.2) |
| 54–69 (7.1–8.5%) | 82 (19.4) |
| 70–86 (8.6–10.0%) | 19 (4.5) |
| ≥ 87 (≥ 10.1%) | 8 (1.9) |
| Missing | 178 (42.1) |
| Diabetes medication | None (diet and lifestyle) | 97 (22.9) |
| DPP-IV | 7 (1.7) |
| GLP-I | 1 (0.2) |
| Insulin | 24 (5.7) |
| Metformin | 145 (34.3) |
| SGLT-2 | 1 (0.2) |
| Sulphonylurea | 10 (2.4) |
| Multiple diabetes medications | 121 (28.6) |
| Other | 0 (0.0) |
| Missing | 17 (4.0) |
| Ever referred to SSME | No | 158 (37.4) |
| Yes | 241 (57.0) |
| Do not know | 14 (3.3) |
| Missing | 10 (2.4) |
| Date of SSME referral | ≤ 1 year | 55 (13.0) |
| > 1 year | 166 (39.2) |
| Do not know | 5 (1.2) |
| Missing | 197 (46.6) |
| Ever attended group SSME | No | 211 (49.9) |
| Yes | 190 (44.9) |
| Missing | 22 (5.2) |
| Type of SSME attended | N/A | 233 (55.1) |
| Unknown | 20 (4.7) |
| DESMOND | 72 (17.0) |
| Juggle | 53 (12.5) |
| Tonic | 1 (0.2) |
| Other | 21 (5.0) |
| Missing | 22 (5.2) |
| Date of SSME attendance | ≤ 1 year | 29 (6.9) |
| > 1 year | 116 (27.4) |
| Missing | 278 (65.7) |
| Re-invited if did not attend | No | 128 (30.3) |
| Yes | 11 (2.6) |
| Missing | 284 (67.1) |
| Reason for not attending SSME | Lack of information | 2 (0.5) |
| Lack of perceived benefit | 16 (3.8) |
| Unsuitable time | 5 (1.2) |
| Suitable transport unavailable | 3 (0.7) |
| Othera | 33 (7.8) |
| Rather not say | 1 (0.2) |
| Missing | 363 (85.8) |
| Ever attended one-to-one SSME | No | 372 (87.9) |
| Yes | 21 (5.0) |
| Do not know | 15 (3.6) |
| Missing | 15 (3.6) |
| Ever attended online SSME | No | 403 (95.3) |
| Yes | 8 (1.9) |
| Do not know | 2 (0.5) |
| Missing | 10 (2.4) |
| Would you attend SSME if invited? | No | 99 (23.4) |
| Yes | 299 (70.7) |
| Missing | 25 (5.9) |
| Reason for not wanting to attend if invited | Lack of information | 1 (0.2) |
| Lack of perceived benefit | 24 (5.7) |
| Unsuitable time | 3 (0.7) |
| Suitable transport unavailable | 9 (2.1) |
| Otherb | 44 (10.4) |
| Rather not say | 1 (0.2) |
| Missing | 341 (80.6) |
| Preferred format | Group | 103 (24.4) |
| One-to-one | 122 (28.8) |
| Online | 64 (15.1) |
| Group/one-to-one | 39 (9.2) |
| Group/online | 9 (2.1) |
| One-to-one/online | 7 (1.7) |
| Any | 12 (2.8) |
| Missing | 67 (15.8) |
