Table 2.
Characteristics of eligible individuals when emulating a target trial of metformin vs. sulfonylurea initiators on the risk of death and dementia in the US RPDR (2007–2017) and the UK CPRD (2001–2017)
| US RPDR cohort (N = 13,191) | UK CPRD cohort (N = 108,025) | |||
|---|---|---|---|---|
| Patient characteristics | Metformin initiators (n = 11,229) | Sulfonylurea initiators (n = 1962) | Metformin initiators (n = 94,208) | Sulfonylurea initiators (n = 13,817) |
| Age at baseline (mean, years) | 68.6 | 72.2 | 64.9 | 70.2 |
| Sex (% male) | 49.2 | 52.9 | 57.4 | 58.3 |
| Race (percent) | ||||
| White | 78.2 | 83.4 | 86.5 | 87.0 |
| Black or African American | 7.6 | 5.4 | 3.6 | 3.0 |
| Asian | 4.4 | 3.7 | Data combined with Other | |
| Other | 9.8 | 7.5 | 9.9 | 10.0 |
| Ethnicity (% Hispanic) | 4.4 | 3.3 | Data not available | |
| Year of first prescription (median) | 2012 | 2012 | 2008 | 2003 |
| SES/IMDa (% low income/most deprived) | 3.1 | 1.8 | 17.3 | 17.5 |
| Cancer (%) | 30.2 | 28.7 | 9.9 | 12.4 |
| CVDb (%) | 42.8 | 44.4 | 53.8 | 50.8 |
| Hypertension (%) | 74.2 | 67.0 | 94.9 | 90.7 |
| COPD (%) | Data not available | 4.7 | 4.6 | |
| Smokera (%) | 17.0 | 18.7 | ||
| Strokeb (%) | 11.9 | 12.1 | Data combined with CVD | |
| Baseline HbA1C levela (percent) | ||||
| <7 (%) | 51.8 | 46.2 | 16.4 | 11.8 |
| 7–10 (%) | 42.0 | 47.9 | 69.1 | 65.3 |
| >10 (%) | 6.2 | 5.9 | 14.5 | 22.9 |
| Baseline BMIa (kg/m2) | ||||
| <25 (%) | 11.1 | 17.5 | 8.1 | 34.8 |
| 25–30 (%) | 29.5 | 36.0 | 32.9 | 43.5 |
| ≥30 (%) | 59.4 | 46.5 | 59.0 | 21.7 |
| All-cause mortality analysis outcomes | ||||
| Median follow-up time (years) | 5.3 | 5.3 | 6.0 | 7.0 |
| Total person-years | 63,060 | 11,047 | 592,948 | 103,777 |
| Deaths (n, %) | 527 (4.7) | 222 (11.3) | 12,941 (13.7) | 5173 (37.4) |
| Competing risk analysis outcomes | ||||
| Median follow-up time (years) | 5.0 | 5.0 | 6.0 | 7.0 |
| Total person-years | 60,683 | 10,508 | 592,072 | 103,209 |
| Deaths prior to dementia (n, %) | 415 (3.7) | 154 (7.8) | 11,560 (12.3) | 4,570 (33.1) |
| Incident dementia cases (n, %) | 869 (7.7) | 241 (12.3) | 5561 (5.9) | 1699 (12.3) |
BMI body mass index, COPD chronic obstructive pulmonary disease, CVD cardio-vascular disease, HbA1C glycosylated hemoglobin. IMD Index of Multiple Deprivation (official measure of relative deprivation by small geographic region in the UK).
aSES (US RPDR) and IMD (UK CPRD) are distinct, country-specific socioeconomic indicators, intended for comparison within—rather than across—the two cohorts. IMD, smoking status, HbA1C, and BMI had 7%, 2%, 21%, and 3% of missing values in the UK CPRD, respectively. The corresponding statistics presented in the table are valid percentages out of patients without missing information.
bStroke and CVD indicators were collapsed.