| Number of patients with diabetes in the study | Number of providers in the study | Outcome measures | Methods | Assessment | ||
---|---|---|---|---|---|---|---|
Selection bias | Study design | Confounders | |||||
LeBlanc et al. [36] | 83 580 | 583 | C | B | C | C | Partial evaluation |
Lippi Bruni et al. [37] | 164 574 | 2 938 | B | A | A | A | Full evaluation |
Iezzi et al. [6] | 164 574 | 2 990 | A | A | A | A | Full evaluation |
Yuan et al. [38] | 2 022 | n.r. | C | C | C | C | Partial evaluation |
Hsieh et al. [39] | 2 986 | n.r. | A | A | A | A | Full evaluation |
Pan et al. [40] | 396 838 | n.r. | B | A | A | A | Full evaluation |
Crawley et al. [41] | 1 173 | n.r. | C | B | C | C | Partial evaluation |
Millet et al. [42] | 154 945 | n.r. | C | A | C | C | Partial evaluation |