The quantitative studies were survey-based with mainly cross-sectional designs and included: 13,476 patients with T2DM receiving insulin, aged 41–99 years; GPs (n = 4,176); diabetes consultants (2,192); general physicians (n = 166); general nurses (n = 51); Diabetes Specialist Nurses (DSNs) (n = 50); and diabetes educators (n = 100). This evidence concerns the gene INS and diabetes mellitus.