INS and neuropathy: In multivariable analysis adjusted by age and sex, the prevalence ratio of neuropathy was 1.4 times higher (95% CI 1.07–1.88) in patients who took insulin plus metformin compared to patients who used one treatment alone, and 1.4 higher (95% CI 1.02–1.93) in patients with ≥10 years of disease compared to those with a shorter duration of disease.