Sliding scale insulin use in a national cohort study of nursing home residents with type 2 diabetes.

Background: Guidelines discourage sliding scale insulin (SSI) use after the first week of a nursing home (NH) admission. We sought to determine the prevalence of SSI and identify factors associated with stopping SSI or transitioning to another short-acting insulin regimen.

Methods: In an observational study from October 1, 2013, to June 30, 2017 of non-hospice Veterans Affairs NH residents with type 2 diabetes and an NH admission over 1 week, we compared the weekly prevalence of SSI versus two other short-acting insulin regimens - fixed dose insulin (FDI) or correction dose insulin (CDI, defined as variable SSI given alongside fixed doses of insulin) - from week 2 to week 12 of admission. Among those on SSI in week 2, we examined factors associated with stopping SSI or transitioning to other regimens by week 5. Factors included demographics (e.g., age, sex, race/ethnicity), frailty-related factors (e.g., comorbidities, cognitive impairment, functional impairment), and diabetes-related factors (e.g., HbA1c, long-acting insulin use, hyperglycemia, and hypoglycemia).

Results: In week 2, 21% of our cohort was on SSI, 8% was on FDI, and 7% was on CDI. SSI was the most common regimen in frail subgroups (e.g., 18% of our cohort with moderate-severe cognitive impairment was on SSI vs 5% on FDI and 4% on CDI). SSI prevalence decreased steadily from 21% to 16% at week 12 (p for linear trend <0.001), mostly through stopping SSI. Diabetes-related factors (e.g., hyperglycemia) were more strongly associated with continuing SSI or transitioning to a non-SSI short-acting insulin regimen than frailty-related factors.

Conclusions: SSI is the most common method of administering short-acting insulin in NH residents. More research needs to be done to explore why sliding scale use persists weeks after NH admission and explore how we can replace this practice with safer, more effective, and less burdensome regimens.