Glycemic control and disability‐free survival in hypoglycemic agent‐treated community‐dwelling older patients with type 2 diabetes mellitus

Abstract

Aim Although lower glycated hemoglobin (HbA 1c ) has been believed to be an important marker of improvement of glycemic control in order to maintain better quality of life for patients with diabetes mellitus, a too low HbA 1c might be harmful in older adults. We investigated whether this was the case with respect to risk of support/care‐need certification in community‐dwelling older patients with type 2 diabetes mellitus. Methods We analyzed 184 diabetes patients aged 65–94 years receiving glucose‐lowering medication/insulin. The end‐points were first support/care‐need certification and/or death. The relationships between four classes of HbA 1c and risk of support/care‐need certification and/or death were determined using the Cox proportional hazards regression model. Results During 5 years, 42 first support/care‐need certifications and 13 deaths occurred. The association of HbA 1c with risk of support/care‐need certification after adjustment for age, sex and confounding variables was J‐shaped, with the nadir at an HbA 1c level of 6.5 to <7.0%, and with an increased risk of support/care‐need certification (HR 3.45, 95% CI 1.02–11.6, P = 0.046) at an HbA 1c level of <6.0% compared with the nadir. When compared with patients with HbA 1c ≥6.0%, those with HbA 1c <6.0% showed a higher risk of support/care‐need certification as a result of dementia (HR 12.5, 95% CI 3.00–52.2, P = 0.001), but not as a result of arthralgia/fracture, stroke or other disorders. Conclusions These observations show that a too low HbA 1c might be associated with a later risk of incident disability as a result of dementia in community‐dwelling older diabetes patients. Geriatr Gerontol Int 2017; 17: 1858–1865 .