HbA1c in a primary care cohort with diabetes and chronic kidney disease: the East and North Hertfordshire Institute of Diabetes and Endocrinology (ENHIDE) Diabetes Renal Telehealth Project

Abstract

Aim: Diabetes mellitus and chronic kidney disease (CKD) commonly co-occur. Control of glycaemia is nuanced, and should be individualised. The Diabetes Renal Telehealth Project identified 2,356 adults with diabetes and CKD, and evaluated determinants and patterns of HbA1c in order to identify under-treatment or potential over-treatment of glycaemia.Method: Comprehensive review of GP diabetes registers by the clinical investigators.Results: The study subjects (52% male, 48% female) were aged 77 years (range 19–103) with median estimated glomerular filtration rate 52 (range 3–171) mL/min and median albumin to creatinine ratio 34 (range <0.05–1428) mg/mmol. 81% were solely managed in primary care. Median HbA1c was 57 (range 10–148) mmol/mol (7.4% (3.1–15.7%)) and at the 58 mmol/mol target in 64%. Anaemia was present in 31%. 22% were solely on dietary management, 29% on insulin therapy (6 in 10 of whom were also on additional agents) and 19% were on sulfonylurea (8 in 10 of whom were on additional agents excluding insulin). Patterns of HbA1c over 2 years were stable for 44%, variable in 19%, rising in 12% and improved in 8%. The 13% initially considered at increased hypoglycaemic risk based on HbA1c measures alone had worse renal function and were more frequently anaemic (both p<0.0005), and 83% were treated with insulin and/or sulfonylureas. Hypoglycaemia hospital admissions were low with 10 people admitted over the study period. There was a reduction in age with increasing quintiles of HbA1c, and those with HbA1c >75 mmol/mol (9.0%) were youngest (mean age 68 years, p<0.001).Conclusions: The majority of people with diabetes and CKD are elderly and managed in primary care, with anaemia in 31%, potentially affecting HbA1c interpretation. Iatrogenic hypoglycaemic risk was identified in 10%, with suboptimal glycaemic control (HbA1c >9% (75 mmol/mol)) through under-treatment in 9%. This study uncovered unmet clinical need, requiring both escalation and de-escalation of glycaemic therapies.