Individual and Combined Relationship between Reduced eGFR and/or Increased Urinary Albumin Excretion Rate with Mortality Risk among Insulin-Treated Patients with Type 2 Diabetes in Routine Practice

Abstract

A low estimated glomerular filtration rate (eGFR) and an increased urinary albumin-to-creatinine ratio (ACR) are well-recognised prognostic markers of cardiovascular (CV) risk, but their individual and combined relationship with CV disease and total mortality among insulin-treated type 2 diabetes (T2D) patients in routine clinical care is unclear. Methods: We analysed data for insulin users with T2D from UK general practices between 2007 and 2014 and examined the association between mortality rates and chronic kidney disease [categorised by low eGFR (< 60 mL/ min/1.73 m2), high eGFR (=60 mL/min/1.73 m2), low ACR (< 300 mg/g); and high ACR (=300 mg/g) at insulin initiation] after a 5-year follow-up period using Cox proportional hazard models. Results: A total of 18,227 patients were identified (mean age: 61.5 13.8 years, mean HbA1c: 8.6 1.8%). After adjusting for confounders, when compared to adults on insulin therapy with an eGFR < 60 and an ACR =300 (low eGFR + high ACR) after a follow-up period of 5 years, patients with an eGFR < 60 and an ACR < 300 (low eGFR + low ACR) had a 6% lower mortality rate (aHR: 0.94; 95% CI 0.79-1.12); those with an eGFR > 60 and an ACR =300 (high eGFR + high ACR) had a 20% lower mortality rate (aHR: 0.80; 95% CI 0.68- 0.96); and those with an eGFR > 60 and an ACR < 300 (high eGFR + low ACR) had the lowest death rate (28% less; aHR: 0.72; 95% CI 0.59-0.87). Conclusion: This study shows that among a large cohort of insulin-treated T2D patients in routine practice, the combination of reduced eGFR with increased ACR was associated with the greatest risk of premature death, followed closely by those with reduced eGFR and normal ACR levels. Adoption of aggressive CV risk management strategies to reduce mortality in patients with a low eGFR and albuminuria is essential in high-risk patients with T2D.