Health care registers can be instrumental for endpoint capture in clinical diabetes trials: example of microvascular complications in Swedish patients with type 2 diabetes

Abstract

Aims SMARTEST is a register-based randomized clinical trial (RRCT) that compares dapagliflozin to metformin in early-stage type 2 diabetes. The primary outcome includes progression of microvascular complications based on data from the Swedish National Diabetes Register (NDR). In this sub-study, the aim was to validate microvascular complication variables in the NDR against electronic health records (EHRs). Methods Data were extracted from EHRs of 276 SMARTEST participants with a median observation period of 3 years in the Uppsala, Örebro and Sörmland counties and compared with NDR data. Agreement was determined for all corresponding data entries as well as for progression of microvascular complications after randomization. Results The agreement for all corresponding data entries was 98.9% (Intraclass Correlation Coefficient 0.999) for creatinine and eGFR, 95.1% for albuminuria, 91.6% for foot-at-risk and 98.2% for retinopathy status (Kappa 0.67-0.91). The agreement for progression of microvascular complications was 98.0% for CKD stage, 98.9% for albuminuria grade, 96.3% for foot-at-risk grade and 99.6% for retinopathy grade progression (Gwet’s AC1 0.96-1.00). Conclusion Microvascular complication variables in the NDR show good agreement with EHR data. The use of a well-established national health care registry, exemplified by the NDR, for endpoint collection in RRCTs such as SMARTEST is supported by this study.

Diabetic retinopathy among the elderly with type 2 diabetes: A Nationwide longitudinal registry study

“…Data reported to NDR includes risk factors associated with long-term diabetes complications such as level of glycated haemoglobin (HbA1c), systolic blood pressure (SBP), lipid profile, diabetes duration, type of glucose-lowering treatment, type of diabetes, presence and severity of DR and nephropathy. Recently, DR status was validated as an endpoint capture in the NDR with excellent agreement between the registry and electronic health records (Lundqvist et al, 2023). The wide span of reported variables in the registry allows for in-depth analyses, in turn facilitating the description of trends and changes in prevalence and the description of DR incidence and factors known to be associated with DR. Over the study period, NDR reported an average yearly coverage of 84.6% of all PwD in Sweden (Nationella Diabetesregistret, 2017).…”