Population attributable fractions of modifiable risk factors for microvascular complications of type 2 diabetes in China: An analysis using national cross-sectional data

Aim: To assess the population attributable fractions (PAFs) for modifiable risk factors for microvascular complications of type 2 diabetes (T2D) in China. Materials and Methods: Data collected from the China National HbA1c Surveillance System from 2009 to 2013 were used. The PAFs of four predefined risk factors, including an HbA1c of 7% or higher, blood pressure (BP) of 130/80 mmHg or higher, low-density lipoprotein-cholesterol (LDL-C) of 1.8 mmol/L or higher and body mass index (BMI) of 24 kg/m² or higher, were calculated for diabetic microvascular complications, including diabetic retinopathy (DR), diabetic kidney disease (DKD) and distal symmetric polyneuropathy (DSPN). PAFs were further adjusted for age, sex and duration of diabetes. Results: In total, there were 998 379 participants with T2D from nationwide mainland China included in this analysis. As for DR, an HbA1c of 7% or higher, BP of 130/80 mmHg or higher, LDL-C of 1.8 mmol/L or higher and BMI of 24 kg/m² or higher conferred PAFs of 16.2%, 15.2%, 5.8% and 2.8%, respectively. In the case of DKD, BP of 130/80 mmHg or higher provided a PAF of 25.2%, followed by an HbA1c of 7% or higher (13.9%), BMI of 24 kg/m² or higher (8.0%) and LDL-C of 1.8 mmol/L or higher (5.6%). As for DSPN, an HbA1c of 7% or higher, BP of 130/80 mmHg or higher, LDL-C of 1.8 mmol/L or higher and BMI of 24 kg/m² or higher contributed to PAFs of 14.2%, 11.7%, 5.9% and 5.8%, respectively. PAFs for diabetic microvascular complications were mildly to moderately reduced after adjusting for participants' age, sex and duration of diabetes. Conclusions: Suboptimal glycaemic and BP control were the main contributors to diabetic microvascular complications, while the PAFs of unmet LDL-C and BMI control targets were quite limited for diabetic microvascular complications. In addition to glycaemic control, BP control should be especially prioritized in the management of diabetic microvascular complications to further reduce the disease burden.