Results from this large-scale survey of almost 240,000 patients throughout China demonstrated that, overall, patients with T2DM do not meet the treatment guideline set by the American Diabetes Association (ADA) and the Chinese Medical Society of an HbA1c <7%. More specifically, less than one third of individuals with type 2 diabetes using OADs, either alone or in combination with insulin or GLP-1 receptor agonists, achieved glycemic control as defined by HbA1c <7.0%. These results are comparable to those obtained in an earlier study that reported 39.7% of patients treated with OADs and/or insulin achieved HbA1c <7% . Because our objective was to characterize Chinese patients receiving OADs for T2DM in China, our analysis did not include patients treated with diet and lifestyle interventions alone or insulin without oral agents.
Glycemic control appeared to be greater among individuals treated with only OADs compared to those receiving more intensive therapy with OADs in combination with insulin. This, however, might be a function of duration of disease. Similarly, among patients using OADs in combination with insulin, glycemic control appeared to be greater among patients receiving prandial insulin alone, basal insulin alone, or insulin premixes compared with basal-bolus therapy, a more intensive intervention. This difference may represent an attempt to improve glycemic control in patients at higher HbA1c levels through the addition of more intensive insulin therapy.
It is also likely that the difference in glycemic control may result from differences in disease severity. This hypothesis is supported by several findings in our study. First, mean HbA1c generally increased and HbA1c goal achievement generally decreased with increasing diabetes duration. The exception in this trend occurred in patients with a diabetes duration of less than 1 year, possibly because the optimal treatment regimen had not yet been identified due to the recentness of the diagnosis. Both the association between glycemic control and diabetes duration, and the differences in glycemic control between individuals using OADs and those using insulin, have been reported in other observational studies, including a recent study of Chinese individuals with type 2 diabetes in the Jiangsu province . It also should be noted that differences in glycemic control among study groups were relatively small, suggesting that treatment was adjusted to accommodate the progressive hyperglycemia seen with advancing diabetes.
Because diabetes is a progressive disease, patients who have had a longer duration of diabetes are likely to have reduced beta-cell function and require more intensive therapy compared to patients with more recently diagnosed disease. In our study, patients using OADs plus insulin therapy had a longer history of diabetes than patients using OADs alone. This trend was apparent even among patients using only OADs: patients using 3 or more OADs had a longer duration of diabetes than patients using only one OAD.
The inverse association between disease severity and glycemic control is also supported by the prevalence of concomitant diseases and diabetes complications in the study. Patients using OADs plus insulin typically had a higher prevalence of complications and concomitant disease than patients using only OADs. Not surprisingly, the prevalence of complications and concomitant disease also increased with diabetes duration, a finding indicative of the association between duration of hyperglycemia and likelihood of adverse vascular effects.
Our study also demonstrated the positive impact of SMBG on glycemic control. Patients who performed SMBG had a lower mean HbA1c and a greater percentage of HbA1c goal achievement compared to patients who did not. Interestingly, patients who performed SMBG had a longer history of diabetes compared with those who did not. This may be due to the increased need for SMBG with the use of more intensive insulin regimens utilized by patients with more advanced disease. Nonetheless, these findings suggest that initiating SMBG may be one way to overcome the loss of diabetes control with diabetes progression despite the increased intensity of treatment.
This study has several limitations. First, this is a descriptive analysis of the results from patient interviews. No attempt was made to control for confounding factors, and statistical analyses of the data were limited. Results collected from patient interviews and self-reports are subject to bias; however, patient interviews are the most practical way of obtaining such information in China .