The overall level of current CVD risk for patients with diabetes was dangerously elevated in our sample, with a substantial level of variation observed across the primary care clinics studied. However, it appears that targeting modifiable risk factors can dramatically reduce this risk, as nearly one-third of baseline risk can possibly be addressed through attention to mutable factors or behavioural changes. This includes both clinical measures (eg, HbA1c
levels or blood pressure) and daily patient behaviour, such as diet modification or treatment adherence. Placing our findings in the context of previous studies, total CVD risk using a variety of algorithms has been found to be 21% to 31% in community settings; attributable risks looking at a finite number of factors ranged from 19% to 38%.16,17
Tanuseputro et al placed the absolute risk of CVD in Canadian patients with T2DM at 23%; no attributable risk was determined, but the prevalence of risk factors (eg, smoking status, HbA1c
levels, etc) fell within the range of our study.18
Findings were mixed regarding the contribution of specific risk factors, as HbA1c
levels have a greater effect on microvascular events while blood pressure has a greater influence on macrovascular events.19
Others have documented that behavioural factors are more important20
; however, although diet management can effectively target weight reduction and metabolic concerns, such efforts might do little to change attributable CVD risk.21
It should be noted though that reducing attributable risk through any means yields quality-of-life benefits other than just CVD risk reduction.22
At the community level, this risk reduction in CVD would translate to a substantial number of preventable CVD events or other serious complications. These measurable clinical outcomes are accompanied by important gains in overall quality of life, along with tremendous savings in treatment costs. Jiang and colleagues estimated that improved primary care could save nearly $2.5 billion annually by reducing preventable hospitalizations arising from diabetes complications.23
Despite the high absolute CVD risk, the substantial proportion observed here to be modifiable is a sanguine finding, as interventions to enhance care coordination and patient behaviour have been demonstrated to yield dramatic benefits in improving quality of care and outcomes. For example, the chronic care model suggests that certain clinic structures and care processes (eg, organizational support, community care linkages) can assist providers and patients in better managing chronic illnesses, which should improve clinical outcomes.24
Previous studies have determined that the presence of chronic care model characteristics is associated with better quality of care and substantial reductions in attributable CVD risk.25,26
The findings of our study are limited by the fact that the cohort was recruited from regional community clinics in the United States caring for a high prevalence of Hispanic patients. Yet the clinical issues raised here and interventions targeting substantial risk factors are generalizable to many treatment settings and patient populations. Notwithstanding the post-hoc examination of missing data, we also acknowledge the possibility of some selection bias resulting from the exclusion of 25% of the original cohort. Finally, although we used a powerful theoretical framework and frequently cited self-management variables, the analyses did rely upon patient survey information and self-reported behaviour to estimate CVD risk.
Specialized efforts to recognize populations at high risk of suboptimal diabetes management are needed to tailor primary care interventions and to direct limited clinical resources. In addition to patient-level behavioural factors that influence the development of CVD events, provider and system factors play important roles in reducing the tremendous burden experienced across health care organizations. For example, given a 20% prevalence rate of diabetes within the US Department of Veterans Affairs system, the risk reduction observed in this study would translate into approximately 25 000 avoidable CVD events and 10 000 avoidable deaths among veterans every year (as per separate author analysis). The individual and cumulative benefits of minimizing preventable diabetes complications should not be underestimated.