Patients with type 2 diabetes who have well controlled risk factors have little or no excess risk of stroke, myocardial infarction (MI) or death, a retrospective cohort study has found.

Data from the Swedish National Diabetes Register recorded between 1998 and 2012 were analysed. Overall, 271,174 patients with type 2 diabetes were included in the study along with 1,355,870 matched controls.

The mean age of the patients was 60.6 years and around half were women. The end points were death from any cause; MI; stroke; and hospitalisation for heart failure. The last three categories included both fatal and non-fatal events.

The populations were stratified with respect to five risk factors: elevated HbA1c, elevated LDL-cholesterol, albuminuria, smoking and elevated blood pressure (BP).

It is worth noting that the HbA1clevel considered for a zero risk was

5.74-6.68% - rather tighter than would be considered safe on some oral hypoglycaemic regimens.

Cox regression statistical analysis was used to examine the relationship between these risk factors and the end points.

During a median follow-up period of 5.7 years there were 175,345 deaths, 37,825 patients with diabetes (13.9%) and 137,520 controls (10.1%).

Type 2 diabetes patients with no risk factor variables outside the target ranges had only a marginally higher risk of death than the controls; hazard ratio (HR) 1.06 (95% CI: 1.0-1.12).

The hazard ratios for MI and stroke were HR 0.84 (95% CI: 0.75-0.93) and HR 0.95 (95% CI: 0.84-1.07) respectively.

However, the excess risk of heart failure was substantially higher compared with controls, HR 1.45 (95% CI: 1.34-1.57)

There was a stepwise increase in the hazard ratios for each additional variable that did not meet the target range in patients with diabetes.

The strongest predictor for death was smoking and the strongest predictor for MI and stroke was raised HbA_1c.

Previous individual risk factor controlled trials have shown reductions in cardiovascular outcomes and deaths, and the Steno-2 study confirmed long-term reductions in mortality and morbidity from lifestyle and drug interventions.¹

This study shows that effective control of risk factors can reduce the excess risk of cardiovascular events and death to that of individuals without diabetes.

An accompanying editorial comments that the results ‘provide clear support for active management of risk factors.’2 In my opinion, the results are further support for the intensive lifestyle interventions currently being considered with new onset diabetes, and vigorous treatment of risk factors in established cases. The low HbA^1c targets will add to the debate about hypoglycaemia risks.

Dr Matthew Lockyer