Number need to treat (NNT) to prevent cardiovascular event if diabetes and hypertension

Mortality and morbidity are increased in diabetes patients who do not achieve BP control (ie, a target value of less than 130/80 mm Hg) (1)

• large randomized controlled trials and meta-analyses of randomized controlled trials have shown that reducing BP pharmacologically is single-handedly the most effective way to reduce rates of death and disability in patients with diabetes, particularly associated cardiovascular risks

Pharmacologically reducing BP in people with diabetes is one of the most effective medical interventions available to prevent death and disability

• randomized controlled trials of BP-lowering treatments in people with diabetes have demonstrated substantial reductions in death, cardiovascular disease, eye disease, and kidney disease rates, and the benefits are accrued in a short time
  
  
  • in the Syst-Eur (Systolic Hypertension in Europe) trial, in which isolated systolic hypertension was clinically defined as having a systolic BP value of more than 160 mm Hg and a diastolic BP value of less than 90 mm Hg
    • active treatment reduced cardiovascular mortality by 76% (number needed to treat [NNT] was approximately 21 for 2 years' treatment) and all cardiovascular events by 67% (NNT approximately 13 for 2 years' treatment), with a reduction in BP of 9.8/3.8 mm Hg
      
      
  • in the diabetes subgroup of the HOT (Hypertension Optimum Treatment) trial, those who were assigned to a target diastolic BP of less than 80 mm Hg were compared with those assigned to a target BP of less than 90 mm Hg
    • achieved difference in BP values between the 2 groups at the end of the study was only 4 mm Hg, this greater reduction in BP levels still resulted in a 66% risk reduction of death from heart disease and stroke (NNT approximately 36 for 3.8 years' treatment)
      
      

Reference:

• Campbell NRC et al. Hypertension in people with type 2 diabetes Update on pharmacologic management.Can Fam Physician. 2011 Sep; 57(9): 997-1002.