[obpe]

Because high blood pressure can have many transient causes: caffeine, exercise, stress, dehydration, even high salt intake. Further, other diseases can also cause high blood pressure, such as diabetes, and Hypertension (high blood pressure) is also it's own disease.

[bell-cot]

Unless non-high blood pressure is rare, this looks like optimal code

   bp = TakeBloodPressure()
   IF( NotHigh( bp ) )
      THEN
         DONE
      ELSE
         InvestigateCause( bp )