Markers of loss of control of hypertension.

OBJECTIVE To identify markers for loss of control of hypertension.

DESIGN Questionnaire administered to patients who had been monitored for 18 months and had had their blood pressure (BP) measured many times.

SETTING Fifty family practices in southeastern Ontario.

PARTICIPANTS Three hundred eighty-five adults with essential hypertension that was initially stable and controlled by medication.

MAIN OUTCOME MEASURES Change in BP (from baseline to mean of three measurements over 18 months) and proportion of patients with BP exceeding threshold values at most follow-up visits.

RESULTS Higher income was associated with an increase in diastolic BP; poor adherence to medication regimens and higher life stress were associated with increases in systolic BP Stress also led to a twofold increase in risk of exceeding BP thresholds. Other factors under study were not related to loss of control.

CONCLUSION Adherence to medication regimens, higher income, and life stress were the only factors associated with elevated BP or loss of control in previously controlled hypertension.