Reduction in adverse symptoms as blood pressure becomes controlled

To evaluate trends in adverse symptoms as blood pressure becomes controlled, and to determine if these symptoms are influenced by social support and self-efficacy.

Secondary analysis from a randomized controlled study of physician-pharmacist collaboration to improve blood pressure control.

Five university-affiliated primary care clinics.

A total of 179 patients (aged 21-85 yrs) with uncontrolled primary hypertension who were taking no antihypertensive drugs or up to three antihypertensive drugs at baseline were randomized to the intervention group, in which pharmacists were involved in their care, or to the control group, who received usual care from their physicians. Of these patients, 160 completed the study: 92 were in the intervention group, and 68 were in the control group.

In both groups, patient-reported symptoms suggestive of adverse drug reactions (ADRs) were recorded at each study visit with use of a structured ADR questionnaire. Social support and self-efficacy questionnaires were also administered at each study visit.

Patients' ADR scores decreased significantly from baseline to the end of the study in both the control (from a mean of 26.5 to 18.4) and intervention (from 29.9 to 22.7) groups (p<0.0001 for both comparisons), although no significant difference was noted between groups. The mean +/- SD number of antihypertensive drugs/patient increased in both the intervention (from 1.5 +/- 1.0 to 2.4 +/- 0.9 drugs) and control (from 1.4 +/- 1.0 to 1.9 +/- 1.0 drugs) groups; however, the difference between groups was significant only at the end of the study. Additional analyses were performed on self-efficacy and social support to determine a potential reason for the reduction in ADR scores despite an increase in drug use. Improvements in self-efficacy and social support scores were significantly and independently associated with improvement in ADR score (p<0.05).

In both groups, ADR scores improved despite an increase in antihypertensive drug use. Improvements in social support and, to a lesser extent, self-efficacy were associated with improvements in ADR scores. Patients should not expect an increase in distressful symptoms as their blood pressure becomes controlled with antihypertensive drugs, especially when adequate social support is available.