Determinants of perceived severity of hypertension and drug-compliance in hypertensive patients.

Background: Severity of illness is not an important determinant of drug-compliance. In this paper we hypothesize that the perceived severity of illness rather than the true severity of illness is a determinant of drug-compliance. If this is true, then it will be worthwhile for physicians to look for factors determining this perceived severity of illness.

Objectives: (I) To test in a prospective survey whether this hypothesis can be confirmed in mildly hypertensive patients, and (II) to identify factors determining their perceived severity of illness.

Methods: 450 patients were invited to participate in a prospective survey if their systolic blood pressure had been between 140 and 170 mm Hg and their diastolic blood pressure between 90 and 100 mm Hg despite treatment, for at least three clinic visits. Based on previously published data three factors possibly contributing to the perceived severity of hypertension were identified: (1) objective medical information, (2) expected physical symptoms, and (3) a positive social identification with fellow-patients. These factors were used as independent determinants in a multiple linear regression model with perceived severity of hypertension as outcome variable. Subsequently, this outcome variable together with patient characteristics was used as an independent variable in a multiple logistic regression model with drug-compliance as outcome variable.

Results: 176 patients, mean age 62 years, 52% females, completed the study. In the multiple linear regression analysis all of the three identified factors were statistically significant predictors of the perceived severity of hypertension with beta-values from 0.22 to 0.26, and p-values between 0.031 and 0.004. The multiple logistic regression analysis demonstrated that, after adjustment for gender, age, school, and general health status, the perceived severity of hypertension was a significant determinant of drug-compliance at p = 0.040.

Discussion: The present study shows what information patients use to conclude on the level of their blood pressure being too high or not. This information can be used to better understand the patients' ideas about health and possibly to influence these ideas. Patients' conclusion about the level of their blood pressure predicted their drug-compliance. Our study increased insight into the psychology of the patient and the results may be helpful to physicians in order to further understand and influence patient behaviors, particularly, adherence to antihypertensive medication.