Response to "Depression and Adherence to Antihypertensive Therapy"

Drug Side Effect Symptoms and Adherence to Antihypertensive Medication

BACKGROUND

Non-adherence to antihypertensive medication increases the risk of uncontrolled hypertension. Antihypertensive drug-related symptoms (side effects) are frequently cited as a main cause of non-adherence, but with little support from prospective studies. We evaluated the association between drug side effects and prospective adherence to treatment.

METHODS

We collected data on the number and dose of antihypertensive drugs at enrollment and at 3, 6, 9, and 12 months of follow-up in a cohort of 175 hypertensive patients starting or restarting antihypertensive treatment (mean age: 50 years; 58% women). During the follow-up visits, we gathered data on 24 side effects during the last month and the pill count adherence ratio (PCAR = pills taken out of number prescribed × 100) since the previous visit. The association between side effects at a visit and adherence through the next visit was estimated using mixed effect models.

RESULTS

Eighty-five percent of the participants experienced side effects, and 34.5% became non-adherent (PCAR <80%). After adjusting for confounders, PCAR was 6.0 percentage points lower (P = 0.04) among individuals with number of side effects above the median value (4 symptoms). Also, in individuals with genitourinary side effects, PCAR was 7.1 percentage points lower (P = 0.02) than in those without such side effects. Specifically, PCAR was 6.5 (P = 0.06) and 7.6 (P = 0.01) percentage points lower among individuals with excessive urination and decrease in sexual drive, respectively.

CONCLUSION

Antihypertensive drug side effects was associated with drug adherence but only excessive urination and decrease in sexual drive significantly predicted lower adherence. These symptoms could be used as markers to screen out patients at high risk of non-adherence.

Symptoms of depression and anxiety and adherence to antihypertensive medication

BACKGROUND

Nonadherence to drug treatment is a major contributor to antihypertensive treatment failure. Mood disorders could impair the patient's desire and ability to follow physician's recommendations. We evaluated the role of symptoms of depression and anxiety on adherence to antihypertensive drug treatment.

METHODS

We conducted a longitudinal cohort study in 20-70 years old patients starting antihypertensive drug treatment, without other chronic conditions, and not taking mood-modifying drugs. Severity of symptoms of depression and anxiety were evaluated at enrollment and 3, 6, 9, and 12 months of follow-up, using the Beck depression inventory-II (BDI-II) and the psychological general well-being index (PGWB), respectively. Treatment adherence was measured by pill count. Nonadherence was defined as taking <80% of the prescribed number of pills. Poisson regression was used to model the association of the exposures with adherence.

RESULTS

We enrolled 178 patients (58% male; mean age: 50 years; 508 follow-up visits). The risk of nonadherence was 52.6% in 12 months (95% confidence interval (CI): 46.1, 59.1). After adjusting for other risk factors, individuals with at least mild depression (BDI-II ≥14) and those with at least mild anxiety (PGWB anxiety score <22) were 2.48 (95% CI: 1.47, 4.18) and 1.59 (95% CI: 0.99, 2.56) times more likely to become nonadherent in the following 3 months, respectively.

CONCLUSIONS

Patients with at least mild anxiety and depression symptoms are at increased risk of becoming nonadherent to antihypertensive medication. Screening for depression and anxiety symptoms could be used to identify high-risk patients. Further evidence is needed to elucidate whether interventions targeting these conditions improve adherence.