Impact of number of medications and age on adherence to antihypertensive medications

Abstract

This study tried to investigate the effects of number of medications and age on antihypertensive medication adherence in a real-world setting using a nationwide representative cohort. We obtained data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) of Korea, which is a sample of 2.2% (N = 1,048,061) of total population (N = 46,605,433). Patients aged 20 years or older (N = 150,550) who took antihypertensive medications for at least 1 year were selected. Medication possession ratio (MPR) was used for measuring adherence. The subjects were divided into 5 subgroups according to total number of medications: 1–2, 3–4, 5–6, 7–8, and 9 or more. The mean age and the mean number of medications were 60.3 ± 12.6 years and 4.1 ± 2.2, respectively. The mean MPR was 80.4 ± 23.9%, and 66.9% (N = 100,645) of total subjects were adherent (MPR ≥ 80%). The overall tendency of antihypertensive medication adherence according to the total number of medications displayed an inverted U-shape with a peak at 3–4 drugs. Adherence consistently increased as the age increased until age 69 and started to decrease from age 70. The proportion of adherent patients (MPR ≥ 80%) according to the total number of medications also showed an inverted U-shape with a peak at 3–4 drugs. When the same number of drugs was taken, the proportion of adherent patients according to age featured an inverted U- shape with a peak at 60 to 69 years. Patients taking 9 or more total drugs had the overall odds ratio (95% CI) of non-adherence (MPR < 80%) with 1.17 (1.11–1.24) compared with those taking 1 to 8 total drugs and the odds ratios in the age subgroups of 40 to 49, 50 to 59, 60 to 69 years were 1.57 (1.31–1.87), 1.21 (1.08–1.36), and 1.14 (1.04–1.25), respectively (P < .05). Association between age, total number of medications, and antihypertensive adherence displayed an inverted U-shape with a peak at 3 to 4 total medications and at age 60 to 69 years. When the total number of drugs was 9 or more, adherence decreased prominently, regardless of age.

<p>Group-Based Trajectory Modeling to Identify Patterns of Adherence and Its Predictors Among Older Adults on Angiotensin-Converting Enzyme Inhibitors (ACEIs)/Angiotensin Receptor Blockers (ARBs)</p>

“…The study findings indicate that patients below 65 had lower adherence. Although the association between age and adherence is mixed with some studies reporting an inverted U-shaped association, 54 our results are consistent with studies that report that medication adherence is positively associated with increasing age. [55][56][57][58] Potential reasons could include an increased disease burden with older adults as compared to younger adults which could lead to increased awareness of their overall health status, an increased perceived risk of hypertension, and a quicker acceptance of their diagnosis.…”

“…[55][56][57][58] Potential reasons could include an increased disease burden with older adults as compared to younger adults which could lead to increased awareness of their overall health status, an increased perceived risk of hypertension, and a quicker acceptance of their diagnosis. 54,55,59 Further, male patients had a higher likelihood of being in the RD trajectory as compared to the adherent trajectory. Prior research has demonstrated a higher adherence among females as compared to males on anti-hypertensive treatment [60][61][62] which illustrates the need to explore sex-specific barriers to medication adherence among older adults on ACEI/ARBs.…”

An Update on Medication Use in Older Adults: a Narrative Review

“…Unsurprisingly, as the number of drugs prescribed to older adults increases, so too do issues with adherence. Increasing age is not necessarily a predictor of non-adherence, although adherence is more likely to be lowest in older age categories of older adults [81,82]. There is greater recognition that adherence is a complex health behaviour with multifaceted determinants [83], and as a result, careful thought is needed when planning how to resolve barriers to adherence.…”

Association between multiple sclerosis disease severity and adherence to disease-modifying therapies

“…31 Statistical analyses demonstrated similar findings in multiple studies regarding adherence and age, with higher adherence being associated with increased age. 19,36,37 This may be related to increased awareness of health status with older age; 38 however, the association between older age and adherence is not well understood. 37 Sex was not determined to be associated with adherence.…”