A Causal Model of Adherence to Therapeutic Regimens Among Older Adults with Hypertension

Abstract

Adherence to therapeutic regimens among older adults with hypertension results in appropriate blood pressure control. Knowledge of factors affecting adherence behaviors are needed to enhance adherence to therapeutic regimens among older adults with hypertension. A descriptive, cross-sectional, predictive correlational design was used to identify and test a causal relationship between cognitive function, physical function, social support from family, provider-patient communication, knowledge of hypertension, perceived benefits, perceived susceptibility, perceived severity, perceived barriers, perceived self-efficacy to adherence and adherence to therapeutic regimens among older adults with hypertension. A total of 341 hypertensive older adults with hypertension aged between 60-88 years were randomly selected from five hypertension clinics at community hospitals in Phayao Province, Thailand. All self-reported questionnaires with acceptable reliability coefficients were used to collect data. Data were analyzed using descriptive statistics, Pearson’s product moment correlation and path analysis by structural equation modeling.

The findings indicated that: 1. Perceived self-efficacy to adherence had a high positive relationship with adherence to therapeutic regimens. Perceived susceptibility, perceived severity, and social support from family had a moderate positive relationship with adherence to therapeutic regimens. Provider-patient communication and perceived benefits had a low positive relationship with adherence to therapeutic regimens. Cognitive function had a low negative relationship with adherence to therapeutic regimens. However, physical function, knowledge of hypertension and perceived barriers had no significant relationship with adherence to therapeutic regimens. 2. The causal model of adherence to therapeutic regimens showed the best fit with the empirical data (X^2 = 23.73, df = 16, p = .10, RMSEA = 0.038, GFI = .99, AGFI =.95, CFI = .98, SRMR = 0.037). The model explained 60% of the total variance in adherence to therapeutic regimens. Physical function (p < .05), perceived self-efficacy to adherence, perceived severity, provider-patient communication, and social support from family had a positive direct effect on adherence to therapeutic regimens (p < .01), whereas perceived barriers had a direct negative effect on adherence to therapeutic regimens (p < .01). Social support from family had a positive indirect effect on adherence to therapeutic regimens (p < .01) via perceived self-efficacy to adherence, provider-patient communication, perceived susceptibility, perceived severity, knowledge of hypertension, and perceived barriers. Perceived susceptibility (p < .01) and perceived barriers (p < .05) had a positive indirect effect on adherence to therapeutic regimens via perceived self-efficacy to adherence, while, cognitive function had a negative indirect effect on adherence to therapeutic regimens (p < .01) via perceived self-efficacy to adherence, knowledge of hypertension and perceived barriers. Provider-patient communication had a positive indirect effect on adherence to therapeutic regimens (p < .01) via knowledge of hypertension, perceived barriers, perceived self-efficacy to adherence, perceived susceptibility and perceived severity. Knowledge of hypertension had an indirect effect on adherence to therapeutic regimens via perceived barriers and perceived self-efficacy to adherence. Perceived benefits had no direct and indirect effect on adherence to therapeutic regimens, but it was affected by provider-patient communication and social support from family (p<.01). The results of the study indicate that to promote adherence to therapeutic regimens among older adults with hypertension, nurses should be aware of factors affecting adherence to therapeutic regimens and modify these predicting factors.