Illness Perception and Medication Adherence Trajectories in Patients with Acute Coronary Syndrome: A 6-Month...

To investigate the trajectories of illness perception and medication adherence in patients with acute coronary syndrome, as well as the predictive relationship between the two.

A total of 311 patients with acute coronary syndrome (ACS) were recruited from the Department of Cardiology, The Second Affiliated Hospital of Chongqing Medical University, using convenience sampling. Participants were assessed at three time points: T1 (within 1 week post-admission), T2 (3 months post-onset), and T3 (6 months post-onset). Data were collected using the Brief Illness Perception Questionnaire (BIPQ) and the Medication Adherence Rating Scale (MARS). Cross-lagged panel modeling (CLPM) and parallel latent growth modeling (LGM) were constructed to analyze the causal relationship between illness perception and medication adherence.

A total of 287 valid questionnaires were returned (valid response rate: 92.28%). From baseline (T1) to 6-month follow-up (T3), illness perception scores significantly decreased from 61.71 ± 7.05 to 36.59 ± 6.56 (F=41.667, P<0.001), while medication adherence scores declined from 6.92 ± 0.89 to 6.02 ± 1.13 (F=35.223, P<0.001). Cross-lagged analysis revealed significant reciprocal relationships: illness perception at each time point positively predicted subsequent medication adherence (T1→T2: β=0.425, P<0.01; T2→T3: β=0.389, P<0.001), and vice versa (T1→T2: β=0.430, P<0.001; T2→T3: β=0.427, P<0.001). Parallel latent growth modeling indicated that higher initial levels of illness perception negatively predicted its own slope (β=-0.306, P=0.012) and the slope of medication adherence (β=-0.318, P=0.024). Similarly, the intercept of medication adherence negatively predicted its own slope (β=-0.301, P=0.012). Furthermore, the slope of illness perception positively predicted the slope of medication adherence (β=0.329, P=0.002).

The illness perception and medication adherence of patients with acute coronary syndrome are on the rise, and illness perception and medication adherence can predict each other.