Nonadherence with immunosuppressive drugs: U.S. compared with European kidney transplant recipients.

BACKGROUND: System factors increasingly are suggested as important yet understudied correlates of nonadherence. OBJECTIVE: To explore the relationship between healthcare system and prevalence of nonadherence with immunosuppressive regimen by studying variation in nonadherence between European and US kidney transplant recipients and as well as nonadherence in European countries. METHODS: We performed a secondary data analysis on data collected in 3 independent cross-sectional studies using comparable methodology including patients from the United States, the Netherlands, Belgium, and Switzerland. Nonadherence was measured using 1 item of the Siegal questionnaire. Patients were categorized as nonadherent if they reported missing a dose of immunosuppression in the last 4 weeks. Analyses were performed by multiple mixed logistic regression, with center as a random effect and clinical and demographical differences between groups as fixed effects. RESULTS: 1563 U.S. and 614 European patients from 3 different countries (Belgium [n=187], the Netherlands [n=85], and Switzerland [n=342]) were included. Prevalence of nonadherence in the United States and Europe was 19.3% and 13.2.%, respectively. This higher nonadherence in US patients was confirmed in a multiple logistic regression analysis (OR = 1.78; 95% CI, 1.10-2.89). Nonadherence differed between Belgium (16%) and the Netherlands (14.1%) (OR = 0.27; 95% CI, 0.09-0.80) and between Belgium and Switzerland (11.4%; OR = 0.17; 95% CI, 0.0-0.42). CONCLUSION: This is the first study showing differences in prevalence of nonadherence between European and US patients and among European patients. Further research should aim at unraveling the dynamics explaining these differences.

Prevalence, consequences, and determinants of nonadherence in adult renal transplant patients: a literature review.

This literature review summarizes the evidence on the prevalence, determinants, clinical and economic consequences of nonadherence with immunosuppressive drugs in renal transplant patients. A literature search yielded 38 articles measuring nonadherence by self-report, collateral report, assay, refill prescriptions or electronic monitoring. The weighted mean prevalence of self-reported nonadherence was 28%. Nonadherence is associated with poor clinical outcomes, contributing to 20% of late acute rejection episodes and 16% of the graft losses (weighted means). In addition, nonadherence results in lower lifetime costs because of shorter survival, yet also in a lower number of quality adjusted life years. Consistent determinants of nonadherence were younger age, social isolation, and cognitions (e.g. low self-efficacy, certain health beliefs). Determinants concerning the health care system/team seem to be under-investigated. Because the evidence summarized in this review is based on older immunosuppressive regimens, further research should focus on prevalence, determinants and consequences of nonadherence with newer immunosuppressive regimens.

Prevalence and correlates of self-reported pretransplant nonadherence with medication in heart, liver, and lung transplant candidates.

BACKGROUND: Evidence on prevalence and correlates of pretransplant medication nonadherence (MNA) is limited. The present study explored self-reported prevalence and correlates of MNA before heart, liver, and lung transplantation. METHODS: This cross-sectional descriptive study included 174 patients: 69 lung, 33 heart, and 72 liver transplant candidates. MNA was assessed by self-report using the following question: "During the past 14 days, how often did you not take your medication?" Patients scoring once or higher on a five-point rating scale were considered to be nonadherent. Correlates of MNA explored were demographics, anxiety and depression (Hospital Anxiety and Depression Inventory), personality traits (NEO Personality Inventory-Revised), perceived health status (Euro-QOL), and social support (Social Support Questionnaire). RESULTS: Prevalence of pretransplant MNA was 16.7% and was comparable among the three groups. After correction for multiple comparisons (i.e., P=0.01), higher educational level (P=0.006) was related to MNA. Less severe depression (P=0.069), lower scores on the personality trait conscientiousness (P=0.021), and less received social support (P=0.062) tended to be related to MNA. Multiple logistic regression revealed that higher educational level (P=0.008), lower received social support (P=0.013), and lower conscientiousness (P=0.023) were independent predictors of pretransplant MNA. CONCLUSIONS: Several correlates of MNA allow identification of patients at risk for pretransplant MNA.