Preferential adherence to immunosuppressive over nonimmunosuppressive medications in kidney transplant recipients

Successful kidney transplantation continues to be associated with an increased risk of death from cardiovascular disease. Treatment for hypertension, hyperlipidemia, and hyperglycemia adds to the pre-existing medication burden of immunosuppression. We postulated that patients are selectively adherent, preferentially taking some medications and choosing not to take others. To test this hypothesis, a random cross-sectional sample of outpatient kidney transplant recipients was interviewed by a person previously unknown to them using a structured closed-ended interview. Nonadherence was defined as missing any dose of medication over the preceding 1 month. By this criteria, 18.4% of patients were nonadherent to immunosuppressive medications, whereas 44.9% of patients were nonadherent to nonimmunosuppressive medication (antihypertensives, antidiabetic agents, and lipid-lowering agents). More patients were selectively nonadherent to their nonimmunosuppressive medications than to their immunosuppressive medications (P = .028). Patients who were nonadherent to nonimmunosuppressant medications were on a higher number of total medications and were more likely to be diabetic. We conclude that patients are more likely to miss or change doses of nonimmunosuppressive medications than immunosuppressive medications. The importance of nonimmunosuppressive medications must also be stressed at clinic visits to facilitate adherence to all classes of medication. Whether nonadherence to medications that treat cardiovascular risk factors contributes to the persistently high cardiovascular death rate in kidney transplant recipients remains to be determined.