A longitudinal assessment of adherence with immunosuppressive therapy following kidney transplantation from the Mycophenolic Acid Observational REnal Transplant (MORE) study.

BACKGROUND

Nonadherence with immunosuppressive therapy after renal transplantation is a major clinical concern, but longitudinal data are sparse. Adherence data were recorded during the Mycophenolic Acid Observational REnal Transplant (MORE) study to help inform compliance management decisions.

MATERIAL AND METHODS

Prospective data were analyzed from the four-year, observational MORE study of de novo adult renal transplant recipients receiving mycophenolic acid (MPA) as enteric-coated mycophenolate sodium (EC-MPS) or mycophenolate mofetil (MMF) at 40 US sites under routine management. Adherence was assessed using the Immunosuppressant Therapy Adherence Scale (ITAS): total score 0-12 (12, adherence; <12, nonadherence). A logistic regression model was used to identify factors associated with nonadherence.

RESULTS

In total, 808/946 recipients (85.4%) provided ≥1 ITAS score. Nonadherence was reported by 24.8%, 31.5%, 33.0%, 39.8%, 35.4% and 26.4% at months 3, 6, 12, 24, 36 and 48, respectively. Mean ITAS score was higher with EC-MPS vs. MMF at months 24 (11.3[1.0] vs. 10.9[1.4], p=0.001) and 36 (11.4[1.0] vs. 11.1[11.3], p=0.024). The odds ratio for nonadherence was 1.60 (95% CI 1.17, 2.19; p=0.003) for African Americans vs. non-African Americans. The rate of biopsy-proven acute rejection was 12.7% (51/401) in nonadherent recipients vs. 11.3% (46/406) in adherent recipients (p=0.59); graft loss was 4.7% (19/402) vs. 3.0% (12/406) (p=0.20); death was 1.5% (6/402) vs. 4.7% (19/406) (p=0.013).

CONCLUSIONS

Adherence to the immunosuppressive regimen decreases over time, highlighting the need to monitor and encourage adherence even in long-term maintenance kidney transplant patients. Other than African American race, demographic factors may be of limited value in predicting nonadherence.