BackgroundAmong kidney transplant recipients, non-adherence with immunosuppressive medications frequently precedes allograft loss. We sought to determine the prevalence and correlates of medication non-adherence among kidney transplant recipients.MethodsWe performed a single-center, cross-sectional study of kidney transplant recipients who were at least 6 months post-transplant. We measured self-reported adherence using the Immunosuppressive Therapy Adherence Scale (ITAS, which is scored from 0 to 12, where higher scores indicate increased adherence) and barriers to adherence using the Immunosuppressive Therapy Barriers Scale (ITBS). We also used validated scales to measure perceived stress, health literacy, anxiety, depression, and interpersonal support.ResultsThe 252 patients included in the study were 59.9% male, 27.0% Black, and at a median of 2.9 years post-transplant (interquartile range [IQR] 1.4-5.8). On the ITAS, 59.1% scored a perfect 12, 26.6% scored 10–11, and 14.3% scored 0–9. In univariate models, non-adherence (defined as ITAS score ≤9) was significantly associated with increased scores on scales for perceived stress (OR 1.12, 95% CI 1.01-1.25) and depression (OR 1.14, 95% CI 1.02-1.28), and with more self-reported barriers to adherence on the ITBS (OR 1.15, 95% CI 1.08-1.22). After adjusting for sociodemographic factors, stress and depression were not associated with non-adherence. Higher scores on the ITBS (corresponding to more self-described barriers to adherence) were associated with lower scores on the ITAS (P < 0.001). Several individual barriers were associated with non-adherence.ConclusionsAmong prevalent kidney transplant recipients, a minority is non-adherent. Practical barriers to adherence may serve as promising targets for future interventions.

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Introduction. Whether changes in adherence are associated with changes in HbA1c is assumed but not known. Methods. We conducted a observational study of 2,844 type 2 diabetes patients who initiated metformin as their first antihyperglycemic drug. Using HbA1c measures before, 6–12 months after, and up to 3 years after metformin initiation, we analyzed HbA1c change as a function of initial adherence and change in adherence. Results. Compared with no adherence, initial adherence of 50–79% was associated with an adjusted reduction in HbA1c of 0.45% while adherence ≥80% was associated with HbA1c reduction of 0.73%. Change from some initial adherence (1–79%) to total nonadherence was associated with 0.25% increase in HbA1c. Change from some to full adherence was associated with an HbA1c decrease of 0.15%. Those associations were accentuated among patients not in glycemic control: change from some to no adherence was associated with an HbA1c increase of 0.63% and change from some to full adherence was associated with an HbA1c decrease of 0.40%. Conclusions. Initial adherence to newly prescribed metformin therapy produces substantial HbA1c reduction. Among those with modest adherence but suboptimal glycemic control, the difference between moving to full adherence versus nonadherence results in lower HbA1c of one percentage point.

AimsThe aim of this study was to examine the relationship between a specific glycated haemoglobin (HbA1c) measurement and a pharmaceutical dispensings‐based measure of adherence calculated over the 90 days before each HbA1c measure among patients who have newly initiated metformin therapy.MethodsWe identified 3109 people with type 2 diabetes who initiated metformin as their first‐ever antihyperglycaemic drug, analysing all 9918 HbA1c measurements that were taken over the next 2 years. We used an adaptation of the ‘proportion of days covered’ method for assessing medication adherence that corresponded to an ∼90‐day interval preceding an HbA1c measurement, terming the adaptation the ‘biological response‐based proportion of days covered’ (BRB‐PDC). To account for multiple observations per patient, we analysed the association between HbA1c and BRB‐PDC within the generalized estimating equation framework. Analyses were stratified by HbA1c level before metformin initiation using a threshold of 8% (64 mmol/mol).ResultsAfter multivariable adjustment using 0% adherence as the reference category, BRB‐PDC in the range 50–79% was associated with HbA1c values lower by −0.113 [95% confidence interval (CI) −0.202, −0.025] among patients with pre‐metformin HbA1c <8%, and by −0.247 (95% CI −0.390, −0.104) among those with HbA1c ≥8% at metformin initiation. Full adherence (≥80%) was associated with HbA1c values lower by −0.175% (95% CI −0.257, −0.093) and by −0.453% (95% CI −0.586, −0.320).ConclusionsUsing this novel short‐interval approach that more closely associates adherence with the expected biological response, the association between better adherence and HbA1c levels was considerably stronger than has been previously reported; however, the strength of the impact was dependent upon the HbA1c level before initiating metformin.

Aims/IntroductionDipeptidyl peptidase‐4 inhibitors (DPP‐4i) are a common first‐line treatment for type 2 diabetes in Japan. However, little is known about patients’ medication adherence, persistence and discontinuation in this setting.Materials and MethodsThis was a retrospective cohort study of new DPP‐4i users in a Japanese claims database. Adult patients (age 18–65 years) with type 2 diabetes diagnosis and no diagnosis of other diabetes or pregnancy during the study period were included if they were prescribed a DPP‐4i as monotherapy or combination oral therapy. Adherence to therapy was measured using the proportion of days covered method over a fixed period of 1 year. The proportion of days covered of ≥80% was considered adherent. Persistence was defined as continuing index DPP‐4i treatment with <90‐day gap between refills. Patient baseline characteristics were explored as potential predictors of DPP‐4i discontinuation and adherence in multivariable models.ResultsThe final sample contained 2,874 monotherapy and 3,016 dual therapy patients. The mean age was approximately 51 years, and 75% were men. The mean proportion of days covered was 76.6% among monotherapy patients and 82.5% among dual therapy patients, with 67.2% of monotherapy and 74.4% of dual therapy patients classified as adherent. At 12 months, 72.2% of monotherapy and 79.2% of dual therapy patients were persistent. In adjusted models, younger age and having fewer concomitant medications were significantly associated with lower adherence and higher discontinuation, in both treatment groups.ConclusionsThose under the age of 45 years, and those with fewer concomitant medications were less likely to be adherent and persistent, and more likely to discontinue DPP‐4i therapy.