Medication adherence and visit-to-visit variability of systolic blood pressure in African Americans with chronic kidney disease in the AASK trial

Cardiovascular Precision Medicine and Remote Intervention Trial Rationale and Design

Background: It has recently been shown that excessive fluctuation in blood pressure readings for an individual over time is closely associated with poor outcomes, including increased risk of cardiovascular mortality, coronary heart disease and stroke. Fluctuations may be associated with inconsistent adherence to medical recommendations. This new marker of risk has not yet been incorporated into a monitoring and intervention strategy that seeks to reduce cardiovascular risk by identifying patients through an algorithm tied to their electronic health record (EHR). Methods: We describe the methods used in an innovative "proof of concept" trial using CP&R (Cardiovascular Precision Medicine and Remote Intervention). A blood pressure variability index is calculated for clinic patients via an EHR review. Consenting patients with excessive variability are offered a remote intervention aimed at improving adherence to medical recommendations. The outcomes include the ability to identify and engage the identified patients and the effects of the intervention on blood pressure variability using a pre-post comparison design without parallel controls. Conclusions: Our innovative approach uses a recently identified marker based on reviewing and manipulating EHR data tied to a remote intervention. This design reduces patient burden and supports equitable and targeted resource allocation, utilizing an objective criterion for behavioral risk. This study is registered under ClinicalTrials.gov Identifier: NCT05814562.

Impact of seasonal blood pressure changes on visit-to-visit blood pressure variability and related cardiovascular outcomes

BACKGROUND

Visit-to-visit blood pressure (BP) variability associates with an increased risk of cardiovascular events. We investigated the role of seasonal BP modifications on the magnitude of BP variability and its impact on cardiovascular risk.

METHODS

In 25 390 patients included in the ONTARGET and TRANSCEND trials, the on-treatment systolic (S) BP values obtained by five visits during the first two years of the trials were grouped according to the month in which they were obtained. SBP differences between winter and summer months were calculated for BP variability quintiles (Qs), as quantified by the coefficient of variation (CV) of on-treatment mean SBP from the five visits. The relationship of BP variability with the risk of cardiovascular events and mortality was assessed by the Cox regression model.

RESULTS

SBP was approximately 4 mmHg lower in summer than in winter regardless of confounders. Winter/summer SBP differences contributed significantly to each SBP-CV quintile. Increase of SBP-CV from Q1 to Q5 was associated with a progressive increase in the adjusted hazard ratio (HR) of the primary endpoint of the trials, i.e. morbid and fatal cardiovascular events. This association was even stronger after removal of the effect of seasonality from the calculation of SBP-CV. A similar trend was observed for secondary endpoints.

CONCLUSIONS

Winter/summer SBP differences significantly contribute to visit-to-visit BP variability. However, this contribution does not participate in the adverse prognostic significance of visit-to-visit BP variations, which seems to be more evident after removal of the BP effects of seasonality from visit-to-visit BP variations.

The improving Medication Adherence in Adolescents and young adults following Liver Transplantation (iMALT) multisite trial: Design and trial implementation considerations

BACKGROUND/AIMS

Medication non-adherence is a leading cause of transplant rejection, organ loss, and death; yet no rigorous controlled study to date has shown compelling clinical benefits from an adherence-improving intervention. Non-adherent patients are less likely to participate in trials, and therefore, most studies enroll a majority of adherent patients who do not stand to benefit from the intervention, as they do not have the condition (non-adherence) under investigation. The improving Medication Adherence in adolescent Liver Transplant recipients trial specifically targets non-adherent patients to investigate whether a remote intervention to improve adherence results in reduced incidence of biopsy-confirmed rejection.

METHODS

Improving Medication Adherence in adolescent Liver Transplant is a randomized single-blind controlled multisite, multinational National Institutes of Health-funded trial involving 13 pediatric transplant centers in the United States and Canada. An innovative, objective adherence biomarker-the Medication Level Variability Index, which is the standard deviation of a series of medication blood levels for each patient, is used to identify non-adherent patients at risk for rejection. The index is computed using electronic health record information for all potentially eligible patients based on repeated reviews of the entire clinic's roster. Identified patients, after consent, are randomized to intervention versus control (treatment as usual) arms. The remote intervention is delivered for 2 years by trained interventionists who reside in various locations in the United States. The primary outcome is the incidence of biopsy-confirmed acute cellular rejection, as confirmed by a majority vote of three pathologists who are masked to the study allocation and clinical information.

DISCUSSION

Improving Medication Adherence in adolescent Liver Transplant includes several innovative design elements. The use of a validated, objective adherence index to survey a large cohort of transplant recipients allows the teams to avoid bias inherent in both convenience sampling and referral-based recruitment and enroll only patients whose computed index indicates substantially increased risk of rejection. The remote intervention paradigm helps to engage patients who are by definition hard to engage. The use of an objective, masked medical (rather than behavioral) outcome measure reduces the likelihood of biases related to clinical information and ensures broad acceptance by the field. Finally, monitoring for potential adverse events related to increased medication exposure due to the adherence intervention acknowledges that a successful intervention (increasing adherence) could have detrimental side effects via increased exposure to and potential toxicity of the medication. Such monitoring is almost never attempted in clinical trials evaluating adherence interventions.

Association between nebuliser therapies adherence and visit-to-visit variability of FEV1 in patients with cystic fibrosis

At the same level of lung function, some patients with cystic fibrosis have large variations in their FEV1 percent predicted (FEV1pp) values while others have stable values. We hypothesised that lower adherence to nebuliser therapies was associated with higher FEV1pp variability. We conducted a post hoc analysis of the ACtiF trial data. Adherence was calculated using data from data-logging nebulisers, and FEV1pp variability using the coefficient of variation equation. Amongst the 543 patients included in the analysis, those poorly adherent (adherence < 50%) had a higher FEV1pp variability than patients moderately (50 to < 80%) and highly adherent (≥ 80%), with median values (IQR1-3) of 8.1% (4.9-13.7), 6.3% (3.9-9.8), and 6.3% (3.9-9.3) respectively (p < 0.01). This result was confirmed by a multiple linear regression including adherence as a continuous variable (p < 0.01). Further studies are needed to determine the implications of these differences in FEV1pp variability on the prognosis of patients.

Is the Association between Herbal Use and Blood-Pressure Control Mediated by Medication Adherence? A Cross-Sectional Study in Primary Care

Herbs have been used worldwide for many health conditions as an alternative treatment, including hypertension. Their use might affect the use of conventional medications, as well as blood-pressure control. This study aims to determine whether the potential associations between herb use and high blood pressure in hypertensive patients was mediated by medication adherence. A cross-sectional study was conducted using questionnaires and available medical databases at a primary care clinic of a tertiary hospital in Chiang Mai, Thailand. The data were collected from 450 patients with essential hypertension. Drug adherence was assessed by the Morisky Green Levine Medication Adherence Scale. The history of herbs used in the past three months was obtained. The goal of controlled blood pressure was defined in accordance with the Thai guidelines on the treatment of hypertension. Of the total 450 patients, 42% had high adherence. Nearly 18% reported herb use in the past three months. High medication adherence was strongly associated with blood-pressure control when adjusted for age, gender, education, the presence of comorbidities, and herb use (aOR 26.73; 95% CI 8.58–83.23; p < 0.001). The association between herb use and blood-pressure control did not achieve statistical significance (p = 0.143). However, the adjusted odds ratio of the association between herb use and blood-pressure control was diluted from 0.67 to 0.83 when adding the factor of medication adherence to the model. In conclusion, herb use was associated with poor medication adherence, which was in turn associated with poor blood-pressure control. Assessing this information contributes to appropriate exploration and counseling.

Preoperative and Intraoperative Blood Pressure Variability Independently Correlate with Outcomes

BACKGROUND

Blood pressure variability (BPV) describes visit-to-visit blood pressure (BP) changes independent of hypertension. Preoperative BPV and intraoperative BPV are associated with increased postoperative outcomes. We investigated the impact of both preoperative BPV and intraoperative BPV on elective surgical outcomes, specifically whether preoperative BPV and intraoperative BPV were independent risk factors for surgical complications.

MATERIALS AND METHODS

We investigated 600 patients undergoing elective surgery lasting more than two h and who had ≥8 outpatient BP recordings over three preoperative years. Age, sex, ethnicity, BMI, current medical problems, and medications at time of surgery were recorded. BPV was calculated as the standard deviation (SD) of systolic or diastolic BP for the 369 valid patients. Average BPV were compared between adverse outcomes of readmission, wound infection, acute kidney injury, death, myocardial infarction, and cerebral vascular accident.

RESULTS

Three-hundred-sixty-nine (52.6% male, 47.4% female, 98.1% non-Hispanic) patients (mean age 62.5) were included in the study. Preoperative systolic (P = 0.043) and diastolic (P = 0.009) BPV were higher for patients with the combined endpoint of all adverse events. Preoperative systolic BPV was correlated with intraoperative BPV (P = 0.010). Both systolic and diastolic preoperative BPV was found to be independent from intraoperative BPV. Otolaryngology procedures were associated with less adverse outcomes (P = 0.034), whil antimicrobials (P = 0.022), autonomic drugs (P < 0.001), or respiratory drugs (P = 0.032) was associated with an increased likelihood of adverse outcome.

CONCLUSION

Preoperative DBPV is associated with increased risk of readmission, wound infection and the combined endpoint of all adverse events. Intraoperative systolic blood pressure variability (SPBV) is associated with increased risk of acute kidney injury and the combined endpoint of all adverse events. Preoperative DBPV and intraoperative SBPV are independent risk factors for ninety-d postoperative outcomes. BPV should be considered in individualized risk assessment when assessing patient eligibility for elective procedures.

Age-Specific Associations of Usual Blood Pressure Variability With Cardiovascular Disease and Mortality: 10-Year Diabetes Mellitus Cohort Study

Background

The detrimental effects of increased variability in systolic blood pressure (SBP) on cardiovascular disease (CVD) and mortality risk in patients with diabetes mellitus remains unclear. This study evaluated age‐specific association of usual SBP visit‐to‐visit variability with CVD and mortality in patients with type 2 diabetes mellitus.

Methods and Results

A retrospective cohort study investigated 155 982 patients with diabetes mellitus aged 45 to 84 years without CVD at baseline (2008–2010). Usual SBP variability was estimated using SBP SD obtained from a mixed‐effects model. Age‐specific associations (45–54, 55–64, 65–74, 75–84 years) between usual SBP variability, CVD, and mortality risk were assessed by Cox regression adjusted for patient characteristics. After a median follow‐up of 9.7 years, 49 816 events (including 34 039 CVD events and 29 211 mortalities) were identified. Elevated SBP variability was independently, positively, and log‐linearly associated with higher CVD and mortality risk among all age groups, with no evidence of any threshold effects. The excess CVD and mortality risk per 5 mm Hg increase in SBP variability within the 45 to 54 age group is >3 times higher than the 70 to 79 age group (hazard ratio, 1.66; 95% CI, 1.49–1.85 versus hazard ratio, 1.19; 95% CI, 1.15–1.23). The significant associations remained consistent among all subgroups. Patients with younger age had a higher association of SBP variability with event outcomes.

Conclusions

The findings suggest that SBP visit‐to‐visit variability was strongly associated with CVD and mortality with no evidence of a threshold effect in a population with diabetes mellitus. As well as controlling overall blood pressure levels, SBP visit‐to‐visit variability should be monitored and evaluated in routine practice, in particular for younger patients.

Impact of visit-to-visit blood pressure variability on hypertensive-mediated target organ damage and future cardiovascular events: the Campania salute network

BACKGROUND

Exaggerated variability of blood pressure (BP) poses additional stress on cardiovascular system independent of BP average value, increasing risk of target organ damage (HMOD) and cardiovascular events. We assessed the impact of visit-to-visit variability (VVV) of BP on development of cardiovascular events and HMOD.

METHODS

Standard deviation (SD) and coefficient of variability of mean SBP and DBP were calculated in 3555 patients from the Campania Salute Network registry, with available echocardiogram and more than six visits during follow-up. Values from the first visit were excluded. The impact of VVV of BP on cardiovascular events, and mediation of HMOD were assessed at final visit.

RESULTS

Mean number of visits was 11 ± 6 with mean interval between visits of 9.1 ± 3.7 months. Mean visit-to-visit SD during follow-up was 13 ± 5 for systolic and 8 ± 3 mmHg for DBP; coefficients of variability were 9.7 ± 3.5 and of 9.6 ± 3.2, respectively. In multivariable analysis, left ventricular mass at follow-up was correlated with systolic VVV of BP independently of significant effect of age, BMI, mean SBP during follow-up and initial left ventricular mass. Follow-up GFR was inversely associated with systolic and diastolic VVV, independently of significant effect of age, mean glucose and SBP during follow-up, and initial GFR. In Cox regression, high VVV of BP was also associated with increased risk of cardiovascular events (hazard ratio 1.49, 95% confidence interval 1.08-2.06, P = 0.015), independently of significant effect of HMOD.

CONCLUSION

VVV is associated with prevalent HMOD and development of cardiovascular events, independently of mean BP value during follow-up and HMOD.

Predictive value of visit-to-visit blood pressure variability for cardiovascular events in patients with coronary artery disease with and without diabetes mellitus

Background

High blood pressure is a major risk factor for cardiovascular disease. Visit-to-visit blood pressure variability (BPV) has recently been shown to predict cardiovascular outcomes. We investigated the predictive value of BPV for major adverse cardiovascular events (MACE) among patients with coronary artery disease (CAD), with and without type 2 diabetes mellitus (T2DM).

Methods

Patients with stable CAD were enrolled and monitored for new MACE. Visit-to-visit BPV was defined as the coefficient of variation (CV) of systolic and diastolic BP across clinic visits. Multivariable logistic regression analysis was performed to evaluate the association of BPV with MACE. Area under the receiver operating characteristic curve (AUC) was used to assess its predictive ability.

Results

Among 1140 Chinese patients with stable CAD, 192 (17%) experienced a new MACE. In multivariable analyses, the risk of MACE was significantly associated with CV of systolic BP (odds ratio [OR] for highest versus lowest quartile, 3.30; 95% CI 1.97–5.54), and diastolic BP (OR for highest versus lowest quartile, 2.39; 95% CI 1.39–4.11), after adjustment for variables of the risk factor model (age, gender, T2DM, hypertension, antihypertensive agents, number of BP measurements) and mean BP. The risk factor model had an AUC of 0.70 for prediction of MACE. Adding systolic/diastolic CV into the risk factor model with mean BP significantly increased the AUC to 0.73/0.72 (P = 0.002/0.007). In subgroup analyses, higher CV of systolic BP remained significantly associated with an increased risk for MACE in patients with and without T2DM, whereas the association of CV of diastolic BP with MACE was observed only in those without T2DM.

Conclusions

Visit-to-visit variability of systolic BP and of diastolic BP was an independent predictor of new MACE and provided incremental prognostic value beyond mean BP and conventional risk factors in patients with stable CAD. The association of BPV in CAD patients without T2DM with subsequent risk for MACE was stronger than in those with T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01280-z.

Association of visit-to-visit variability in blood pressure and first stroke risk in hypertensive patients with chronic kidney disease

OBJECTIVE

Data on the association between visit-to-visit variability (VVV) in blood pressure (BP) and the risk of stroke among hypertensive patients with chronic kidney disease (CKD) is limited. We aimed to evaluate the relation of VVV in BP with the risk of stroke, and examine any possible effect modifiers in hypertensive patients with mild-to-moderate CKD.

METHODS

This is a post-hoc analysis of the China Stroke Primary Prevention Trial. A total of 3091 patients with estimated glomerular filtration rate 30-60 ml/min per 1.73 m and/or proteinuria at baseline, without occurring stroke and with BP measurements of at least two visits from randomization to the 12-month visit were included. The main VVV in BP was expressed as SD. The primary outcome was first stroke.

RESULTS

The median subsequent treatment duration was 3.7 years. After multivariable adjustment, including baseline SBP and mean SBP during the first 12-month follow-up, there was a significantly positive relationship of SD SBP with the risk of subsequent first stroke (per SD increment; odds ratio, 1.41; 95% confidence interval: 1.17-1.69) and first ischemic stroke (odds ratio, 1.55; 95% confidence interval: 1.26-1.90). Results were consistent across various subgroups, including age, sex, baseline SBP, treatment compliance, and mean SBP, concomitant usage of calcium channel blocker during the first 12-month follow-up period. Similar trends were also found for coefficient of variation SBP, and SD or coefficient of variation DBP. However, there was no significant association between BP variability and first hemorrhagic stroke.

CONCLUSION

In hypertensive adults with mild-to-moderate CKD, visit-to-visit variability in BP was significantly associated with the risk of subsequent first stroke.

Medication non-adherence in chronic kidney disease: a mixed-methods review and synthesis using the theoretical domains framework and the behavioural change wheel

OBJECTIVE

Medication non-adherence is a well-recognised issue in chronic diseases but data in patients with chronic kidney disease (CKD) not receiving kidney replacement therapy (KRT) remains limited. This review summarised the prevalence of medication non-adherence and assessed determinants and outcomes associated with it in adults with CKD, not on KRT.

METHOD

We searched PubMed, Embase, PsychInfo, Web of Science, and Cochrane (CENTRAL) for studies published until January 2020. Pooled prevalence of medication non-adherence was reported. Determinants of adherence-identified from quantitative and qualitative studies-were mapped into the theoretical domains framework and interventions proposed using the behavioural change wheel.

RESULTS

Twenty-seven studies (22 quantitative and 5 qualitative) were included. The pooled prevalence of medication non-adherence was 39% (95% CI 30-48%). Nine studies reported association between non-adherence and outcomes, including blood pressure, disease progression, adverse events, and mortality. Modifiable determinants of non-adherence were mapped into 11 of the 14 Theoretical Domains Framework-of which, six appeared most relevant. Non-adherence decisions were usually due to lack of knowledge on CKD, comorbidities, and medications; polypharmacy and occurrence of medication side effects; changes in established routines such as frequent medication changes; higher medication cost, poor accessibility to medications, services and facilities; inadequate patient-healthcare professional communication; and forgetfulness. Using the behavioural change wheel, we identified several areas where interventions can be directed to improve medication adherence.

CONCLUSION

Medication non-adherence is common in adults with CKD, not on KRT and may lead to poor outcomes. Evidence synthesis using mixed study designs was crucial in identifying determinants of non-adherence, drawing on a parsimonious approach from behaviour science.

PROSPERO REGISTRATION

CRD42020149983.

Progression of Beat-to-Beat Blood Pressure Variability Despite Best Medical Management

Supplemental Digital Content is available in the text.

Beat-to-beat variability in blood pressure (BP) is associated with recurrent stroke despite good control of hypertension. However, no study has identified rates of progression of beat-to-beat BP variability (BPV), its determinants, or which patient groups are particularly affected, limiting understanding of its potential as a treatment target. In consecutive patients one month after a transient ischaemic attack or nondisabling stroke (Oxford Vascular Study), continuous noninvasive BP was measured beat-to-beat over 5 minutes (Finometer). Arterial stiffness was measured by carotid-femoral pulse wave velocity (Sphygmocor). Repeat assessments were performed at the 5-year follow-up visit and agreement determined by intraclass correlation coefficient. Rates of progression of systolic BPV (SBPV) and diastolic BPV (DBPV) and their determinants were estimated by mixed-effect linear models, adjusted for age, sex, and cardiovascular risk factors. One hundred eighty-eight of 310 surviving, eligible patients had repeat assessments after a median of 5.8 years. Pulse wave velocity was highly reproducible but SBPV and DBPV were not (intraclass correlation coefficient: 0.71, 0.10, and 0.16, respectively), however, all 3 progressed significantly (pulse wave velocity, 2.39%, P<0.0001; SBPV, 8.36%, P<0.0001; DBPV, 9.7, P<0.0001). Rate of progression of pulse wave velocity, SBPV, and DBPV all increased significantly with age (P<0.0001), with an increasingly positive skew and were particularly associated with female sex (pulse wave velocity P=0.00035; SBPV P<0.0001; DBPV P<0.0001) and aortic mean SBP (SBPV P=0.037, DBPV P<0.0001). Beat-to-beat BP variability progresses significantly in high-risk patients, particularly in older individuals with elevated aortic systolic pressure. Beat-to-beat BPV and its progression represent potential new therapeutic targets to reduce cardiovascular risk.

Prognostic importance of long-term SBP variability in high-risk hypertension

OBJECTIVE

In addition to high blood pressure variability (BPV), low BPV was associated with adverse cardiovascular prognosis in selected high-risk patients. We explored this issue in the Systolic Blood Pressure Intervention Trial (SPRINT) using a nonlinear approach with BPV as a continuous variable.

METHODS

Long-term systolic BPV (SBPV) (coefficient of variation, CoV %) was calculated on quarterly visits until a fatal/nonfatal cardiovascular event or all-cause mortality, excluding titration period and patients with missing visits. We used Cox proportional hazard models with penalized smoothing splines to shape the risk of outcomes against the continuum of SBPV (independent variable). Adjusted hazard ratios (aHR, 95% CI) were calculated using the reference range derived from the nonlinear model. Sensitivity analysis based on propensity score matching (PSM) was performed.

RESULTS

The association of SBPV with fatal/nonfatal cardiovascular events was J-shaped, whereas that with all-cause mortality was linear. After multivariate adjustment, however, the only significant associations remained that of low SBPV (CoV <5%) with cardiovascular events (hazard ratio 1.85, 95% CI 1.24-2.75, P = 0.003), and of high SBPV (CoV >10%) with the composite of cardiovascular events and all-cause mortality (hazard ratio 1.35, 95% CI 1.02-1.80; P = 0.037). Low SBPV was associated with ischemic heart disease (hazard ratio 2.76, 95% CI 1.55-4.91; P < 0.001). There was a significant U-shaped association of SBPV with cardiovascular events in the PSM cohort.

CONCLUSION

Nonlinear modeling indicates that low and high long-term SBPV have prognostic relevance in high-risk hypertensive individuals from SPRINT. Randomized trials are needed to test these findings and their potential therapeutic implications.

Differential Diagnoses and Clinical Implications of Medication Nonadherence in Older Patients with Chronic Kidney Disease: A Review

Older adults with chronic kidney disease (CKD) often have many comorbidities, which requires them to take multiple medications. As the number of daily medications prescribed increases, the risk for polypharmacy increases. Understanding and improving medication adherence in this patient population is vital to avoiding the drug-related adverse events of polypharmacy. The primary objective of this review is to summarize the existing literature and to understand the factors leading to medication nonadherence in older patients with CKD. In this review, we discuss the prevalence of polypharmacy, the current lack of consensus on the incidence of medication nonadherence, the heterogeneity of assessing medication adherence, and the most common differential diagnoses for medication nonadherence in this population. Specifically, the most common differential diagnoses for medication nonadherence in older adults with CKD are (1) medication complexity; (2) cognitive impairment; (3) low health literacy; and (4) systems-based barriers. We provide tailored strategies to address these differential diagnoses and subsequently improve medication adherence. The clinical implications include deprescribing to decrease medication complexity and polypharmacy, utilizing a team-based approach to identify and support patients with cognitive impairment, enriching communication between health providers and patients with low health literacy, and improving health care access to address systems-based barriers. Further research is needed to determine the effects of addressing these differential diagnoses and medication adherence in older adults with CKD.

Preoperative outpatient blood pressure variability predicts postoperative mortality, readmission and morbidity after surgery

BACKGROUND

Outpatient blood pressure variability (BPV) predicts hospitalization and death in non-surgical patients independently of hypertension. We hypothesized that preoperative BPV predicts postoperative outcomes.

METHODS

We assessed 22,233 veterans undergoing CABG, colectomy, hip replacement, pancreatectomy, carotid endarterectomy or AV-fistula with ≥10 outpatient BP's over three preoperative years. Calculating BPV as SD of systolic or diastolic BP, we used logistic regression considering demographics, comorbidities, and pre-admission cardiovascular medications to estimate odds ratios for 90-day mortality or readmission, MI, CVA, renal failure, and wound infection, choosing the lowest 5%ile of systolic/diastolic BPV for reference.

RESULTS

Covariate-adjusted ORs for adverse outcomes increased as BPV increased. For instance, the highest 5%ile of systolic BPV had covariate-adjusted ORs of 2.96 and 1.78 for 90-day mortality and readmission. Systolic and diastolic BPV trended together but affected outcomes independently.

CONCLUSIONS

Preoperative BPV predicts postoperative outcomes. BPV should be considered in individualized risk assessment and subgroup risk stratification.

Adherence to Hypertension Medications and Lifestyle Recommendations among Underserved African American Middle-Aged and Older Adults

Background: For African American middle-aged and older adults with hypertension, poor adherence to medication and lifestyle recommendations is a source of disparity in hypertension outcomes including higher rates of stroke in this population relative to whites. Aims: To study demographic, social, behavioral, cognitive, and medical predictors of adherence to medication and lifestyle recommendations among underserved African American middle-aged and older adults with hypertension. Methods: This was a community-based cross-sectional survey in South Los Angeles with 338 African American middle-aged and older adults with hypertension who were 55 years or older. Age, gender, continuity of care, comorbidity, financial difficulty, self-rated health, depression, educational attainment, adherence knowledge, and adherence worries were the independent variables. Data was analyzed using linear regression with two outcomes, namely, adherence to medication (measured by the first 9 items of the Blood Pressure Self-Care Scale) and adherence to lifestyle recommendations (measured by the second 9 items of the Blood Pressure Self-Care Scale). Results: There were about twice more females than males, with a total mean age of 70 years (range 55–90 years). Various demographic, social, behavioral, and medical factors predicted adherence to medication but not adherence to lifestyle recommendations. Females with hypertension with higher continuity of care, less financial strain, higher knowledge, less negative general beliefs, and concerns about antihypertensive medications had higher adherence to antihypertensive medications. The presence of depressive symptoms, reduced knowledge, and disease management worries were associated with a reduced adherence to lifestyle recommendations. Conclusions: There seem to be fewer demographic, social, behavioral, cognitive, and medical factors that explain adherence to lifestyle recommendations than adherence to medication in economically disadvantaged underserved African American middle-aged and older adults with hypertension. More research is needed on factors that impact adherence to lifestyle recommendations of African American middle-aged and older adults with hypertension.

The utility of long-term blood pressure variability for cardiovascular risk prediction in primary care

OBJECTIVES

Blood pressure (BP) is a long-established risk factor for cardiovascular disease (CVD). SBP is used in all widely used cardiovascular risk scores for clinical decision-making. Recently, within-person BP variability has been shown to be a major predictor of CVD. We investigated whether cardiovascular risk scores could be improved by incorporating BP variability with standard risk factors.

METHODS

We used cohort data on patients aged 40-74 on 1 January 2005, from English general practices contributing to the Clinical Practice Research Datalink, a research database derived from electronic health records. Data were linked to hospital episodes and mortality data. SBP variability independent of the mean was calculated across up to six clinic visits. We divided data geographically into derivation and validation data sets. In the derivation data set, we developed a reference model, incorporating risk factors used in previous scores and an index model, incorporating the same factors and BP variability. We calculated model validation statistics in the validation data set including calibration ratio and c-statistic.

RESULTS

In the derivation data set, BP variability was associated with CVD, independently of other risk factors (P = 0.005). However, in the validation data set, both models had similar c-statistic (0.7415 and 0.7419, respectively), R (31.8 and 32.0, respectively) and calibration ratio (0.938 and 0.940, respectively).

CONCLUSION

The association of BP variability with CVD is statistically significant in a large data set but does not substantially improve the performance of a cardiovascular risk score.

Factors affecting medication adherence among pre-dialysis chronic kidney disease patients: a systematic review and meta-analysis of literature

BACKGROUND

Medication adherence plays an essential role in slowing the progression of chronic kidney disease (CKD). This review aims to summarise factors affecting medication adherence among these pre-dialysis CKD patients.

METHODS

A systematic review of the literature was performed in Medline®, Embase®, SCOPUS® and CINAHL®. Peer-reviewed, English language articles which evaluated factors associated with medication adherence among pre-dialysis CKD patients were included. Meta-analysis was performed to assess the pooled medication adherence rates across studies. Factors identified were categorised using the World Health Organization's five dimensions of medication adherence (condition, patient, therapy, health-system, and socio-economic domains).

RESULTS

Of the 3727 articles reviewed, 18 articles were included. The pooled adherence rate across studies was 67.4% (95% CI 61.4-73.3%). The most studied medication class was anti-hypertensives (55.6%). A total of 19 factors and 95 sub-factors related to medication adherence were identified. Among condition-related factors, advanced CKD was associated with poorer medication adherence. Patient-related factors that were associated with lower medication adherence included misconceptions about medication and lack of perceived self-efficacy in medication use. Therapy-related factors which were associated with poorer medication adherence included polypharmacy while health system-based factors included loss of confidence in the physician. Socioeconomic factors such as poor social support and lower education levels were associated with poorer medication adherence.

CONCLUSION

Factors associated with poor medication adherence among pre-dialysis CKD patients were highlighted in this review. This will aid clinicians in designing interventions to optimise medication adherence among pre-dialysis CKD patients.

Factors Associated with Visit-to-Visit Variability of Blood Pressure Measured as Part of Routine Clinical Care among Patients Attending Cardiology Outpatient Department of a Tertiary Care Centre in Northern Sri Lanka

Visit-to-visit variability (VVV) is a relatively new concept in the hypertensive arena. Data regarding VVV are lacking in our region, and factors associated with VVV are rarely examined in previous studies. This study was conducted among 406 patients attended to the cardiology outpatient department of Teaching Hospital, Jaffna, Sri Lanka, in 2018 to assess the long-term variability of blood pressure (BP) by reviewing last six consecutive BP readings from the records retrospectively. Data regarding sociodemographic variables and behavioural factors such as medication adherence, physical activity, smoking, alcohol consumption, and relevant comorbidities were taken through an interviewer-administered questionnaire. Data were analysed by using SPSS version 25 and VVV of systolic blood pressure (SBP) matrix expressed as mean of SD and association were examined with various factors and VVV of SBP. SBP showed high VVV among the participants as expressed by mean of SD which was 13.06 ± 5.64. When comparing mean SD among the categories of different variables, female sex (P=0.023) and comorbidities such as diabetes mellitus (DM) (P=0.013), chronic kidney disease (CKD) (P=0.007), and risk of developing obstructive sleep apnoea (OSA) (P=0.04) showed significant variation. Medication adherence to prescribed hypertensive medication was a major issue even though significant association was not found with high VVV (P=0.536). The SD of SBP was then classified into high and low VVV groups by means of a cutoff point at the 50th percentile. Bivariate analysis by using Chi-squared test revealed comorbidities such as DM, CKD, and physical activity (P=0.044) were significantly associated with high VVV. Further multivariate regression analysis revealed that comorbidities such as DM and CKD have 1.561 times and 5.999 times more risk to show high variability, respectively. In conclusion, we recommend simple practical measures to achieve sustainable BP control among hypertensive patients with DM and CKD to minimize the VVV and improve their cardiovascular outcome.

Long term evolution of renal function in essential hypertensive patients with no baseline proteinuria

Data on the long term evolution of renal function in essential hypertensive patients are scarce, showing a low incidence of end stage renal diseases but without information on how the renal function evolves. Our aim is to describe the long term evolution of renal function and possible trajectories in hypertensive patients. We included patients from an ongoing cohort with essential hypertension, no proteinuria at baseline and no diabetes during follow-up and with at least two creatinine dosages 4 years apart. A long term (average 16 years) follow-up was available in 609 patients (baseline age 51.8 ± 11.1 years, 52 % male, mean office BP 156//95 mmHg). The trajectories of creatinine were modeled through a flexible latent class mixed model. The analysis identified three classes of significantly different trajectories. In the first (n = 560), there was no significant variation of creatinine over time. In the second (n = 40), there was a significant rise of creatinine (117 ± 20 vs 85 ± 17 µmol/l, p < 0.0001). The third class (n = 9) was very heterogeneous, mainly composed of outliers. Further analysis showed the nonlinearity of the evolution of creatinine in classes 2 and 3. So the model of progressive renal deterioration in essential hypertension does not fit with our results. A large majority (92%) of patients show no significant change in creatinine level with time. In the others 8%, the increase in creatinine is not progressive but conversely show one or more sudden bouts of elevation.

Environmental and individual predictors of medication adherence among elderly patients with hypertension and chronic kidney disease: A geospatial approach

BACKGROUND

Few studies have examined how adherence to antihypertensive medications varies across different regions or how neighborhood-level factors were related to individuals' medication-taking behaviors in patients.

OBJECTIVE

To explore local variation in medication adherence and examine environmental and individual influences on adherence to angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) among elderly hypertensive patients with chronic kidney disease (CKD) in the United States.

METHODS

The Medicare 5% sample claim data (2006-2013), American Community Survey 5-Year Data (2005-2009) and the Health Resources and Services Administration Primary Care Service Area data (2007). The primary outcome was medication adherence, measured by Proportion of Days Covered (PDC). Geographically weighted regression (GWR) and linear mixed-effects models were used to investigate the relationship between environmental factors, individual risk factors and medication adherence.

RESULTS

A total of 70,201 hypertensive CKD patients residing in 2,981 counties of the US were selected. Significant spatial autocorrelation was observed in ACEIs/ARBs PDC. The West North Central and New England regions demonstrated higher adherence compared to the East South Central and West South Central regions. Residing in Medically Underserved Areas, counties with high deprivation scores, and not receiving Part D Low-income Subsidy were associated with poor medication adherence.

CONCLUSIONS

Medication adherence is geographically differentiated across the US. Environmental and individual factors identified may be helpful in the design of local interventions focused on improving patient outcomes from a population perspective.

Stress, adherence, and blood pressure control: A baseline examination of Black women with hypertension participating in the SisterTalk II intervention

The prevalence of hypertension is highest among Black women, but treatment adherence is reportedly low. Stress unique to the experiences of Black Americans may be associated with low adherence and poor blood pressure control, but few studies have examined the relationships between stress, adherence, and blood pressure control among hypertensive Black women. This study seeks to fill gaps in research by examining the association between stress, adherence, and blood pressure control. The baseline sample (n = 571) of at-risk or hypertensive Black women from the SisterTalk II RCT (Northeastern USA, 2004-2006) to improve adherence to recommendations for hypertension was analyzed. Participants self-reported stress, pharmacological adherence, non-pharmacological adherence (i.e. lifestyle management such as diet and exercise), and demographics. Blood pressure and anthropometrics (BMI and waist circumference) were measured. Statistical analysis included ANOVA, t-tests, linear regression. Tests of mediation examined if adherence mediated the relationship between stress and blood pressure control. This study found that stress was associated with lower age (p < .001) and being a single parent (p < .001). Stress was also associated with higher systolic blood pressure (p = .029), and poor blood pressure control (p = .043). Participants who reported higher stress also reported lower non-pharmacological adherence (p = .042). Non-pharmacological adherence was found to mediate the association between stress and blood pressure control. Hence, results document a relationship between stress with non-pharmacological adherence and blood pressure control among Black American women. More research is necessary to examine the relationship between stress and treatment adherence.

Visit-to-Visit Variability of Blood Pressure Is Associated With Hospitalization and Mortality in an Unselected Adult Population

BACKGROUND

Blood pressure variability (BPV) has been associated with poor health outcomes in high-risk patients, but its association with more general populations is poorly understood.

METHODS

We analyzed outcomes from 240,622 otherwise unselected patients who had 10 or more outpatient blood pressure readings recorded over a 3-year period and were aged from 20 to 100 years.

RESULTS

Whether calculated as SD, average change, or greatest change and systolic or diastolic blood pressure, we found that higher outpatient BPV was associated with subsequent hospitalization and mortality. Systolic pressure average change exceeding 10-12 mm Hg or diastolic exceeding 8 mm Hg significantly increased risk of hospitalization and death (odds ratios [ORs] from 2.0 to 4.5). Variability in the highest decile increased risks even more dramatically, with propensity-matched ORs from 4.4 to 42. A systolic change exceeding 35 mm Hg increased the relative risk of death 4.5-fold. Similarly, a diastolic change greater than 23-24 mm Hg almost tripled the risks of hospitalization and death. Neither stratification for hypertension nor propensity matching for risk factors within the database affected these associations.

CONCLUSIONS

Systolic and diastolic variabilities were each associated with subsequent adverse outcomes. Physicians should pay special attention to patients with swings in blood pressure between clinic visits. Electronic medical records should flag such variability.

[What is the goal blood pressure in non-diabetic chronic kidney disease?]

High blood pressure during renal disease is highly prevalent and an important risk factor for cardiovascular disease and renal progression. Its optimal management is therefore necessary to improve the prognosis of patients. Several trials concerning the blood pressure target in patients with chronic non-diabetic kidney disease have been published in recent years, we will detail them in this article in order to determine which blood pressure target provides the best benefit in terms of progression of renal diseases and cardiovascular prevention.

Self-reported Medication Adherence and CKD Progression

Introduction

In the general population, medication nonadherence contributes to poorer outcomes. However, little is known about medication adherence among adults with chronic kidney disease (CKD). We evaluated the association of self-reported medication adherence with CKD progression and all-cause death in patients with CKD.

Methods

In this prospective observational study of 3305 adults with mild-to-moderate CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, the baseline self-reported medication adherence was assessed by responses to 3 questions and categorized as high, medium, and low. CKD progression (50% decline in eGFR or incident end-stage renal disease) and all-cause death were measured using multivariable Cox proportional hazards.

Results

Of the patients, 68% were categorized as high adherence, 17% medium adherence, and 15% low adherence. Over a median follow-up of 6 years, there were 969 CKD progression events and 675 deaths. Compared with the high-adherence group, the low-adherence group experienced increased risk for CKD progression (hazard ratio = 1.27, 95% confidence interval = 1.05, 1.54) after adjustment for sociodemographic and clinical factors, cardiovascular medications, number of medication types, and depressive symptoms. A similar association existed between low adherence and all-cause death, but did not reach standard statistical significance (hazard ratio = 1.14 95% confidence interval = 0.88, 1.47).

Conclusion

Baseline self-reported low medication adherence was associated with an increased risk for CKD progression. Future work is needed to better understand the mechanisms underlying this association and to develop interventions to improve adherence.

Visit-to-Visit Office Blood Pressure Variability and Cardiovascular Outcomes in SPRINT (Systolic Blood Pressure Intervention Trial)

Studies of visit-to-visit office blood pressure (BP) variability (OBPV) as a predictor of cardiovascular events and death in high-risk patients treated to lower BP targets are lacking. We conducted a post hoc analysis of SPRINT (Systolic Blood Pressure Intervention Trial), a well-characterized cohort of participants randomized to intensive (<120 mm Hg) or standard (<140 mm Hg) systolic BP targets. We defined OBPV as the coefficient of variation of the systolic BP using measurements taken during the 3-,6-, 9-, and 12-month study visits. In our cohort of 7879 participants, older age, female sex, black race, current smoking, chronic kidney disease, and coronary disease were independent determinants of higher OBPV. Use of thiazide-type diuretics or dihydropyridine calcium channel blockers was associated with lower OBPV whereas angiotensin-converting enzyme inhibitors or angiotensin receptor blocker use was associated with higher OBPV. There was no difference in OBPV in participants randomized to standard or intensive treatment groups. We found that OBPV had no significant associations with the composite end point of fatal and nonfatal cardiovascular events (n=324 primary end points; adjusted hazard ratio, 1.20; 95% confidence interval, 0.85-1.69, highest versus lowest quintile) nor with heart failure or stroke. The highest quintile of OBPV (versus lowest) was associated with all-cause mortality (adjusted hazard ratio, 1.92; confidence interval, 1.22-3.03) although the association of OBPV overall with all-cause mortality was marginal (P=0.07). Our results suggest that clinicians should continue to focus on office BP control rather than on OBPV unless definitive benefits of reducing OBPV are shown in prospective trials.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Prognostic Value of Variability in Systolic Blood Pressure Related to Vascular Events and Premature Death in Type 2 Diabetes Mellitus: The ADVANCE-ON Study

Visit-to-visit variability in systolic blood pressure (SBP) is a risk factor for cardiovascular events. However, whether it provides additional predictive information beyond traditional risk factors, including mean SBP, in the long term is unclear. The ADVANCE trial (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation) was a randomized controlled trial in patients with type 2 diabetes mellitus; ADVANCE-ON (ADVANCE-Observational) followed-up patients subsequently. In these analyses, 9114 patients without major macrovascular or renal events or death during the first 24 months were included. Data on SBP from 6 visits during the first 24 months after randomization were used to estimate visit-to-visit variability in several ways: the primary measure was the standard deviation. Events accrued during the following 7.6 years. The primary outcome was a composite of major macrovascular and renal events and all-cause mortality. Standard deviation of SBP was log-linearly associated with an increased risk of the primary outcome (P<0.001) after adjustment for mean SBP and other cardiovascular risk factors. The hazard ratio (HR; 95% confidence interval [CI]) in the highest, compared with the lowest, tenth of the standard deviation was 1.39 (1.15-1.69). Results were similar for major macrovascular events alone and all-cause mortality alone (both P<0.01). Addition of standard deviation of SBP significantly improved 8-year risk classification (continuous net reclassification improvement, 5.3%). Results were similar for other measures of visit-to-visit variability, except maximum SBP. Visit-to-visit variability in SBP is an independent predictor of vascular complications and death, which improves risk prediction beyond that provided by traditional risk factors, including mean SBP.

Variation in lung function as a marker of adherence to oral and inhaled medication in cystic fibrosis

The aim of this study was to characterise adherence in an adult population with cystic fibrosis (CF) and to investigate if variation in lung function was a predictor of adherence to treatment.

The adherence of patients aged ≥16 years from an adult CF centre was measured by medication possession ratio (MPR) and self-report. Patients were assigned to one of three adherence categories (<50%, 50 to <80%, ≥80%) by their composite score (MPR). Ordinal regression was used to identify predictors of adherence, including coefficient variation measures for forced expiratory volume in 1 s (FEV1), weight and C-reactive protein concentration, measured from 6 months and 12 months before baseline.

MPR data for 106 of 249 patients (mean age 29.8±9.2 years) was retrieved, indicating a mean adherence of 63%. The coefficient of variation for FEV1 was inversely related to adherence and was a univariate predictor of adherence (6 months: OR 0.92, 95% CI 0.87–0.98, p=0.005; 12 months: OR 0.94, 95% CI 0.93–0.99, p=0.03) and remained significant in the final models. The coefficient of variation of weight and C-reactive protein were not predictive of adherence.

The coefficient of variation of FEV1 was identified as an objective predictor of adherence. Further evaluation of this potential marker of adherence is now required.

Association of Visit-to-Visit Variability of Systolic Blood Pressure With Cardiovascular Disease and Mortality in Primary Care Chinese Patients With Type 2 Diabetes-A Retrospective Population-Based Cohort Study

OBJECTIVE

This study aimed to evaluate the impact of visit-to-visit variability (VVV) of systolic blood pressure (SBP) on cardiovascular disease (CVD) and mortality among primary care Chinese patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

A retrospective cohort study was conducted in 124,105 Chinese adult primary care patients with T2DM and without prior diagnosed CVD from August 2008 to December 2009. The VVV of SBP was evaluated using SDs of SBP over 24 months. The risks of CVD and all-cause mortality associated with variability in SBP were evaluated using Cox proportional hazards regression. Subgroup analysis was conducted by the stratification of age, sex, duration of diabetes, the presence of chronic kidney disease, baseline SBP and trend, and the number and class of antihypertensive drugs.

RESULTS

A positive linear relationship between the VVV of SBP and the first incidence of CVD and all-cause mortality was identified over a median follow-up time of 39.5 months. Patients with a low SD of SBP of <5 mmHg had the lowest risks of CVD and all-cause mortality, and patients with an SD of SBP of ≥10 mmHg had significantly higher risks. For every 1 SD increase in the SD of SBP, the risks of CVD, all-cause mortality, and the composite of both events increased by 2.9% (95% CI 2.4-3.4%), 4.0% (95% CI 3.5-4.6%), and 3.4% (95% CI 3.0-3.8%), respectively. A direct linear relationship was also observed in all selected subgroups.

CONCLUSIONS

SBP variability, irrespective of the mean SBP level, is a potential predictor for the development of CVD and all-cause mortality in patients with diabetes. In addition to monitoring BP targets for their patients with diabetes, clinicians should also remain vigilant about the visit-to-visit fluctuation of BP.

Visit-to-visit variability of blood pressure and death, end-stage renal disease, and cardiovascular events in patients with chronic kidney disease

OBJECTIVES

Visit-to-visit variability of blood pressure (VVV of BP) is an important independent risk factor for premature death and cardiovascular events, but relatively little is known about this phenomenon in patients with chronic kidney disease (CKD) not yet on dialysis.

METHODS

We conducted a retrospective study in a community-based cohort of 114 900 adults with CKD stages 3-4 (estimated glomerular filtration rate 15-59 ml/min per 1.73 m). We hypothesized that VVV of BP would be independently associated with higher risks of death, incident treated end-stage renal disease, and cardiovascular events. We defined systolic VVV of BP using three metrics: coefficient of variation, standard deviation of the mean SBP, and average real variability.

RESULTS

The highest versus the lowest quintile of the coefficient of variation was associated with higher adjusted rates of death (hazard ratio 1.22; 95% confidence interval 1.11-1.34) and hemorrhagic stroke (hazard ratio 1.91; confidence interval 1.36-2.68). VVV of BP was inconsistently associated with heart failure, and was not significantly associated with acute coronary syndrome and ischemic stroke. Results were similar when using the other two metrics of VVV of BP. VVV of BP had inconsistent associations with end-stage renal disease, perhaps because of the relatively low incidences of this outcome.

CONCLUSION

Higher VVV of BP is independently associated with higher rates of death and hemorrhagic stroke in patients with moderate to advanced CKD not yet on dialysis.

The Association Between Antihypertensive Medication Nonadherence and Visit-to-Visit Variability of Blood Pressure: Findings From the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial

Low adherence to antihypertensive medication has been hypothesized to increase visit-to-visit variability (VVV) of blood pressure (BP). We assessed the association between antihypertensive medication adherence and VVV of BP in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT). VVV of BP was calculated using SD independent of mean, SD, and average real variability across study visits conducted 6 to 28 months after randomization. Participants who reported taking <80% of their antihypertensive medication at ≥1 study visits were categorized as nonadherent. Participants were followed up for cardiovascular events and mortality after the assessment of adherence and VVV of BP. SD independent of mean of BP was higher for nonadherent (n=2912) versus adherent (n=16 878) participants; 11.4±4.9 versus 10.5±4.5 for systolic BP; 6.8±2.8 versus 6.2±2.6 for diastolic BP (each P<0.001). SD independent of mean of BP remained higher among nonadherent than among adherent participants after multivariable adjustment (0.8 [95% confidence interval, 0.7-1.0] higher for systolic BP and 0.4 [95% confidence interval, 0.3-0.5] higher for diastolic BP]. SD and average real variability of systolic BP and diastolic BP were also higher among nonadherent than among adherent participants. Adjustment for nonadherence did not explain the association of VVV of BP with higher fatal coronary heart disease or nonfatal myocardial infarction, stroke, heart failure, or mortality risk. In conclusion, improving medication adherence may lower VVV of BP. However, VVV of BP is associated with cardiovascular outcomes independent of medication adherence.

The agreement of patient-reported versus observed medication adherence in type 2 diabetes mellitus (T2DM)

OBJECTIVE

Medication adherence in type 2 diabetes mellitus (T2DM) improves glycemic control and is associated with reduced adverse clinical events, and accurately assessing adherence assessment is important. We aimed to determine agreement between two commonly used adherence measures-the self-reported Morisky Medication Adherence Scale (MMAS) and direct observation of medication use by nurse practitioners (NPs) during home visits-and determine the relationship between each measure and glycated hemoglobin (HbA1c).

RESEARCH DESIGN AND METHODS

We evaluated agreement between adherence measures in the Southeastern Diabetes Initiative (SEDI) prospective clinical intervention home visit cohort, which included high-risk patients (n=430) in 4 SEDI-participating counties. The mean age was 58.7 (SD 11.6) years. The majority were white (n=210, 48.8%), female (n=236, 54.9%), living with a partner (n=316, 74.5%), and insured by Medicare/Medicaid (n=361, 84.0%). Medication adherence was dichotomized to 'adherent' or 'not adherent' using established cut-points. Inter-rater agreement was evaluated using Cohen's κ coefficient. Relationships among adherence measures and HbA1c were evaluated using the Wilcoxon rank-sum test and c-statistics.

RESULTS

Fewer patients (n=261, 61%) were considered adherent by self-reported MMAS score versus the NP-observed score (n=338; 79%). Inter-rater agreement between the two adherence measures was fair (κ=0.24; 95% CI 0.15 to 0.33; p<0.0001). Higher adherence was significantly associated with lower HbA1c levels for both measures, yet discrimination was weak (c-statistic=0.6).

CONCLUSIONS

Agreement between self-reported versus directly observed medication adherence was lower than expected. Though scores for both adherence measures were significantly associated with HbA1c, neither discriminated well for discrete levels of HbA1c.