Overestimation of the effects of adherence on outcomes: a case study in healthy user bias and hypertension

Non-adherence to cardiometabolic medication as assessed by LC-MS/MS in urine and its association with kidney and cardiovascular outcomes in type 2 diabetes mellitus

AIMS/HYPOTHESIS

Non-adherence to medication is a frequent barrier in the treatment of patients with type 2 diabetes mellitus, potentially limiting the effectiveness of evidence-based treatments. Previous studies have mostly relied on indirect adherence measures to analyse outcomes based on adherence. The aim of this study was to use LC-MS/MS in urine-a non-invasive, direct and objective measure-to assess non-adherence to cardiometabolic drugs and analyse its association with kidney and cardiovascular outcomes.

METHODS

This cohort study includes 1125 participants from the PROVALID study, which follows patients with type 2 diabetes mellitus at the primary care level. Baseline urine samples were tested for 79 cardiometabolic drugs and metabolites thereof via LC-MS/MS. An individual was classified as totally adherent if markers for all drugs were detected, partially non-adherent when at least one marker for one drug was detected, and totally non-adherent if no markers for any drugs were detected. Non-adherence was then analysed in the context of cardiovascular (composite of myocardial infarction, stroke and cardiovascular death) and kidney (composite of sustained 40% decline in eGFR, sustained progression of albuminuria, kidney replacement therapy and death from kidney failure) outcomes.

RESULTS

Of the participants, 56.3% were totally adherent, 42.0% were partially non-adherent, and 1.7% were totally non-adherent to screened cardiometabolic drugs. Adherence was highest to antiplatelet and glucose-lowering agents and lowest to lipid-lowering agents. Over a median (IQR) follow-up time of 5.10 (4.12-6.12) years, worse cardiovascular outcomes were observed with non-adherence to antiplatelet drugs (HR 10.13 [95% CI 3.06, 33.56]) and worse kidney outcomes were observed with non-adherence to antihypertensive drugs (HR 1.98 [95% CI 1.37, 2.86]).

CONCLUSIONS/INTERPRETATION

This analysis shows that non-adherence to cardiometabolic drug regimens is common in type 2 diabetes mellitus and negatively affects kidney and cardiovascular outcomes.

The Association of Sodium-Glucose Cotransporter 2 Inhibitors With Cardiovascular Outcomes in Anthracycline-Treated Patients With Cancer

Background

Sodium glucose cotransporter-2 inhibitors (SGLT2is) are hypothesized to reduce the risk of anthracycline-associated cardiotoxicity.

Objectives

This study sought to determine the association between SGLT2is and cardiovascular disease (CVD) after anthracycline-containing chemotherapy.

Methods

Using administrative data sets, we conducted a population-based cohort study of people >65 years of age with treated diabetes and no prior heart failure (HF) who received anthracyclines between January 1, 2016, and December 31, 2019. After estimating propensity scores for SGLT2i use, the average treatment effects for the treated weights were used to reduce baseline differences between SGLT2i-exposed and -unexposed controls. The outcomes were hospitalization for HF, incident HF diagnoses (in- or out-of-hospital), and documentation of any CVD in future hospitalizations. Death was treated as a competing risk. Cause-specific HRs for each outcome were determined for SGLT2i-treated people relative to unexposed controls.

Results

We studied 933 patients (median age 71.0 years, 62.2% female), 99 of whom were SGLT2i treated. During a median follow-up of 1.6 years, there were 31 hospitalizations for HF (0 in the SGLT2i group), 93 new HF diagnoses, and 74 hospitalizations with documented CVD. Relative to controls, SGLT2i exposure was associated with HR of 0 for HF hospitalization (P < 0.001) but no significant difference in incident HF diagnosis (HR: 0.55; 95% CI: 0.23-1.31; P = 0.18) or CVD diagnosis (HR: 0.39; 95% CI: 0.12-1.28; P = 0.12). There was no significant difference in mortality (HR: 0.63; 95% CI: 0.36-1.11; P = 0.11).

Conclusions

SGLT2is may reduce the rate of HF hospitalization after anthracycline-containing chemotherapy. This hypothesis warrants further testing in randomized controlled trials.

Evidence-based medication adherence among seniors in the first year after heart failure hospitalisation and subsequent long-term outcomes: a restricted cubic spline analysis of adherence-outcome relationships

PURPOSE

Non-adherence to heart failure (HF) medications is associated with poor outcomes. We used restricted cubic splines (RCS) to assess the continuous relationship between adherence to renin-angiotensin system inhibitors (RASI) and β-blockers and long-term outcomes in senior HF patients.

METHODS

We identified a population-based cohort of 4234 patients, aged 65-84 years, 56% male, who were hospitalised for HF in Western Australia between 2003 and 2008 and survived to 1-year post-discharge (landmark date). Adherence was calculated using the proportion of days covered (PDC) in the first year post-discharge. RCS Cox proportional-hazards models were applied to determine the relationship between adherence and all-cause death and death/HF readmission at 1 and 3 years after the landmark date.

RESULTS

RCS analysis showed a curvilinear adherence-outcome relationship for both RASI and β-blockers which was linear above PDC 60%. For each 10% increase in RASI and β-blocker adherence above this level, the adjusted hazard ratio for 1-year all-cause death fell by an average of 6.6% and 4.8% respectively (trend p < 0.05) and risk of all-cause death/HF readmission fell by 5.4% and 5.8% respectively (trend p < 0.005). Linear reductions in adjusted risk for these outcomes at PDC ≥ 60% were also seen at 3 years after landmark date (all trend p < 0.05).

CONCLUSION

RCS analysis showed that for RASI and β-blockers, there was no upper adherence level (threshold) above 60% where risk reduction did not continue to occur. Therefore, interventions should maximise adherence to these disease-modifying HF pharmacotherapies to improve long-term outcomes after hospitalised HF.

Core concepts in pharmacoepidemiology: Key biases arising in pharmacoepidemiologic studies

Pharmacoepidemiology has an increasingly important role in informing and improving clinical practice, drug regulation, and health policy. Therefore, unrecognized biases in pharmacoepidemiologic studies can have major implications when study findings are translated to the real world. We propose a simple taxonomy for researchers to use as a starting point when thinking through some of the most pervasive biases in pharmacoepidemiology. We organize this discussion according to biases best assessed with respect to the study population (including confounding by indication, channeling bias, healthy user bias, and protopathic bias), the study design (including prevalent user bias and immortal time bias), and the data source (including misclassification bias and missing data/loss to follow up). This tutorial defines, provides a curated list of recommended references, and illustrates through relevant case examples these key biases to consider when planning, conducting, or evaluating pharmacoepidemiologic studies.

Randomized Trial of Postoperative Venous Thromboembolism Prophylactic Compliance: Aspirin and Mobile Compression Pumps

BACKGROUND

Aspirin, as a routine venous thromboembolism (VTE) prophylaxis, is approved along with pneumatic compression pumps by the American College of Chest Physicians. We assessed compliance of aspirin and pump use after total joint arthroplasty.

METHODS

A randomized trial of aspirin alone or aspirin/mobile compression pumps after total joint arthroplasty was performed. Aspirin and pump compliance, VTE events, and satisfaction with pump use were collected. Compliance was assessed through an internal device monitor and drug log book. Patients were also contacted 90 days postoperatively for reported symptomatic VTEs.

RESULTS

Each group had 40 patients and greater than 94% compliance with aspirin use, with no difference between groups (P = 0.55). Overall pump compliance during the first 14 days after hospital discharge was 51% (SD ± 33), which was significantly worse than aspirin compliance at 99% (SD ± 4.1) (P < 0.0001). Only 10 patients were compliant (>20 hr/d) with recommended pump use throughout the entire recommended period. There was no notable association between aspirin compliance and VTE within 90 days. There was no notable association between pump compliance and VTE at 90 days. However, average pump use compliance was 20% in patients with VTE and 54% in patients without VTE within 90 days. With the numbers available in this compliance study, there was no significant difference (P = 0.11).

DISCUSSION

Aspirin compliance was notably greater than pump compliance. In this study, we found that pump compliance was not associated with lower VTE risk. In fact, no increased risk was recognized in patients with an average pump usage of >50%. Further study is warranted to define the duration of pump use required for clinical significance. The recommended use of compression pumps should continue to be examined.

Better Medications Adherence Lowers Cardiovascular Events, Stroke, and All-Cause Mortality Risk: A Dose-Response Meta-Analysis

Aims: We investigated the association between vascular medication adherence, assessed by different methods, and the risk of cardio-cerebrovascular events and all-cause mortality. Methods: A meta-analysis with a systematic search of PubMed, Web of Science, EMBASE, and Cochrane databases from inception date to 21 June 2021 was used to identify relevant studies that had evaluated the association between cardiovascular medication adherence levels and cardiovascular events (CVEs), stroke, and all-cause mortality risks. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects meta-analysis. Restricted cubic splines were used to model the dose-response association. Results: We identified 46 articles in the dose-response meta-analysis. The dose-response analysis indicated that a 20% increment in cardiovascular medication, antihypertensive medication, and lipid-lowering medication adherence level were associated with 9% (RR: 0.91, 95% CI 0.88–0.94), 7% (RR 0.93, 95% CI: 0.84–1.03), and 10% (RR 0.90, 95% CI: 0.88–0.92) lowers risk of CVEs, respectively. The reduced risk of stroke respectively was 16% (RR: 0.84, 95% CI: 0.81–0.87), 17% (RR 0.83, 95% CI: 0.78–0.89), and 13% (RR 0.87, 95% CI: 0.84–0.91). The reduced risk of all-cause mortality respectively was 10% (RR: 0.90, 95% CI: 0.87–0.92), 12% (RR 0.88, 95% CI: 0.82–0.94), and 9% (RR 0.91, 95% CI: 0.89–0.94). Conclusions: A better medication adherence level was associated with a reduced risk of cardio-cerebrovascular events and all-cause mortality.

Non-adherence to antidiabetic and cardiovascular drugs in type 2 diabetes mellitus and its association with renal and cardiovascular outcomes: A narrative review

Cardiovascular and renal complications are a major burden for individuals with type 2 diabetes mellitus (T2DM). Besides lifestyle interventions, current guidelines recommend combination drug therapy to prevent or delay the incidence and progression of comorbidities. However, non-adherence to pharmacotherapy is common in chronic conditions such as T2DM and a barrier to successful disease management. Numerous studies have associated medication non-adherence with worse outcome as well as higher health care costs. This narrative review provides (i) an overview on adherence measures used within and outside research settings, (ii) an estimate on the prevalence of non-adherence to antidiabetic and cardiovascular drugs in T2DM, and (iii) specifically focuses on the association of non-adherence to these drugs with renal and cardiovascular outcomes.

Are patients more adherent to newer drugs?

The annual preventable cost from non-adherence in the US health care system amounts to $100 billion. While the relationship between adherence and the health system, the condition, patient characteristics and socioeconomic factors are established, the role of the heterogeneous productivity of drug treatment remains ambiguous. In this study, we perform cross-sectional retrospective analyses to study whether patients who use newer drugs are more adherent to pharmacotherapy than patients using older drugs within the same therapeutic class, accounting for unobserved heterogeneity at the individual level (e.g. healthy adherer bias). We use US Marketscan commercial claims and encounters data for 2008-2013 on patients initiating therapy for five chronic conditions. Productivity is captured by a drug's earliest Food and Drug Administration (FDA) approval year ("drug vintage") and by FDA" therapeutic potential" designation. We control for situational factors as promotional activity, copayments and distribution channel. A 10-year increase in mean drug vintage is associated with a 2.5 percentage-point increase in adherence. FDA priority status, promotional activity and the share of mail-order prescription fills positively influenced adherence, while co-payments had a negative effect. Newer drugs not only may be more effective in terms of clinical benefits, on average. They provide means to ease drug therapy to increase adherence levels as one component of drug quality, a notion physicians and pharmacy benefit managers should be aware of.

Antihypertensive Treatment in Elderly Frail Patients: Evidence From a Large Italian Database

Aim of our study was to assess the relationship between adherence with antihypertensive drugs and the risk of death in frail versus nonfrail old individuals. Using the database of the Lombardy Region (Italy), we identified 1 283 602 residents aged ≥65 years (mean age 76) who had ≥3 prescriptions of antihypertensive drugs between 2011 and 2012. A nested case-control design was applied, with cases being the cohort members who died during the observation period (7 years). Logistic regression was used to model the association of interest, with adjustment for potential confounders. Adherence was measured by the proportion of the follow-up covered by prescriptions, and the analysis was separately performed in patients with a good, medium, poor, and very poor clinical status, as assessed by a score that has been shown to be a sensitive predictor of death in the Italian population. The 7-year death probability increased from 16% (good) to 64% (very poor) clinical status. Compared with patients with very low adherence with antihypertensive treatment (<25% of follow-up time covered by prescriptions), those with high adherence (>75% of time covered by prescriptions) exhibited a lower risk of all-cause mortality in each group, the difference decreasing progressively (-44%, -43%, -40%, and -33%) from the good to the very poor clinical status. Adherence with antihypertensive drug treatment was also associated with a lower risk of cardiovascular mortality. Adherence with antihypertensive appears to be protective in frail old patients, but the benefit is less marked than in patients with a good clinical status.

Adherence in Hypertension

The global epidemic of hypertension is largely uncontrolled and hypertension remains the leading cause of noncommunicable disease deaths worldwide. Suboptimal adherence, which includes failure to initiate pharmacotherapy, to take medications as often as prescribed, and to persist on therapy long-term, is a well-recognized factor contributing to the poor control of blood pressure in hypertension. Several categories of factors including demographic, socioeconomic, concomitant medical-behavioral conditions, therapy-related, healthcare team and system-related factors, and patient factors are associated with nonadherence. Understanding the categories of factors contributing to nonadherence is useful in managing nonadherence. In patients at high risk for major adverse cardiovascular outcomes, electronic and biochemical monitoring are useful for detecting nonadherence and for improving adherence. Increasing the availability and affordability of these more precise measures of adherence represent a future opportunity to realize more of the proven benefits of evidence-based medications. In the absence of new antihypertensive drugs, it is important that healthcare providers focus their attention on how to do better with the drugs they have. This is the reason why recent guidelines have emphasize the important need to address drug adherence as a major issue in hypertension management.

The association between pharmacy refill-adherence metrics and healthcare utilisation: a prospective cohort study of older hypertensive adults

AIMS

Methods that enable targeting and tailoring of adherence interventions may facilitate implementation in clinical settings. We aimed to determine whether community pharmacy refill-adherence metrics are useful to identify patients at higher risk of healthcare utilisation due to low antihypertensive adherence, who may benefit from an adherence intervention.

METHODS

We conducted a prospective cohort study, recruiting participants (n = 905) from 106 community pharmacies across the Republic of Ireland. Participants completed a structured interview at baseline and 12 months. Antihypertensive medication adherence was evaluated from linked pharmacy records using group-based trajectory modelling (GBTM) and proportion of days covered (PDC). Healthcare utilisation included self-reported number of hospital visits (emergency department visits and inpatient admissions) and general practitioner (GP) visits, over a 6-month period. Separate regression models were used to estimate the association between adherence and number of hospital/GP visits. The relative statistical fit of each model using different adherence metrics was determined using the Bayesian information criterion (BIC).

RESULTS

For the number of hospital visits, significant associations were observed only for PDC but not for GBTM. Each 10% increase in refill-adherence by PDC was significantly associated with a 16% lower rate of hospital visits (adjusted incidence rate ratio 0.84, 95% CI 0.72-0.98, P = 0.036). Poorer adherence using both measures was associated with higher GP visits. Improvements in BIC favoured models using PDC.

CONCLUSIONS

Medication refill-adherence, measured using PDC in community pharmacy settings, could be used to recognise poor antihypertensive adherence to enable effective targeting of clinical interventions to improve hypertension management and outcomes.

Association between gaps in antihypertensive medication adherence and injurious falls in older community-dwelling adults: a prospective cohort study

OBJECTIVE

Growing evidence suggests that older adults are at an increased risk of injurious falls when initiating antihypertensive medication, while the evidence regarding long-term use of antihypertensive medication and the risk of falling is mixed. However, long-term users who stop and start these medications may have a similar risk of falling to initial users of antihypertensive medication. Our aim was to evaluate the association between gaps in antihypertensive medication adherence and injurious falls in older (≥65 years) community-dwelling, long-term (≥≥1 year) antihypertensive users.

DESIGN

Prospective cohort study.

SETTING

Irish Community Pharmacy.

PARTICIPANTS

Consecutive participants presenting a prescription for antihypertensive medication to 106 community pharmacies nationwide, community-dwelling, ≥65 years, with no evidence of cognitive impairment, taking antihypertensive medication for ≥1 year (n=938).

MEASURES

Gaps in antihypertensive medication adherence were evaluated from linked dispensing records as the number of 5-day gaps between sequential supplies over the 12-month period prior to baseline. Injurious falls during follow-up were recorded via questionnaire during structured telephone interviews at 12 months.

RESULTS

At 12 months, 8.1% (n=76) of participants reported an injurious fall requiring medical attention. The mean number of 5-day gaps in medication refill behaviour was 1.47 (SD 1.58). In adjusted, modified Poisson models, 5-day medication refill gaps at baseline were associated with a higher risk of an injurious fall during follow-up (aRR 1.18, 95% CI 1.02 to 1.37, p=0.024).

CONCLUSION

Each 5-day gap in antihypertensive refill adherence increased the risk of self-reported injurious falls by 18%. Gaps in antihypertensive adherence may be a marker for increased risk of injurious falls. It is unknown whether adherence-interventions will reduce subsequent risk. This finding is hypothesis generating and should be replicated in similar populations.

Cost-effectiveness Analysis of Sequential Treatment of Abaloparatide Followed by Alendronate Versus Teriparatide Followed by Alendronate in Postmenopausal Women With Osteoporosis in the United States

BACKGROUND

The US Food and Drug Administration has recently approved abaloparatide (ABL) for treatment of women with postmenopausal osteoporosis (PMO) at high risk of fracture. With increasing health care spending and drug prices, it is important to quantify the value of newly available treatment options for PMO.

OBJECTIVE

To determine cost-effectiveness of ABL compared with teriparatide (TPTD) for treatment of women with PMO in the United States.

METHODS

A discrete-event simulation (DES) model was developed to assess cost-effectiveness of ABL from the US health care perspective. The model included three 18-month treatment strategies with either placebo (PBO), TPTD, or ABL, all followed by additional 5-year treatment with alendronate (ALN). High-risk patients were defined as women with PMO ⩾65 years old with a prior vertebral fracture. Baseline clinical event rates, risk reductions, and patient characteristics were based on the Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE) trial.

RESULTS

Over a 10-year period, the DES model yielded average total discounted per-patient costs of $10 212, $46 783, and $26 837 and quality-adjusted life-years (QALYs) of 6.742, 6.781, and 6.792 for PBO/ALN, TPTD/ALN, and ABL/ALN, respectively. Compared with TPTD/ALN, ABL/ALN accrued higher QALYs at lower cost and produced an incremental cost-effectiveness ratio (ICER) of $333 266/QALY relative to PBO/ALN. In high-risk women, ABL/ALN also had more QALYs and less cost over TPTD/ALN and yielded an ICER of $188 891/QALY relative to PBO/ALN. Conclusion and Relevance: ABL is a dominant treatment strategy over TPTD. In women with PMO at high risk of fracture, ABL is an alternative cost-effective treatment.

Estimating Adherence Based on Prescription or Dispensation Information: Impact on Thresholds and Outcomes. A Real-World Study With Atrial Fibrillation Patients Treated With Oral Anticoagulants in Spain

Objective: To estimate drug exposure, Proportion of Days Covered (PDC) and percentage of patients with PDC ≥ 80% from a cohort of atrial fibrillation patients initiating oral anticoagulant (OAC) treatment. We employed three different approaches to estimate PDC, using either data from prescription and dispensing (PD cohort) or two common designs based on dispensing information only, requiring at least one (D1) or at least two (D2) refills for inclusion in the cohorts. Finally, we assessed the impact of adherence on health outcomes according to each method. Methods: Population-based retrospective cohort of all patients with Non Valvular Atrial Fibrillation (NVAF), who were newly prescribed acenocoumarol, apixaban, dabigatran or rivaroxaban from November 2011 to December 2015 in the region of Valencia (Spain). Patients were followed for 12 months to assess adherence using three different approaches (PD, D1 and D2 cohorts). To analyze the relationship between adherence (PDC ≥ 80) defined according to each method of calculation and health outcomes (death for any cause, stroke or bleeding) Cox regression models were used. For the identification of clinical events patients were followed from the end of the adherence assessment period to the end of the available follow-up period. Results: PD cohort included all patients with an OAC prescription (n = 38,802), D1 cohort excluded fully non-adherent patients (n = 265) and D2 cohort also excluded patients without two refills separated by 180 days (n = 2,614). PDC ≥ 80% ranged from 94% in the PD cohort to 75% in the D1 cohort. Drug exposure among adherent (PDC ≥ 80%) and non-adherent (PDC < 80%) patients was different between cohorts. In adjusted analysis, high adherence was associated with a reduced risk of death [Hazard Ratio (HR): from 0.82 to 0.86] and (except in the PD cohort) the risk for ischemic stroke (HR: from 0.61 to 0.64) without increasing the risk of bleeding. Conclusion: Common approaches to assess adherence using measures based on days' supply exclude groups of non-adherent patients and, also, misattribute periods of doctors' discontinuation to patient non-adherence, misestimating adherence overall. Physician-initiated discontinuation is a major contributor to reduced OAC exposure. When using the PDC80 threshold, very different groups of patients may be classified as adherent or non-adherent depending on the method used for the calculation of days' supply measures. High adherence and high exposure to OAC treatment in NVAF patients is associated with better health outcomes.

Potential contribution of lifestyle and socioeconomic factors to healthy user bias in antihypertensives and lipid-lowering drugs

Objectives

Healthy user bias arises when users of preventive medications such as lipid-lowering drugs (LLDs), hormone replacement therapy and antihypertensive (AH) medications are healthier than non-users due to factors other than medication effects, making the medications appear more beneficial in observational studies of effectiveness and safety. The purpose of the study is to examine factors contributing to healthy user effect in patients taking AHs or LLDs.

Methods

Among patients with hypertension or hyperlipidaemia in a population-based sample from the National Health and Nutrition Examination Survey (1999–2010), we assessed the association between socioeconomic and lifestyle factors and the use of AHs/LLDs by logistic regression with adjustment for demographics and comorbidities in a cross-sectional study.

Results

When 9715 AH/LLD users were compared with 3725 non-users, AH/LLD users were more likely to be: highly educated (OR 1.2, 95% CI 1.2 to 1.3), non-impoverished (OR 1.3, 95% CI 1.2 to 1.4), current non-smokers (OR 1.2, 95% CI 1.1 to 1.4), physically active (OR 1.1, 95% CI 1.0 to 1.2) and consume more calcium (OR 1.1, 95% CI 1.0 to 1.3) but less likely to have normal body mass index (OR 0.6, 95% CI 0.6 to 0.7) or to meet dietary sodium recommendations (OR 0.8, 95% CI 0.7 to 0.9).

Conclusions

We identified several salutary lifestyle factors associated with AH/LLD use in a representative US population. Healthy user effect may be partly explained by better socioeconomic profiles and lifestyles in AH/LLD users compared with non-users.

Predictors of Early Discontinuation of Pegylated Interferon for Reasons Other Than Lack of Efficacy in United States Veterans With Chronic Hepatitis C

During the dual-therapy era, many patients with chronic hepatitis C discontinued therapy for reasons other than lack of efficacy (non-LOE). We determined whether selected patient characteristics predicted non-LOE discontinuation using national databases of U.S. veterans with Genotypes 1-4. We identified U.S. veterans in the Veterans Health Administration system in 2004-2009 who had hepatitis C-confirming RNA laboratory results and initiated therapy with pegylated interferon and ribavirin. We used a rule to classify patients who discontinued pegylated interferon early, based on pharmacy refill and viral response data. Multivariate Cox regression was used to identify predictors of non-LOE discontinuation. Of 321,238 patients with a hepatitis C International Classification of Diseases, Ninth Revision, code, 15,297 (4.8%) met all inclusion criteria. Non-LOE discontinuers comprised 30.3% of patients. For Genotypes 1-4, the predictors (adjusted hazard ratio) of greatest magnitude were comorbidities of myocardial infarction/congestive heart failure (1.36), renal disease (1.34), and platelets 100/mm or more (1.38). For Genotypes 2 and 3, predictors of greatest magnitude were Black race (1.30), myocardial infarction/congestive heart failure (1.84), albumin 3.5 mg/dl or more (1.65), sleep aid use (1.32), and poor persistence with antidepressants (1.31) and antihypertensive agents (1.37). Our study suggests that many host factors may have contributed to non-LOE dual-therapy discontinuation in veterans and may possibly predict non-LOE discontinuation in triple therapy.

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

Background

Electronic health records (EHRs), when linked across primary and secondary care and curated for research use, have the potential to improve our understanding of care quality and outcomes.

Objective

To evaluate new opportunities arising from linked EHRs for improving quality of care and outcomes for patients at risk of or with coronary disease across the patient journey.

Design

Epidemiological cohort, health informatics, health economics and ethnographic approaches were used.

Setting

230 NHS hospitals and 226 general practices in England and Wales.

Participants

Up to 2 million initially healthy adults, 100,000 people with stable coronary artery disease (SCAD) and up to 300,000 patients with acute coronary syndrome.

Main outcome measures

Quality of care, fatal and non-fatal cardiovascular disease (CVD) events.

Data platform and methods

We created a novel research platform [ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER)] based on linkage of four major sources of EHR data in primary care and national registries. We carried out 33 complementary studies within the CALIBER framework. We developed a web-based clinical decision support system (CDSS) in hospital chest pain clinics. We established a novel consented prognostic clinical cohort of SCAD patients.

Results

CALIBER was successfully established as a valid research platform based on linked EHR data in nearly 2 million adults with > 600 EHR phenotypes implemented on the web portal (seehttps://caliberresearch.org/portal). Despite national guidance, key opportunities for investigation and treatment were missed across the patient journey, resulting in a worse prognosis for patients in the UK compared with patients in health systems in other countries. Our novel, contemporary, high-resolution studies showed heterogeneous associations for CVD risk factors across CVDs. The CDSS did not alter the decision-making behaviour of clinicians in chest pain clinics. Prognostic models using real-world data validly discriminated risk of death and events, and were used in cost-effectiveness decision models.

Conclusions

Emerging ‘big data’ opportunities arising from the linkage of records at different stages of a patient’s journey are vital to the generation of actionable insights into the diagnosis, risk stratification and cost-effective treatment of people at risk of, or with, CVD.

Future work

The vast majority of NHS data remain inaccessible to research and this hampers efforts to improve efficiency and quality of care and to drive innovation. We propose three priority directions for further research. First, there is an urgent need to ‘unlock’ more detailed data within hospitals for the scale of the UK’s 65 million population. Second, there is a need for scaled approaches to using EHRs to design and carry out trials, and interpret the implementation of trial results. Third, large-scale, disease agnostic genetic and biological collections linked to such EHRs are required in order to deliver precision medicine and to innovate discovery.

Study registration

CALIBER studies are registered as follows: study 2 – NCT01569139, study 4 – NCT02176174 and NCT01164371, study 5 – NCT01163513, studies 6 and 7 – NCT01804439, study 8 – NCT02285322, and studies 26–29 – NCT01162187. Optimising the Management of Angina is registered as Current Controlled Trials ISRCTN54381840.

Funding

The National Institute for Health Research (NIHR) Programme Grants for Applied Research programme (RP-PG-0407-10314) (all 33 studies) and additional funding from the Wellcome Trust (study 1), Medical Research Council Partnership grant (study 3), Servier (study 16), NIHR Research Methods Fellowship funding (study 19) and NIHR Research for Patient Benefit (study 33).

The Effects of Intra-Aortic Balloon Pumps on Mortality in Patients Undergoing High-Risk Coronary Revascularization: A Meta-Analysis of Randomized Controlled Trials of Coronary Artery Bypass Grafting and Stenting Era

BACKGROUND

Intra-aortic balloon pumps (IABP) have generally been used for patients undergoing high-risk mechanical coronary revascularization. However, there is still insufficient evidence to determine whether they can improve outcomes in reperfusion therapy patients, mainly by percutaneous coronary intervention (PCI) with stenting or coronary artery bypass graft (CABG). This study was designed to determine the difference between high-risk mechanical coronary revascularization with and without IABPs on mortality, by performing a meta-analysis on randomized controlled trials of the current era.

METHODS

Pubmed and Embase databases were searched from inception to May 2015. Unpublished data were obtained from the investigators. Randomized clinical trials of IABP and non-IABP in high-risk coronary revascularization procedures (PCI or CABG) were included. In the case of PCI procedures, stents should be used in more than 80% of patients. Numbers of events at the short-term and long-term follow-up were extracted.

RESULTS

A total of 12 randomized trials enrolling 2155 patients were included. IABPs did not significantly decrease short-term mortality (relative risk (RR) 0.66; 95% CI, 0.42-1.01), or long-term mortality (RR 0.79; 95% CI, 0.47-1.35), with low heterogeneity across the studies. The findings remained stable in patients with acute myocardial infarction with or without cardiogenic shock. But in high-risk CABG patients, IABP was associated with reduced mortality (71 events in 846 patients; RR 0.40; 95%CI 0.25-0.67).

CONCLUSION

In patients undergoing high-risk coronary revascularization, IABP did not significantly decrease mortality. But high-risk CABG patients may be benefit from IABP. Rigorous criteria should be applied to the use of IABPs.

Adherence to Treatment in Hypertension

The lack of adherence to treatment in hypertension affects approximately 30 % of patients. The elderly, those with several co-morbidities, social isolation, low incomes or depressive symptoms are the most vulnerable to this problem. There is no ideal method to quantify the adherence to the treatment. Indirect methods are recommended in clinical practice. Any intervention strategy should not blame the patient and try a collaborative approach. It is recommended to involve the patient in decision-making. The clinical interview style must be patient-centered including motivational techniques. The improvement strategies that showed greater effectiveness in the compliance of hypertension treatment were: treatment simplification, appointment reminders systems, blood pressure self-monitoring, organizational improvements and nurse and pharmacists care. The combination of different interventions are recommended against isolated interventions.

Simulating Strategies for Improving Control of Hypertension Among Patients with Usual Source of Care in the United States: The Blood Pressure Control Model

BACKGROUND

Only half of hypertensive adults achieve blood pressure (BP) control in the United States, and it is unclear how BP control rates may be improved most effectively and efficiently at the population level.

OBJECTIVE

We sought to compare the potential effects of system-wide isolated improvements in medication adherence, visit frequency, and higher physician prescription rate on achieving BP control at 52 weeks.

DESIGN

We developed a Markov microsimulation model of patient-level, physician-level, and system-level processes involved in controlling hypertension with medications. The model is informed by data from national surveys, cohort studies and trials, and was validated against two multicenter clinical trials (ALLHAT and VALUE).

SUBJECTS

We studied a simulated, nationally representative cohort of patients with diagnosed but uncontrolled hypertension with a usual source of care.

INTERVENTIONS

We simulated a base case and improvements of 10 and 50%, and an ideal scenario for three modifiable parameters: visit frequency, treatment intensification, and medication adherence. Ideal scenarios were defined as 100% for treatment intensification and adherence, and return visits occurring within 4 weeks of an elevated office systolic BP.

MAIN OUTCOME

BP control at 52 weeks of follow-up was examined.

RESULTS

Among 25,000 hypothetical adult patients with uncontrolled hypertension (systolic BP ≥ 140 mmHg), only 18% achieved BP control after 52 weeks using base-case assumptions. With 10/50%/idealized enhancements in each isolated parameter, enhanced treatment intensification achieved the greatest BP control (19/23/71%), compared with enhanced visit frequency (19/21/35%) and medication adherence (19/23/26%). When all three processes were idealized, the model predicted a BP control rate of 95% at 52 weeks.

CONCLUSION

Substantial improvements in BP control can only be achieved through major improvements in processes of care. Healthcare systems may achieve greater success by increasing the frequency of clinical encounters and improving physicians' prescribing behavior than by attempting to improve patient adherence to medications.

Evaluation of the Back College for nursing staff

Background

Work-related musculoskeletal pain- particularly back pain - is an important individual and socioeconomic problem. The Back College for the insurance holders of the Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services (BGW) is based on a multimodal concept and has been evaluated with respect to pain relief and continuing in the nursing profession.

Methods

In a retrospective cohort study, the participants in the Back College from 2009 to 2011 were surveyed in writing. Besides demographic data, the survey covered information on qualification, length of employment, institution, employment status, periods of inability to work, applicability of working techniques and continuation in the profession. Back pain was recorded at three time points - T1 (before the Back College), T2 (directly after the Back College) and T3 (at the time of the survey). Pain changes were submitted to tests for paired samples. Multivariate logistic analysis was applied to determine potential factors influencing unfavourable changes in pain or leaving nursing due to back pain.

Results

The survey covered 1,282 insurance holders, with a response rate of 80%. Statistically significant reductions in pain were found for the whole group and for all subgroups. For persons who predominantly worked in old people’s homes and who did not take part in refresher services, an increased odds ratio was found for unfavourable changes in pain (OR: 1.9 or 1.4, respectively). Persons with a qualification in geriatric nursing or in intensive care/OP/anaesthesia had an increased risk of leaving nursing due to back pain (OR: 2.5 in each case). An increased risk of leaving was also found for persons who did not take part in workplace support (OR: 2.9).

Conclusion

Within the context of the study design, the multimodal concept of the Back College is clearly related to relief of back pain. The Back College appears to be less successful for geriatric nurses and persons with qualifications in intensive care/OP/anaesthesia. Further studies are needed to ascertain why some participants experience less relief in stress from the working techniques they have learnt.

Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation: an observational study

BACKGROUND

The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available.

METHODS

We followed 4,154 patients treated with coronary drug-eluting stents in Western Denmark for 1 year and obtained data on redeemed clopidogrel prescriptions and major adverse cardiovascular events (MACE, i.e., cardiac death, myocardial infarction, or stent thrombosis) from medical databases.

RESULTS

Discontinuation of clopidogrel within the first 3 months after stent implantation was associated with a significantly increased rate of MACE at 1-year follow-up (hazard ratio (HR) 2.06; 95% confidence interval (CI): 1.08-3.93). Discontinuation 3-6 months (HR 1.29; 95% CI: 0.70-2.41) and 6-12 months (HR 1.29; 95% CI: 0.54-3.07) after stent implantation were associated with smaller, not statistically significant, increases in MACE rates. Among patients who discontinued clopidogrel, MACE rates were highest within the first 2 months after discontinuation.

CONCLUSIONS

Discontinuation of clopidogrel was associated with an increased rate of MACE among patients treated with drug-eluting stents. The increase was statistically significant within the first 3 months after drug-eluting stent implantation but not after 3 to 12 months.

Expanding the framework of assessing adherence and medication-taking behavior

This analysis critiques recently published concepts of medication adherence assessment and elucidates the importance of finding new measures of adherence. Improving concepts and methods of adherence assessment is key to improving adherence outcomes. It proposes a new framework that contains more inclusive concepts and more standardized terminology. These new concepts and terms not only describe adherence and its specific measures in more detail, but also describe all medication-taking behavior. It argues for the integration of and measurement of behavior associated with specific dose times, types, or schedules. Last, it describes promising research enabled by the new framework that, if implemented, might lead to improved adherence.

Adherence to antihypertensive agents after ischemic stroke and risk of cardiovascular outcomes

OBJECTIVE

To evaluate the relationship between antihypertensive (AH) drug adherence and cardiovascular (CV) outcomes among patients with a recent ischemic stroke and assess the validity of our approach.

METHODS

A cohort of 14,227 patients diagnosed with an ischemic stroke was assembled from individuals 65 years and older who were treated with AH agents from 1999 to 2007 in Quebec, Canada. A nested case-control design was used to evaluate the occurrence of nonfatal major CV outcomes and mortality. Each case was matched to 15 controls by age and cohort entry time. Medication possession ratio was used for AH agent adherence level. Adjusted conditional logistic regression models were used to estimate the rate ratio of CV events. The validity of the approach was assessed by evaluating the adherence level of CV-protective and non-CV-protective drugs.

RESULTS

Mean age was 75 years, 54% were male, 38% had coronary artery disease, 23% had diabetes, 47% dyslipidemia, and 14% atrial fibrillation or flutter. High adherence to AH therapy was mirrored by similar adherence to statins and antiplatelet agents and was associated with a lower risk of nonfatal vascular events compared with lower adherence (rate ratio 0.77 [0.70-0.86]). We observed a paradoxic link between adherence to several drugs and all-cause mortality.

CONCLUSION

Adherence to AH agents is associated with adherence to other secondary preventive therapies and a risk reduction for nonfatal vascular events after an ischemic stroke. Overestimation of all-cause mortality reduction may be related to frailty and comorbidities, which may confound the apparent benefit of different drugs.

Association between treated and untreated obstructive sleep apnea and risk of hypertension

CONTEXT

Systemic hypertension is prevalent among patients with obstructive sleep apnea (OSA). Short-term studies indicate that continuous positive airway pressure (CPAP) therapy reduces blood pressure in patients with hypertension and OSA.

OBJECTIVE

To determine whether CPAP therapy is associated with a lower risk of incident hypertension.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study of 1889 participants without hypertension who were referred to a sleep center in Zaragoza, Spain, for nocturnal polysomnography between January 1, 1994, and December 31, 2000. Incident hypertension was documented at annual follow-up visits up to January 1, 2011. Multivariable models adjusted for confounding factors, including change in body mass index from baseline to censored time, were used to calculate hazard ratios (HRs) of incident hypertension in participants without OSA (controls), with untreated OSA, and in those treated with CPAP therapy according to national guidelines.

MAIN OUTCOME MEASURE

Incidence of new-onset hypertension.

RESULTS

During 21,003 person-years of follow-up (median, 12.2 years), 705 cases (37.3%) of incident hypertension were observed. The crude incidence of hypertension per 100 person-years was 2.19 (95% CI, 1.71-2.67) in controls, 3.34 (95% CI, 2.85-3.82) in patients with OSA ineligible for CPAP therapy, 5.84 (95% CI, 4.82-6.86) in patients with OSA who declined CPAP therapy, 5.12 (95% CI, 3.76-6.47) in patients with OSA nonadherent to CPAP therapy, and 3.06 (95% CI, 2.70-3.41) in patients with OSA and treated with CPAP therapy. Compared with controls, the adjusted HRs for incident hypertension were greater among patients with OSA ineligible for CPAP therapy (1.33; 95% CI, 1.01-1.75), among those who declined CPAP therapy (1.96; 95% CI, 1.44-2.66), and among those nonadherent to CPAP therapy (1.78; 95% CI, 1.23-2.58), whereas the HR was lower in patients with OSA who were treated with CPAP therapy (0.71; 95% CI, 0.53-0.94).

CONCLUSION

Compared with participants without OSA, the presence of OSA was associated with increased adjusted risk of incident hypertension; however, treatment with CPAP therapy was associated with a lower risk of hypertension.

Clopidogrel discontinuation after acute coronary syndromes: frequency, predictors and associations with death and myocardial infarction--a hospital registry-primary care linked cohort (MINAP-GPRD)

Aims

Adherence to evidence-based treatments and its consequences after acute myocardial infarction (MI) are poorly defined. We examined the extent to which clopidogrel treatment initiated in hospital is continued in primary care; the factors predictive of clopidogrel discontinuation and the hazard of death or recurrent MI.

Methods and results

We linked the Myocardial Ischaemia National Audit Project registry and the General Practice Research Database to examine adherence to clopidogrel in primary care among patients discharged from hospital after MI (2003–2009). Hospital Episode Statistics and national mortality data were linked, documenting all-cause mortality and non-fatal MI. Of the 7543 linked patients, 4650 were prescribed clopidogrel in primary care within 3 months of discharge. The adjusted odds of still being prescribed clopidogrel at 12 months were similar following non-ST-elevation myocardial infarction (NSTEMI) 53% (95% CI, 51–55) and ST-elevation myocardial infarction (STEMI) 54% (95% CI, 52–56), but contrast with statins: NSTEMI 84% (95% CI, 82–85) and STEMI 89% (95% CI, 87–90). Discontinuation within 12 months was more frequent in older patients [>80 vs. 40–49 years, adjusted hazard ratio (HR) 1.50 (95% CI, 1.15–1.94)] and with bleeding events [HR 1.34 (95% CI, 1.03–1.73)]. 18.15 patients per 100 person-years (95% CI, 16.83–19.58) died or experienced non-fatal MI in the first year following discharge. In patients who discontinued clopidogrel within 12 months, the adjusted HR for death or non-fatal MI was 1.45 (95% CI, 1.22–1.73) compared with untreated patients, and 2.62 (95% CI, 2.17–3.17) compared with patients persisting with clopidogrel treatment.

Conclusion

This is the first study to use linked registries to determine persistence of clopidogrel treatment after MI in primary care. It demonstrates that discontinuation is common and associated with adverse outcomes.