Measuring drug exposure: concordance between defined daily dose and days' supply depended on drug class

Estimation of adherence to urate-lowering therapy in people living with gout using Australia's Pharmaceutical Benefits Scheme and patient-reported dosing

AIMS

The aim of this study was to estimate adherence to urate-lowering therapy (ULT), predominately allopurinol, from Australia's Pharmaceutical Benefits Scheme (PBS) claims database in association with (1) patient-reported doses and (2) World Health Organization's (WHO) defined daily doses (DDD), namely, allopurinol (400 mg/day) or febuxostat (80 mg/day).

METHODS

Proportion of days covered (PDC) was calculated in 108 Gout App (Gout APP) trial participants with at least two recorded ULT dispensings in an approximately 12-month period before provision of intervention or control apps. Adherence was defined as PDC ≥80%. We measured the correlation between the two methods of calculating PDC using a Wilcoxon signed rank test. Agreement between ULT-taking status (self-reports) and ULT-dispensed status (PBS records) was tested with Cohen's kappa (κ), and positive and negative percent agreement.

RESULTS

Allopurinol was prescribed in 93.5% of participants taking ULT. Their self-reported mean daily dose (SD) was 291 (167) mg/day. Mean PDC (SD) for allopurinol was 83% (21%) calculated using self-reported dose, and 63% (24%) using WHO's DDD. Sixty-three percent of allopurinol users were identified as adherent (PDC ≥80%) using self-reported dose. There was good agreement between self-reported ULT use and PBS dispensing claims (κ = 0.708, P < .001; positive percent agreement = 90%, negative percent agreement = 82%).

CONCLUSIONS

Participant-reported allopurinol daily doses, in addition to PBS dispensing claims, may enhance confidence in estimating PDC and adherence compared to using DDD. This approach improves adherence estimations from pharmaceutical claims datasets for medications where daily doses vary between individuals or where there is a wide therapeutic dose range.

Influence of Low-Density Lipoprotein Cholesterol Levels on NSAID-Associated Cardiovascular Risks After Myocardial Infarction: A Population-Based Cohort Study

Aim

To examine whether low-density lipoprotein cholesterol (LDL-C) levels influence the cardiovascular risk associated with non-aspirin non-steroidal anti-inflammatory drug (NSAID) use after myocardial infarction (MI).

Methods

Using Danish health registries, we conducted a population-based cohort study of all adult patients with first-time MI during 2010-2020 with an LDL-C value before discharge. Based on the latest LDL-C value, we categorized patients into a low and a high LDL-C group (<3.0 vs ≥3.0 mmol/L). We used time varying Cox regression to compute hazard ratios (HRs) with 95% confidence intervals of the association between NSAID use and a major adverse cardiovascular event (MACE: recurrent MI, ischemic stroke, and all-cause death).

Results

We followed 50,573 patients for a median of 3.1 years. While exposed, 521 patients experienced a MACE: 312 in the low LDL-C group and 209 in the high LDL-C group. The HRs for MACE comparing NSAID use with non-use were 1.21 (1.11-1.32) overall, 1.19 (1.06-1.33) in the low LDL-C group, and 1.23 (1.07-1.41) in the high LDL-group. The HRs for recurrent MI and ischemic stroke were comparable between the LDL-C subgroups. The HRs for all-cause death were 1.22 (1.07-1.39) in the low LDL-C group and 1.54 (1.30-1.83) in the high LDL-C group. Changing the cut-off value for LDL-C to 1.8 and 1.4 mmol/L showed consistent results.

Conclusion

In patients with MI, LDL-C levels did not influence the increased risk of MACE associated with NSAID use, but might influence the association between NSAID use and all-cause death.

Impact of hemoglobin A1c level on the association between non-steroidal anti-inflammatory drug use and cardiovascular events in patients with type 2 diabetes: A population-based cohort study

OBJECTIVE

Non-steroidal anti-inflammatory drugs (NSAIDs) should be used cautiously in patients with type 2 diabetes. We examined whether the cardiovascular risks associated with NSAID use depended on HbA1c level in patients with type 2 diabetes.

METHODS

We conducted a population-based cohort study of all adult Danes with a first-time HbA1c measurement ≥48 mmol/mol during 2012-2020 (n = 103 308). We used information on sex, age, comorbidity burden, and drug use to calculate time-varying inverse probability of treatment weights. After applying these weights in a pooled logistic regression, we estimated hazard ratios (HRs) of the association between use of NSAIDs (ibuprofen, naproxen, or diclofenac) and cardiovascular events (a composite of myocardial infarction, ischemic stroke, congestive heart failure, atrial fibrillation or flutter, and all-cause death). We stratified all analyses by HbA1c level (<53 or ≥53 mmol/mol).

RESULTS

For ibuprofen use, the HR of a cardiovascular event was 1.53 (95% confidence interval [CI]: 1.34-1.75) in patients with HbA1c <53 and 1.24 (95% CI: 1.00-1.53) in patients with HbA1c ≥53 mmol/mol. For naproxen use, the HR was 1.14 (95% CI: 0.59-2.21) in patients with HbA1c <53 and 1.30 (95% CI: 0.49-3.49) in patients with HbA1c ≥53 mmol/mol. For diclofenac use, the HR was 2.40 (95% CI: 1.62-3.56) in patients with HbA1c <53 and 2.89 (95% CI: 1.65-5.04) in patients with HbA1c ≥53 mmol/mol.

CONCLUSIONS

In patients with type 2 diabetes, glycemic dysregulation did not affect the cardiovascular risk associated with NSAID use.

Impact of Lifestyle and Socioeconomic Position on the Association Between Non-steroidal Anti-inflammatory Drug Use and Major Adverse Cardiovascular Events: A Case-Crossover Study

INTRODUCTION

It is unknown whether the cardiovascular risks associated with non-steroidal anti-inflammatory drug (NSAID) use differ according to lifestyle and socioeconomic position.

OBJECTIVE

We examined the association between NSAID use and major adverse cardiovascular events (MACE) within subgroups defined by lifestyle and socioeconomic position.

METHODS

We conducted a case-crossover study of all adult first-time respondents to the Danish National Health Surveys of 2010, 2013, or 2017, without previous cardiovascular disease, who experienced a MACE from survey completion through 2020. We used a Mantel-Haenszel method to obtain odds ratios (ORs) of the association between NSAID use (ibuprofen, naproxen, or diclofenac) and MACE (myocardial infarction, ischemic stroke, heart failure, or all-cause death). We identified NSAID use and MACE via nationwide Danish health registries. We stratified the analyses by body mass index, smoking status, alcohol consumption, physical activity level, marital status, education, income, and employment.

RESULTS

Compared with non-use, the OR of MACE was 1.34 (95% confidence interval: 1.23-1.46) for ibuprofen, 1.48 (1.04-2.43) for naproxen, and 2.18 (1.72-2.78) for diclofenac. When comparing NSAID use with non-use or the individual NSAIDs with each other, we observed no notable heterogeneity in the ORs within subgroups of lifestyle and socioeconomic position for any NSAID. Compared with ibuprofen, diclofenac was associated with increased risk of MACE in several subgroups with high cardiovascular risk, e.g., individuals with overweight (OR 1.52, 1.01-2.39) and smokers (OR 1.54, 0.96-2.46).

CONCLUSIONS

The relative increase in cardiovascular risk associated with NSAID use was not modified by lifestyle or socioeconomic position.

Emissions of pharmaceuticals and plant protection products to the lagoon of Venice: development of a new emission inventory

Estimating the emissions of chemical pollutants to water is a fundamental step for the development and application of effective and sustainable management strategies of water resources, but methods applied so far to build chemicals inventories at the European or national scale show several limitations when applied at the local scale. The issue is particularly relevant when considering contaminants of emerging concern (CECs), whose environmental releases and occurrence are still poorly studied and understood. In this work, an approach to estimate water emissions of nine active pharmaceutical ingredients (APIs) and ten most applied plant protection products (PPPs) is presented, considering proxy indicators (e.g., sales data and census information). The application area is the lagoon of Venice (Italy), a complex transitional environment highly influenced by anthropic pressures (e.g., agricultural and industrial activities, animal breeding, and wastewater discharge). The presented approach can be tailored to the information available for any local scale case study. Data on annual regional sales of PPPs and APIs were integrated with georeferenced demographic and economic statistics (such as census and land-use information) to estimate chemicals emissions to surface water and groundwater. A sensitivity and uncertainty analysis identified the main factors affecting emissions estimates, and those contributing more significantly to results uncertainty. Results showed the highest estimated emissions of APIs for antibiotics (i.e., amoxicillin, clarithromycin, azithromycin, and ciprofloxacin) used for humans and animals, while most of hormones' emission (i.e., 17- α-ethinylestradiol and 17-β-estradiol) derived from animal breeding. Regarding PPPs, glyphosate and imidacloprid emissions were one to two orders of magnitude higher compared to the other chemicals. Uncertainty and sensitivity analysis showed that the variability of each parameter used to estimate emissions depends greatly both on the target chemical and the specific emission source considered. Excretion rates and removal during wastewater treatment were major key parameters for all the target pharmaceutical compounds, while for PPPs the key parameter was their loss into the natural waters after application.

A data-informed approach using individualised dispensing patterns to estimate medicine exposure periods and dose from pharmaceutical claims data

Pharmaceutical claims data are often used as the primary information source to define medicine exposure periods in pharmacoepidemiological studies. However, often critical information on directions for use and the intended duration of medicine supply are not available. In the absence of this information, alternative approaches are needed to support the assignment of exposure periods. This study summarises the key methods commonly used to estimate medicine exposure periods and dose from pharmaceutical claims data; and describes a method using individualised dispensing patterns to define time-dependent estimates of medicine exposure and dose. This method extends on important features of existing methods and also accounts for recent changes in an individual's medicine use. Specifically, this method constructs medicine exposure periods and estimates the dose used by considering characteristics from an individual's prior dispensings, accounting for the time between prior dispensings and the amount supplied at prior dispensings. Guidance on the practical applications of this method is also provided. Although developed primarily for application to databases, which do not contain duration of supply or dose information, use of this method may also facilitate investigations when such information is available and there is a need to consider individualised and/or changing dosing regimens. By shifting the reliance on prescribed duration and dose to determine exposure and dose estimates, individualised dispensing information is used to estimate patterns of exposure and dose for an individual. Reflecting real-world individualised use of medicines with complex and variable dosing regimens, this method offers a pragmatic approach that can be applied to all medicine classes.

Association between use of antacid medications (proton pump inhibitors and histamine-2 receptor antagonists) and the incidence of lung cancer: A population-based cohort analysis

This study investigated the association between antacid administration and lung cancer incidence in a real-world setting. This was a nationwide, retrospective cohort study. The cohort comprised random samples (n = 1,031,392) from the entire South Korean population in 2002. The duration of antacid administration between January 2006 and December 2010 was recorded for each participant. Newly developed lung cancers were counted during the 5-year observation period (January 1, 2006 to December 31, 2010). A total of 437,370 participants aged ≥ 40 years were included, of whom 301,201 (68.9%) had antacid exposure before the diagnosis of lung cancer. A total of 1230 (0.28%) antacid-exposed patients developed lung cancer. Among patients with no antacid exposure or underexposure (n = 136,171), 597 (0.44%) developed lung cancer. In the multivariable analysis, antacid exposure before the diagnosis of lung cancer was independently associated with a reduced incidence of lung cancer (hazard ratio: 0.64; 95% confidence interval: 0.55-0.74; P < .001). Antacid use might be independently associated with a decreased risk of lung cancer development in this cohort study.

Core Concepts in Pharmacoepidemiology: Measures of drug utilization based on individual-level drug dispensing data

Background

Drug utilization studies are essential to facilitate rational drug use in the society.

Aim

In this review, we provide an overview of drug utilization measures that can be used with individual‐level drug dispensing data, referencing additional reading on the individual analysis. This is intended to serve as a primer for those new to drug utilization research and a shortlist from which researchers can identify useful analytical approaches when designing their drug utilization study.

Results and Discussion

We provide an overview of: (1) basic measures of drug utilization which are used to describe changes in drug use over time or compare drug use in different populations; (2) treatment adherence measures with specific focus on persistence and implementation; (3) how to measure drug combinations which is useful when assessing drug–drug interactions, concomitant treatment, and polypharmacy; (4) prescribing quality indicators and measures to assess variations in drug use which are useful tools to assess appropriate use of drugs; (5) proxies of prescription drug misuse and skewness in drug use; and (6) considerations when describing the characteristics of drug users or prescribers.

Low-Dose Olanzapine in the Treatment of Adolescents with Anorexia Nervosa: An Observational Naturalistic Case-Control Study

Background: Although recent articles have investigated the use of low-dose olanzapine in different psychiatric conditions, only one study so far has assessed this treatment in 13 girls with anorexia nervosa (AN). Methods: Observational naturalistic case-control study aimed at reporting the use and tolerability of low-dose olanzapine in the context of a multidisciplinary hospital intervention for adolescents with AN. Three groups with AN were compared: group 1 was treated with low-dose olanzapine (≤5 mg/day), group 2 with full-dose olanzapine (>5 mg/day), and group 3 (control group) was treated without antipsychotics. Psychopathology was assessed at admission (T0) and discharge (T1) with Eating Disorders Inventory-3 Eating Disorders Risk, Body Uneasiness Test Global Severity Index (BUT-GSI), Beck's Depression Inventory-II (BDI-II), and Self-administered Psychiatric Scales for Children and Adolescents, Depression subtest (SAFA-D). Possible differences among the three groups, concerning clinical and treatment variables, were screened. Then, potential differences of T0-T1 modifications in psychopathological variables among the three treatment groups were assessed with analyses of covariance, corrected for baseline psychopathology and potential confounders, including possible concurrent antidepressants. Results: A total of 118 patients were enrolled (F = 94.1%; mean age = 15.4 ± 1.7 years), including 52 controls, 37 treated with low-dose olanzapine, and 29 with full-dose olanzapine. Low-dose olanzapine was well tolerated and used for a mean of 132.1 (±98.6) days, starting with a dosage of 3.4 (±1.2) mg/day and increasing to a maximum dose of 4.4 (±1.1) mg/day. The multidisciplinary intervention resulted in an improvement of BUT-GSI (p < 0.001), BDI-II (p < 0.001), and SAFA-D (p < 0.001) for the entire sample. Individuals treated with full-dose olanzapine experienced a significantly lower improvement in depressive measures: BDI-II (F[2,61] = 12.653, p < 0.001, η² = 0.269) and SAFA-D (F[2,57] = 7.413, p = 0.001, η² = 0.170), than the other groups. Discussion: This naturalistic controlled study expands the existing evidence on the use and tolerability of low-dose olanzapine in adolescents with AN. These results should be assessed in wider and prospective samples.

The comparative effectiveness of antidepressants for youths with major depressive disorder: a nationwide population-based study in Taiwan

Background:

Guidelines recommend fluoxetine as a first-line medication for youths diagnosed with major depressive disorder (MDD). However, little is known about the long-term effectiveness of different antidepressants in juveniles in the real world. This study aimed to compare the effectiveness of antidepressants in youths with MDD.

Methods:

Youths (<20 years old) with a diagnosis of MDD who were new users of antidepressants were selected from a nationwide population-based cohort in Taiwan between 1997 and 2013. We divided a total of 16,981 users (39.9% male; mean age: 16.6 years) into 10 different antidepressant groups (fluoxetine, sertraline, paroxetine, venlafaxine, citalopram, escitalopram, bupropion, fluvoxamine, mirtazapine and moclobemide). Regarding treatment outcomes (hospitalisation and medication discontinuation), Cox proportional hazards regression models were applied to estimate the hazards of such outcomes.

Results:

Compared with the youths treated with fluoxetine, the bupropion-treated group demonstrated lower rates of hospitalisation and discontinuation. Mirtazapine-treated group demonstrated a higher hospitalisation risk mainly when administered for single depressive episodes. Furthermore, patients treated with sertraline and fluvoxamine had higher discontinuation rates. Among the younger teenage subgroups (< 16 years), significantly higher rates of discontinuation were observed in those treated with sertraline, escitalopram and fluvoxamine. Among the older teenage subgroups (⩾ 16 years), bupropion was superior to fluoxetine in preventing hospitalisation and discontinuation.

Conclusion:

We concluded that bupropion might surpass fluoxetine with regard to hospitalisation prevention and drug therapy maintenance among youths with MDD, while mirtazapine users demonstrated a higher hospitalisation risk. Our findings might serve as a reference for clinicians in future studies.

The Random Effects Warfarin Days' Supply (REWarDS) Model: Development and Validation of a Novel Method for Estimating Exposure to Warfarin Using Administrative Data

Warfarin's complex dosing is a significant barrier to measurement of its exposure in observational studies using population databases. Using population-based administrative data (1996-2019) from British Columbia, Canada, we developed a method based on statistical modeling (Random Effects Warfarin Days' Supply (REWarDS)) that involves fitting a random-effects linear regression model to patients' cumulative dosage over time for estimation of warfarin exposure. Model parameters included a minimal universally available set of variables from prescription records for estimation of patients' individualized average daily doses of warfarin. REWarDS estimates were validated against a reference standard (manual calculation of the daily dose using the free-text administration instructions entered by the dispensing pharmacist) and compared with alternative methods (fixed window, fixed tablet, defined daily dose, and reverse wait time distribution) using Pearson's correlation coefficient (r), the intraclass correlation coefficient, and the root mean squared error. REWarDS-estimated days' supply showed strong correlation and agreement with the reference standard (r = 0.90 (95% confidence interval (CI): 0.90, 0.90); intraclass correlation coefficient = 0.95 (95% CI: 0.94, 0.95); root mean squared error = 8.24 days) and performed better than all of the alternative methods. REWarDS-estimated days' supply was valid and more accurate than estimates from all other available methods. REWarDS is expected to confer optimal precision in studies measuring warfarin exposure using administrative data.

Comparative effectiveness of antidepressants on geriatric depression: Real-world evidence from a population-based study

BACKGROUND

There is little real-world evidence about effectiveness of different antidepressants on geriatric depression.

METHODS

We used population-based claims data in Taiwan between 1997 and 2013 to include older patients (≥ 60 years of age) who were diagnosed with depression and started to use antidepressants. All patients were followed up until discontinuation of antidepressant use or the end of the study period. Treatment outcomes were set as the risk of switching to another antidepressant, receiving augmentation therapy, and psychiatric hospitalization. We used cox proportional hazards regression models to calculate hazard ratios with 95% confidence intervals (CIs) and adjust for several confounding factors (aHRs).

RESULTS

During the study period, a total of 207,946 elderly patients with depression received one of the following 11 antidepressants: sertraline, fluoxetine, paroxetine, escitalopram, citalopram, fluvoxamine, venlafaxine, duloxetine, moclobemide, mirtazapine, and bupropion. Compared to the patients treated with sertraline, those treated with fluvoxamine / venlafaxine had significantly but modestly higher risks of switching (aHR [95% CI]: 1.16 [1.11-1.21] / 1.10 [1.06-1.14]), augmentation (1.06 [1.02-1.10] / 1.08 [1.05-1.12]), and hospitalization (1.28 [1.03-1.58] / 1.37 [1.16-1.62]). Otherwise, the remaining 9 antidepressants yielded no consistent result in the three outcomes.

LIMITATIONS

This study is a multi-arm and active controlled trial, lacking a placebo group.

CONCLUSION

As treating geriatric depression, no individual antidepressant posed consistently better effectiveness in the outcomes of switching antidepressant, receiving augmentation, and psychiatric hospitalization than any other one, whereas clinicians should be cautious when prescribing fluvoxamine and venlafaxine.

Prescription Patterns and Relationship to Pharmacogenomics Testing in the Military Health System

INTRODUCTION

Clinical utilization of pharmacogenomics (PGx) testing is highly institutionally dependent, and little information is known about provider practices of PGx testing in the Military Health System (MHS). In this study, we aimed to characterize Clinical Pharmacogenetics Implementation Consortium (CPIC) actionable prescription (Rx) patterns and their temporal relationship with PGx testing in the MHS.

METHODS

Using data from the Military Health System Management Analysis and Reporting Tool (M2) database, this retrospective cohort study included all patients receiving at least one PGx test and at least one CPIC actionable Rx from January 2015 to August 2020 (845 patients, 1,471 PGx, 7,725 index CPIC actionable Rxs). Rx patterns and temporal relationships with PGx testing were characterized via descriptive statistics. Binomial regression was used to determine which patient and provider characteristics were associated with a patient receiving a PGx test within 30 days of an index Rx.

RESULTS

Patients had a median of 9 index CPIC actionable Rx's (range 1-26). Pain medications were most commonly prescribed (N = 794, 94% patients with at least 1 Rx). However, pain medication had the lowest Rx-PGx match rate (40%) compared to an average of 62% Rx-PGx match rate for all CPIC drugs. Antidepressants were also commonly prescribed (N = 668, 79.1% patients with at least 1 Rx), and antidepressants had the highest Rx-PGx match rate of 86.7%. A minority of providers (20%, N = 249) ordered the majority of PGx tests (86.1%, N = 1,266) and only 8.3% of PGx tests (N = 398) matched to a CPIC actionable drug within 30 days of the test (defined by Rxs ordered within 30 days before or after the PGx test). However, approximately 39.8% of patients (N = 317) had at least one drug match to a PGx test within 30 days. The largest predictor of whether a patient received a PGx test within 30 days of any index Rx was whether or not a specific psychiatry provider ordered the PGx test (odds ratio; OR 3.7, 95% CI 2.13-6.54, P < 0.001). Neither the CPIC level of evidence nor FDA PGx actionable or informative labels had a significant effect on PGx test timing.

CONCLUSIONS

PGx testing was generally limited to high Rx-drug users and was found to be an under-utilized resource. PGx testing did not typically follow CPIC guidelines. Implementing PGx testing protocols, simplifying PGx test-ordering by incorporating at minimum CYP2D6, CYP2C19, and CYP2C9 into PGx-testing panels, and unifying providers' PGx knowledgebase in the MHS are feasible and would improve the clinical utilization of PGx tests in the MHS.

Defining the duration of the dispensation of oral anticoagulants in administrative healthcare databases

PURPOSE

In clinical practice, warfarin therapy requires frequent dose adjustments. In pharmacy claims, the days supplied value may not reflect the true duration of warfarin dispensation. This may affect the measures of association comparing the safety of direct oral anticoagulants (DOACs) versus warfarin.

METHODS

Using Quebec healthcare administrative databases, we formed a cohort of 55 230 patients newly treated with oral anticoagulants between 2010 and 2016. The duration of dispensations was defined using two approaches: the recorded days supplied value, and the longitudinal coverage approximation (data-driven) that may account for individual variation in drug usage patterns. Propensity scores adjusted Cox proportional hazards regression models were used to estimate the hazard ratio (HR) of major bleeding with dabigatran or rivaroxaban versus warfarin.

RESULTS

Using the days supplied, the mean (and standard deviation) dispensation durations for dabigatran, rivaroxaban, and warfarin were 19 (15), 19 (14), and 13 (12) days, respectively. Using the data-driven approach, the durations were 20 (16), 19 (15), and 15 (16) days, respectively. The choice of the approach had no impact on the HR estimates.

CONCLUSIONS

In our settings, the data-driven approach closely approximated the recorded days supplied value for the standard dose therapies such as dabigatran and rivaroxaban. For warfarin, the data-driven approach captured more variability in the duration of dispensations compared to the days supplied value, which may better reflect the true drug-taking behavior of warfarin. Both approaches may provide valid estimates when comparing the safety of DOACs versus warfarin.

Association between Antibiotic Consumption and Incidence of Clostridioides difficile Infection in a Hospital

Previous exposure to antimicrobials is a major risk factor for Clostridioides difficile infection (CDI). Antibiotic prescription and C. difficile toxin assay records of patients admitted to a tertiary hospital in Korea from 2009 to 2013 were collected to investigate the association between antibiotic consumption and CDI incidence. A Spearman's correlation analysis between CDI incidence (positive result of toxin assay/10,000 admissions) and antibiotic consumption (defined daily dose/1,000 patient-days) was performed on a monthly basis. Using the matched month approach, we found a significant correlation between CDI rate and moxifloxacin consumption (Spearman's r = 0.351, P < 0.001). Furthermore, using the one-month delay approach, we found that the consumption of clindamycin (Spearman's r = 0.272, P = 0.037) and moxifloxacin (Spearman's r = 0.297, P = 0.022) was significantly correlated with CDI incidence. Extended-spectrum cephalosporins did not have any effect on CDI incidence.

No association between proton pump inhibitor use and ALS risk: a nationwide nested case-control study

The use of proton pump inhibitors (PPIs) has been proposed as a potential risk factor for neurodegenerative diseases, but little is known regarding its role in amyotrophic lateral sclerosis (ALS). We therefore aimed to assess the association of PPI use with the subsequent risk of ALS, and performed a register-based nationwide nested case–control study, including 2,484 ALS cases diagnosed during July 2006–December 2013 in Sweden and 10 population controls per case that were individually matched to the case by sex, age, and area of residence. Dispenses and cumulative defined daily doses (cDDDs) of PPIs were extracted from the Swedish Prescribed Drug Register. The association of PPI use with the risk of ALS was assessed using conditional logistic regression, after applying different lag windows to avoid reverse causation. ALS patients were more likely to be dispensed with PPIs before diagnosis than controls. However, previous PPI use was not associated with an increased risk of ALS (OR = 1.08, 95% CI 0.97–1.19), and there was no dose–response relationship between cDDDs of PPIs and ALS risk (p = 0.0874), after excluding dispenses during the year before ALS diagnosis. The results were similar after excluding dispenses during the 2 or 3 years before ALS diagnosis.

Brand-Name Antidepressants Outperform Their Generic Counterparts in Preventing Hospitalization for Depression: The Real-World Evidence from Taiwan

BACKGROUND

Generic antidepressants are approved on the market based on evidence of bioequivalence to their brand-name versions. We aimed to assess whether generic antidepressants exert equal effectiveness as their brand-name counterparts for treating patients with depressive disorders.

METHODS

In a nationwide, population-based cohort in Taiwan from 1997 through 2013, patients with a diagnosis of a depressive disorder aged between 18 and 65 years who were new users of antidepressant drugs were classified into either the brand-name group or the generic group. All patients were followed up until medication discontinuation or the end of the study period. We assessed the risk for hospitalization as a primary outcome and augmentation therapy, daily dose, medication discontinuation, or switching to another antidepressant as secondary outcomes.

RESULTS

A total of 277 651 brand-name users (35.8% male; mean age: 41.2 years) and 270 583 generic users (35.8% male; mean age: 41.0 years) were divided into 10 different antidepressant groups (fluoxetine, sertraline, paroxetine, escitalopram, citalopram, venlafaxine, mirtazapine, moclobemide, imipramine, and bupropion). We found that patients treated with the generic form of sertraline, paroxetine, escitalopram, venlafaxine, mirtazapine, and bupropion demonstrated significantly higher risks of psychiatric hospitalization (adjusted hazard ratios ranged from 1.20-2.34), compared to their brand-name counterparts. The differences between brand-name antidepressants and their generic counterparts in secondary outcomes varied across different drugs.

CONCLUSIONS

Compared to most generic antidepressants, brand-name drugs exhibited more protective effects on psychiatric hospitalization for depressive patients. These findings could serve as an important reference for clinicians when encountering patients with depressive disorder.

Adherence with brand versus generic bisphosphonates among osteoporosis patients: a new-user cohort study in the French National Healthcare Insurance database

Several studies documented declines in treatment adherence with generic forms of oral bisphosphonates in osteoporosis compared to branded forms, while others did not support this relation. Our aim was to compare medication adherence with brand versus generic forms of oral bisphosphonates. A new-user cohort study was conducted using routinely collected administrative and healthcare data linked at the individual level extracted from a nationwide representative sample of the French National Healthcare Insurance database. We included all patients aged 50 and older, new users of oral bisphosphonates for primary osteoporosis between 01/01/2009 and 31/12/2015. Two components of adherence were measured: implementation (continuous multiple-interval measure of medication availability version 7; CMA7) and persistence (time to discontinuation). The sample was composed of 1,834 in the "brand bisphosphonate" group and 1,495 patients in the "generic bisphosphonate" group. Initiating oral bisphosphonate treatment with brand was associated with a higher risk of discontinuation within 12 months (Hazard Ratio = 1.08; 95%CI = [1.02;1.14]). The risk of good implementation (CMA7 ≥ 0.90) was significantly lower in "brand bisphosphonate" group (Risk Ratio = 0.90; 95%CI = [0.85; 0.95]). We did not find any evidence to support the hypothesis of a lower adherence to generic bisphosphonates. In fact, prescribing of generic bisphosphonates led to a higher persistence rate and to better implementation at 1 year.

Metabolic and Addiction Indices in Patients on Opioid Agonist Medication-Assisted Treatment: A Comparison of Buprenorphine and Methadone

Metabolic hormones stabilize brain reward and motivational circuits, whereas excessive opioid consumption counteracts this effect and may impair metabolic function. Here we addressed the role of metabolic processes in the course of the agonist medication-assisted treatment for opioid use disorder (OUD) with buprenorphine or methadone. Plasma lipids, hemoglobin A1C, body composition, the oral glucose tolerance test (oGTT) and the Sweet Taste Test (STT) were measured in buprenorphine- (n = 26) or methadone (n = 32)- treated subjects with OUD. On the whole, the subjects in both groups were overweight or obese and insulin resistant; they displayed similar oGTT and STT performance. As compared to methadone-treated subjects, those on buprenorphine had significantly lower rates of metabolic syndrome (MetS) along with better values of the high-density lipoproteins (HDL). Subjects with- vs. without MetS tended to have greater addiction severity. Correlative analyses revealed that more buprenorphine exposure duration was associated with better HDL and opioid craving values. In contrast, more methadone exposure duration was associated with worse triglycerides-, HDL-, blood pressure-, fasting glucose- and hemoglobin A1C values. Buprenorphine appears to produce beneficial HDL- and craving effects and, contrary to methadone, its role in the metabolic derangements is not obvious. Our data call for further research aimed at understanding the distinctive features of buprenorphine metabolic effects vis-à-vis those of methadone and their potential role in these drugs' unique therapeutic profiles.

Methods for constructing treatment episodes and impact on exposure-outcome associations

PURPOSE

To assess the impact on exposure time and outcome misclassifications, and consequent impact on exposure-outcome associations from treatment episode construction. We investigated the dosage assumptions of 1 unit per day, and 1 DDD per day, versus actual prescribed dosage under different handling of gaps and overlaps of prescriptions.

METHODS

Data on mirtazapine and citalopram exposure (years 2006-2014) from the Swedish Prescribed Drug register were used. Via a within individuals design we compared method A, based on actual dosage, with methods B and C based on 1 unit of drug per day and 1 DDD per day assumptions, respectively, including consideration of gaps and overlaps. Four outcomes were used, hospitalizations and outpatient visits for all and for psychiatric causes.

RESULTS

Relative to method A, both alternative methods lead to misclassification of exposure time. With regard to outcome misclassifications, method B overestimates the effect of the exposure on the outcome in 77% and 100% of exposure definition comparisons for mirtazapine and citalopram respectively, while 23% of the comparisons for mirtazapine results in underestimation of exposure-outcome associations. Conversely, treatment episodes based on DDD (method C) result in underestimation of the exposure-outcome association in 100% and 87.5% of exposure definition comparisons for mirtazapine and citalopram respectively, while 12.5% of the comparisons for citalopram results in overestimation of the exposure-outcome associations.

CONCLUSIONS

The study provides results that have consistent clinical relevance. We have showed that a non-accurate construction of exposure time may lead to errors on outcome detection during exposed time, and consequently affect conclusions on safety or efficacy profile of a treatment.

Decrease in Antibacterial Use and Facility-Level Variability After the Introduction of Guidelines and Implementation of Physician-Pharmacist-Nurse Quality Circles in Swiss Long-term Care Facilities

OBJECTIVES

The objective of this study is to describe antibacterial use in long-term care facilities and to investigate the determinants of use.

DESIGN

This study is a quality improvement study conducted from January 2011 to December 2016.

SETTING

Long-term care facilities in the canton of Vaud, Western Switzerland, were investigated.

PARTICIPANTS

Twenty-three long-term care facilities were included in this study.

INTERVENTION

The intervention included the publication of local guidelines on empirical antibacterial therapy and the implementation of physician-pharmacist-nurse quality circles.

MEASURES

The main outcome was antibacterial use, expressed as defined daily doses (DDD) per 1000 beds per day. Statistical analyses were performed through a 1-level mixed model for repeated measurements.

RESULTS

Antibacterial use decreased from 45.6 to 35.5 DDD per 1000 beds per day (-22%, P < .01) over the 6-year study period, which was mostly explained by reduced fluoroquinolone use (-59%, P < .001). A decrease in range of use among LTCFs was observed during the study period, and 27% of antibacterial use was related to the WATCH group (antibiotics with higher toxicity concerns and/or resistance potential) according to the AWaRe categorization of the WHO, decreasing from 17.3 DDD per 1000 beds per day to 9.5 (-45%) over the study period. The use of antibacterials from the RESERVE group ("last-resort" treatment options) was very low.

CONCLUSION AND IMPLICATIONS

A reduction in facility-level antibacterial use and in variability across LTCFs was observed over the study period. The dissemination of empirical antibacterial prescription guidelines and the implementation of physician-pharmacist-nurse quality circles in all LTCFs of the canton of Vaud likely contributed to this reduction. Antibacterials from the WATCH group still represented 27% of the total use, providing targets for future antibiotic stewardship activities.

Descriptive analysis of real-world medication use pattern of statins and antiplatelet agents among patients with acute coronary syndrome in Hong Kong and the USA

OBJECTIVES

The objective was to explore the differences in medication use pattern of lipid-lowering drug (LLD) and antiplatelet agents among post-percutaneous coronary intervention patients with acute coronary syndrome aged <65 in Hong Kong (HK) and the USA.

DESIGN

Retrospective study.

SETTING

This study used deidentified claims data from Clinformatics Data Mart database (OptumInsight, Eden Prairie, Minnesota, USA) and electronic health records from HK Hospital Authority Clinical Data Analysis and Reporting System database.

PARTICIPANTS

We used 1 year prescription records of LLDs and antiplatelet agents among 1013 USA patients and 270 HK Chinese patients in 2011-2013.

PRIMARY AND SECONDARY OUTCOME MEASURES

Continuity was investigated on the assumption that one defined daily dose represented 1 day treatment. Medication possession ratio method was used to evaluate the adherence. Multivariate-adjusted logistic regressions were constructed to compare the good continuity and adherence levels in the merged database with the cutoffs set at 80%, and Cox proportional hazard models were built using the time to discontinuation as the dependent variable, to assess the persistence level.

RESULTS

HK Chinese patients were less adherent (67.41% vs 84.60%, adjusted odds ratio (AOR) for Americans over Chinese=2.23 (95% CI=1.60 to 3.12), p<0.001) to antiplatelet agents compared with American patients but better adherent to statins (90.00% vs 78.18%, AOR=0.37 (0.23 to 0.58), p<0.001). The discontinuation with statins was more common in American patients (13.33% vs 34.25%, adjusted hazard ratio (AHR)=2.95 (2.05 to 4.24), p<0.001). Low-to-moderate potency statins and clopidogrel were favoured by our HK local physicians, while American patients received higher doses of statins and prasugrel.

CONCLUSIONS

We seemed to find HK physicians tended to prescribe cheaper and lower doses of statins and antiplatelet agents when compared with the privately insured patients in the USA, though the adherence and persistence levels of HK patients with statins were relatively good.

Can Disease-Modifying Anti-Rheumatic Drugs Reduce the Risk of Developing Dementia in Patients with Rheumatoid Arthritis?

Disease-modifying anti-rheumatic drugs (DMARDs) can reduce inflammation and slow progression of rheumatoid arthritis (RA). It remains unknown what impact DMARDs may have on dementia, where inflammation also plays a critical role in pathogenesis. Patients without a prior history of dementia who were newly diagnosed with RA between 2000 and 2005 were identified from Taiwan's National Health Insurance Research Database. The participants were stratified by age and gender. The outcome of interest was all-cause dementia, and Cox regression models were used to estimate the hazard ratio (HR) of dementia. The cumulative DMARD dosage was stratified by quartiles of defined daily doses. A total of 20,707 patients were diagnosed with RA, and 62,121 non-RA individuals aged 20 years or older were included. Cox proportional hazard regression analysis revealed that the RA cohort was 37% less likely to develop dementia compared with the non-RA cohort [adjusted HR 0.63, 95% confidence interval (CI) 0.55-0.72]. Further decreased risk was noted in DMARD users (adjusted HR 0.48, 95% CI 0.39-0.58) with dose-dependent effect. Subgroup analysis identified DMARD use as having a protective effect against developing dementia in female and younger patients. Also, in male and older patients, DMARD use further reduced the risk. These observations suggest that DMARDs may reduce the risk of developing dementia, and its effect is further increased at high cumulative dosages. These findings warrant further examination in randomized control trials.

Polypharmacy and injurious falls in older adults: a nationwide nested case-control study

Objective

To determine whether or not the exposure to multiple drugs (polypharmacy) increases the risk of fall-related injury among older adults, beyond the effect of fall-risk increasing drugs and chronic multimorbidity.

Methods

Nested case-control study using linked register data with national coverage in Sweden. We defined cases as older adults (≥70 years) who had an incident non-elective admission due to a fall between 1 January and 31 December 2013. Cases were matched 1:1 on sex, age and index date to randomly selected controls from the general population. The number of prescription drugs during the 7 days preceding the index date was the main exposure.

Results

A total of 49,609 cases were included and matched to an equal number of controls. The number of prescription drugs was higher among cases than among controls (mean difference 1.2, 95% CI 1.16–1.26). While adjusting for potential confounders, we found that the risk of injurious falls increased in a nearly linear fashion for each additional drug (OR, 1.02; 95% CI, 1.01–1.03). When using a cut-off value of ≥4 drugs to define polypharmacy, the population attributable fraction for injurious falls was 5.2% (95% CI 2.8–7.6).

Conclusion

This study shows a monotonic dose-response relationship between the number of drugs and the risk of injurious falls. However, after comprehensive adjustment for known confounders (including fall-risk increasing drugs and chronic multimorbidity), this association is substantially weaker than previously reported. Moreover, even if the relationship between polypharmacy and injurious falls is really causal, the population attributable risk fraction is low.

Gender differences in the prevalence, comorbidities and antipsychotic prescription of early-onset schizophrenia: a nationwide population-based study in Taiwan

Early-onset schizophrenia (EOS) is defined as patients diagnosed with schizophrenia before the age of 18. Whether the EOS population has gender differences is currently a matter of considerable debate. This study used a representative nationwide sample to examine potential gender differences in the prevalence, comorbidities, and prescription of antipsychotics among the EOS population. We identified a total of 401 patients with EOS (200 males and 201 females) from Taiwan's National Health Insurance Database between 2000 and 2012. The annual prevalence rate of overall patients with EOS increased significantly from 17.1 to 41.8 per 100,000 persons among the youth population (≤ 18 years). Sulpiride, Risperidone, and Aripiprazole were the most common antipsychotics of first choice for treating EOS. Compared to female patients, male patients were more likely to experience the following comorbidities: attention deficit hyperactivity disorder (15.5% vs. 5.5%), autism spectrum disorder (10.0% vs. 3.0%), intellectual disability (19.0% vs. 10.4%), developmental disorder (8.0% vs. 3.0%), and history of physical injury (65.5% vs. 48.8%), prior to being diagnosed with schizophrenia. We observed no significant gender differences with regard to incidence, prevalence, age of onset, and categories and doses of patients' first antipsychotic prescription. Our findings did not support the empirical opinion that males with EOS experience the onset earlier or are more prevalent than EOS female patients. However, male patients were more likely to have neurodevelopmental comorbidities and a history of physical injury. These results can function as an important reference for planning services that target real-world patient treatment.

β2-adrenoreceptor medications and risk of Parkinson disease

OBJECTIVE

A recent study observed a 2-fold greater risk of Parkinson disease (PD) in relation to the β2-adrenoreceptor antagonist propranolol and a markedly lower risk of PD for the β2-adrenoreceptor agonist salbutamol. We examined whether confounding by clinical indication for these medications, that is, tremor and smoking-related pulmonary conditions, explained these associations.

METHODS

In a large, population-based case-control study of United States Medicare beneficiaries in 2009 with diagnosis codes, procedure codes, and prescription data (48,295 incident PD cases, 52,324 controls), we examined the risk of PD in relation to use of selected β antagonists (propranolol, carvedilol, metoprolol), the β2 agonist salbutamol, and other medications used for the same clinical indications (primidone, inhaled corticosteroids). We adjusted for demographics, smoking, and overall use of medical care. We then examined the effect of also adjusting for clinical indication and applying medication exposure lagging.

RESULTS

Propranolol appeared to increase PD risk (odds ratio [OR] = 3.62, 95% confidence interval [CI] = 3.31-3.96). When we adjusted for tremor or abnormal involuntary movement prior to the PD diagnosis/reference date and lagged propranolol exposure, the association was 0.97 (95% CI = 0.80-1.18). Primidone, also used for tremor, was similarly sensitive to this adjustment and lagging. β Antagonists not indicated for tremor appeared to reduce PD risk (carvedilol: OR = 0.77, 95% CI = 0.73-0.81; metoprolol: OR = 0.94, 95% CI = 0.91-0.97) and were insensitive to adjustment for indications and lagging. Neither salbutamol nor inhaled corticosteroids were consistently associated with PD risk.

INTERPRETATION

β2-adrenoreceptor agonists and antagonists do not appear to alter PD risk. Ann Neurol 2018;84:691-701.

Empirical validation of the reverse parametric waiting time distribution and standard methods to estimate prescription durations for warfarin

PURPOSE

In many prescription databases, the duration of treatment for the single prescription is not recorded. This study aimed to validate 2 different types of approaches for estimating prescription durations, using the oral anticoagulant warfarin as a case.

METHODS

The approaches undergoing empirical validation covered assumptions of a fixed daily intake of either 0.5 or 1.0 defined daily dose (DDD), as well as estimates based on the reverse parametric waiting time distribution (rWTD), with different sets of covariates. We converted estimates of prescription duration to daily dose and compared them to prescribed daily dose as recorded in a clinical registry (using Bland-Altman plots). Methods were compared based on their average prediction error (logarithmic scale) and their limit of agreement ratio (ratio of mean error ± 1.96 SD after transformation to original scale).

RESULTS

Estimates of daily doses were underestimated by 19% or overestimated by 62% when assumptions of 0.5 or 1.0 DDD were applied. The limit of agreement ratio was 6.721 for both assumptions. The rWTD-based approaches performed better when using the estimated mean value of the inter-arrival density, yielding on average negligible bias (relative difference of 0 to 2%) and with limit of agreement ratios decreasing upon additional covariate adjustment (from 6.857 with no adjustment to 4.036 with the fully adjusted model).

CONCLUSIONS

Comparing the different methods, the rWTD algorithm performed best and led to unbiased estimates of prescribed doses and thus prescription durations and reduced misclassification on the individual level upon inclusion of covariates.

Prescription duration and treatment episodes in oral glucocorticoid users: application of the parametric waiting time distribution

Purpose

Glucocorticoids are widely used medications. In many pharmacoepidemiological studies, duration of individual prescriptions and definition of treatment episodes are important issues. However, many data sources lack this information. We aimed to estimate duration of individual prescriptions for oral glucocorticoids and to describe continuous treatment episodes using the parametric waiting time distribution.

Methods

We used Danish nationwide registries to identify all prescriptions for oral glucocorticoids during 1996-2014. We applied the parametric waiting time distribution to estimate duration of individual prescriptions each year by estimating the 80th, 90th, 95th and 99th percentiles for the interarrival distribution. These corresponded to the time since last prescription during which 80%, 90%, 95% and 99% of users presented a new prescription for redemption. We used the Kaplan-Meier survival function to estimate length of first continuous treatment episodes by assigning estimated prescription duration to each prescription and thereby create treatment episodes from overlapping prescriptions.

Results

We identified 5,691,985 prescriptions issued to 854,429 individuals of whom 351,202 (41%) only redeemed 1 prescription in the whole study period. The 80th percentile for prescription duration ranged from 87 to 120 days, the 90th percentile from 116 to 150 days, the 95th percentile from 147 to 181 days, and the 99th percentile from 228 to 259 days during 1996-2014. Based on the 80th, 90th, 95th and 99th percentiles of prescription duration, the median length of continuous treatment was 113, 141, 170 and 243 days, respectively.

Conclusion

Our method and results may provide an important framework for future pharmacoepidemiological studies. The choice of which percentile of the interarrival distribution to apply as prescription duration has an impact on the level of misclassification. Use of the 80th percentile provides a measure of drug exposure that is specific, while the 99th percentile provides a sensitive measure.

Pharmacoepidemiology resources in Ireland-an introduction to pharmacy claims data

Introduction

Administrative health data, such as pharmacy claims data, present a valuable resource for conducting pharmacoepidemiological and health services research. Often, data are available for whole populations allowing population level analyses. Moreover, their routine collection ensures that the data reflect health care utilisation in the real-world setting compared to data collected in clinical trials.

Setting and methods

The Irish Health Service Executive-Primary Care Reimbursement Service (HSE-PCRS) community pharmacy claims database is described. The availability of demographic variables and drug-related information is discussed. The strengths and limitations associated using this database for conducting research are presented, in particular, internal and external validity. Examples of recently conducted research using the HSE-PCRS pharmacy claims database are used to illustrate the breadth of its use.

Results and conclusions

The HSE-PCRS national pharmacy claims database is a large, high-quality, valid and accurate data source for measuring drug exposure in specific populations in Ireland. The main limitation is the lack of generalisability for those aged <70 years and the lack of information on indication or outcome.

Different approaches to the assessment of adherence and persistence with cardiovascular-disease preventive medications

OBJECTIVE

To assess suitability and comparability of the most common methods of treatment adherence and persistence assessment, as applied to the same pharmacy dataset.

METHODS

Data on drugs prescribed for cardiovascular primary prevention to participants in the Aragon Workers' Health Study (AWHS) were collected from a regional electronic drug prescription database. Several different approaches were used to measure treatment adherence (with the medication possession ratio [MPR]) and proportion of days covered [PDC]) and persistence in new users by therapeutic subgroup. Defined daily dose (DDD) was used as a proxy of the number of days' supply, or substituted with surrogate daily dose values.

RESULTS

Higher mean adherence values and proportions of adherent patients were obtained using MPR versus PDC, with additional differences depending on the approach used. The proportion of adherent patients was lowest for oral antidiabetics (14.4%-30.6%) and highest for antihypertensives (70.2%-82.1%). The use of surrogate daily dose values increased adherence for antidiabetics and statins and decreased adherence for antihypertensives. After a 1 year follow-up, treatment persistence was observed for 21.1%, 58.7%, and 29.5% of antidiabetic, antihypertensive and statin users, respectively.

CONCLUSIONS

Our findings indicate that use of multiple measures of treatment adherence and persistence provides a more complete overview of medication use patterns, and certain limitations associated with DDD for some drug groups can be overcome with replacement by surrogate doses. The PDC indicator seems to provide a more accurate reflection of patient behavior and treatment continuity than the MPR. Any comparison of adherence/persistence should always consider the method used, variables analyzed, and corresponding data collection process.

Persistence With Statins in Primary Prevention of Cardiovascular Disease: Findings From a Cohort of Spanish Workers

INTRODUCTION AND OBJECTIVES

The aim of this study was to assess patterns of treatment persistence in a cohort of male Spanish workers receiving statin therapy for primary prevention of cardiovascular disease.

METHODS

This descriptive study was conducted within the framework of the prospective longitudinal Aragon Workers' Health Study (N = 5400). Incident male statin users were identified based on data collected from the regional government's medication consumption information system. Patterns of treatment persistence with statins prescribed for primary cardiovascular disease prevention were assessed and the relevance of potential predictors explored.

RESULTS

Among the 725 new statin users, less than one third remained persistent during the 1 year of follow-up. About 15% of nonpersistent users discontinued statin therapy after dispensation of the first prescription; of these, 42.1% did not recommence treatment within the following year. Factors reducing the likelihood of treatment discontinuation were older age (HR, 0.55; 95%CI, 0.39-0.77) and cotreatment with antihypertensive drugs (HR, 0.68; 95%CI, 0.56-0.82). No association was observed between treatment persistence and cotreatment with antidiabetic or antithrombotic drugs, baseline low-density lipoprotein levels, or total cholesterol levels. However, persistence was influenced by the type of statin first prescribed.

CONCLUSIONS

Our analysis of a cohort of healthy male workers revealed poor statin persistence. These findings underscore the need for a better understanding of patterns of statin use, especially in apparently healthy individuals, and for the incorporation of patient behavior into prescribing decisions.

Evidence of potential bias in a comparison of β blockers and calcium channel blockers in patients with chronic obstructive pulmonary disease and acute coronary syndrome: results of a multinational study

OBJECTIVES

A number of observational studies have reported that, in patients with chronic obstructive pulmonary disease (COPD), β blockers (BBs) decrease risk of mortality and COPD exacerbations. To address important methodological concerns of these studies, we compared the effectiveness and safety of cardioselective BBs versus non-dihydropyridine calcium channel blockers (non-DHP CCBs) in patients with COPD and acute coronary syndromes (ACS) using a propensity score (PS)-matched, active comparator, new user design. We also assessed for potential unmeasured confounding by examining a short-term COPD hospitalisation outcome.

SETTING AND PARTICIPANTS

We identified 22 985 patients with COPD and ACS starting cardioselective BBs or non-DHP CCBs across 5 claims databases from the USA, Italy and Taiwan.

PRIMARY AND SECONDARY OUTCOME MEASURES

Stratified Cox regression models were used to estimate HRs for mortality, cardiovascular (CV) hospitalisations and COPD hospitalisations in each database after variable-ratio PS matching. Results were combined with random-effects meta-analyses.

RESULTS

Cardioselective BBs were not associated with reduced risk of mortality (HR, 0.90; 95% CI 0.78 to 1.02) or CV hospitalisations (HR, 1.06; 95% CI 0.91 to 1.23), although statistical heterogeneity was observed across databases. In contrast, a consistent, inverse association for COPD hospitalisations was identified across databases (HR, 0.54; 95% CI 0.47 to 0.61), which persisted even within the first 30 days of follow-up (HR, 0.55; 95% CI 0.37 to 0.82). Results were similar across a variety of sensitivity analyses, including PS trimming, high dimensional-PS matching and restricting to high-risk patients.

CONCLUSIONS

This multinational study found a large inverse association between cardioselective BBs and short-term COPD hospitalisations. The persistence of this bias despite state-of-the-art pharmacoepidemiologic methods calls into question the ability of claims data to address confounding in studies of BBs in patients with COPD.

Association of Proton Pump Inhibitors Usage with Risk of Pneumonia in Dementia Patients

OBJECTIVES

To determine the association between usages of proton pump inhibitors (PPIs) and subsequent risk of pneumonia in dementia patients.

DESIGN

Retrospective cohort study.

SETTING

Taiwanese National Health Insurance Research Database.

PARTICIPANTS

The study cohort consisted of 786 dementia patients with new PPI usage and 786 matched dementia patients without PPI usage.

MEASUREMENTS

The study endpoint was defined as the occurrence of pneumonia. The Cox proportional hazard model was used to estimate the pneumonia risk. Defined daily dose methodology was applied to evaluate the cumulative and dose-response relationships of PPI.

RESULTS

Incidence of pneumonia was higher among patients with PPI usage (adjusted hazard ratio (HR) = 1.89; 95% CI = 1.51-2.37). Cox model analysis also demonstrated that age (adjusted HR = 1.05; 95% CI = 1.03-1.06), male gender (adjusted HR = 1.57; 95% CI = 1.25-1.98), underlying cerebrovascular disease (adjusted HR = 1.30; 95% CI = 1.04-1.62), chronic pulmonary disease (adjusted HR = 1.39; 95% CI = 1.09-1.76), congestive heart failure (adjusted HR = 1.54; 95% CI = 1.11-2.13), diabetes mellitus (adjusted HR = 1.54; 95% CI = 1.22-1.95), and usage of antipsychotics (adjusted HR = 1.29; 95% CI = 1.03-1.61) were independent risk factors for pneumonia. However, usage of cholinesterase inhibitors and histamine receptor-2 antagonists were shown to decrease pneumonia risk.

CONCLUSION

PPI usage in dementia patients is associated with an 89% increased risk of pneumonia.

The international generalisability of evidence for health policy: A cross country comparison of medication adherence following policy change

Copayments for prescriptions may increase morbidity and mortality via reductions in adherence to medications. Relevant data can inform policy to minimise such unintended effects. We explored the generalisability of evidence for copayments by comparing two international copayment polices, one in Massachusetts and one in Ireland, to assess whether effects on medication adherence were comparable. We used national prescription data for public health insurance programmes in Ireland and Medicaid data in the U.S. New users of oral anti-hypertensive, anti-hyperlipidaemic and diabetic drugs were included (total n=14,259 in U.S. and n=43,843 in Ireland). We examined changes in adherence in intervention and comparator groups in each setting using segmented linear regression with generalised estimating equations. In Massachusetts, a gradual decrease in adherence to anti-hypertensive medications of -1% per month following the policy occurred. In contrast, the response in Ireland was confined to a -2.9% decrease in adherence immediately following the policy, with no further decrease over the 8 month follow-up. Reductions in adherence to oral diabetes drugs were larger in the U.S. group in comparison to the Irish group. No difference in adherence changes between the two settings for anti-hyperlipidaemic drugs occurred. Evidence on cost-sharing for prescription medicines is not 'one size fits all'. Time since policy implementation and structural differences between health systems may influence the differential impact of copayment policies in international settings.

Comparative evaluation of methods approximating drug prescription durations in claims data: modeling, simulation, and application to real data

PURPOSE

The purpose of this study was to compare the predictive accuracy of different methods suggested for approximation of drug prescription durations in claims data.

METHODS

We expanded a well-established modeling and simulation framework to compare approximated drug prescription durations with 'true' (i.e., simulated) durations. Real claims data of persons aged ≥65 years insured by the German nationwide 'Statutory Health Insurance Fund' AOK between 2010 and 2012 provided empiric input parameters that were completed with missing information on actual dosing patterns from an observational cohort. The distinct approximation methods were based on crude measures (one tablet a day), population-averaged measures (defined daily doses), or individually-derived measures (longitudinal coverage approximation of the applied dose, COV). As a proof-of-principle, we assessed the methods' performance to predict the well-characterized bleeding risks of anticoagulant, antiplatelet, and/or non-steroidal anti-inflammatory drugs.

RESULTS

When applied to modeling and simulation data sets, the closest, least biased, and thus most accurate approximation was observed using the COV approximation. In a real-data example, rather similar results to an external reference were obtained for all methods. However, some of the differences between methods were meaningful, and the most reasonable and consistent results were obtained with the COV approach.

CONCLUSION

Based on theoretically most accurate approximations and practically reasonable estimates, the individual COV approach was preferable over the population-averaged defined daily dose technique, although the latter might be justified in certain situations. Advantages of the COV approach are expected to be even bigger for drug therapies with particularly large dosing heterogeneity. Copyright © 2016 John Wiley & Sons, Ltd.