Adaptability of High Dimensional Propensity Score Procedure in the Transition from ICD-9 to ICD-10 in the US Healthcare System

Background

High-Dimensional Propensity Score procedure (HDPS) is a data-driven approach to assist control for confounding in pharmacoepidemiologic research. The transition to the International Classification of Disease (ICD-9/10) in the US health system may pose uncertainty in applying the HDPS procedure.

Methods

We assembled a base cohort of patients in MarketScan^® Commercial Claims Database who had newly initiated celecoxib or traditional NSAIDs to compare gastrointestinal bleeding risk. We then created bootstrapped hypothetical cohorts from the base cohort with predefined patient selection patterns from the ICD eras. Three strategies for HDPS deployment were tested: 1) split the cohort by ICD era, deploy HDPS twice, and pool the relative risks (pooled RR), 2) consider codes from each ICD era as a separate data dimension and deploy HDPS in the entire cohort (data dimensions) and 3) map ICD codes from both eras to Clinical Classifications Software (CCS) concepts before deploying HDPS in the entire cohort (CCS mapping). We calculated percent bias and root-mean-squared error to compare the strategies.

Results

A similar bias reduction was observed in cohorts where patient selection pattern from each ICD era was comparable between the exposure groups. In the presence of considerable disparity in patient selection, we observed a bimodal distribution of propensity scores in the data dimensions strategy, indicating instrument-like covariates. Moreover, the CCS mapping strategy resulted in at least 30% less bias than pooled RR and data dimensions strategies (RMSE: 0.14, 0.19, 0.21, respectively) in this scenario.

Conclusion

Mapping ICD codes to a stable terminology like CCS serves as a helpful strategy to reduce residual bias when deploying HDPS in pharmacoepidemiologic studies spanning both ICD eras.

Assessment of the Risk Evaluation and Mitigation Strategy (REMS) for Phentermine-Topiramate to Prevent Exposure During Pregnancy

BACKGROUND

The U.S. Food and Drug Administration approved phentermine-topiramate for obesity in 2012 and required a Risk Evaluation and Mitigation Strategy (REMS) to prevent prenatal exposure. No such requirement was introduced for topiramate.

OBJECTIVE

To evaluate the rate of prenatal exposure, contraceptive use, and pregnancy testing among patients with phentermine-topiramate compared with topiramate or other antiobesity medications (AOMs).

DESIGN

Retrospective cohort study.

SETTING

Nationwide health insurance claims database.

PARTICIPANTS

Females aged 12 to 55 years with no infertility diagnosis or sterilization procedure. Patients with other indications for topiramate were excluded to identify a cohort that was likely treated for obesity.

MEASUREMENTS

Patients initiated use of phentermine-topiramate, topiramate, or an AOM (liraglutide, lorcaserin, or bupropion-naltrexone). Pregnancy at treatment initiation, conception during treatment, contraceptive use, and pregnancy testing outcomes were ascertained. Measurable confounders were adjusted for, and extensive sensitivity analyses were done.

RESULTS

A total of 156 280 treatment episodes were observed. Adjusted prevalence of pregnancy at treatment initiation was 0.9 versus 1.6 per 1000 episodes (prevalence ratio, 0.54 [95% CI, 0.31 to 0.95]) for phentermine-topiramate versus topiramate. The incidence rate of conception during treatment was 9.1 versus 15.0 per 1000 person-years (rate ratio, 0.61 [CI, 0.40 to 0.91]) for phentermine-topiramate versus topiramate. Both outcomes were similarly lower for phentermine-topiramate compared with AOM. Prenatal exposure was marginally lower in topiramate users compared with AOM users. Approximately 20% of patients in all cohorts had at least 50% of treatment days covered by contraceptives. Few patients had pregnancy tests before treatment (≤5%), but this was more common among phentermine-topiramate users.

LIMITATIONS

Outcome misclassification; unmeasured confounding due to lack of prescriber data to account for possible clustering and spillover effects.

CONCLUSION

Prenatal exposure seemed to be significantly lower among phentermine-topiramate users under the REMS. Pregnancy testing and contraceptive use appeared to be inadequate for all groups, which deserves attention to prevent the remaining potential exposures.

PRIMARY FUNDING SOURCE

None.

Prevalence of ocular comorbidities in patients with multiple myeloma: An analysis of U.S. claims data

8038

Background: Multiple myeloma (MM) predominantly affects older patients (pts) (median age at diagnosis 69 yrs) in whom comorbidities must be considered to manage the disease appropriately. Some anti-MM therapies can be associated with ocular toxicities and require careful attention when used among pts with pre-existing ocular comorbidities (OC). In 2018, 41% of Medicare enrollees had OC. Despite the potential implication on treatment decisions, information on pre-existing OC (e.g., disorders of lens, glaucoma) in MM pts is limited. This study aims to describe the prevalence of OCs among real-world pts with MM in 2011-2020 in the US. Methods: Adults with newly diagnosed MM (NDMM) with or without treatment, with 1L systemic therapy, and with relapsed/refractory MM (RRMM) who received up to 4 lines of systemic therapies (LOT) for MM were identified in the IQVIA PharMetrics Plus data. The index date was the date of initial MM diagnosis or a LOT initiation date. The prevalence of OC in each group was defined as the presence of any OC ICD 9/10 diagnosis codes in the 12 months prior to the index date. OCs (e.g., disorders of conjunctiva, lens, choroid, retina, glaucoma) were considered a potentially MM-related disease manifestation or MM treatment-related toxicity based on published literature and clinical expert opinion. Results: The median age at initial MM diagnosis was 64 yrs overall (N=49,814), and 63 yrs among treated pts (N=22,963). The median age was 63 yrs at 1L initiation and 64 yrs at 2L, 3L, and 4L initiation. The prevalence of OC at initial MM diagnosis was 39.0% overall and 35.2% among treated pts (Table). The OC prevalence was 35.8% prior to 1L initiation and higher in RRMM pts (42.1%, 44.9%, and 45.7% prior to 2L, 3L, and 4L initiation, respectively). This trend was observed across all OC categories, among MM-related OCs, and across all age groups. The prevalence of OC by MM stage was stable over the years. Conclusions: Approximately 40% of NDMM pts have a pre-existing OC, and the prevalence increases with the number of LOT in RRMM. While some OC may be due to aging, the impact of OC on treatment decisions for MM should be explored. [Table: see text]

Utilization of chronic lung disease treatment before the respiratory syncytial virus season as palivizumab prophylaxis qualifier in the American Academy of Pediatrics Guidelines

Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. We examined variations in CLD treatment for ten consecutive 20-day segments preceding RSV season onset. Among infants and children with CLD (n = 19,026), 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received supplemental oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. To avoid the capture of intermittent use of corticosteroids for acute infections, we found requiring a minimum of 45 days cumulative exposure was reasonable to determine chronic use. What is Known: • Guidelines from the American Academy of Pediatrics recommend palivizumab immunoprophylaxis for children with CLD in their second year of life if they continue to need treatment within 6 months before the RSV season. • The utilization patterns of treatment (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) are not well understood. A definition of chronic corticosteroid therapy in this setting is not available. What is New: • Among infants and children with CLD of prematurity, 35.2% received one or more medical treatments for CLD any time within 200 days before entering the second RSV season: 8.6%, 3.2%, and 29.7% received oxygen, diuretics, and corticosteroids, respectively. Utilization decreased as infants' age increased with corticosteroids surpassing oxygen and diuretics. • A minimum of 45 days cumulative corticosteroid use within the past 90 days would accurately capture chronic use to fulfill criteria for immunoprophylaxis while limiting the inclusion of intermittent use of corticosteroids for acute infections.

Calibration of Chronic Lung Disease Severity as a Risk Factor for Respiratory Syncytial Virus Hospitalization

BACKGROUND

Guidelines assume children with chronic lung disease (CLD) who require medical support within 6 months before the second respiratory syncytial virus (RSV) season remains at high risk of severe RSV disease. We determined the number of days since the last treatment (DSL) when the risk of RSV hospitalization among children with CLD becomes equivalent to the risk for those not qualified for immunoprophylaxis.

METHODS

The study cohort was assembled using Medicaid billing records from 1999 to 2010 linked to Florida and Texas birth certificate records. We developed DSL-trend discrete time logistic regression models within a survival analysis framework, adjusting for use of immunoprophylaxis, to compare the hospitalization risk of CLD infants at 4 age points to that of term infants at 1 month of age with siblings.

RESULTS

The study cohort included 858 830 healthy term and 5562 preterm infants with CLD. Among 1-month-old term infants, the RSV hospitalization risk averaged across all covariate strata was 14.8 (95% confidence interval [CI], 13.5-16.1) per 1000 patient season-months. Risk for preterm CLD children reached the threshold derived from term infants when DSL was 76 (95% CI, 22-198.5), 52 (95% CI, 6.5-123), 35 (95% CI, 0-93.5), and 12 (95% CI, 0-61.5) at the respective ages of 12, 15, 17.2, and 21 months.

CONCLUSIONS

The 180-day threshold used to define CLD severity at season start can be shortened to 120 days, 90 days, and 60 days for children with CLD at age 15, 17.2, and 21 months, respectively.

Guidelines for Data Linkage in Pharmacoepidemiology: Assessing Feasibility, Evaluating Quality and Transparent Reporting

IntroductionIncreasingly in pharmacoepidemiology, linking is required to enrich analytic data to more accurately define study populations, enable adjustment for confounding, and improve capture of health outcomes. When creating such novel linked datasets, researchers should consider their suitability to meet research objectives, assess source data completeness and population coverage, and ensure well-defined data governance standards and protections exist. Additionally, while the RECORD-PE guidelines assist in the reporting of studies using observational health data specific to pharmacoepidemiology, they do not address the unique requirements for transparent evaluation and reporting of the data linkage process. Objectives and ApproachWe aimed to 1) provide guidance on data linkage appropriateness and feasibility to plan purposeful and sustainable new linkages that advance pharmacoepidemiological research and 2) generate a checklist with specific recommendations to assist researchers in providing clear and transparent assessment of the linkage process. To develop these guidelines, a working group comprised of members of the International Society of harmacoepidemiology was formed. Recommendations were open for comment by Society members and endorsed by the Society. ResultsGuidance for feasibility assessment was categorized into five domains: (1) research objectives and justification; (2) data quality and completeness; (3) the linkage process; (4) data ownership and governance; and (5) overall value added by linkage. A checklist for evaluation and reporting of data-linkage processes covered five domains including; (1) data sources; (2) linkage variables; (3) linkage methods; (4) linkage results; and (5) linkage evaluation, including validation and verification of the resulting linked data. Conclusion/ImplicationsOur guidelines for data linkage feasibility assessment and reporting can be used to inform the design of sustainable linked data resources and for transparent communication of linkage processes. Together, these guidelines will help various stakeholders to critically assess the potential for bias in research based on linked data and help generate actionable evidence.

Evaluation of the US Food and Drug Administration Sentinel Analysis Tools Using a Comparator with a Different Indication: Comparing the Rates of Gastrointestinal Bleeding in Warfarin and Statin Users

BACKGROUND

The US Food and Drug Administration's Sentinel System was established to monitor safety of regulated medical products. Sentinel investigators identified known associations between drugs and adverse events to test reusable analytic tools developed for Sentinel. This test case used a comparator with a different indication.

OBJECTIVE

We tested the ability of Sentinel's reusable analytic tools to identify the known association between warfarin and gastrointestinal bleeding (GIB). Statins, expected to have no effect on GIB, were the comparator. We further explored the impact of analytic features, including matching ratio and stratifying Cox regression analyses, on matched pairs.

METHODS

This evaluation included data from 14 Sentinel Data Partners. New users of warfarin and statins, aged 18 years and older, who had not received other anticoagulants or had recent GIB were matched on propensity score using 1:1 and 1:n variable ratio matching, matching statin users with warfarin users to estimate the average treatment effect in warfarin-treated patients. We compared the risk of GIB using Cox proportional hazards regression, following patients for the duration of their observed continuous treatment or until a GIB. For the 1:1 matched cohort, we conducted analyses with and without stratification on matched pair. The variable ratio matched cohort analysis was stratified on the matched set.

RESULTS

We identified 141,398 new users of warfarin and 2,275,694 new users of statins. In analyses stratified on matched pair/set, the hazard ratios (HR) for GIB in warfarin users compared with statin users were 2.78 (95% confidence interval [CI] 2.36-3.28) in the 1:1 matched cohort and 3.10 (95% CI 2.76-3.49) in the variable ratio matched cohort. The HR was lower in the analysis of the 1:1 matched cohort not stratified by matched pair (2.22, 95% CI 1.97-2.49), and highest early in treatment. Follow-up for warfarin users tended to be shorter than for statin users.

CONCLUSIONS

This study identified the expected GIB risk with warfarin compared with statins using an analytic tool developed for Sentinel. Our findings suggest that comparators with different indications may be useful in surveillance in select circumstances. Finally, in the presence of differential censoring, stratification by matched pair may reduce the potential for bias in Cox regression analyses.

Use of Sodium-Glucose Cotransporter 2 Inhibitors in Patients With Type 1 Diabetes and Rates of Diabetic Ketoacidosis

OBJECTIVE

To estimate real-world off-label use of sodium-glucose cotransporter 2 (SGLT2) inhibitors in patients with type 1 diabetes, estimate rates of diabetic ketoacidosis (DKA), and compare them with DKA rates observed in sotagliflozin clinical trials.

RESEARCH DESIGN AND METHODS

We identified initiators of SGLT2 inhibitors in the Sentinel System from March 2013 to June 2018, determined the prevalence of type 1 diabetes using a narrow and a broad definition, and measured rates of DKA using administrative claims data. Standardized incidence ratios (SIRs) were calculated using age- and sex-specific follow-up time in Sentinel and age- and sex-specific DKA rates from sotagliflozin trials 309, 310, and 312.

RESULTS

Among 475,527 initiators of SGLT2 inhibitors, 0.50% and 0.92% met narrow and broad criteria for type 1 diabetes, respectively. Rates of DKA in the narrow and broad groups were 7.3/100 person-years and 4.5/100 person-years, respectively. Among patients who met narrow criteria for type 1 diabetes, rates of DKA were highest for patients aged 25-44 years, especially females aged 25-44 years (19.7/100 person-years). More DKA events were observed during off-label use of SGLT2 inhibitors in Sentinel than would be expected based on sotagliflozin clinical trials (SIR = 1.83; 95% CI 1.45-2.28).

CONCLUSIONS

Real-world off-label use of SGLT2 inhibitors among patients with type 1 diabetes accounted for a small proportion of overall SGLT2 inhibitor use. However, the risk for DKA during off-label use was notable, especially among young, female patients. Although real-word rates of DKA exceeded the expectation based on clinical trials, results should be interpreted with caution due to differences in study methods, patient samples, and study drugs.

Usability of encounter data for Medicaid comprehensive managed care vs traditional Medicaid fee-for-service claims among pregnant women

BACKGROUND

The completeness of medical encounters capture among Medicaid enrollees in comprehensive managed care (CMC) has been shown to vary across states and years. CMC penetration has grown, and CMC encounter capture specific to pregnancy care is understudied.

OBJECTIVES

To compare the completeness of encounter data for pregnant beneficiaries in CMC versus traditional fee-for-service (FFS) in Texas and Florida between 2007 and 2010.

METHODS

Using Medicaid Analytic eXtract (MAX) data linked to Florida and Texas birth certificate records, for each state and study year, we compared proportions using seven themes: (a) delivery; (b) prenatal visits; (c) dispensed prescriptions during pregnancy; (d) gestational diabetes and blood glucose testing; (e) antidiabetics and diagnosis of diabetes mellitus; (f) antibiotics for urinary tract infection and outpatient encounter; and (g) bacterial vaginosis and dispensing for metronidazole or clindamycin. We considered CMC data to be acceptable if proportions were no less than 10% below the corresponding (2007 to 2010) FFS control values.

RESULTS

Pregnancy-related characteristics of FFS vs CMC denominators were comparable. Proportions for the seven measures among FFS controls ranged from 26% to 98%. In Texas, CMC encounter data met the thresholds for all measures between 2007 and 2010. Florida had usable CMC encounter data starting from 2009 with incomplete medical and pharmacy records in 2007 and 2008.

CONCLUSIONS

The quality of CMC encounter data in MAX files for pregnant women varied in Florida and Texas and improved over time. Use of pregnancy-specific measures can aid researchers in selecting states and years with acceptable encounter data quality.

Misclassification in Assessment of First Trimester In-utero Exposure to Drugs Used Proximally to Conception: the Example of Letrozole Utilization for Infertility Treatment

Letrozole is an aromatase inhibitor that has an unapproved use for ovulation induction with infertility. Because of the proximity of this use to conception, we selected letrozole to study the effect of 3 different methods for identifying the pregnancy start date and their impact on exposure misclassification. Using electronic health data from the US Sentinel database (2001-2015), we identified live-birth pregnancies conceived through in-vitro fertilization or intrauterine insemination. The pregnancy start was calculated using 1) a validated algorithm to estimate the last menstrual period (LMP), 2) LMP + 14 days (i.e., conception estimate), and 3) the fertility-procedure date. We identified 47,628 live-births after intrauterine insemination (n = 24,962) and in-vitro fertilization (n = 22,666), in which 2,458 (5.3%) mothers received letrozole. The algorithm-based conception estimate occurred within 14 days of the fertility procedure for 78.3% of pregnancies. Defining pregnancy start as LMP (45.7/1,000 pregnancies) or LMP + 14 days (12.7/1,000 pregnancies) overestimated letrozole exposure during pregnancy by 8.4-fold and 2.3-fold, respectively, compared with defining it at the date of the fertility procedure (5.5/1,000 pregnancies). While most studies of drug utilization in pregnancy use LMP as the conventional pregnancy start, this introduced substantial exposure misclassification in the example of letrozole. LMP + 14 days was less biased. Researchers should carefully consider the impact of the method for identifying the pregnancy start date on the potential for exposure misclassification.

Prospective Postmarketing Surveillance of Acute Myocardial Infarction in New Users of Saxagliptin: A Population-Based Study

OBJECTIVE

The cardiovascular safety of saxagliptin, a dipeptidyl-peptidase 4 inhibitor, compared with other antihyperglycemic treatments is not well understood. We prospectively examined the association between saxagliptin use and acute myocardial infarction (AMI).

RESEARCH DESIGN AND METHODS

We identified patients aged ≥18 years, starting from the approval date of saxagliptin in 2009 and continuing through August 2014, using data from 18 Mini-Sentinel data partners. We conducted seven sequential assessments comparing saxagliptin separately with sitagliptin, pioglitazone, second-generation sulfonylureas, and long-acting insulin, using disease risk score (DRS) stratification and propensity score (PS) matching to adjust for potential confounders. Sequential testing kept the overall chance of a false-positive signal below 0.05 (one-sided) for each pairwise comparison.

RESULTS

We identified 82,264 saxagliptin users and more than 1.5 times as many users of each comparator. At the end of surveillance, the DRS-stratified hazard ratios (HRs) (95% CI) were 1.08 (0.90-1.28) in the comparison with sitagliptin, 1.11 (0.87-1.42) with pioglitazone, 0.79 (0.64-0.98) with sulfonylureas, and 0.57 (0.46-0.70) with long-acting insulin. The corresponding PS-matched HRs were similar. Only one interim analysis of 168 analyses met criteria for a safety signal: the PS-matched saxagliptin-pioglitazone comparison from the fifth sequential analysis, which yielded an HR of 1.63 (1.12-2.37). This association diminished in subsequent analyses.

CONCLUSIONS

We did not find a higher AMI risk in saxagliptin users compared with users of other selected antihyperglycemic agents during the first 5 years after U.S. Food and Drug Administration approval of the drug.

A systematic review of pregnancy exposure registries: examination of protocol-specified pregnancy outcomes, target sample size, and comparator selection

PURPOSE

Our study sought to systematically evaluate protocol-specified study methodology in prospective pregnancy exposure registries including pre-specified pregnancy outcomes, power calculations for sample size, and comparator group selection.

METHODS

U.S. pregnancy exposure registries designed to evaluate safety of drugs or biologics were identified from www.clinicaltrials.gov, the FDA's Office of Women's Health website, and the FDA's list of postmarketing studies. Protocols or similar documentation were obtained.

RESULTS

We identified 35 U.S. registries for drugs or biologic use during pregnancy. All registries assessed risk for overall major congenital malformations. Pre-specified target enrollment was stated for 18 (51%) registries, and ranged from 150 to 500 exposed pregnancies (median 300). Thirty-two (91%) registries identified at least one comparison group, but only nine (26%) planned to use an internal comparator. The most common external comparator group (n = 24, 69%) was the Metropolitan Atlanta Congenital Defects Program (MACDP).

CONCLUSIONS

No registries were designed to have sufficient power to assess specific malformations, despite the plausibility that most teratogens cause specific defects. Only half of the registries included a power analysis. Despite their common use, external comparators, including MACDP, have important limitations. In the absence of randomized controlled trial data in pregnant women, pregnancy registries remain an important tool as part of a comprehensive pregnancy surveillance program; however, pregnancy registries alone may not be sufficient to obtain adequate data regarding risks of specific malformations. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Use of Prescription Drug Samples in the USA: A Descriptive Study with Considerations for Pharmacoepidemiology

INTRODUCTION

Free prescription drug samples provided in physician offices can lead to exposure misclassification in pharmacoepidemiologic studies that rely on pharmacy claims data.

METHODS

We quantified drug-specific sample provision rates based on nationally projected data from a survey of over 3200 US office-based physicians for 1993-2013.

RESULTS

Between 2009 and 2013, a total of 44.7 % of newly initiated brand-only sitagliptin but only 3.6 % of generically available metformin therapy was provided as samples. We observed similar discrepancies between newly initiated rosuvastatin and simvastatin, dabigatran and warfarin, atomoxetine and methylphenidate, and between oral antibiotic drugs. During continued therapy, sample use was still present though to a lesser extent (sitagliptin 17.0 %, rosuvastatin 23.9 %), and remained high for some oral contraceptives (norethindrone 55.8 %). Oral contraceptives had the longest average days of sample supply (levonorgestrel, continued use 85.1 days). The average days of supply for all other chronically used study drugs ranged from 13.4 (dabigatran, new use) to 25.3 (exenatide, continued use) per sample provided. From 1993 to 2013, we found pronounced drops in sample provisions over time coinciding with more recent generic approval dates.

CONCLUSIONS

We observed markedly differential exposure to medication samples between branded and generic drugs. This can introduce bias in pharmacoepidemiologic studies, especially when adverse events that occur soon after drug initiation are of interest.

Risk for Hospitalized Heart Failure Among New Users of Saxagliptin, Sitagliptin, and Other Antihyperglycemic Drugs: A Retrospective Cohort Study

BACKGROUND

Recent postmarketing trials produced conflicting results about the risk for hospitalized heart failure (hHF) associated with dipeptidyl peptidase-4 (DPP-4) inhibitors, creating uncertainty about the safety of these antihyperglycemic agents.

OBJECTIVE

To examine the associations of hHF with saxagliptin and sitagliptin.

DESIGN

Population-based, retrospective, new-user cohort study.

SETTING

18 health insurance and health system data partners in the U.S. Food and Drug Administration's Mini-Sentinel program.

PATIENTS

Patients aged 18 years or older with type 2 diabetes who initiated therapy with saxagliptin, sitagliptin, pioglitazone, second-generation sulfonylureas, or long-acting insulin products from 2006 to 2013.

MEASUREMENTS

Hospitalized HF, identified by International Classification of Diseases, Ninth Revision, Clinical Modification codes 402.x1, 404.x1, 404.x3, and 428.xx recorded as the principal discharge diagnosis.

RESULTS

78 553 saxagliptin users and 298 124 sitagliptin users contributed an average of 7 to 9 months of follow-up data to 1 or more pairwise comparisons. The risk for hHF was not higher with DPP-4 inhibitors than with the other study drugs. The hazard ratios from the disease risk score (DRS)-stratified analyses were 0.83 (95% CI, 0.70 to 0.99) for saxagliptin versus sitagliptin, 0.63 (CI, 0.47 to 0.85) for saxagliptin versus pioglitazone, 0.69 (CI, 0.54 to 0.87) for saxagliptin versus sulfonylureas, and 0.61 (CI, 0.50 to 0.73) for saxagliptin versus insulin. The DRS-stratified hazard ratios were 0.74 (CI, 0.64 to 0.85) for sitagliptin versus pioglitazone, 0.86 (CI, 0.77 to 0.95) for sitagliptin versus sulfonylureas, and 0.71 (CI, 0.64 to 0.78) for sitagliptin versus insulin. Results from the 1:1 propensity score-matched analyses were similar. Results were also similar in subgroups of patients with and without prior cardiovascular disease and in a subgroup defined by the 2 highest DRS deciles.

LIMITATION

Residual confounding and short follow-up.

CONCLUSION

In this large cohort study, a higher risk for hHF was not observed in users of saxagliptin or sitagliptin compared with other selected antihyperglycemic agents.

PRIMARY FUNDING SOURCE

U.S. Food and Drug Administration.

Patient understanding of drug risks: an evaluation of medication guide assessments

PURPOSE

When a Medication Guide (MG) is part of Risk Evaluation and Mitigation Strategy (REMS), manufacturers assess the effectiveness of MGs through patient surveys, which have not undergone systematic evaluation. We aimed to characterize knowledge rates from these patient surveys, describe their design and respondent characteristics, and explore predictors of acceptable knowledge rates.

METHODS

We analyzed MG assessments submitted to the Food and Drug Administration from September 2008 through June 2012. We evaluated the prevalence of specific characteristics, and calculated knowledge rates, whereby we defined "acceptable knowledge" when ≥ 80% of respondents correctly answered questions about the primary drug risk. Univariate logistic models were used to investigate the predictors of acceptable knowledge rates.

RESULTS

We analyzed the first completed MG assessment for each drug with a patient survey, resulting in 66 unique MG assessments. The mean knowledge rate was 63.8%, with 20 MG assessments (30.3%) achieving the 80% threshold. Compared to assessments that did not reach acceptable knowledge rates, those that did were more likely associated with additional REMS elements (e.g. Elements to Assure Safe Use or Communication Plans). Other factors, including mean age, reading or understanding the MG, and being offered or accepting counseling were not associated with knowledge rates. There was considerable variation in the design of MG assessments.

CONCLUSIONS

Most MG assessments did not reach the 80% knowledge threshold, but those associated with additional interventions were more likely to achieve it. Our study highlights the need to improve patient-directed information and the methods of assessing it.

Emergency hospitalizations for unsupervised prescription medication ingestions by young children

BACKGROUND

Emergency department visits and subsequent hospitalizations of young children after unsupervised ingestions of prescription medications are increasing despite widespread use of child-resistant packaging and caregiver education efforts. Data on the medications implicated in ingestions are limited but could help identify prevention priorities and intervention strategies.

METHODS

We used nationally representative adverse drug event data from the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project and national retail pharmacy prescription data from IMS Health to estimate the frequency and rates of emergency hospitalizations for unsupervised prescription medication ingestions by young children (2007-2011).

RESULTS

On the basis of 1513 surveillance cases, 9490 estimated emergency hospitalizations (95% confidence interval: 6420-12,560) occurred annually in the United States for unsupervised prescription medication ingestions among children aged <6 years from 2007 through 2011; 75.4% involved 1- or 2-year old children. Opioids (17.6%) and benzodiazepines (10.1%) were the most commonly implicated medication classes. The most commonly implicated active ingredients were buprenorphine (7.7%) and clonidine (7.4%). The top 12 active ingredients, alone or in combination with others, were implicated in nearly half (45.0%) of hospitalizations. Accounting for the number of unique patients who received dispensed prescriptions, the hospitalization rate for unsupervised ingestion of buprenorphine products was significantly higher than rates for all other commonly implicated medications and 97-fold higher than the rate for oxycodone products (200.1 vs 2.1 hospitalizations per 100,000 unique patients).

CONCLUSIONS

Focusing unsupervised ingestion prevention efforts on medications with the highest hospitalization rates may efficiently achieve large public health impact.

Use of antidiabetic drugs in the U.S., 2003-2012

OBJECTIVE

To describe market trends for antidiabetic drugs, focusing on newly approved drugs, concomitant use of antidiabetic drugs, and effects of safety concerns and access restrictions on thiazolidinedione use.

RESEARCH DESIGN AND METHODS

Nationally projected data on antidiabetic prescriptions for adults dispensed from U.S. retail pharmacies were extracted from IMS Health Vector One National and Total Patient Tracker for 2003-2012 and from Encuity Research Treatment Answers and Symphony Health Solutions PHAST Prescription Monthly for 2012.

RESULTS

Since 2003, the number of adult antidiabetic drug users increased by 42.9% to 18.8 million in 2012. Metformin use increased by 97.0% to 60.4 million prescriptions dispensed in retail pharmacies in 2012. Among antidiabetic drugs newly approved for marketing between 2003 and 2012, the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin had the largest share with 10.5 million prescriptions in 2012. Rosiglitazone use plummeted to <13,000 prescriptions dispensed in retail or mail-order pharmacies in 2012. Concomitancy analyses showed that 44.9% of metformin use was for monotherapy. Between 33.4 and 48.1% of sulfonylurea, DPP-4 inhibitor, thiazolidinedione, and glucagon-like peptide 1 analog use was not accompanied by metformin.

CONCLUSIONS

The antidiabetic drug market is characterized by steady increases in volume, and newly approved drugs experienced substantial uptake, especially DPP-4 inhibitors. The use of rosiglitazone has been negligible since restrictions were put in place in 2011. Further study is needed to understand why one-third to one-half of other noninsulin antidiabetic drug use was not concomitant with metformin use despite guidelines recommending that metformin be continued when other agents are added to treatment.

Appropriateness of age thresholds for respiratory syncytial virus immunoprophylaxis in moderate-preterm infants: a cohort study

IMPORTANCE Recommendations concerning the appropriate age threshold for respiratory syncytial virus (RSV) prophylaxis in moderate-preterm infants are highly debated. OBJECTIVE To determine the age at which moderate-preterm infants' risk of RSV hospitalization has decreased to the risk observed in low-risk term infants. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of Florida and Texas Medicaid fee-for-service billing records matched to birth certificates from Medicaid beneficiaries aged 0 to 12 months with a sibling younger than 5 years and without other indications for RSV prophylaxis between January 1, 1999, and December 31, 2004. EXPOSURES For each state, we used discrete time survival analysis to develop age trend models for RSV hospitalizations for 2 groups: moderate-preterm infants (32-34 weeks' gestational age) and term infants (37-41 weeks' gestational age). MAIN OUTCOMES AND MEASURES Age at which preterm infants' risk of RSV hospitalization equaled the risk for term infants at age 1 month. RESULTS Our cohort included 247,566 eligible infants with 5322 RSV hospitalizations. Preterm status doubled the risk for RSV hospitalization in both Florida (odds ratio = 2.41; 95% CI, 1.85-3.12) and Texas (odds ratio = 1.94; 95% CI, 1.64-2.30). Preterm infants' risk of RSV hospitalization was similar to that for 1-month-old term infants at ages 4.2 months (95% CI, 2.5-5.7) in Florida and 4.5 months (95% CI, 2.8-6.4) in Texas. CONCLUSIONS AND RELEVANCE The age at which moderate-preterm infants showed RSV hospitalization risk similar to their healthy term counterparts supports the more restrictive age thresholds in RSV immunoprophylaxis recommendations. Further studies are warranted to investigate the age-dependent risk of RSV hospitalization in other RSV risk groups.

Use of prescription antiobesity drugs in the United States

STUDY OBJECTIVE

To examine national trends in prescription antiobesity drug use in the United States.

DESIGN

Data analysis.

DATA SOURCE

The IMS Health Vector One National and Total Patient Tracker and Encuity Research Treatment Answers databases, the Source Healthcare Analytics Source Lx database, and IMS LifeLink database.

MEASUREMENTS AND MAIN RESULTS

National drug use estimates from 1991-2011 were extracted from the IMS Health Vector One National database, and patient characteristics from 2008-2011 were extracted from the Vector One Total Patient Tracker and Encuity Research Treatment Answers databases. The Source Healthcare Analytics Source Lx database was used to examine duration of antiobesity drug use from 2002-2011, with a sensitivity analysis performed using the IMS LifeLink database. In 2011, approximately 2.74 million patients used antiobesity drugs, predominantly phentermine (2.43 million patients). The use of prescription orlistat and sibutramine was relatively uncommon. Eighty-five percent of antiobesity drug users were female, 62% were aged 17-44 years, and 4.5% had a body mass index of ≤ 24.9 kg/m(2) . Duration of use was generally short and most patients only had one episode of antiobesity drug use during the observation period. The longest episode of use was 30 days or less in 47-58% of patients. Approximately one quarter of the patients used antiobesity drugs for longer than 90 days, including phentermine and other amphetamine congeners whose labels recommend short-term use, not exceeding "a few weeks." Only 1.3-4.2% of antiobesity drug users used them for longer than 1 year. Concomitant use of two or more prescription weight-loss drugs was generally uncommon, although phentermine was dispensed during 13-16% of benzphetamine, diethylpropion, or phendimetrazine episodes of use.

CONCLUSION

Phentermine dominated the prescription weight-loss market. Despite the indication of short-term use for amphetamine congeners, duration of use was similar to other antiobesity drugs. Nevertheless, the reasons for and implications of the limited duration of use observed with all prescription antiobesity drugs deserve further investigation.

Validity of laboratory-based surveillance for detection of respiratory syncytial virus seasons

In this study, we validated the Centers for Disease Control and Prevention's use of a 10% threshold of median proportion of positive laboratory tests (median proportion positive (MPP)) to identify respiratory syncytial virus (RSV) seasons against a standard based on hospitalization claims. Medicaid fee-for-service recipients under 2 years of age from California, Florida, Illinois, and Texas (1999-2004), continuously eligible since birth, were categorized for each week as high-risk or low-risk with regard to RSV-related hospitalization based on medical and pharmacy claims data and birth certificates. Weeks were categorized as on-season if the RSV hospitalization incidence rate in high-risk children exceeded the seasonal peak of the incidence rate in low-risk children. Receiver operating characteristic (ROC) curves were used to measure the ability of MPP to discriminate between on-season and off-season weeks as determined from hospitalization data. Areas under the ROC curve ranged from 0.88 (95% confidence interval: 0.83, 0.92) in Illinois to 0.96 (95% confidence interval: 0.94, 0.98) in California. Requiring at least 5 positive tests in addition to the 10% MPP threshold optimized accuracy, as indicated by minimized root mean square errors. The 10% MPP with the added requirement of at least 5 positive tests is a valid method for identifying clinically significant RSV seasons across geographically diverse states.

Prevalence, trends, and patterns of use of antidiabetic medications among pregnant women, 2001-2007

OBJECTIVE

To describe the prevalence, trends, and patterns in use of antidiabetic medications to treat hyperglycemia and insulin resistance before and during pregnancy in a large U.S. cohort of insured pregnant women.

METHODS

Pregnancies resulting in live births were identified (N=437,950) from 2001 to 2007 among 372,543 females 12-50 years of age at delivery from 10 health maintenance organizations participating in the Medication Exposure in Pregnancy Risk Evaluation Program. Information for these descriptive analyses, including all antidiabetic medications dispensed during this period, was extracted from electronic health records and newborn birth certificates.

RESULTS

A little more than 1% (1.21%) of deliveries were to women dispensed antidiabetic medication in the 120 days before pregnancy. Use of antidiabetic medications before pregnancy increased from 0.66% of deliveries in 2001 to 1.66% of deliveries in 2007 (P<.001) because of an increase in metformin use. Most women using metformin before pregnancy had a diagnosis code for polycystic ovaries or female infertility (67.2%), whereas only 13.6% had a diagnosis code for diabetes. The use of antidiabetic medications during the second or third trimester of pregnancy increased from 2.8% of deliveries in 2001 to 3.6% in 2007 (P<.001). Approximately two thirds (68%) of women using metformin before pregnancy did not use any antidiabetic medications during pregnancy.

CONCLUSIONS

Antidiabetic medication use before and during pregnancy increased from 2001 to 2007, possibly because of increasing prevalence of gestational diabetes mellitus, type 1 and type 2 diabetes, and other conditions associated with insulin resistance.

LEVEL OF EVIDENCE

III.

Feasibility of short-term infusion of magnesium sulfate in pediatric patients with status asthmaticus

OBJECTIVE

This report describes the feasibility of high-dose magnesium sulfate infusion in pediatric patients with status asthmaticus.

METHODS

Retrospective chart review over a 3-year period of all patients younger than 18 years of age with status asthmaticus who underwent a high-dose magnesium sulfate infusion for 4 hours. All patients were breathing spontaneously but were refractory to conventional therapy. The magnesium sulfate infusion regimen was 50 mg/kg (for patients weighing >30 kg) or 75 mg/kg (for those weighing ≤30 kg) over a period of 30 to 45 minutes, followed by a continuous infusion of 40 mg/kg/hr for 4 hours. Information regarding vital and clinical respiratory signs, serum magnesium (SrMg), ionized magnesium (iMg), electrocardiograms, and cardiac troponin levels were retrieved. We analyzed the relationship between SrMg and iMg by using linear regression analysis.

RESULTS

Nineteen patients were included. At the end of the infusion, SrMg levels were 4.4 ± 0.8 mg/dL, and iMg levels were 0.95 ± 0.2 mmol/L. SrMg levels only moderately predicted iMg (r(2) = 0.541). There were no reports of hypotension, respiratory failure, neurological problems, or nausea. Discomfort at the site of infusion was reported in three cases. Troponin levels (n = 12) and electrocardiograms (n = 12), when available, were noted at the end of the infusion and were normal in all patients p=0.01.

CONCLUSIONS

In this case series, short-term high-dose administration of magnesium sulfate in the context of status asthmaticus was feasible, and we did not observe clinical complications with its use. Total SrMg was inadequate to reflect the active form of magnesium, iMg. The dose used achieved theoretical therapeutic levels of iMg.

Invasive fungal infections in lung transplant recipients not receiving routine systemic antifungal prophylaxis: 12-year experience at a university lung transplant center

STUDY OBJECTIVE

To determine the rate of invasive fungal infection among the lung transplant population at a center that does not provide routine systemic antifungal prophylaxis, and to compare that rate with rates currently reported in the literature.

DESIGN

Retrospective medical record review.

SETTING

University-affiliated lung transplant center.

PATIENTS

Two hundred forty-two adults without cystic fibrosis who underwent lung transplantation between March 1, 1994, and June 30, 2006.

MEASUREMENTS AND MAIN RESULTS

Patients were followed by the adult lung transplant service. Twenty-three cases of invasive fungal infections were identified in 22 patients, resulting in a 9.1% overall invasive fungal infection rate in our study population. Aspergillus infections were the most common type of fungal infection identified, occurring in 11 (47.8%) of the 23 cases, with an overall rate of 4.5% (11/242 patients). Invasive fungal infections in lung transplant recipients have been reported in the literature at a rate 15-35%, with rates of Aspergillus infections reported as 3-15%.

CONCLUSION

Despite the absence of routine systemic antifungal prophylaxis, the overall invasive fungal infection rate and the Aspergillus infection rate in these lung transplant recipients do not appear to be higher than the rates reported in the literature.

Longitudinal study of optic cup progression in children

PURPOSE

To determine the normative rate of cup-to-disc-ratio (C:D) progression in children and the effect of prematurity and low birth weight on this rate.

METHOD

In a single pediatric ophthalmology practice, a single examiner evaluated optic cup size by serial ophthalmoscopy over a minimum of 5 years in 92 patients (184 eyes) without intraocular surgery or optic nerve disease. A cross-sectional analysis of C:D was performed per year of age from 0 to 10 years and linear regression was used to compare C:D progression between preterm and term children and between low versus normal birth weight children.

RESULTS

Children exhibited progressive optic cupping. In term children, mean C:D increased by 0.0075 per year. Rate of mean C:D progression was double in children born preterm: 0.0160 (P = .049, comparison to term) per age-year. A similar, nonsignificant trend is observed when comparing low birth weight to normal children (P = .131).

CONCLUSION

Prematurity and low birth weight are associated with increased rate of cupping in children. Clinicians should recognize that C:D progression is not a specific sign of glaucoma in children.

Cost-effectiveness of respiratory syncytial virus prophylaxis in various indications

OBJECTIVES

To evaluate the cost-effectiveness of immunoprophylaxis against respiratory syncytial virus (RSV) infections with palivizumab based on actual cost and observed incidence rates in various pediatric risk groups.

DESIGN

Decision tree analysis comparing children with various combinations of the following indications: chronic lung disease, congenital heart disease, or prematurity (≤32 weeks gestation), and children with none of these indications. One-way sensitivity analyses and Monte Carlo simulations were used to quantify parameter uncertainty.

SETTING

Florida during the 2004-2005 RSV season.

PARTICIPANTS

A total of 159,790 Medicaid-eligible children aged 0 to 2 years.

INTERVENTION

Palivizumab prophylaxis compared with no prophylaxis.

OUTCOMES MEASURE

Incremental cost (2010 US dollars) per hospitalization for RSV infection avoided.

RESULTS

The mean cost of palivizumab per dose ranged from $1661 for infants younger than 6 months of age to $2584 for children in their second year of life. Among preterm infants younger than 6 months of age without other indications, immunoprophylaxis with palivizumab cost $302,103 (95% confidence interval, $141,850-$914,798) to prevent 1 RSV-related hospitalization. Given a mean cost of $8910 for 1 RSV-related hospitalization in this subgroup, palivizumab would be cost-neutral at a per-dose cost of $47. Incremental cost-effectiveness ratios for the other subgroups ranged from $361,727 to more than $1.3 million per RSV-related hospitalization avoided in children up to 2 years of age with chronic lung disease and no additional risk factors. Younger age and multiple indications were associated with improvements in the incremental cost-effectiveness ratio.

CONCLUSIONS

The cost of immunoprophylaxis with palivizumab far exceeded the economic benefit of preventing hospitalizations, even in infants at highest risk for RSV infection.

Review of a large clinical series: once- versus twice-daily enoxaparin for venous thromboembolism prophylaxis in high-risk trauma patients

BACKGROUND

Consensus guidelines support the use of low-molecular-weight heparin for venous thromboembolism (VTE) prophylaxis in high-risk trauma patients but do not recommend a specific regimen. The current study compared the effectiveness and safety of enoxaparin 40 mg once-daily versus enoxaparin 30 mg twice-daily for VTE prophylaxis in high-risk trauma patients.

METHODS

A retrospective chart review was conducted of all trauma patients older than 18 years of age admitted to Shands at the University of Florida between July 1, 2005 and June 30, 2007, who received either dosing regimen. Excluded were patients with Injury Severity Score <9, surviving <2 days, hospital length of stay <2 days, receipt of >1 agent, and/or dosing regimen for VTE prophylaxis during hospitalization, interruption in therapy, pregnancy, or diagnosis of a VTE within 24 hours of admission.

RESULTS

A total of 409 patients were treated with once-daily dosing and 278 patients were treated with twice-daily dosing. The overall rate of VTE was 2.9% (95% confidence interval, 1.52, 5.07) in the once-daily group and 1.1% in the twice-daily group (95% confidence interval, 0.22, 3.12; P = .118). Major bleeding occurred in 11 patients in the once-daily group and 5 patients in the twice-daily group (1.8% vs 2.7%; P = .608).

CONCLUSION

Enoxaparin 30 mg twice-daily may be more effective than enoxaparin 40 mg once-daily for prevention of VTE in high-risk trauma patients; however, statistical significance was not achieved. There were no statistically significant differences observed in clinically significant bleeding. Further study is needed to clarify which dosing regimen of enoxaparin is superior with regard to safety and effectiveness.

Root cause analysis and subsequent intervention to improve first dose antibiotic turnaround time for hospitalized pediatric patients

OBJECTIVE

Antibiotic timing is used as a quality standard for hospital accreditation and is an important quality measure. The study aim was to identify barriers in the process of first dose antibiotic administration on the pediatric floors at a tertiary healthcare center and carry out and test an intervention to improve turnaround time to less than one hour.

METHODS

We conducted a quasi-experimental pre-post study of hospitalized pediatric patients up to 18 years of age initiated on intravenous antibiotics. Every order for a first dose intravenous antibiotic was assessed on all pediatric floors (10/2008). Orders that did not meet the overall turnaround time goal of ≤ 1 hour were identified. A root cause analysis (RCA) was performed to identify reasons for delayed antibiotic administration. Barriers identified in the RCA were used to develop interventions (03/2009) to improve compliance, and the proportion of orders that met the goal was compared pre- (10/2008-02/2009) and post-intervention (04/2009-05/2009).

RESULTS

During the pre-intervention assessment period, 32 out of 46 total physician orders for a first dose intravenous antibiotic did not meet the one-hour overall turnaround goal. A main reason for delay was failure to label antibiotic orders as first dose. We designed an intervention that included antibiotic audits and individualized feedback to prescribers. The mean ± SD time from the written physician order to drug administration was 228 ± 58 minutes; timing improved to 55 ± 4 minutes after the intervention. The proportion of antibiotics administered within one hour improved from 42.2% to 63% (p=0.0015).

CONCLUSIONS

We identified system barriers associated with delayed antibiotic administration. Antibiotic timing was improved after continued surveillance and individualized feedback to providers.

Palivizumab utilization and compliance: trends in respiratory syncytial virus prophylaxis in Florida

OBJECTIVES

To analyze adherence to guidelines to prevent respiratory syncytial virus hospitalization and to a monthly immunoprophylaxis schedule in the absence of prior authorization requirements.

STUDY DESIGN

Among Florida Medicaid fee-for-service recipients 0 to 2 years of age from the 1998/1999 season through the 2004/2005 season with available birth certificates, we identified indications for palivizumab prophylaxis based on claims data. At least 4 doses of palivizumab in the 5 core season-months were considered full season coverage.

RESULTS

Of 302 101 children-seasons, 6089 were associated with 24 469 doses of palivizumab. In the 2004/2005 season, 73.6% of children with chronic lung disease received immunoprophylaxis, 67.6% children with gestational age <32 weeks, 37% with congenital heart disease, 26.4% with cystic fibrosis, and 19.4% with severe immunodeficiency. Multiple indications increased the likelihood for prophylaxis from 34.9% to 80.4%. Full season coverage was consistent across indications at approximately 70%. From the 1998/1999 season through the 2004/2005 season, 8038 doses were administered during 2051 children-seasons without any indication; mostly (69.6%) where premature children had exceeded the recommended age range for prophylaxis.

CONCLUSIONS

High utilization rates were found in children with multiple indications, and compliance with a monthly schedule was consistently high. One third of doses were administered outside of guidelines, suggesting suboptimal utilization of resources in the absence of prior authorization.

Root Cause Analysis and Subsequent Intervention to Improve First Dose Antibiotic Turnaround Time for Hospitalized Pediatric Patients

OBJECTIVE

Antibiotic timing is used as a quality standard for hospital accreditation and is an important quality measure. The study aim was to identify barriers in the process of first dose antibiotic administration on the pediatric floors at a tertiary healthcare center and carry out and test an intervention to improve turnaround time to less than one hour.

METHODS

We conducted a quasi-experimental pre-post study of hospitalized pediatric patients up to 18 years of age initiated on intravenous antibiotics. Every order for a first dose intravenous antibiotic was assessed on all pediatric floors (10/2008). Orders that did not meet the overall turnaround time goal of ≤ 1 hour were identified. A root cause analysis (RCA) was performed to identify reasons for delayed antibiotic administration. Barriers identified in the RCA were used to develop interventions (03/2009) to improve compliance, and the proportion of orders that met the goal was compared pre- (10/2008–02/2009) and post-intervention (04/2009–05/2009).

RESULTS

During the pre-intervention assessment period, 32 out of 46 total physician orders for a first dose intravenous antibiotic did not meet the one-hour overall turnaround goal. A main reason for delay was failure to label antibiotic orders as first dose. We designed an intervention that included antibiotic audits and individualized feedback to prescribers. The mean ± SD time from the written physician order to drug administration was 228 ± 58 minutes; timing improved to 55 ± 4 minutes after the intervention. The proportion of antibiotics administered within one hour improved from 42.2% to 63% (p=0.0015).

CONCLUSIONS

We identified system barriers associated with delayed antibiotic administration. Antibiotic timing was improved after continued surveillance and individualized feedback to providers.

Cost-utility analysis of rimonabant in the treatment of obesity

OBJECTIVE

To estimate the incremental cost-utility ratio (ICUR) of rimonabant 20 mg/day in the treatment of obesity from a third-party payer's perspective.

METHODS

Pooled data from three randomized clinical trials were used to develop a decision tree with five treatment alternatives: 1- and 2-year treatment with rimonabant, 2-year placebo, 1-year rimonabant followed by 1-year placebo, and no treatment. All alternatives, except no treatment, were accompanied by lifestyle interventions. Treatment benefits included gains in quality-adjusted life-years (QALYs) and reduced incidence of type-2 diabetes mellitus and coronary heart disease (CHD). Drug acquisition cost was based on the average wholesale price of a comparator drug minus 15%. One-way and probabilistic sensitivity analyses were conducted to assess the stability of the base-case results.

RESULTS

One-year rimonabant and 1-year rimonabant followed by placebo were extensively dominated. Rimonabant for 2 years showed an average weight reduction of 8.49 kg, a body mass index reduction of 2.98 kg/m(2) and reduced waist circumference by 8.24 cm (placebo: 3.55 kg, 1.22 kg/m(2), 4.18 cm). Two-year rimonabant was associated with a relative reduction in the 5-year incidence of CHD by 7.15% and of diabetes by 9.28%. Incremental benefits (costs) were 0.0984 QALYs ($5209) compared to no treatment and 0.0581 QALYs ($4182) compared to placebo, producing ICURs of $52,936/QALY (95% confidence interval $39K-$69K) and $71,973/QALY ($51K-$98K), respectively.

CONCLUSIONS

Rimonabant combined with lifestyle interventions has the potential to decrease the rate of obesity-related comorbidities and improve health-related quality of life, albeit at considerable cost.

A single-chain TNF receptor antagonist is an effective inhibitor of TNF mediated cytotoxicity

Tumour necrosis factor (TNF) is an important mediator of immune and inflammatory responses and has been recognized as a major pathogenic factor in several autoimmune and inflammatory diseases. TNF receptor TR60 plays a critical role in signalling the pathogenic activities of TNF. We here describe molecular cloning and bacterial production of a single-chain antibody (scFv H398) directed against TR60 which possesses antagonistic activity. VH and VL encoding sequences were isolated by PCR from the murine hybridoma cell line H398, cloned into a scFv expression vector and expressed in Escherichia coli. The recombinant antibody (Ab) fragment was found as an active soluble protein in the periplasm but also formed inclusion bodies. Re-folded scFv H398 purified from inclusion bodies was shown to be functional and stable at 37 degrees C with a half-life of 50 h. Comparison of the antigen binding characteristics of scFv with the parental enzymatically produced Fab H398 revealed that both Ab fragments have the same epitope specificity and an identical antigen binding affinity of 1.5 nM. In an in vitro assay it was demonstrated that scFv H398 is an efficient inhibitor of TNF mediated cytotoxicity with an IC50 of 22 nM, which is comparable to the antagonistic activity of natural Fab H398 with an IC50 of 12 nM. As scFv H398 possesses the high affinity TR60 binding and receptor antagonistic activity of the parental Ab H398 but is expected to be less antigenic in man, it provides a valuable tool for the development of novel therapeutic reagents against TNF mediated diseases.