A systematic review of validated methods for identifying hypersensitivity reactions other than anaphylaxis (fever, rash, and lymphadenopathy), using administrative and claims data

PURPOSE

The Food and Drug Administration's Mini-Sentinel pilot program aims to conduct active surveillance to refine safety signals that emerge for marketed medical products. A key facet of this surveillance is to develop and understand the validity of algorithms for identifying health outcomes of interest from administrative and claims data. This article summarizes the process and findings of the algorithm review of hypersensitivity reactions.

METHODS

PubMed and Iowa Drug Information Service searches were conducted to identify citations applicable to the hypersensitivity reactions of health outcomes of interest. Level 1 abstract reviews and Level 2 full-text reviews were conducted to find articles using administrative and claims data to identify hypersensitivity reactions and including validation estimates of the coding algorithms.

RESULTS

We identified five studies that provided validated hypersensitivity-reaction algorithms. Algorithm positive predictive values (PPVs) for various definitions of hypersensitivity reactions ranged from 3% to 95%. PPVs were high (i.e. 90%-95%) when both exposures and diagnoses were very specific. PPV generally decreased when the definition of hypersensitivity was expanded, except in one study that used data mining methodology for algorithm development.

CONCLUSIONS

The ability of coding algorithms to identify hypersensitivity reactions varied, with decreasing performance occurring with expanded outcome definitions. This examination of hypersensitivity-reaction coding algorithms provides an example of surveillance bias resulting from outcome definitions that include mild cases. Data mining may provide tools for algorithm development for hypersensitivity and other health outcomes. Research needs to be conducted on designing validation studies to test hypersensitivity-reaction algorithms and estimating their predictive power, sensitivity, and specificity.

A systematic review of validated methods for identifying acute respiratory failure using administrative and claims data

PURPOSE

The Food and Drug Administration's (FDA) Mini-Sentinel pilot program initially aims to conduct active surveillance to refine safety signals that emerge for marketed medical products. A key facet of this surveillance is to develop and understand the validity of algorithms for identifying health outcomes of interest (HOIs) from administrative and claims data. This paper summarizes the process and findings of the algorithm review of acute respiratory failure (ARF).

METHODS

PubMed and Iowa Drug Information Service searches were conducted to identify citations applicable to the anaphylaxis HOI. Level 1 abstract reviews and Level 2 full-text reviews were conducted to find articles using administrative and claims data to identify ARF, including validation estimates of the coding algorithms.

RESULTS

Our search revealed a deficiency of literature focusing on ARF algorithms and validation estimates. Only two studies provided codes for ARF, each using related yet different ICD-9 codes (i.e., ICD-9 codes 518.8, "other diseases of lung," and 518.81, "acute respiratory failure"). Neither study provided validation estimates.

CONCLUSIONS

Research needs to be conducted on designing validation studies to test ARF algorithms and estimating their predictive power, sensitivity, and specificity.

Over-the-counter ibuprofen and risk of gastrointestinal bleeding complications: a systematic literature review

BACKGROUND

Exposure to over-the-counter (OTC) ibuprofen and other OTC non-steroidal anti-inflammatory drugs (NSAIDs) is substantial. Although the literature on gastrointestinal (GI) safety of NSAID therapy is extensive, the risk profiles of OTC and prescription dosing are seldom separated, and few studies provide risks specific to OTC ibuprofen.

OBJECTIVE

To conduct a literature review to evaluate the risk of GI bleeding events related to OTC ibuprofen use.

METHODS

Published clinical trials, observational studies, and meta-analyses of OTC ibuprofen use, defined as up to 1200 mg/day or stated as 'over the counter,' reporting endpoints of incidence rates and proportions of GI bleeding events (e.g., GI bleeding-related hospitalizations and deaths) were identified via MEDLINE through 2010. Data from these studies were summarized.

RESULTS

Twenty studies (nine observational, ten clinical trials, one meta-analysis) reporting incidence rates and proportions of a GI bleeding-related event associated with OTC or OTC-specific doses of ibuprofen were included. The frequency of a GI-related hospitalization was <0.2% for patients on OTC-comparable doses. Incidence rates among those using OTC-comparable doses ranged from 0 to 3.19 per 1000 patient-years. The incidence of a GI bleeding-related event increased with age and the use of concomitant medications, and there was a general, though not always statistically significant, ibuprofen dose-response relationship. The relative risk of any GI bleeding-related event ranged from 1.1 to 2.4 for users of OTC-specific doses of ibuprofen compared to non-users.

CONCLUSIONS

Studies reported low incidence of GI bleeding events with use of OTC ibuprofen. Few published studies that specifically investigated OTC ibuprofen use were identified. Varying methodologies and definitions of exposure and outcomes prevented direct comparison of many results. Only studies that used the methods herein described were identified. Further research evaluating the risk of GI bleeding events in patients taking OTC-specific ibuprofen use may be useful.

Trend analyses of insulin delivery systems in the United States

BACKGROUND

Despite potential advantages in insulin pen delivery systems (IPDSs), the percentage of patients using an IPDS is relatively low in the United States.

OBJECTIVE

Our aim was to investigate the trend of initiating IPDSs among patients with type 2 diabetes mellitus (T2DM) who newly initiated insulin therapy.

METHODS

A retrospective analysis was conducted using a U.S. database from January 1, 2004, to December 31, 2008. Patients with T2DM who initiated a new insulin type and delivery system were included. The Cochran-Armitage test was used to assess the significance of the trend of initiating an insulin delivery system, including vial/syringe, IPDS overall, reusable pen delivery systems (RPDSs), and prefilled pen delivery systems (PPDSs). Different types of insulin (e.g., basal analog, prandial analog) were examined separately.

RESULTS

Patients initiating an IPDS increased from 10.6% in 2004 to 48.5% in 2008 (p < .001), most notably in basal analog and prandial analog insulin therapies. Although the percentage of patients using a PPDS increased by 36.2 percentage points (from 9.2% in 2004 to 45.4% in 2008; p < .001), use of a RPDS increased only by 1.7 percentage points (from 1.4% in 2004 to 3.1% in 2008; p < .001).

CONCLUSION

There was an overall increase in the use of IPDSs in the United States among patients with T2DM who newly initiated insulin from July 1, 2004, to December 31, 2008. This increase was driven by the use of PPDSs for basal analog and prandial analog insulin therapies. Despite the increasing use of IPDS over time, approximately 50% of patients still initiated insulin using a vial/syringe in 2008.

Methods to identify and compare parenteral nutrition administered from hospital-compounded and premixed multichamber bags in a retrospective hospital claims database

PURPOSE

Use of parenteral nutrition (PN) is indicated for patients who are unable to meet their needs enterally. PN may be administered via custom-compounded mix or commercially available ready-to-use multichamber bags (MCB), but little is known about potential differences in clinical outcomes between these delivery systems. This study was undertaken to assess the feasibility of comparing custom-compounded and MCB PN in a large hospital claims database.

METHODS

Hospital claims data from the Premier Perspective Comparative Hospital Database (PCD) reported from 2005 through 2007 were analyzed. The authors searched the data for patients who received any PN products, including compounded PN and MCB PN. Coding algorithms for identifying patient characteristics, risk factors, and outcomes of interest were explored.

RESULTS

Using hospital billing claims, the authors identified patients in the database treated with premixed PN from multichamber bags ("MCB only," n = 4699) and patients treated with custom-compounded PN solution ("compounded PN," n = 64,315). Methods of identifying PN administration groups, patient characteristics and risk factors, outcomes of interest, and data limitations are described.

CONCLUSIONS

Exploratory analysis suggests that comparisons of PN administered via compounding and MCB are possible using the Premier data. The ability to control for many identifiable risk factors allows data to be presented for the use of PN and related outcomes in both a clinically sensible and relevant manner, albeit with some limitations.

Impact of bleeding-related complications and/or blood product transfusions on hospital costs in inpatient surgical patients

Background

Inadequate surgical hemostasis may lead to transfusion and/or other bleeding-related complications. This study examines the incidence and costs of bleeding-related complications and/or blood product transfusions occurring as a consequence of surgery in various inpatient surgical cohorts.

Methods

A retrospective analysis was conducted using Premier's Perspective™ hospital database. Patients who had an inpatient procedure within a specialty of interest (cardiac, vascular, non-cardiac thoracic, solid organ, general, reproductive organ, knee/hip replacement, or spinal surgery) during 2006-2007 were identified. For each specialty, the rate of bleeding-related complications (including bleeding event, intervention to control for bleeding, and blood product transfusions) was examined, and hospital costs and length of stay (LOS) were compared between surgeries with and without bleeding-related complications. Incremental costs and ratios of average total hospital costs for patients with bleeding-related complications vs. those without complications were estimated using ordinary least squares (OLS) regression, adjusting for demographics, hospital characteristics, and other baseline characteristics. Models using generalized estimating equations (GEE) were also used to measure the impact of bleeding-related complications on costs while accounting for the effects related to the clustering of patients receiving care from the same hospitals.

Results

A total of 103,829 cardiac, 216,199 vascular, 142,562 non-cardiac thoracic, 45,687 solid organ, 362,512 general, 384,132 reproductive organ, 246,815 knee/hip replacement, and 107,187 spinal surgeries were identified. Overall, the rate of bleeding-related complications was 29.9% and ranged from 7.5% to 47.4% for reproductive organ and cardiac, respectively. Overall, incremental LOS associated with bleeding-related complications or transfusions (unadjusted for covariates) was 6.0 days and ranged from 1.3 to 9.6 days for knee/hip replacement and non-cardiac thoracic, respectively. The incremental cost per hospitalization associated with bleeding-related complications and adjusted for covariates was highest for spinal surgery ($17,279) followed by vascular ($15,123), solid organ ($13,210), non-cardiac thoracic ($13,473), cardiac ($10,279), general ($4,354), knee/hip replacement ($3,005), and reproductive organ ($2,805).

Conclusions

This study characterizes the increased hospital LOS and cost associated with bleeding-related complications and/or transfusions occurring as a consequence of surgery, and supports implementation of blood-conservation strategies.

Comparison of utilization, cost, adherence, and hypoglycemia in patients with type 2 diabetes initiating rapid-acting insulin analog with prefilled pen versus vial/syringe

BACKGROUND

Studies examining outcomes of different insulin delivery systems are limited. The objective of this study was to compare healthcare utilization, costs, adherence, and hypoglycemia rates in patients with type 2 diabetes mellitus (T2DM) initiating rapid-acting insulin analog (RAIA) using prefilled pen versus vial/syringe.

METHODS

A retrospective analysis was conducted using a US claims database (1/1/2007 to 12/31/2008). Inclusion criteria were: ≥18 years old, with T2DM, ≥12 months of continuous eligibility, and new to RAIA. Difference-in-difference analyses after propensity score matching were conducted to compare changes in outcomes from 6 months prior to and 6 months after initiating RAIA with a prefilled pen versus vial/syringe (Wilcoxon rank-sum test for costs and t-test for other outcomes). Categories of utilization and costs (2009 USD) included total and diabetes-related inpatient, outpatient, and emergency room. Adherence was measured by proportion of days covered (PDC). Hypoglycemia was identified using ICD-9-CM codes.

RESULTS

Baseline characteristics were similar between the prefilled pen (n = 239) and vial/syringe (n = 590) cohorts after matching. Adherence to RAIA was greater in the prefilled pen cohort than the vial/syringe cohort (PDC: 54.6 vs. 45.2%, p < 0.001). While the increase in diabetes-related pharmacy costs from before to after initiating RAIA was greater in the prefilled pen cohort than the vial/syringe cohort (+$900 vs. +$607, p < 0.001), the prefilled pen cohort was associated with greater reductions in the total diabetes-related costs (-$235 vs. +$61, p = 0.006) and the utilization of oral anti-hyperglycemic agents (-1.3 vs. -0.7, p = 0.016). There were no significant differences in other outcomes.

LIMITATIONS

Claims databases do not provide optimal measures for adherence or T2DM severity, and only capture hypoglycemia events requiring clinical intervention.

CONCLUSION

Initiating RAIA with a prefilled pen was associated with better adherence and greater reduction in total diabetes-related costs than a vial/syringe. There was no significant difference in total healthcare costs.

Persistence and adherence to disease modifying drugs among patients with multiple sclerosis

OBJECTIVE

This retrospective database study aimed to evaluate the adherence of multiple sclerosis (MS) patients on immunomodulatory treatments using claims data, and to identify differences between compliance and persistency measurements in the context of this disease.

METHODS

Continuously enrolled MS patients treated with subcutaneous IFNbeta-1b (Betaseron * ), subcutaneous IFNbeta-1a (Rebif dagger ), intramuscular IFNbeta-1a (Avonex double dagger ), and subcutaneous glatiramer acetate (Copaxone section sign ).) were identified from the PharMetrics patient-centric database, and all information related to patient demographics and pharmacy claims for the drugs of interest were extracted.

OUTCOME MEASURES

The main outcomes were treatment switches and discontinuations for patients initiated on the drugs of interest. Various compliance and persistency metrics including the proportion of days covered, treatment prevalence at 6-monthly time points after initiation, and the continuous time on drug were also examined.

RESULTS

A total of 6134 MS patients were started on one of the four drugs of interest. The number of patients switching or discontinuing therapy rose over the study period. The proportion of patients switching was similar between study drugs, by the different metrics, with the highest switch rates for subcutaneous IFNbeta-1b and the lowest for subcutaneous glatiramer acetate. Discontinuation rates were highest for subcutaneous IFNbeta-1b and lowest for intramuscular IFNbeta-1a. Regression models showed that intramuscular IFNbeta-1a and subcutaneous IFNbeta-1a had similar and higher persistency compared to subcutaneous IFNbeta-1b and subcutaneous glatiramer acetate.

CONCLUSIONS

Although treatment switching and discontinuation is common in MS patients, there is some noticeable variability between drugs and across measures of persistency and adherence. Also, claims data do not allow distinguishing between clinical patterns of MS, direct estimation of disease severity and observation of care that occurs outside of insurance coverage, and results need to be cautiously interpreted. The compliance to the various MS drugs was 80% or higher at all times for all four drugs. The highest rate of treatment persistency existed in the intramuscular IFNbeta-1a initiator group, while subcutaneous IFNbeta-1b was associated with a significantly lower persistence (p < 0.0001).

Healthcare resource utilization following switch or discontinuation in multiple sclerosis patients on disease modifying drugs

OBJECTIVE

The objective of this study was to explore the cost and utilization in the period following discontinuations or switches of disease modifying drugs (DMDs) for patients with multiple sclerosis (MS). Secondary objectives included an assessment of the time to switch or discontinuation from index DMD treatment.

METHODS

Cases were defined as a billed MS diagnosis in continuously enrolled patients initiated with interferon-beta1a IM, interferon-beta1b SC, glatiramer acetate, and interferon-beta1a SC found in the PharMetrics Patient-Centric Database. Information on patient demographics, diagnoses, procedures, pharmacy-dispensed drugs, and costs was extracted; reasons for discontinuation and expenses outside of the healthcare system were not available. Treatment discontinuations and switches between study drugs were defined using pharmacy prescription patterns and analyzed by descriptive and regression methods. The non-pharmacy medical costs in the 18 months following switching or discontinuation were compared to the costs in a randomly selected similar period for those patients who did not switch or discontinue these agents.

RESULTS

A total of 5,772 MS patients were continuously enrolled and were treated with one or more of the four drugs of interest, and about half of these patients switched drugs or discontinued treatment for at least 90 days. Patients initiated with interferon-beta1b SC were more likely to discontinue treatment compared to interferon-beta1a IM users. Non-pharmaceutical medical costs were highest for those switching treatments followed by those discontinuing DMDs in the 18 months following a switch or discontinuation, compared to persistent users of these drugs. Interferon beta1b SC initiators had higher costs following changes or discontinuations, while glatiramer acetate and interferon-beta1a SC users had lower subsequent costs compared to interferon-beta1a IM users.

LIMITATIONS

Unfortunately, the reasons for stopping the initial treatment cannot be determined from analysis of an administrative claims database. Also, the MS cases followed in this analysis are billing diagnostic events unconfirmed through a review of medical records or other data sources. The results are unstratified in terms of severity and thus while treatment patterns may vary for patients with different types of MS (e.g., progressive vs. relapsing-remitting), this cannot be examined in this analysis.

CONCLUSION

Changing or discontinuing DMDs is common among MS patients and is associated with higher non-pharmaceutical medical costs that vary based on the initiating drug and other demographics characteristics.

Topical bovine thrombin and adverse events: a review of the literature

OBJECTIVE

To review published evidence suggesting a link between topical bovine thrombin (TBT) and important adverse events (AEs).

RESEARCH DESIGN AND METHODS

English language articles and abstracts were obtained from MEDLINE using combinations of text and MeSH terms for thrombin, bovine thrombin and their trade names. References from summary articles were also retrieved. Published case reports, review articles, and retrospective, prospective or observational studies involving either immunogenicity or AEs were selected for further assessment. Retrieved articles were evaluated separately as AE case reports, quantitative studies of antibodies, or quantitative studies of AEs.

MAIN OUTCOME MEASURES

Presence of case causal information, temporal pattern of case report publication, reproducibility of aggregate data findings, and study design features.

RESULTS

The major limitations of reviewed publications were insufficient information regarding TBT and other exposures, and designs in which linkage between laboratory immune phenomena and AEs could not be evaluated. While immunogenicity studies did support an increased risk for post-TBT antibodies, there was no consistent evidence that this led to an increased AE risk or severity. Common evidentiary deficiencies included case reports from high incidence environments, studies of combination or mixture products, biased study designs, lack of patient-level exposure data, inadequate control groups and insufficient sample sizes. The best designed study (a randomized, controlled comparison of TBT to a recombinant bovine product) documented post-TBT antibody production, but no important efficacy or AE differences. An examination of publication dates for case reports showed a peak between 1992 and 1994 followed by a substantial drop. Since 1997 the number of published AE case reports has continued to decline.

CONCLUSIONS

TBT increases the risk for antibody elevations in patients. A careful review of published evidence does not show that either TBT itself or any associated elevations in anti-bovine antibodies are risk factors for clinically important AEs.

Pregnancy outcomes in women with epilepsy: a systematic review and meta-analysis of published pregnancy registries and cohorts

PURPOSE

To conduct a systematic review and meta-analysis to quantify the incidence of congenital malformations (CMs) and other pregnancy outcomes as a function of in utero anti-epileptic drug (AED) exposure.

METHODS

We performed a systematic literature review to identify all published registries and cohort studies of births from pregnant women with epilepsy (WWE) that reported incidence of CMs. Overall incidences were calculated using a random effects model.

RESULTS

The review included 59 studies that met inclusion/exclusion criteria, involving 65,533 pregnancies in WWE and 1,817,024 in healthy women. The calculated incidence of births with CM in WWE [7.08%; 95% CIs 5.62, 8.54] was higher than healthy women [2.28%; CIs 1.46, 3.10]. Incidence was highest for AED polytherapy [16.78%; CIs 0.51, 33.05]. The AED with the highest CM incidence was valproate, which was 10.73% [CIs 8.16, 13.29] for valproate monotherapy.

CONCLUSIONS

Results of this systematic literature review suggest that the overall incidence of CMs in children born of WWE is approximately threefold that of healthy women. The risk is elevated for all AED monotherapy and further elevated for AED polytherapy compared to women without epilepsy. The risk was significantly higher for children exposed to valproate monotherapy and to polytherapy of 2 or more drugs when the polytherapy combination included phenobarital, phenytoin, or valproate. Further research is needed to delineate the specific risk for each individual AED and to determine underlying mechanisms including genetic risk factors.

Risk of bleeding in surgical patients treated with topical bovine thrombin sealants: a review of the literature

BACKGROUND

One of the most anticipated, but potentially serious complications during or after surgery are bleeding events. Among the many potential factors associated with bleeding complications in surgery, the use of bovine thrombin has been anecdotally identified as a possible cause of increased bleeding risk. Most of these reports of bleeding events in association with the use of topical bovine thrombin have been limited to case reports lacking clear cause and effect relationship determination. Recent studies have failed to establish significant differences in the rates of bleeding events between those treated with bovine thrombin and those treated with either human or recombinant thrombin.

METHODS

We conducted a search of MEDLINE for the most recent past 10 years (1997-2007) and identified all published studies that reported a study of surgical patients with a clear objective to examine the risk of bleeding events in surgical patients. We also specifically noted the reporting of any topical bovine thrombin used during surgical procedures. We aimed to examine whether there were any differences in the risk of bleeds in general surgical populations as compared to those studies that reported exposure to topical bovine thrombin.

RESULTS

We identified 21 clinical studies that addressed the risk of bleeding in surgery. Of these, 5 studies analyzed the use of bovine thrombin sealants in surgical patients. There were no standardized definitions for bleeding events employed across these studies. The rates of bleeds in the general surgery studies ranged from 0.1%-20.2%, with most studies reporting rates between 2.6%-4%. The rates of bleeding events ranged from 0.0%-13% in the bovine thrombin studies with most studies reporting between a 2%-3% rate.

CONCLUSION

The risk of bleeds was not clearly different in those studies reporting use of bovine thrombin in all patients compared to the other surgical populations studied. A well-designed and well-controlled study is needed to accurately examine the bleeding risks in surgical patients treated and unexposed to topical bovine thrombin, and to evaluate the independent risk associated with topical bovine thrombin as well as other risk factors.

Impact of clinical trial design and execution-related factors on incidence of thromboembolic events in cancer patients: a systematic review and meta-analysis

OBJECTIVE

The objective of this study was to quantify the incidence of thromboembolic events (specifically, deep vein thromboses [DVT] and pulmonary embolism [PE]) in patients with cancer, and to examine the effects of a major clinical trial design and execution factors on those incidence rates.

RESEARCH DESIGN AND METHODS

The study included a systematic review of Medline, Current Contents, and accepted study bibliographies, as well as an analysis of studies. Studies included both longitudinal studies (prospective and retrospective) published in the English language between January 1990 and October 2005. Studies of patients with cancer that reported the incidence of thromboembolic events (DVT, PE, and total venous thromboembolic events [VTE]) were eligible for inclusion. Incidence of these events was calculated by study design, surveillance type (active or passive), length of follow-up, and other treatment risk factors. Incidence rates were estimated by random effects Poisson meta-regression modeling.

RESULTS

One hundred and eighty-three studies met all inclusion criteria. Incidence rates of all outcomes (DVT, PE, and total VTE) were 3-55 times higher for active surveillance than for passive surveillance. Studies with a follow-up time </= 6 months reported thromboembolic event rates that were 3-26 times higher than study groups with a follow-up time > 6 months. Additionally, the incidence rates for all outcome events when using passive surveillance were 3-12 times higher in non-randomized clinical trials (non-RCTs) than in RCTs.

CONCLUSIONS

These results provide a benchmark for the incidence of thromboembolic events in patients with cancer. Factors such as study design, length of follow-up, and method of case ascertainment (type of surveillance - active or passive) must be considered when interpreting thromboembolic incidence rates. This review is comprehensive in its inclusion of all studies with a scientific objective of examining the risk of thromboembolic events in patients with cancer from 1990 to 2005. However, other studies published prior to 1990, more recently than 2005, or with other scientific objectives in their research may also provide supportive information to these risk estimates.

The experience of sexual assault: findings from a statewide victim needs assessment

A statewide assessment was conducted of assaults, experiences, needs, and recommendations of 125 adult victims receiving care at 19 sexual assault centers (SACs) in the State of Maryland. More than one half of the victims (55.6%) waited years before disclosing, with delays in reporting especially likely if the assault was perpetrated by a family member (the most frequent perpetrators at 42.4% of respondents). About one half of the victims (51.3%) had been previously sexually assaulted, yet only 9% of these victims had sought treatment. The majority of respondents (69.4%) indicated they would not be filing charges against perpetrators, and of those who did, 46.2% reported dissatisfaction with the interview with police. Psychological symptoms such as depression and anxiety were the most common reasons for seeking care at the centers. Nearly all of respondents rated the care they received at the centers as very good or excellent. Respondents recommended more SACs, better advertising of their services, more mental health care within them (especially group therapy), and improved laws and law enforcement of perpetrators.