Risk of serious spinal adverse events associated with epidural corticosteroid injections in the Medicare population.

BACKGROUND: Epidural corticosteroid injections (ESIs) are widely performed and have an unquantified risk of serious spinal adverse events (SSAEs). We sought to determine the rate of SSAEs following ESI and to compare the rates by spinal level, injection approach and corticosteroid formulation. METHODS: We included patients enrolled in Medicare parts A and B who had an ESI between 1 January 2009 and 30 September 2015. We identified potential cases as patients with spine-related diagnoses within 3 days after the first eligible ESI. Event categorization as probable, possible or non-case was based on review of medical records. The rates of probable and possible cases were expressed per 1 000 000 patients overall, and by spinal level, injection approach and corticosteroid formulation. A score test was used to compare these rates. RESULTS: We identified 1 355 957 eligible ESIs during the study period. Of the 110 potential cases, 43 were selected for medical record review and 11 were categorized as probable, yielding a rate of 8.1 per 1 000 000 patients (95% CI 4.5 to 14.5). Risk of SSAEs was statistically higher with cervical/thoracic injections (29.4, 95% CI 12.5 to 68.8) compared with lumbar/sacral injections (5.1, 95% CI 2.3 to 11.0) (p value 0.001). Event rates for lumbar/sacral non-transforaminal injections was 8.8 (95% CI 4.0 to 19.1). Event rates for particulate (7.5, 95% CI 3.9 to 14.2) and non-particulate formulations (13.1, 95% CI 3.6 to 47.9) appeared similar (p value 0.47). CONCLUSION: Between 2009 and 2015, rates of SSAEs following ESI in the Medicare population were low. Patients receiving cervical/thoracic ESIs were at higher risk of SSAE than those receiving lumbar/sacral ESIs. Event rates were similar for each corticosteroid formulation.

Assessment of Potentially Inappropriate Prescribing of Opioid Analgesics Requiring Prior Opioid Tolerance.

Importance: Opioid-tolerant only (OTO) medications, such as transmucosal immediate-release fentanyl products and certain extended-release opioid analgesics, require prior opioid tolerance for safe use, as patients without tolerance may be at increased risk of overdose. Studies using insurance claims have found that many patients initiating these medications do not appear to be opioid tolerant. Objectives: To measure prevalence of opioid tolerance in patients initiating OTO medications and to determine whether linked electronic health record (EHR) data contribute evidence of opioid tolerance not found in insurance claims data. Design, Setting, and Participants: This retrospective cohort study used a national database of deidentified longitudinal health information, including medical and pharmacy claims, insurance enrollment, and EHR data, from January 1, 2007, to December 31, 2016. Data included 131 756 US residents with at least 183 days of continuous enrollment in commercial or Medicare Advantage insurance (including medical and pharmacy benefits) who had received an OTO medication and who had no inpatient stays in the 30 days prior to starting an OTO medication; of these, 20 044 individuals had linked EHR data within the prior 183 days. Data were analyzed from July 1, 2017, to August 31, 2018. Exposures: Initiating an OTO medication. Main Outcomes and Measures: Prior opioid tolerance demonstrated through pharmacy fills or EHR data on prescriptions written. Results: Among 153 385 OTO use episodes identified, 89 029 (58.0%) occurred among women, 62 900 (41.0%) occurred among patients with Medicare Advantage insurance, 39 394 (25.7%) occurred in the Midwest, 17 366 (11.3%) occurred in the Northeast, 73 316 (47.8%) occurred in the South, and 23 309 (15.2%) occurred in the West. Less than half of use episodes (73 117 episodes [47.7%]) involved patients with evidence in claims data of opioid tolerance prior to initiating therapy with an OTO medication, including 31 392 of 101 676 episodes (30.9%) involving transdermal fentanyl, 1561 of 2440 episodes (64.0%) involving transmucosal fentanyl, 36 596 of 43 559 episodes (84.0%) involving extended-release oxycodone, and 3568 of 5710 episodes (62.5%) involving extended-release hydromorphone. Among 20 044 OTO use episodes with linked EHR and claims data, less than 1% of OTO episodes identified in claims had evidence of opioid tolerance in structured EHR data that was not present in claims data (108 episodes [0.5%]). After limiting the sample to OTO episodes identified in claims with a matching OTO prescription within 14 days in the structured EHR data, only 40 of 939 episodes (4.0%) occurred among patients with evidence of tolerance that was not present in claims data. Conclusions and Relevance: This cohort study found that most patients initiating OTO medications did not have evidence of prior opioid tolerance, suggesting they were at increased risk of opioid-related harms, including fatal overdose. Data from EHRs did not contribute substantial additional evidence of opioid tolerance beyond the data found in prescription claims. Future research is needed to understand the clinical rationale behind these observed prescribing patterns and to quantify the risk of harm to patients associated with potentially inappropriate prescribing.

Assessment of prior opioid tolerance among new users of fentanyl transdermal system in FDA's Sentinel System.

PURPOSE: Fentanyl transdermal system (FTS) is intended only for patients with prior opioid tolerance. The purpose of this study is to identify the proportion of new FTS users who had evidence of prior opioid tolerance, by dosage strength, in FDA's Sentinel System. METHODS: We identified new FTS episodes (183-day washout) from 2009 through 2013. Members were <65 years and enrolled in medical and pharmacy coverage for 183 days prior to initial FTS dispensing (index). We assessed the proportion of users with prior tolerance stratified by dosage strength of FTS using four definitions of opioid tolerance: ≥30-mg oxycodone equivalents/day in each of 7 consecutive days immediately prior to index; ≥30-mg oxycodone equivalents/day for any 7 days in the 30 days prior to index (secondary); any dose in each of 7 days in the 7 consecutive days immediately prior to index (tertiary); and any dose for any 7 days in the 30 days prior to index (quaternary). RESULTS: Of 44 450 episodes of 25 mcg/hr FTS, 37% met the primary definition, and 77% met the quaternary definition. Of 3507 episodes of 100 mcg/hr FTS, 57% and 74% met the primary and quaternary definitions, respectively. Those aged 25 to 34 years had the highest proportion of episodes with prior tolerance; those aged 55 to 64 accounted for more of the episodes overall. CONCLUSIONS: In Sentinel, many new users of FTS did not have evidence of prior opioid tolerance by the primary definition, ie, the product label definition, which is the minimum standard for the lowest FTS dose (12 mcg/hr), especially at the highest strength (100 mcg/hr). Validation of this metric is warranted, but our findings suggest the need for further prescriber education regarding appropriate prescribing of FTS.

Opioid tolerance and urine drug testing among initiates of extended-release or long-acting opioids in Food and Drug Administration's Sentinel System.

OBJECTIVE: A risk evaluation and mitigation strategy for extended-release and long-acting (ER/LA) opioid analgesics was approved by the Food and Drug Administration in 2012. Our objective was to assess frequency of opioid tolerance and urine drug testing for individuals initiating ER/LA opioid analgesics. DESIGN: Retrospective cohort study. SETTING: Sentinel, a distributed database with electronic healthcare data on >190 million predominantly commercially insured members. PATIENTS, PARTICIPANTS: Members under age 65 initiating ER/LA opioid analgesics between January 2009 and December 2013. MAIN OUTCOME MEASURE(S): We examined the proportion of opioid-tolerant-only ER/LA opioid analgesic initiates meeting tolerance criteria: receipt of ≥30 mg oxycodone equivalents per day in 7 days prior to the first opioid-tolerant-only dispensing. We separately examined the proportion of new users of extended-release oxycodone (ERO) and other ER/LA opioid analgesics with a claim for a urine drug test in the 30 days prior to, and separately for the 183 days after, dispensing. RESULTS: We identified 79,824 ERO, 7,343 extended-release hydromorphone, and 91,778 transdermal fentanyl opi-oid-tolerant-only episodes. Tolerance criteria were met in 64 percent of ERO, 64 percent of extended-release hydromorphone and 40 percent of transdermal fentanyl episodes. We identified 210,581 incident ERO and 311,660 other ER/LA opioid analgesic episodes. Use of urine drug testing for ERO compared with other ER/LA opioid analgesics was: 4 percent vs 14 percent respectively in the 30 days prior to initiation and 9 percent vs 23 percent respectively in the 183 days following initiation. CONCLUSIONS: These results suggest potential areas for improving appropriate ER/LA opioid analgesic prescribing practices.

More methemoglobin is produced by benzocaine treatment than lidocaine treatment in human in vitro systems.

The clinical use of local anesthetic products to anesthetize mucous membranes has been associated with methemoglobinemia (MetHba), a serious condition in which the blood has reduced capacity to carry oxygen. An evaluation of spontaneous adverse event reporting of MetHba submitted to FDA through 2013 identified 375 reports associated with benzocaine and 16 reports associated with lidocaine. The current study was performed to determine the relative ability of benzocaine and lidocaine to produce methemoglobin (MetHb) in vitro. Incubation of 500µM benzocaine with whole human blood and pooled human liver S9 over 5h resulted in MetHb levels equaling 39.8±1.2% of the total hemoglobin. No MetHb formation was detected for 500µM lidocaine under the same conditions. Because liver S9 does not readily form lidocaine hydrolytic metabolites based on xylidine, a primary metabolic pathway, 500µM xylidine was directly incubated with whole blood and S9. Under these conditions MetHb levels of 4.4±0.4% were reached by 5h. Studies with recombinant cytochrome P450 revealed benzocaine to be extensively metabolized by CYP 1A2, with 2B6, 2C19, 2D6, and 2E1 also having activity. We conclude that benzocaine produces much more MetHb in in vitro systems than lidocaine or xylidine and that benzocaine should be more likely to cause MetHba in vivo as well.

Cardiovascular and mortality risks in older Medicare patients treated with varenicline or bupropion for smoking cessation: an observational cohort study.

PURPOSE: To compare cardiovascular and mortality risks in elderly patients treated with varenicline or bupropion for smoking cessation. METHODS: Elderly Medicare beneficiaries were entered into new-user cohorts of varenicline or bupropion for smoking cessation and followed on therapy for primary outcomes of acute myocardial infarction (AMI), stroke, mortality, and a composite of any of these events. Secondary outcomes were unstable angina, coronary revascularization, and a composite of any primary or secondary outcome event. Propensity score stratification was used to adjust for baseline differences in potential confounding factors. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards, with bupropion as reference. RESULTS: In cohorts of 74 824 varenicline and 14 133 bupropion users, there were 164 AMI, 96 stroke, 87 death, 317 primary composite, and 814 secondary composite events while on therapy. The HRs (95%CI) were 0.79 (0.50-1.24) for AMI, 1.27 (0.63-2.55) for stroke, 0.58 (0.30-1.13) for death, 0.84 (0.58-1.23) for the primary composite, and 0.92 (0.73-1.14) for the secondary composite. The risk of AMI or the primary composite outcome did not differ in subgroups defined by age, diabetes status, or presence of underlying ischemic heart disease. Only 30% of patients remained on either study drug beyond their first prescription. CONCLUSION: Cardiovascular and mortality risks were not increased in older patients treated with varenicline compared with bupropion for smoking cessation. A potential increase in the risk of stroke with varenicline could not be excluded. Treatment persistence with either drug was low. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Candidate metrics for evaluating the impact of prescriber education on the safe use of extended-release/long-acting (ER/LA) opioid analgesics.

OBJECTIVE: The objective of this study was to develop metrics to assess opioid prescribing behavior as part of the evaluation of the Extended-Release/Long-Acting (ER/LA) Opioid Analgesic Risk Evaluation and Mitigation Strategies (REMS). DESIGN: Candidate metrics were selected using published guidelines, examined using sensitivity analyses, and applied to cross-sectional rolling cohorts of Medicare patients prescribed with extended-release oxycodone (ERO) between July 2, 2006 and July 1, 2011. Potential metrics included prescribing opioid-tolerant-only ER/LA opioid analgesics to non-opioid-tolerant patients, prescribing early fills to patients, and ordering drug screens. RESULTS: Proposed definitions for opioid tolerance were seven continuous days of opioid usage of at least 30 mg oxycodone equivalents, within the 7 days (primary) or 30 days (secondary) prior to first opioid-tolerant-only ERO prescription. Forty-four percent of opioid-tolerant-only ERO episodes met the primary opioid tolerance definition; 56% met the secondary definition. Fills were deemed "early" if a prescription was filled before 70% (primary) or 50% (secondary) of the prior prescription's days' supply was to be consumed. Five percent (primary) and 2% (secondary) of episodes had more than or equal to two early fills during treatment. At least one drug screen was billed in 14% of episodes. Stratified analyses indicated that older patients were less likely to be opioid tolerant at the time of the first opioid-tolerant-only ERO prescription. CONCLUSIONS: Investigators propose three metrics to monitor changes in prescribing behaviors for opioid analgesics that might be used to evaluate the ER/LA Opioid Analgesics REMS. Low frequencies of patients, particularly those >85 years, were likely to be opioid tolerant prior to receiving prescriptions for opioid-tolerant-only ERO.

Bleeding events following concurrent use of warfarin and oseltamivir by Medicare beneficiaries.

BACKGROUND: During the 2009 H1N1 influenza pandemic, the UK Medicines and Healthcare Products Regulatory Agency received case reports suggesting a potentiation of warfarin anticoagulation by the antiviral drug oseltamivir. We evaluated this putative interaction using Medicare data. OBJECTIVE: To determine the frequency of bleeding following addition of oseltamivir or comparator drugs among Medicare beneficiaries taking warfarin. METHODS: This was a retrospective cohort evaluation using Medicare nationwide data. Cohort members were Medicare Parts A, B, and D beneficiaries from June 30, 2006 to October 31, 2010 receiving warfarin for at least 1 month prior to a concomitant drug of interest (oseltamivir, ampicillin, trimethoprim-sulfamethoxazole (TMP-SMX), and angiotensin-converting enzyme (ACE) inhibitors). Bleeding within 14 days of new prescriptions for oseltamivir or comparators was identified using inpatient or emergency department ICD-9 (International Classification of Diseases, ninth revision) discharge diagnosis codes for gastrointestinal hemorrhage, epistaxis, hematuria, and intracranial bleeding. Patients with bleeding within 30 days preceding the prescription concomitant to warfarin were excluded. RESULTS: With concomitant ACE inhibitors as reference, adjusted odds ratios (ORs) for any bleeding events within 14 days were 1.47 (95% confidence interval [CI] = 1.08-1.88), 1.24 (95% CI = 0.97-1.57), and 2.74 (95% CI = 2.53-3.03), for warfarin plus ampicillin, oseltamivir, and TMP-SMX, respectively. In a sensitivity analysis, adjusted ORs over a 7-day period were 1.89 (95% CI = 1.29-2.59), 1.47 (95% CI = 1.06-2.02), and 3.07 (95% CI = 2.76-3.49) for warfarin plus ampicillin, oseltamivir, and TMP-SMX, respectively. CONCLUSIONS: Bleeding with oseltamivir plus warfarin was not significantly increased over a 14-day observation period; a sensitivity analysis showed a statistically significant increase over a 7-day period; in contrast, the data consistently showed the known tendency of TMP-SMX to potentiate the effects of warfarin. The results should be interpreted with the limitations of this approach in mind, including the inability to control for unmeasured confounders.

Validity of diagnostic codes to identify cases of severe acute liver injury in the US Food and Drug Administration's Mini-Sentinel Distributed Database.

PURPOSE: The validity of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes to identify diagnoses of severe acute liver injury (SALI) is not well known. We examined the positive predictive values (PPVs) of hospital ICD-9-CM diagnoses in identifying SALI among health plan members in the Mini-Sentinel Distributed Database (MSDD) for patients without liver/biliary disease and for those with chronic liver disease (CLD). METHODS: We selected random samples of members (149 without liver/biliary disease; 75 with CLD) with a principal hospital diagnosis suggestive of SALI (ICD-9-CM 570, 572.2, 572.4, 572.8, 573.3, 573.8, or V42.7) in the MSDD (2009-2010). Medical records were reviewed by hepatologists to confirm SALI events. PPVs of codes and code combinations for confirmed SALI were determined by CLD status. RESULTS: Among 105 members with available records and no liver/biliary disease, SALI was confirmed in 26 (PPV, 24.7%; 95%CI, 16.9-34.1%). Combined hospital diagnoses of acute hepatic necrosis (570) and liver disease sequelae (572.8) had high PPV (100%; 95%CI, 59.0-100%) and identified 7/26 (26.9%) events. Among 46 CLD members with available records, SALI was confirmed in 19 (PPV, 41.3%; 95%CI, 27.0-56.8%). Acute hepatic necrosis (570) or hepatorenal syndrome (572.4) plus any other SALI code had a PPV of 83.3% (95%CI, 51.6-97.9%) and identified 10/19 (52.6%) events. CONCLUSIONS: Most individual hospital ICD-9-CM diagnoses had low PPV for confirmed SALI events. Select code combinations had high PPV but did not capture all events.

Assessment of case definitions for identifying acute liver injury in large observational databases.

BACKGROUND: Determining the aetiology of acute liver injury (ALI) may be challenging to both clinicians and researchers. Observational research is particularly useful in studying rare medical outcomes such as ALI; however, case definitions for ALI in previous observational studies lack consistency and sensitivity. ALI is a clinically important condition with various aetiologies, including drug exposure. OBJECTIVE: The aim of this study was to evaluate four distinct case definitions for ALI across a diverse set of large observational databases, providing a better understanding of ALI prevalence and natural history. DATA SOURCES: Seven healthcare databases: GE Healthcare, MarketScan(®) Lab Database, Humana Inc., Partners HealthCare System, Regenstrief Institute, SDI Health (now IMS Health, Inc.), and the National Patient Care Database of the Veterans Health Administration. METHODS: We evaluated prevalence of ALI through the application of four distinct case definitions across seven observational healthcare databases. We described how laboratory and clinical characteristics of identified case populations varied across definitions and examined the prevalence of other hepatobiliary disorders among identified ALI cases that may decrease suspicion of drug-induced liver injury (DILI) in particular. RESULTS: This study demonstrated that increasing the restrictiveness of the case definition resulted in fewer cases, but greater prevalence of ALI clinical features. Considerable heterogeneity in the frequency of laboratory testing and results observed among cases meeting the most restrictive definition suggests that the clinical features, monitoring patterns and suspicion of ALI are highly variable among patients. CONCLUSIONS: Creation of four distinct case definitions and application across a disparate set of observational databases resulted in significant variation in the prevalence of ALI. A greater understanding of the natural history of ALI through examination of electronic healthcare data can facilitate development of reliable and valid ALI case definitions that may enhance the ability to accurately identify associations between ALI and drug exposures. Considerable heterogeneity in laboratory values and frequency of laboratory testing among individuals meeting the criteria for ALI suggests that the evaluation of ALI is highly variable.

Validation of acute myocardial infarction in the Food and Drug Administration's Mini-Sentinel program.

PURPOSE: To validate an algorithm based upon International Classification of Diseases, 9(th) revision, Clinical Modification (ICD-9-CM) codes for acute myocardial infarction (AMI) documented within the Mini-Sentinel Distributed Database (MSDD). METHODS: Using an ICD-9-CM-based algorithm (hospitalized patients with 410.x0 or 410.x1 in primary position), we identified a random sample of potential cases of AMI in 2009 from four Data Partners participating in the Mini-Sentinel Program. Cardiologist reviewers used information abstracted from hospital records to assess the likelihood of an AMI diagnosis based on criteria from the Joint European Society of Cardiology and American College of Cardiology Global Task Force. Positive predictive values (PPVs) of the ICD-9-based algorithm were calculated. RESULTS: Of the 153 potential cases of AMI identified, hospital records for 143 (93%) were retrieved and abstracted. Overall, the PPV was 86.0% (95% confidence interval; 79.2%, 91.2%). PPVs ranged from 76.3% to 94.3% across the four Data Partners. CONCLUSIONS: The overall PPV of potential AMI cases, as identified using an ICD-9-CM-based algorithm, may be acceptable for safety surveillance; however, PPVs do vary across Data Partners. This validation effort provides a contemporary estimate of the reliability of this algorithm for use in future surveillance efforts conducted using the Food and Drug Administration's MSDD.

Active surveillance of postmarket medical product safety in the Federal Partners' Collaboration.

After half a century of monitoring voluntary reports of medical product adverse events, the Food and Drug Administration (FDA) has launched a long-term project to build an adverse events monitoring system, the Sentinel System, which can access and evaluate electronic health care data to help monitor the safety of regulated medical products once they are marketed. On the basis of experience gathered through a number of collaborative efforts, the Federal Partners' Collaboration pilot project, involving FDA, the Centers for Medicare & Medicaid Services, the Department of Veteran Affairs, and the Department of Defense, is already enabling FDA to leverage the power of large public health care databases to assess, in near real time, the utility of analytical tools and methodologies that are being developed for use in the Sentinel System. Active medical product safety surveillance is enhanced by use of these large public health databases because specific populations of exposed patients can be identified and analyzed, and can be further stratified by key variables such as age, sex, race, socioeconomic status, and basis for eligibility to examine important subgroups.

Empirical assessment of methods for risk identification in healthcare data: results from the experiments of the Observational Medical Outcomes Partnership.

BACKGROUND: Expanded availability of observational healthcare data (both administrative claims and electronic health records) has prompted the development of statistical methods for identifying adverse events associated with medical products, but the operating characteristics of these methods when applied to the real-world data are unknown. METHODS: We studied the performance of eight analytic methods for estimating of the strength of association-relative risk (RR) and associated standard error of 53 drug-adverse event outcome pairs, both positive and negative controls. The methods were applied to a network of ten observational healthcare databases, comprising over 130 million lives. Performance measures included sensitivity, specificity, and positive predictive value of methods at RR thresholds achieving statistical significance of p < 0.05 or p < 0.001 and with absolute threshold RR > 1.5, as well as threshold-free measures such as area under receiver operating characteristic curve (AUC). RESULTS: Although no specific method demonstrated superior performance, the aggregate results provide a benchmark and baseline expectation for risk identification method performance. At traditional levels of statistical significance (RR > 1, p < 0.05), all methods have a false positive rate >18%, with positive predictive value <38%. The best predictive model, high-dimensional propensity score, achieved an AUC = 0.77. At 50% sensitivity, false positive rate ranged from 16% to 30%. At 10% false positive rate, sensitivity of the methods ranged from 9% to 33%. CONCLUSIONS: Systematic processes for risk identification can provide useful information to supplement an overall safety assessment, but assessment of methods performance suggests a substantial chance of identifying false positive associations.

The U.S. Food and Drug Administration's Mini-Sentinel program: status and direction.

The Mini-Sentinel is a pilot program that is developing methods, tools, resources, policies, and procedures to facilitate the use of routinely collected electronic healthcare data to perform active surveillance of the safety of marketed medical products, including drugs, biologics, and medical devices. The U.S. Food and Drug Administration (FDA) initiated the program in 2009 as part of its Sentinel Initiative, in response to a Congressional mandate in the FDA Amendments Act of 2007. After two years, Mini-Sentinel includes 31 academic and private organizations. It has developed policies, procedures, and technical specifications for developing and operating a secure distributed data system comprised of separate data sets that conform to a common data model covering enrollment, demographics, encounters, diagnoses, procedures, and ambulatory dispensing of prescription drugs. The distributed data sets currently include administrative and claims data from 2000 to 2011 for over 300 million person-years, 2.4 billion encounters, 38 million inpatient hospitalizations, and 2.9 billion dispensings. Selected laboratory results and vital signs data recorded after 2005 are also available. There is an active data quality assessment and characterization program, and eligibility for medical care and pharmacy benefits is known. Systematic reviews of the literature have assessed the ability of administrative data to identify health outcomes of interest, and procedures have been developed and tested to obtain, abstract, and adjudicate full-text medical records to validate coded diagnoses. Mini-Sentinel has also created a taxonomy of study designs and analytical approaches for many commonly occurring situations, and it is developing new statistical and epidemiologic methods to address certain gaps in analytic capabilities. Assessments are performed by distributing computer programs that are executed locally by each data partner. The system is in active use by FDA, with the majority of assessments performed using customizable, reusable queries (programs). Prospective and retrospective assessments that use customized protocols are conducted as well. To date, several hundred unique programs have been distributed and executed. Current activities include active surveillance of several drugs and vaccines, expansion of the population, enhancement of the common data model to include additional types of data from electronic health records and registries, development of new methodologic capabilities, and assessment of methods to identify and validate additional health outcomes of interest.

Design for validation of acute myocardial infarction cases in Mini-Sentinel.

PURPOSE: To describe the acute myocardial infarction (AMI) validation project, a test case for health outcome validation within the US Food and Drug Administration-funded Mini-Sentinel pilot program. METHODS: The project consisted of four parts: (i) case identification-developing an algorithm based on the International Classification of Diseases, Ninth Revision, to identify hospitalized AMI patients within the Mini-Sentinel Distributed Database; (ii) chart retrieval-establishing procedures that ensured patient privacy (collection and transfer of minimum necessary amount of information, and redaction of direct identifiers to validate potential cases of AMI); (iii) abstraction and adjudication-trained nurse abstractors gathered key data using a standardized form with cardiologist adjudication; and (iv) calculation of the positive predictive value of the constructed algorithm. RESULTS: Key decision points included (i) breadth of the AMI algorithm, (ii) centralized versus distributed abstraction, and (iii) approaches to maintaining patient privacy and to obtaining charts for public health purposes. We used an algorithm limited to International Classification of Diseases, Ninth Revision, codes 410.x0-410.x1. Centralized data abstraction was performed because of the modest number of charts requested (<155). The project's public health status accelerated chart retrieval in most instances. CONCLUSIONS: We have established a process to validate AMI within Mini-Sentinel, which may be used for other health outcomes. Challenges include the following: (i) ensuring that only minimum necessary data are transmitted by Data Partners for centralized chart review, (ii) establishing procedures to maintain data privacy while still allowing for timely access to medical charts, and (iii) securing access to charts for public health uses that do not require approval from an institutional review board while maintaining patient privacy.