Detection and incidence of drug-induced agranulocytosis in hospital: a prospective analysis from laboratory signals

Pilot Algorithm Designed to Help Early Detection of HMG-CoA Reductase Inhibitor-Induced Hepatotoxicity

Objectives

To enable early detection of adverse drug reactions (ADRs) in patients using HMG-CoA reductase inhibitors (statins), we developed an algorithm that automatically detects liver injury caused by statins from Electronic Medical Record (EMR) data. We verified the performance of our algorithm through manual ADR assessment and a direct chart review.

Methods

The subjects in this study were patients who had been prescribed a statin for the first time among outpatients in Seoul St. Mary's Hospital in Korea between January 2009 and December 2012. We extracted basic information about the patients, including laboratory information, underlying disease, diagnosis information, prescription information, and concomitant drugs. We developed an automatic ADR detection algorithm by using EMR data. We validated the results of the algorithm through a chart review.

Results

We developed the algorithm to assess ADR occurrences based on alanine transaminase (ALT) and alkaline phosphatase (ALP) levels. According to the proposed algorithm, any of these result options could be attained: ADR-free, little association, strong association, and weak association or indeterminable. The results of the ADR assessments obtained using the proposed algorithm showed that the data of 126 patients (1.4% of all 9,241 patients) included suspicious figures, thus indicating the possibility of an ADR. In the EMR chart review for verifying the algorithm, ADRs of 33 patients were not associated with statin use; therefore, the ADR occurrence rate was found to be 1.0% (93/9,241). Therefore, the positive predictive value was calculated to be 73.8% (93/126; 95% confidence interval, 69.2%–77.6%). No differences were observed between statin types (p = 0.472).

Conclusions

For early detection of statin-induced liver injury, we developed an automatic ADR assessment algorithm. We expect that algorithms that are more reliable can be developed if we conduct supplement clinical studies with a focus on adverse drug effects.

Nonchemotherapy drug-induced agranulocytosis in children detected by a prospective pharmacovigilance program

OBJECTIVES

A prospective evaluation of nonchemotherapy drug-induced agranulocytosis (DIA) cases, which are infrequent in the pediatric population. We characterize agranulocytosis cases and assess lab test differences between drug- and nondrug-induced agranulocytosis.

METHODS

Through our Prospective Pharmacovigilance Program from Laboratory Signals at Hospital we detected pediatric agranulocytosis cases from July 2007 to December 2010. This program estimates the incidence, drug causality, clinical features, outcomes of DIA pediatric cases, and assesses laboratory differences with respect to non-DIA.

RESULTS

We detected 662 agranulocytosis in 308 pediatric patients, of which 14 were caused by nonchemotherapy drugs. The incidence rate of DIA for 10,000 pediatric patients was 3.92 (Poisson 95% confidence interval 1.09-8.77); 78.6% of DIA cases occurred in patients younger than 3 years. The final outcome was recovery without sequela in all cases. The pharmacologic group most frequently implicated was antimicrobial drugs (11 drugs), 7 of which were beta-lactams. The drugs most frequently suspected were cefotaxime and vancomycin (3 cases each). We found 3 drugs (cloperastine, codeine, and enoxaparin) not previously described to induce DIA. Automatic linear modeling (n = 56, R² = 45.2%) showed a significant inverse association with platelets (R² = 17.5%), hemoglobin, and alanine transaminase, and a direct association with red cell distribution (R² = 16.2%). A generalized linear model (Type III, n = 1188; DIA, n = 86; likelihood ratio chi-squared = 156.16) retained eosinophils (p <.001), platelets (p <.001), total serum proteins (p <.001), and hemoglobin (p =.039).

CONCLUSIONS

We found a higher incidence of DIA in children than previously described. Our findings also suggest an immune-mediated destruction or myeloid toxicity, possibly facilitated by an increase in drug exposure.

Use of administrative hospital database to identify adverse drug reactions in a Pediatric University Hospital

PURPOSE

The aim of the study was to detect adverse drug reactions (ADRs) in pediatric inpatients using the medical administrative database "Programme de Médicalisation des Systèmes d'Information" (PMSI) and to compare these cases ADRs with those spontaneously reported to a regional PharmacoVigilance (PV) Centre.

METHODS

The study was conducted from January 2008 to December 2011 in the Children University Hospital of Toulouse (Midi-Pyrénées, South-west France). From PMSI database, all discharge summaries including selected ICD-10 codes (10th International Classification of Diseases) were analyzed. All ADRs spontaneously reported by the Children Hospital of Toulouse and registered in the French PV Database (FPVDB) were included. The capture-recapture method was applied to estimate the incidence of ADRs.

RESULTS

During the study period, we identified 60 reports from the PMSI database and 200 from the FPVDB. The rate of "serious" ADRs was higher in PMSI reports (74.6 % vs 38.9 %, p < 0.0001). The most frequent ADRs reported were musculoskeletal (12.4 %) and central (11.3 %) ADRs in PMSI database versus cutaneous (22.4 %) and general (17.5 %) ADRs in FPVDB. The most frequently suspected drugs were antineoplastic drugs (31.1 %) in PMSI database versus anti-infectives (38.2 %) in FPVDB. The estimated number of ADRs was 717 [95 % confidence interval (CI) 513, 921], and the incidence of ADRs among admissions was 0.6 % (95 % CI 0.4, 0.8).

CONCLUSIONS

Use of PMSI database improves from around 30 % detection of ADRs in children. In comparison with classical pharmacovigilance database, it also allows to detect different ADRs and drugs, thus enhancing safe medicine use for pediatric patients.

Detection of pharmacovigilance-related adverse events using electronic health records and automated methods

Electronic health records (EHRs) are an important source of data for detection of adverse drug reactions (ADRs). However, adverse events are frequently due not to medications but to the patients' underlying conditions. Mining to detect ADRs from EHR data must account for confounders. We developed an automated method using natural-language processing (NLP) and a knowledge source to differentiate cases in which the patient's disease is responsible for the event rather than a drug. Our method was applied to 199,920 hospitalization records, concentrating on two serious ADRs: rhabdomyolysis (n = 687) and agranulocytosis (n = 772). Our method automatically identified 75% of the cases, those with disease etiology. The sensitivity and specificity were 93.8% (confidence interval: 88.9-96.7%) and 91.8% (confidence interval: 84.0-96.2%), respectively. The method resulted in considerable saving of time: for every 1 h spent in development, there was a saving of at least 20 h in manual review. The review of the remaining 25% of the cases therefore became more feasible, allowing us to identify the medications that had caused the ADRs.

A systematic review to evaluate the accuracy of electronic adverse drug event detection

OBJECTIVE

Adverse drug events (ADEs), defined as adverse patient outcomes caused by medications, are common and difficult to detect. Electronic detection of ADEs is a promising method to identify ADEs. We performed this systematic review to characterize established electronic detection systems and their accuracy.

METHODS

We identified studies evaluating electronic ADE detection from the MEDLINE and EMBASE databases. We included studies if they contained original data and involved detection of electronic triggers using information systems. We abstracted data regarding rule characteristics including type, accuracy, and rationale.

RESULTS

Forty-eight studies met our inclusion criteria. Twenty-four (50%) studies reported rule accuracy but only 9 (18.8%) utilized a proper gold standard (chart review in all patients). Rule accuracy was variable and often poor (range of sensitivity: 40%-94%; specificity: 1.4%-89.8%; positive predictive value: 0.9%-64%). 5 (10.4%) studies derived or used detection rules that were defined by clinical need or the underlying ADE prevalence. Detection rules in 8 (16.7%) studies detected specific types of ADEs.

CONCLUSION

Several factors led to inaccurate ADE detection algorithms, including immature underlying information systems, non-standard event definitions, and variable methods for detection rule validation. Few ADE detection algorithms considered clinical priorities. To enhance the utility of electronic detection systems, there is a need to systematically address these factors.

Adverse drug reactions in a complementary medicine hospital: a prospective, intensified surveillance study

Background. Anthroposophic medicine is one of the widely used approaches of complementary and alternative medicine. However, few prospective studies have generated safety data on its use. Objectives. We aimed to assess adverse drug reactions (ADRs) caused by anthroposophical medicines (AMEDs) in the anthroposophical Community Hospital Havelhoehe, GERMANY. Study Design and Methods. Between May and November 2007, patients of six medical wards were prospectively assessed for ADRs. Suspected ADRs occurring during hospitalization were documented and classified in terms of organ manifestation (WHO SOC-code), causality (according to the Uppsala Monitoring Centre WHO criteria), and severity. Only those ADRs with a severity of grade 2 and higher according to the CTCAE classification system are described here. Results. Of the 3,813 patients hospitalized, 174 patients (4.6%) experienced 211 ADRs (CTCAE grade 2/3 n = 191, 90.5%, CTCAE grade 4/5 n = 20, 9.5%) of which 57 ADRs (27.0%) were serious. The median age of patients with ADRs (62.1% females) was 72.0 (IQR: 61.0; 80.0). Six patients (0.2%) experienced six ADRs (2.8% of ADRs) caused by eight suspected AMEDs, all of which were mild reactions (grade 2). Conclusion. Our data show that ADRs caused by AMEDs occur rarely and are limited to mild symptoms.

Life-threatening drug-associated hyperkalemia: a retrospective study from laboratory signals

PURPOSE

Life-threatening hyperkalemia may be induced by drugs and preventable in at-risk patients. This study was designed to describe cases of 'serious' drug-associated hyperkalemia.

METHODS

Adult subjects with a serum potassium concentration above 6.5 mmol/L detected at admission or during hospital stay in nephrology, cardiology, geriatric, emergency or intensive care units were identified by biology laboratories of hospitals and clinics located in Midi-Pyrenees (southwest France). Patients dialyzed for end-stage kidney disease were excluded. Data were collected from medical files. Hyperkalemia was defined as drug-associated if at least one drug known to increase serum potassium concentration was taken when hyperkalemia occurred (among drugs taken in outpatient care for hyperkalemia detected at admission and among drugs taken in outpatient care and continued at hospital and drugs introduced from admission for hyperkalemia detected during hospital stay).

RESULTS

Of 168 hyperkalemia cases, 102 (60.7%) were classified as drug-associated. They concerned elderly patients (mean age: 76.1 years) often having arterial hypertension and/or cardiac diseases (88.2%). Risk factors, mainly acute kidney failure, were observed in almost all cases (98.0%). Drugs predominantly involved were angiotensin-converting enzyme inhibitors (47.1%), spironolactone (41.2%), angiotensin II receptor antagonists (23.5%) and potassium supplements (23.5%). In 10% of cases, death could be attributed to hyperkalemia.

CONCLUSIONS

Laboratory databases allowed an exhaustive identification of hyperkalemia cases. The frequency of drug-related hyperkalemia and their characteristics suggest that treatment with drugs known to increase serum potassium concentration can be inappropriate, especially regarding associations or indications, and is highly risky for predisposed patients.

Proton pump inhibitor-induced neutropenia: possible cross-reactivity between omeprazole and pantoprazole

Proton pump inhibitors (PPIs) are widely used drugs in the treatment or prophylaxis of peptic ulcer and gastro-oesophageal reflux disease. In addition to their well documented efficacy, these drugs are generally well tolerated with only rare serious adverse effects having been reported. Neutropenia and agranulocytosis are rare adverse events associated with PPI treatment. All previously published cases of isolated neutropenia have involved omeprazole, but leukopenia is labelled as a possible adverse effect in the summary of product characteristics of the other PPIs. In this report, we describe a case of omeprazole-induced neutropenia with further recurrence upon pantoprazole treatment. A 60-year-old man with chronic alcoholism and a medical history of pulmonary tuberculosis, untreated chronic C hepatitis, peripheral artery disease, chronic obstructive pulmonary disease and stable stage 3 chronic kidney disease was admitted with dehydration and malnutrition. Omeprazole 20 mg/day and sucralfate 3 g/day were started for diffuse gastritis on gastric endoscopy. While the patient's blood cell count had been within the normal range before this treatment, routine laboratory examination revealed moderate neutropenia (0.9 x 109/L) after 9 days of treatment. His blood cell count returned to the normal range after discontinuation of omeprazole and no further episodes of neutropenia were noted in the following months. One year later, oesophago-gastroscopy revealed a hiatal hernia with an extensive zone of Barrett's oesophagus. As the lesions did not improve with ranitidine and sucralfate therapy, the patient was started on pantoprazole 40 mg/day. His initial white blood cell count was normal, but moderate neutropenia (0.8 x 109/L) was again noted after only 2 days of pantoprazole treatment. Complete and further stable normalization was obtained within 3 days after replacement of pantoprazole with ranitidine. Toxic and immune-mediated mechanisms are the two commonly proposed mechanisms to explain the pathogenesis of drug-induced neutropenia. This report suggests that PPI-induced neutropenia is immune mediated and argues for a possible cross-reactivity between the two PPIs, as has already been described for PPI-induced hypersensitivity reactions. The report also indicates that patients with a history of neutropenia induced by one PPI may be at risk of recurrence of neutropenia if given another member of this drug class. In these patients, close haematological monitoring is proposed.

A pharmacovigilance program from laboratory signals for the detection and reporting of serious adverse drug reactions in hospitalized patients

The detection and reporting of serious adverse drug reactions (SADRs) have become important components of monitoring and evaluation activities performed in hospitals. We present the implementation of a prospective pharmacovigilance program based on automatic laboratory signals (ALSs) at a hospital. We also report the general findings after the first year of operation of the program, which involved ALSs that indicate various SADRs: agranulocytosis, aplastic anemia, liver injury, thrombocytopenia, hyponatremia, and rhabdomyolysis. The number of hospitalizations during the year was 54,525, and 1,732 patients experienced at least one ALS. The review of electronic medical records (EMRs) showed that no alternative cause (i.e., no non-SADR explanation) for the ALS was identified in 520 (30%) of the patients. After the individual ALS-patient evaluation, a total of 110 SADRs (6.35% of those identified after reviewing EMRs and 21.15% of those requiring individual patient evaluations) were identified. In other words, in order to identify a single SADR, we had to review the electronic records of approximately 16 patients and personally visit 5 patients.

Drug-induced hematologic syndromes

Objective. Drugs can induce almost the entire spectrum of hematologic disorders, affecting white cells, red cells, platelets, and the coagulation system. This paper aims to emphasize the broad range of drug-induced hematological syndromes and to highlight some of the newer drugs and syndromes. Methods. Medline literature on drug-induced hematologic syndromes was reviewed. Most reports and reviews focus on individual drugs or cytopenias. Results. Drug-induced syndromes include hemolytic anemias, methemoglobinemia, red cell aplasia, sideroblastic anemia, megaloblastic anemia, polycythemia, aplastic anemia, leukocytosis, neutropenia, eosinophilia, immune thrombocytopenia, microangiopathic syndromes, hypercoagulability, hypoprothrombinemia, circulating anticoagulants, myelodysplasia, and acute leukemia. Some of the classic drugs known to cause hematologic abnormalities have been replaced by newer drugs, including biologics, accompanied by their own syndromes and unintended side effects. Conclusions. Drugs can induce toxicities spanning many hematologic syndromes, mediated by a variety of mechanisms. Physicians need to be alert to the potential for iatrogenic drug-induced hematologic complications.