Spontaneous reporting of adverse drug reactions: who reports and what?

Recognition and reporting of suspected adverse drug reactions by surveyed healthcare professionals in Uganda: key determinants

OBJECTIVE

To assess extent and determinants of past-month recognition of suspected adverse drug reactions (ADR) and past-year ADR reporting among healthcare professionals (HCPs) in Uganda.

SETTING

Geographically diverse health facilities (public, private for-profit, private not-for-profit).

PARTICIPANTS

Of 2000 questionnaires distributed, 1345 were completed: return rate of 67%.

PRIMARY AND SECONDARY OUTCOME MEASURES

Per cent HCPs who suspected ADR in the past month; reported ADR in the past year.

RESULTS

Nurses were the majority (59%, 792/1345). Only half the respondents had heard about pharmacovigilance: 39% of nurses (295/763; 95% CI 35% to 42%), 70% otherwise (383/547; 95% CI 66% to 74%). One fifth (268/1289 or 21%; 95% CI 19% to 23%) had suspected an ADR in the previous 4 weeks, 111 of them were nurses; 15% (190/1296) had reported a suspected ADR in the past year, 103 of them were nurses. Past-month ADR suspicion was more likely by non-nurses (OR=1.7, 95% CI 1.16 to 2.40) and with medical research involvement (OR=1.5, 95% CI 1.05 to 2.15) but past-month receipt of patient ADR-complaint predominated (OR=19, 95% CI 14 to 28). Past-year ADR reporting was higher by hospital staff (OR=1.9, 95% CI 1.18 to 3.10), especially in medicine (OR=2.3, 95% CI 1.08 to 4.73); but lower from private for-profit health facilities (OR=0.5, 95% CI 0.28 to 0.77) and by older staff (OR=0.6, 95% CI 0.43 to 0.91); more likely by HCPs who had ever encountered a fatal ADR (OR=2.9, 95% CI 1.94 to 4.25), knew to whom to report (OR=1.7, 95% CI 1.18 to 2.46), or suggested how to improve ADR reporting (OR=1.6, 95% CI 1.04 to 2.49). Two attitudinal factors were important: diffidence and lethargy.

CONCLUSIONS

One in five HCPs suspected an ADR in the past-month and one in seven reported ADR in the previous year. Empowering patients could strengthen ADR detection and reporting in Africa.

Estimating time-to-onset of adverse drug reactions from spontaneous reporting databases

BACKGROUND

Analyzing time-to-onset of adverse drug reactions from treatment exposure contributes to meeting pharmacovigilance objectives, i.e. identification and prevention. Post-marketing data are available from reporting systems. Times-to-onset from such databases are right-truncated because some patients who were exposed to the drug and who will eventually develop the adverse drug reaction may do it after the time of analysis and thus are not included in the data. Acknowledgment of the developments adapted to right-truncated data is not widespread and these methods have never been used in pharmacovigilance. We assess the use of appropriate methods as well as the consequences of not taking right truncation into account (naive approach) on parametric maximum likelihood estimation of time-to-onset distribution.

METHODS

Both approaches, naive or taking right truncation into account, were compared with a simulation study. We used twelve scenarios for the exponential distribution and twenty-four for the Weibull and log-logistic distributions. These scenarios are defined by a set of parameters: the parameters of the time-to-onset distribution, the probability of this distribution falling within an observable values interval and the sample size. An application to reported lymphoma after anti TNF- α treatment from the French pharmacovigilance is presented.

RESULTS

The simulation study shows that the bias and the mean squared error might in some instances be unacceptably large when right truncation is not considered while the truncation-based estimator shows always better and often satisfactory performances and the gap may be large. For the real dataset, the estimated expected time-to-onset leads to a minimum difference of 58 weeks between both approaches, which is not negligible. This difference is obtained for the Weibull model, under which the estimated probability of this distribution falling within an observable values interval is not far from 1.

CONCLUSIONS

It is necessary to take right truncation into account for estimating time-to-onset of adverse drug reactions from spontaneous reporting databases.

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.

A potential competition bias in the detection of safety signals from spontaneous reporting databases

PURPOSE

To study whether reports related to known drug-event associations could hinder the detection of new signals by increasing the detection thresholds when using disporportionality analyses in spontaneous reporting (SR) databases.

METHODS

The French SR database (2005-2006 data) was used to test this hypothesis for the following events: bleeding, headache, hepatitis, myalgia, myocardial infarction, stroke, and toxic epidermal necrolysis (TEN). For each of these, using the Proportional Reporting Ratio (PRR) and the Reporting Odds Ratio (ROR), the number of cases needed to trigger a signal out of 50, 100, and 200 reports for a hypothetical newly introduced drug were computed before and after removing from the database reports involving drugs known to be associated with the event.

RESULTS

For bleeding and stroke, removing potentially competitive data resulted in a decrease of the number of cases needed to trigger a signal for a newly introduced drug for both PRR and ROR (e.g., from 9 to 4, and 5 to 3 cases out of 50 reports for bleeding and stroke, respectively using the PRR). They were not or only slightly modified for the other studied events.

CONCLUSIONS

Removing reports related to known drug-event associations could increase the sensitivity of signal detection in SR databases. This should be considered when using SR databases for signal detection as it could result in earlier identification of new drug-event associations.

Cutaneous adverse effects of ketoprofen for topical use: clinical patterns and costs

BACKGROUND

Since its introduction in France, ketoprofen for topical use has been associated with a large number of cutaneous adverse effect reports. Therefore, the French Medicine Agency progressively introduced warnings and contraindications to its use. Despite this, serious adverse drug reactions (ADRs) still occur.

OBJECTIVE

To describe clinical patterns and estimate costs of spontaneously reported cutaneous ADRs of topical ketoprofen.

METHODS

All cases of cutaneous ADRs of topical ketoprofen reported to the Bordeaux regional pharmacovigilance center between January 1989 and December 2006 were included. Clinical patterns, in respect of adherence to recommendations, causality, seriousness, and direct costs incurred by the ADRs, were assessed.

RESULTS

A total of 136 cases were reported (median age: 42 years, 55.9% women). Proper use of topical ketoprofen regarding indications, warnings, and contraindications was not respected by one-third of the patients. Almost all cases occurred during sunny months. Symptoms consisted predominantly of bullous eruptions (29.4%) or contact dermatitis (27.2%). Generalized lesions were observed in 37.5% of patients. Causality was considered at least possible for most of the cases (92.6%). These ADRs induced hospital admission in 15 cases (11.0%). The total estimated cost was euro 42,962 ($US 66,559), corresponding to euro 316 per case. This mean cost was nine times higher for serious ADRs.

CONCLUSION

Topical ketoprofen is used to treat benign symptoms but can be associated with serious and costly cutaneous ADRs. Furthermore, the number of cases and the calculated costs may have been greatly under-estimated in the present study.

Effect of date of drug marketing on disproportionality measures in pharmacovigilance: the example of suicide with SSRIs using data from the UK MHRA

BACKGROUND

Warnings concerning an increased risk of suicide in patients treated with selective serotonin reuptake inhibitors (SSRIs) re-emerged in early 2003, culminating in the broadcast of a television programme in the UK. In the following months, cumulated proportional reporting ratios showed that the most recently marketed drug, escitalopram, had a much higher proportion of reports of suicide to other adverse drug reactions (ADRs) than the other drugs in the class.

OBJECTIVE

To study the reporting patterns over time concerning suicide with the six SSRIs marketed in the UK as of March 2003 and their potential effect on disproportionality signal detection.

METHODS

Monthly cumulated numbers of reports were obtained from the UK Medicines and Healthcare products Regulatory Agency (MHRA), from the time of the first marketing of the drugs concerned and monthly for the 2 months prior to and the 9 months following the broadcast of the television programme (broadcast date: 11 May 2003), and the monthly ratio of suicide to other reports was computed for each SSRI individually and for all SSRIs combined.

RESULTS

Of the six SSRIs studied, five (citalopram, paroxetine, fluoxetine, sertraline and venlafaxine) had been marketed for several years and escitalopram for only a few months. At the end of the analysis period, 1.42% (4/281) of all ADR reports for escitalopram were of suicide versus 0.58% for the other five drugs combined (146/25 197). For all SSRIs combined, suicide represented 0.5% (123/24 315) of reports before the broadcast of the television programme, and increased to 2.3% (27/1163) following the programme. For escitalopram, suicide represented 1.1% (1/89) of all ADR reports before the television programme and 1.6% (3/192) afterwards. For the five other drugs combined, suicide represented 0.5% (122/24 226) of ADR reports before the television programme and 2.5% (24/971) afterwards (varying from 1.4% to 4.7% for the various drugs). The post-programme events represented 68% of all reports and 75% of suicides for escitalopram, whereas for older drugs they represented 3.6% of reports and 13% of suicides.

CONCLUSION

For older drugs, the events reported during the high-reporting post-television programme period were diluted by years of low reporting. For escitalopram, although the television programme had little absolute impact on the number of reports, because the drug had been on the market for such a short period of time, a large relative effect was observed. Differential effects related to time on market on cumulated reporting of adverse drug reactions should be taken into account when analysing spontaneous reporting databases with automated signal generation methods after an alert has changed the spontaneous reporting patterns. Proper use of measures of disproportionality requires thorough knowledge of potential biases and careful analysis of reporting patterns. We found no obvious differences between SSRIs once these were taken into account.

Determinants of under-reporting of adverse drug reactions: a systematic review

A voluntary reporting system of adverse drug reactions (ADRs) is fundamental to drug safety surveillance but under-reporting is its major limitation. This bibliographic review sought to assess the influence of personal and professional characteristics on ADR reporting and to identify knowledge and attitudes associated with ADR reporting. A systematic review was conducted using the MEDLINE and EMBASE databases. We included papers that were published in English, French and Spanish, and covered a study population made up of health professionals. In each case, the following data were extracted: study population; workplace; study type; sample size; type of questionnaire; type of scale for measuring knowledge; response rate; personal and professional factors; and knowledge and attitudes (based on Inman's 'seven deadly sins') associated with reporting. Based on a search of computerized databases, we identified a total of 657 papers in MEDLINE and 973 in EMBASE. In all, the review covered 45 papers that fulfilled the inclusion criteria. Medical specialty was the professional characteristic most closely associated with under-reporting in 76% of studies involving physicians. Other factors associated with under-reporting were ignorance (only severe ADRs need to be reported) in 95%; diffidence (fear of appearing ridiculous for reporting merely suspected ADRs) in 72%; lethargy (an amalgam of procrastination, lack of interest or time to find a report card, and other excuses) in 77%; indifference (the one case that an individual doctor might see could not contribute to medical knowledge) and insecurity (it is nearly impossible to determine whether or not a drug is responsible for a particular adverse reaction) in 67%; and complacency (only safe drugs are allowed on the market) in 47% of studies. While personal and professional factors display a weak influence, the knowledge and attitudes of health professionals appear to be strongly related with reporting in a high proportion of studies. This result may have important implications in terms of public health, if knowledge and attitudes are viewed as potentially modifiable factors.

Adverse drug reactions of antidepressants and antipsychotics: experience, knowledge and attitudes among Norwegian psychiatrists

Efficient prevention of adverse drug reactions (ADRs) requires knowledge about their severity and pharmacological mechanisms and is dependent on reliable data on their frequencies and possible risk factors. The study was conducted to investigate the prescribers' experience and understanding of the ADRs of psychotropic drugs, and their attitude towards reporting these. In a questionnaire, physicians treating adult psychiatric patients were asked which ADRs that they regarded bothersome for some of the most widely used antidepressants and antipsychotics. Questions about the relationship between blockade of drug receptors and ADRs, and about the physicians' personal experience of and attitudes towards reporting of ADRs were also included. In total, 70 of 91 questionnaires (78%) were returned. The mean number of ADRs regarded bothersome ranged from 2.4 to 9.3 for the various drugs/drug classes. Qualified psychiatrists stated a significantly higher number of bothersome ADRs than did the residents. The percentage of physicians associating blockade of a receptor with a specific ADR varied from 76% (histamine receptor blockade and sedation) to 37% (alpha(1)-adrenergic blockade and tachycardia). Thirty-nine per cent of the physicians had never reported an ADR to the Norwegian Medicines Agency. The number of ADRs considered bothersome was relatively high. The pattern of these ADRs generally mirrored the typical ADR profiles of the drugs. The knowledge of the underlying mechanisms of ADRs was more or less incomplete. The reporting rate of ADRs to the national regulatory authorities was low.

Variability in the assessment of adverse events in a multicenter clinical trial

BACKGROUND

Consistent documentation, characterization, and evaluation of adverse events (AEs) are needed during multicenter clinical trials to ensure accuracy of data reported to the US Food and Drug Administration and in the medical literature.

OBJECTIVE

The purpose of this study was to identify and characterize variations in the assessment of AEs by clinical trial personnel.

METHODS

During the annual meeting of personnel from a multicenter, controlled clinical trial of an investigational new drug treatment for opioid dependence, an oral presentation of procedures for AE data collection was given to 25 principal investigators and ancillary study personnel who assessed AEs for the study. A post-test using 3 hypothetical AE cases in which AEs were categorized by type of reaction, relatedness to study drug, severity, action taken, and outcome was completed by study participants. Cases and expected responses were reviewed for content and validity by clinical research pharmacists who were not involved with the study. The level of agreement with expected responses was assessed using McNemar symmetry chi-square tests.

RESULTS

Assessments of type of AE, relatedness to study drug, and severity were less frequently aligned with expected responses than were action taken and outcome (P < 0.013). Less consistency with expected responses was found in I case than in the other 2, suggesting that certain types of AEs may be more difficult to assess.

CONCLUSIONS

There was considerable variability in categorization of AEs in an exercise following training for AE data collection. Type of report, relatedness, and severity were found to have more variability in reporting than did action taken or outcome. The results suggest that unless data are gathered to verify reliability of reporting, subcategorization of AE data should be undertaken cautiously. Further research is needed regarding methods for improving consistency in reporting of AEs.