Japanese and American reports of randomized trials: differences in the reporting of adverse effects

Assessment of adverse effects in clinical studies of antipsychotic medication: survey of methods used

BACKGROUND

Clinical studies of antipsychotic medication are a primary source of data on the nature of, and relative liability for, adverse effects, relevant to prescribing decisions in clinical practice.

AIMS

To identify how safety and tolerability data were collected and reported in recent clinical studies of antipsychotics.

METHOD

A survey was conducted of all 167 eligible studies published between 2002 and 2007 on the Cochrane Schizophrenia Group register.

RESULTS

Extrapyramidal side-effects (EPS) and weight gain were most frequently assessed. A minority of reports addressed metabolic abnormalities, aversive subjective experiences and sexual dysfunction. Published rating scales were frequently used to evaluate EPS, but systematic methods were rarely applied to other treatment-emergent problems. The definition of individual adverse effects and the manner of reporting were inconsistent.

CONCLUSIONS

The way in which safety and tolerability data are collected and reported in clinical studies does not allow for fair and meaningful comparison of the relative risk profiles of individual antipsychotic drugs.

Hepatitis B immunisation for newborn infants of hepatitis B surface antigen-positive mothers

BACKGROUND

Hepatitis B vaccine and hepatitis B immunoglobulin are considered for newborn infants of HBsAg-positive mothers to prevent hepatitis B infection.

OBJECTIVES

To assess the beneficial and harmful effects of hepatitis B vaccines and hepatitis B immunoglobulin in newborn infants of HBsAg-positive mothers.

SEARCH STRATEGY

Trials were identified through The Cochrane Neonatal Group Controlled Trials Register, The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, and EMBASE (until February 2004), authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised clinical trials comparing: plasma-derived vaccine (PDV) or recombinant vaccine (RV) versus no intervention, placebo, or other active vaccines; hepatitis B immunoglobulin versus no intervention, placebo, or other control immunoglobulin; as well as PDV or RV plus hepatitis B immunoglobulin versus no intervention, placebo, or other control vaccines or immunoglobulin.

DATA COLLECTION AND ANALYSIS

Outcomes are assessed at maximal follow-up. The primary outcome measure was hepatitis B occurrence, based on a blood specimen positive for HBsAg, HBeAg, or antibody to hepatitis B core antigen (anti-HBc). Binary outcomes are reported as relative risks (RR) with 95% confidence interval (CI). Subgroup analyses were performed with regard to methodological quality of the trial, mother's HBe-Ag status, and time of immunisation after birth.

MAIN RESULTS

We identified 29 randomised clinical trials, five of which were considered high quality. Only three trials reported inclusion of hepatitis B e-antigen negative mothers. Compared with placebo/no intervention, vaccine reduced hepatitis B occurrence (RR 0.28, 95% confidence interval (CI) 0.20 to 0.40, 4 trials). No significant differences of hepatitis B occurrence were found comparing recombinant vaccine (RV) versus plasma-derived vaccine (PDV) (RR 1.00, 95% CI 0.71 to 1.42, 4 trials) and high-dose versus low-dose vaccine (PDV: RR 0.97, 95% CI 0.55 to 1.68, 3 trials; RV: RR 0.78, 95% CI 0.31 to 1.94, 1 trial). Compared with placebo/no intervention, hepatitis B immunoglobulin or the combination of vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (hepatitis B immunoglobulin: RR 0.50, 95% CI 0.41 to 0.60, 1 trial; PDV plus hepatitis B immunoglobulin: RR 0.08, 95% CI 0.03 to 0.17, 3 trials). Compared with vaccine, vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (RR 0.54, 95% CI 0.41 to 0.73, 10 trials). Hepatitis B vaccine and hepatitis B immunoglobulin seem safe, but few trials reported on adverse events.

AUTHORS' CONCLUSIONS

Vaccine, hepatitis B immunoglobulin, and vaccine plus hepatitis B immunoglobulin prevent hepatitis B occurrence in newborn infants of HBsAg positive mothers.

Effect of hepatitis B immunisation in newborn infants of mothers positive for hepatitis B surface antigen: systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of hepatitis B vaccine and immunoglobulin in newborn infants of mothers positive for hepatitis B surface antigen.

DESIGN

Systematic review and meta-analysis of randomised clinical trials.

DATA SOURCES

Electronic databases and hand searches.

REVIEW METHODS

Randomised clinical trials were assessed for methodological quality. Meta-analysis was undertaken on three outcomes: the relative risks of hepatitis B occurrence, antibody levels to hepatitis B surface antigen, and adverse events.

RESULTS

29 randomised clinical trials were identified, five of which were considered high quality. Only three trials reported inclusion of mothers negative for hepatitis B e antigen. Compared with placebo or no intervention, vaccination reduced the occurrence of hepatitis B (relative risk 0.28, 95% confidence interval 0.20 to 0.40; four trials). No significant difference in hepatitis B occurrence was found between recombinant vaccine and plasma derived vaccine (1.00, 0.71 to 1.42; four trials) and between high dose versus low dose vaccine (plasma derived vaccine 0.97, 0.55 to 1.68, three trials; recombinant vaccine 0.78, 0.31 to 1.94, one trial). Compared with placebo or no intervention, hepatitis B immunoglobulin or the combination of plasma derived vaccine and hepatitis B immunoglobulin reduced hepatitis B occurrence (immunoglobulin 0.50, 0.41 to 0.60, one trial; vaccine and immunoglobulin 0.08, 0.03 to 0.17, three trials). Compared with vaccine alone, vaccine plus hepatitis B immunoglobulin reduced hepatitis B occurrence (0.54, 0.41 to 0.73; 10 trials). Hepatitis B vaccine and hepatitis B immunoglobulin seem safe, but few trials reported adverse events.

CONCLUSION

Hepatitis B vaccine, hepatitis B immunoglobulin, and vaccine plus immunoglobulin prevent hepatitis B occurrence in newborn infants of mothers positive for hepatitis B surface antigen.

Availability of large-scale evidence on specific harms from systematic reviews of randomized trials

PURPOSE

To assess how frequently systematic reviews of randomized controlled trials convey large-scale evidence on specific, well-defined adverse events.

METHODS

We searched the Cochrane Database of Systematic Reviews for reviews containing quantitative data on specific, well-defined harms for at least 4000 randomized subjects, the minimum sample required for adequate power to detect an adverse event due to an intervention in 1% of subjects. Main outcome measures included the number of reviews with eligible large-scale data on adverse events, the number of ineligible reviews, and the magnitude of recorded harms (absolute risk, relative risk) based on large-scale evidence.

RESULTS

Of 1727 reviews, 138 included evidence on > or =4000 subjects. Only 25 (18%) had eligible data on adverse events, while 77 had no harms data, and 36 had data on harms that were nonspecific or pertained to <4000 subjects. Of 66 specific adverse events for which there were adequate data in the 25 eligible reviews, 25 showed statistically significant differences between comparison arms; most pertained to serious or severe adverse events and absolute risk differences <4%. In 29% (9/31) of a sample of large trials in reviews with poor reporting of harms, specific harms were presented adequately in the trial reports but were not included in the systematic reviews.

CONCLUSION

Systematic reviews can convey useful large-scale information on adverse events. Acknowledging the importance and difficulties of studying harms, reporting of adverse effects must be improved in both randomized trials and systematic reviews.

An application of meta-analysis techniques in the evaluation of adverse experiences with antihypertensive agents

PURPOSE

To investigate the profiles of adverse events (AEs) in randomized controlled trials of antihypertensive agents therapy with the technique of meta-analysis.

METHODS

A total of 620 articles were selected from MEDLINE, EMBASE, JAPIC-DOC, JMEDICINE and manual searching. Two independent reviewers examined the 620 selected articles according to the following criteria: (1) the methods of randomization, (2) making for allocating treatments, (3) therapeutic class of drugs, (4) sample sizes, (5) duration of the treatment, (6) primary endpoint, (7) reporting method for all adverse events, (8) method of monitoring AEs, and (9) incidence rates of all reported AEs. To combine the risk difference and risk ratios of incidence between CCBs and beta blockers or diuretics, the method of DerSimonian and Laird based on random effect model was applied.

RESULTS

A total of 3073 patients were included in this meta-analysis of serious adverse events (SAEs). There was no significant difference in the total incidence of SAEs between CCBs and diuretics or between CCBs and beta blockers. We found that patients treated with CCBS had 0.14% fewer SAEs compared with the patients treated with diuretics. Contrarily, the patients treated with CCBs had 0.29% more SAEs compared with the patients treated with beta blockers. There was a significant difference between the patients treated with CCBs and those treated with diuretics in the symptoms with headache and oedema. With respect to the comparison between CCBs and beta blockers, flushing occurred 8.75% more frequently in the CCBs group than in the beta blockers group.

CONCLUSION

A meta-analysis can be applied to safety analyses of data obtained in clinical trials if all of the RCT articles used include a complete description of adverse experiences.

Serious adverse events in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD)

AIMS

The study estimated serious adverse event (SAE) rates among entrants to pharmacotherapies for opioid dependence, during treatment and after leaving treatment.

DESIGN

A longitudinal study based on data from 12 trials included in the Australian National Evaluation of Pharmacotherapies for Opioid Dependence (NEPOD).

PARTICIPANTS AND SETTINGS

A total of 1244 heroin users and methadone patients treated in hospital, community and GP settings. Intervention Six trials included detoxification; all included treatment with methadone, buprenorphine, levo-alpha-acetyl-methadol (LAAM) or naltrexone.

FINDINGS

During 394 person-years of observation, 79 SAEs of 28 types were recorded. Naltrexone participants experienced 39 overdoses per 100 person-years after leaving treatment (44% occurred within 2 weeks after stopping naltrexone). This was eight times the rate recorded among participants who left agonist treatment. Rates of all other SAEs were similar during treatment versus out of treatment, for both naltrexone-treated and agonist-treated participants. Five deaths occurred, all among participants who had left treatment, at a rate of six per 100 person-years. Total SAE rates during naltrexone and agonist treatments were similar (20, 14 per 100 person-years, respectively). Total SAE and death rates observed among participants who had left treatment were three and 19 times the corresponding rates during treatment.

CONCLUSIONS

Individuals who leave pharmacotherapies for opioid dependence experience higher overdose and death rates compared with those in treatment. This may be due partly to a participant self-selection effect rather than entirely to pharmacotherapy being protective. Clinicians should alert naltrexone treatment patients in particular about heroin overdose risks. Duty of care may extend beyond cessation of dosing.

Improving safety reporting from randomised trials

Randomised clinical trials offer a unique opportunity for capturing safety information under a controlled setting that minimises biases in the comparison of different therapeutic options. Nevertheless, empirical evidence across diverse medical fields suggests that the reporting of safety information in clinical trials is largely neglected and receives less attention compared with efficacy outcomes. An analysis of 192 randomised trials has shown that reasons for withdrawals due to toxicity were specified per study arm in only 46% of the trial reports. Adequate reporting of clinical adverse effects and laboratory-determined toxicity occurred in only 39 and 29% of the trials, respectively, even with lenient definitions of what constitutes adequate reporting. The use of standardised scales for adverse effects is a prerequisite for improved reporting on safety in randomised trials. Safety data need to be collected and analysed in a systematic fashion and active surveillance for toxicity during the conduct of a randomised trial is preferable to passive surveillance. Standardised reporting of safety data does not necessarily require extensive space to accomplish. It is essential to provide numerical data per study arm on each type of adverse effect along with a categorisation of the severity of the adverse effects with an emphasis on severe and life-threatening reactions. The severity grading must be referred to well-known standardised scales and new scales need to be carefully defined. Information on withdrawals due to toxicity is also important to report, along with the specific reasons leading to discontinuation. Tabulation of information may be helpful and rare or not previously reported adverse effects should be described in detail. The availability of newer options such as electronic publication, publication of raw databases, large database research, meta-analytic approaches, and prospective registration of clinical trials and of their databases may further improve the safety insights we can gain from randomised clinical trials.

Precision and comparability of adverse event rates of newer antidepressants

Due to the scarcity of clinical trials (CTs) directly comparing newer antidepressants, clinicians and reviewers often compare drugs on the basis of active drug and placebo-subtracted adverse event rates (AERs) published in references such as the Physician's Desk Reference in the United States, the Compendium of Pharmaceutical Specialities in Canada, and product monographs. This study examined the suitability of the above data and methods for comparing AERs of nine newer antidepressants: bupropion, citalopram, fluoxetine, fluvoxamine, moclobemide, nefazodone, paroxetine, sertraline, and venlafaxine. First, the authors examined data precision and comparability across drugs by analyzing placebo-arm AERs and their 95% confidence limits for each drug and by testing the homogeneity of placebo-arm AERs across drugs. The rationale was that placebo AER heterogeneity is likely a reflection of heterogeneity of nonpharmacologic factors among CTs. For all 16 adverse events examined, placebo AERs were found to be significantly heterogenous, suggesting significant nonpharmacologic heterogeneity across drugs. Second, using placebo AER heterogeneity as a measure of nonpharmacologic heterogeneity, the authors estimated the degree to which active drug and placebo-subtracted AERs were related to nonpharmacologic heterogeneity by estimating the degree of association between active drug and placebo AERs and between placebo-subtracted and placebo AERs. Also, 95% confidence limits for placebo-subtracted AERs were calculated. It was found that most active drug AERs and some placebo-subtracted AERs were significantly correlated with placebo AERs, suggesting a relationship with nonpharmacologic heterogeneity. Placebo-subtracted AERs were less strongly related than were active drug AERs. Finally, the authors discuss factors that may be associated with the observed heterogeneity and offer suggestions that may improve the methodology and reporting of CTs.