Article type
Year
Abstract
Introduction/Objective: To investigate assessment and reporting of adverse effects with reference to the Standards for Reporting in Trials Group (CONSORT) guidelines, using randomised comparisons of paracetamol or ibuprofen with placebo in moderate to severe postoperative pain.
Methods: Published reports of randomised trials of paracetamol or ibuprofen compared with placebo were identified by systematic searching of a number of bibliographic databases (including MEDLINE and the Cochrane Library). Information on adverse effect reporting was extracted.
Results: Fifty-two studies (4,366 patients) were retrieved. Nineteen trials (37%) published before 1994 did not comply with the guidelines. Only two of the 52 trials made no mention of adverse effects. No method of assessment was given in 19 trials, patient diaries were used in 18, spontaneous reporting in seven and direct questioning in six. When all adverse effects at all doses were analysed together patients reported significantly more adverse effects with paracetamol or ibuprofen than with placebo (number-needed-to-harm 25 for paracetamol and 26 for ibuprofen). Studies which used patient diaries yielded a significantly higher incidence of adverse effects than those which used other forms of assessment. For individual adverse effects, there was no difference between active (paracetamol 1000 mg or ibuprofen 400 mg) and placebo, except for somnolence/drowsiness with ibuprofen 400 mg (number-needed-to-harm 19 (95% confidence interval 12 to 41). Nine out of 10 trials reporting somnolence/drowsiness with ibuprofen 400 mg were in dental pain.
Discussion: Different methods of assessing adverse effects can produce different reported incidence and, hence, statistical importance. We outline recommendations to improve the reporting of adverse effects in clinical trials.
Methods: Published reports of randomised trials of paracetamol or ibuprofen compared with placebo were identified by systematic searching of a number of bibliographic databases (including MEDLINE and the Cochrane Library). Information on adverse effect reporting was extracted.
Results: Fifty-two studies (4,366 patients) were retrieved. Nineteen trials (37%) published before 1994 did not comply with the guidelines. Only two of the 52 trials made no mention of adverse effects. No method of assessment was given in 19 trials, patient diaries were used in 18, spontaneous reporting in seven and direct questioning in six. When all adverse effects at all doses were analysed together patients reported significantly more adverse effects with paracetamol or ibuprofen than with placebo (number-needed-to-harm 25 for paracetamol and 26 for ibuprofen). Studies which used patient diaries yielded a significantly higher incidence of adverse effects than those which used other forms of assessment. For individual adverse effects, there was no difference between active (paracetamol 1000 mg or ibuprofen 400 mg) and placebo, except for somnolence/drowsiness with ibuprofen 400 mg (number-needed-to-harm 19 (95% confidence interval 12 to 41). Nine out of 10 trials reporting somnolence/drowsiness with ibuprofen 400 mg were in dental pain.
Discussion: Different methods of assessing adverse effects can produce different reported incidence and, hence, statistical importance. We outline recommendations to improve the reporting of adverse effects in clinical trials.