Quality of published clinical trials on asthma

The quality of reporting of randomised controlled trials in asthma: a systematic review

BACKGROUND

There are concerns about the reporting quality of asthma trials.

AIMS

To describe the reporting of contemporary asthma trials and to identify factors associated with better reporting quality.

METHODS

Two reviewers independently searched MEDLINE for randomised controlled trials (RCTs) of asthma published between January 2010 and July 2012 in leading generalist and specialist journals. We calculated the proportion of trials that adequately reported each Consolidated Standards of Reporting Trials (CONSORT) checklist item and an overall quality score for each trial. Factors associated with better reporting quality were investigated.

RESULTS

Thirty-five RCTs satisfied our eligibility criteria. Four trials adequately reported <50% of the items, 15 adequately reported 50-60% of items, and 16 adequately reported >60% of items. Seventeen of the 38 CONSORT items were consistently well reported in more than two-thirds of the articles. In contrast, nine items were poorly reported in more than half the trials - namely, identification as a randomised trial in the title (40.0%), an adequate structured summary/abstract (48.6%), details of eligibility criteria (34.3%), recruitment (48.6%), randomisation procedures (22.9%), intervention (38.5%), harms (34.3%), the funding source (45.7%), and access to the full trial protocol (17.1%). Studies led by teams in high-income country settings were associated with better quality of reporting (relative risk=1.33, 95% CI 1.09 to 1.64).

CONCLUSIONS

The quality of reporting in contemporary asthma literature remains suboptimal. We have identified important areas in which reporting quality needs to be improved.

A systematic review of trends in the methodological quality of randomized controlled trials in various research fields

OBJECTIVES

We sought to evaluate the trends in the methodological quality of randomized controlled trials in various medical fields.

STUDY DESIGN AND SETTING

Relevant studies were retrieved by the PubMed and the ISI Web of science databases.

RESULTS

Thirty-five out of 457 retrieved studies met the inclusion criteria. Twenty-one out of 35 selected studies reported significant improvement in at least one methodological quality factor. Overall quality scores were increased in 13 out of 26 studies providing relevant data. The most commonly separately examined key quality factors were allocation concealment and blinding in 13 out of 21 studies that reported relevant data. Allocation concealment was the quality characteristic most commonly reported as significantly improving during the reviewed period (in five out of eight studies reporting relevant comparative data).

CONCLUSION

Certain aspects of methodological quality have improved significantly over time, but others remain stagnant. Further efforts to improve study design, conduct, and reporting of randomized controlled trials are warranted.

Quality of controlled clinical trials on glaucoma and intraocular high pressure

AIM

To study the quality of controlled clinical trials on glaucoma.

METHODS

Two hundred and twenty-six clinical trials published between 1980 and 1999 were selected from seven international ophthalmological journals. Their quality was assessed by four researchers with epidemiological skills using a structured questionnaire.

RESULTS

Sample size was pre-estimated in 34 (15.0%) papers, which were of greater size (P = 0.05). Randomization was performed in 98.2% of the trials, although the procedure of randomization was scarcely reported. Masking was reported in 56.6% of the papers, and was more frequent in medical treatments (P < 0.001). The basal characteristics of the groups were compared in 139 papers (61.5%). Patient losses during the follow-up period were fully described in only 27 trials. Intention-to-treat analysis was used in 17 (7.7%) papers. Most trials reported P values, but a measure of effect (mean, proportion, or relative risk) appeared in only 16 trials (7.7%). Trials performed in the US more frequently compared baseline characteristics of the groups (P = 0.03), described the patient flow (P = 0.04), and used adequate statistical procedures (P = 0.03). Those trials that included a statistician or an epidemiologist among the authors were more commonly blinded (P = 0.06) and they always avoided the analyses of subgroups (P = 0.006). Several methodological issues have improved throughout the studied period.

CONCLUSIONS

Several methodological characteristics should be improved when reporting a clinical trial on glaucoma. Using a checklist like that suggested by the CONSORT can help to achieve this.