An assessment of quality characteristics of randomised control trials published in dental journals
Introduction
Dental research aims at evaluating patient interventions with the objective to reach valid conclusions about current and future treatment modalities. The trustworthiness of the conclusions depends greatly on what is called “internal validity” which pertains to the qualitative characteristics of the design and methodology of the particular trial. An experiment conducted following appropriate methodology is more likely to give results that are considered reliable and may positively impact clinical practice.[1], [2]
It has been reported that lack of a number of factors including control, randomisation, allocation concealment, blinding, and accounting for loss to follow-up in trials, may introduce bias and thus render the study results invalid.[1], [3] Among the various study designs the randomised controlled trial is considered the design that has the potential to provide the highest quality evidence,1 however, there is substantial evidence in the biomedical literature that RCTs’ quality is suboptimal.[4], [5], [6], [7]
In an effort to standardise and guide researchers in conducting and reporting clinical trials the Consolidated Standards of Reporting Trials (CONSORT) guidelines have been developed which consist of 25 items that cover all key aspects of clinical trials and set standards on how to design, conduct, analyse and report such studies.1 Numerous studies in the past have assessed quality of randomised controlled trials using various methods,[3], [4], [8], [9], [10], [11] and recently studies have evaluated the RCTs’ quality using the CONSORT guidelines.[6], [7]
According to the CONSORT guidelines some of the important features that experimental design and reporting must account for are:
- (a)
Sample size calculation and power analysis, since adequate sample size and increased power reduce the chance of type II errors (false negative results).[11], [12], [13], [14]
- (b)
Randomisation, which facilitates a fair comparison of treatments and reduces bias by guarding against participants being allocated treatment according to some systematic arrangement or by the judgement of the investigator.15
- (c)
Blinding; in the absence of which the results favour the new treatment compared to the standard therapy.[16], [17], [18], [19]
- (d)
Reporting of effect size, confidence intervals, and statistical significance (p-values).[20], [21], [22], [23], [24], [25], [26], [27]
- (e)
Subgroup analyses; as more data are analysed there is an increased risk of finding “positive” results by chance and the danger that these results may be selectively emphasised.[28], [29], [30], [31], [32]
- (f)
Confounding/stratification (more applicable to epidemiology studies). Associations found in trials may be attributed to true effect, chance, bias, or confounding.33 Confounding, unlike bias, can be evaluated quantitatively and controlled for during the design of the trial by assuring equal distribution of risk factors and during the analysis of the study through stratification and multivariate analysis.34
In lieu of the above, the objective of this study was to evaluate the quality of randomised clinical trials using the CONSORT guidelines in the dental journals with the highest impact factor, in six key specialty areas. Additionally, the aim was to determine whether specific study characteristics such as dental subspecialty, country of origin, number of authors, single or multicentre involvement, significance of results and ethics committee approval were related to reporting quality.
Section snippets
Materials and methods
The following six dental journals, which presented the highest impact factor for each of dental specialty in 2009, were included in the study:
- 1.
American Journal of Orthodontics and Dentofacial Orthopedics (AJODO).
- 2.
International Journal of Prosthetic Dentistry (IJPD).
- 3.
Journal of Clinical Periodontology (JCP).
- 4.
Journal of Endodontics (JOE).
- 5.
Journal of Oral and Maxillofacial Surgery (JOMS).
- 6.
Journal of Pediatric Dentistry (JPD).
The content of the most recent 24 issues per journal published up to July 2009
Results
The results of this study are summarised in Table 1, Table 2, Table 3, Table 4.
Table 1 displays the characteristics of all 95 dental randomised controlled trials by dental journal, country or origin, number of authors, involvement of statistician/epidemiologist, single or multicentre study, ethics committee approval and statistical significance of main finding. The number of articles (N) and corresponding frequencies are given per characteristic.
Table 2 presents the overall modified CONSORT
Discussion
The results from RCTs provide the highest quality of evidence and therefore it is of paramount importance to secure that they are designed, conducted and reported by adhering to the strictest standards. The validity of the RCTs result would influence decision making in today's clinical practice and in the future since RCTs are the backbone of systematic reviews.
Overall, the results of this study showed a quality score in a percentage scale ranging from 56.1% to 69% indicating a rather low
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