Dataset Information

Evidence and risk indicators of non-random sampling in clinical trials in implant dentistry: A systematic appraisal.

ABSTRACT:

Aim

Analysis of distribution of p-values of continuous differences between test and controls after randomization provides evidence of unintentional error, non-random sampling, or data fabrication in randomized controlled trials (RCTs). We assessed evidence of highly unusual distributions of baseline characteristics of subjects enrolled in clinical trials in implant dentistry.

Materials and methods

RCTs published between 2005 and 2020 were systematically searched in Pubmed, Embase, and Cochrane databases. Baseline patient data were extracted from full text articles by two independent assessors. The hypothesis of non-random sampling was tested by comparing the expected and the observed distribution of the p-values of differences between test and controls after randomization.

Results

One-thousand five-hundred and thirty-eight unique RCTs were identified, of which 409 (26.6%) did not report baseline characteristics of the population, and 671 (43.6%) reported data in forms other than mean and standard deviation and could not be used to assess their random sampling. Four-hundred and fifty-eight trials with 1449 baseline variables in the form of mean and standard deviation were assessed. The study observed an over-representation of very small p-values [<.001, 1.38%, 95% confidence interval (CI) 0.85-2.12 compared to the expected 0.10%, 95% CI 0.00-0.26]. No evidence of over-representation of larger p-values was observed. Unusual distributions were present in 2.38% of RCTs and more frequent in non-registered trials, in studies supported by non-industry funding, and in multi-centre RCTs.

Conclusions

The inability to assess random sampling due to insufficient reporting in 26.6% of trials requires attention. In trials reporting suitable baseline data, unusual distributions were uncommon, and no evidence of data fabrication was detected, but there was evidence of non-random sampling. Continued efforts are necessary to ensure high integrity and trust in the evidence base of the field.

SUBMITTER: Shi JY

PROVIDER: S-EPMC9299163 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:The National Institute for Health and Care Excellence (NICE) invited Alimera Sciences, the company manufacturing fluocinolone acetonide intravitreal implant (FAc) 0.19 mg (tradename ILUVIEN®), to submit evidence on the clinical and cost-effectiveness of FAc for treating recurrent non-infectious uveitis. Kleijnen Systematic Reviews Ltd, in collaboration with Maastricht University Medical Centre?+?, was commissioned to act as the independent Evidence Review Group (ERG). This paper contains a summary of the clinical and cost-effectiveness evidence submitted by the company, the ERG's critique on the submitted evidence, and the guidance issued by the NICE Appraisal Committee (AC). The company submission (CS) was mainly informed by the PSV-FAI-001 trial in which FAc was compared with (limited) current practice [(L)CP], which was not considered to be representative of UK clinical practice by the ERG. There was no comparison of FAc to any treatment listed in the final scope, and especially to the dexamethasone intravitreal implant (dexamethasone), which was considered to be a relevant comparator by the AC. The primary outcome of the PSV-FAI-001 was recurrence of uveitis in the treated eye. Most of the events for the primary outcome were imputed during the PSV-FAI-001 trial, which probably led to an overestimation of the number of recurrences of disease, and a biased estimate of the relative effectiveness of FAc versus (L)CP. Finally, the place of FAc in the treatment pathway was not clearly defined by the company. Substantial uncertainty surrounded the cost-effectiveness results due to the shortcomings of the clinical evidence. Additionally, the quality of life of patients was not measured during the PSV-FAI-001 trial and long-term effectiveness data of FAc were lacking. The ERG adjusted several issues identified in the CS and added dexamethasone as a comparator in the decision analytic model. The ERG presented multiple analyses as base-cases because several elements of the assessment remained uncertain. The fully incremental ERG results ranged from dexamethasone (extendedly) dominating FAc (when assuming a hazard ratio of 1 or 0.7 for dexamethasone versus FAc) to an incremental cost-effectiveness ratio (ICER) of £30,153 per quality-adjusted life-year (QALY) gained for FAc versus (L)CP [when assuming a hazard ratio of 0.456 for dexamethasone versus (L)CP]. The ICER of FAc versus (L)CP ranged from £12,325 to £30,153 per QALY gained. After a second AC meeting where alternative company scenarios comparing FAc with dexamethasone were considered by the AC, the AC concluded that "the results of the company's analyses ranged from the fluocinolone acetonide implant being dominant (that is, it was more effective and costs less), to an ICER of £29,461 per QALY gained, and most of the ICERs were below £20,000 per QALY gained". Therefore, the AC recommended FAc as a cost-effective use of National Health Service (NHS) resources for treating recurrent non-infectious uveitis affecting the posterior segment of the eye in the final TA590 guidance (published July 2019).