Patient characteristics and refusal to participate in a head and neck cancer intervention trial: experience of two tertiary UK head and neck cancer centres.

INTRODUCTION: Randomised clinical trials are an essential component for robust clinical evaluation. They are expensive to deliver but can fail to achieve the required outcomes. This paper reports details of trial recruitment in a head and neck Patient Concerns Inventory intervention trial from two UK head and neck tertiary centres. MATERIALS AND METHODS: Data were collected for a pragmatic cluster preference randomised control trial with 15 consultants recruiting patients treated with curative intent after a diagnosis of head and neck cancer (all sites, disease stages, treatments). Ethical approval was given to report on those not recruited by the following characteristics: trial site, trial arm, age, sex, tumour site, overall stage, index of multiple deprivation quintile, timeframe. RESULTS: There were 368 patients approached who remained eligible and 80 (22%) declined to participate. Logistic regression suggested that age group (p = 0.008) and index of multiple deprivation quintile group (p = 0.003) were independent predictors of refusal. CONCLUSIONS: Although recruitment to the trial was very good, it raised the issue of lower recruitment in the more deprived older group and lower social economic strata. Innovative ways need to be explored to facilitate the 'hard to reach' group contributing to, and benefiting from, clinical trials.

Cost-effectiveness of silicone and alginate impressions for complete dentures.

OBJECTIVE: The aim of this study was to assess the cost effectiveness of silicone and alginate impressions for complete dentures. METHODS: Cost effectiveness analyses were undertaken alongside a UK single centre, double blind, controlled, crossover clinical trial. Taking the perspective of the healthcare sector, effectiveness is measured using the EuroQol (EQ-5D-3L) which provides a single index value for health status that may be combined with time to produce quality adjusted life years (QALYs); and Oral Health Impact Profile (OHIP-EDENT). Incremental cost effectiveness ratios are presented representing the additional cost per one unit gained. RESULTS: Mean cost was higher in the silicone impression group (£388.57 vs. £363.18). Negligible between-group differences were observed in QALY gains; the silicone group had greater mean OHIP-EDENT gains. The additional cost using silicone was £3.41 per change of one point in the OHIP-EDENT. CONCLUSIONS: The silicone group was more costly, driven by the cost of materials. Changes in the EQ-5D and QALY gains over time and between arms were not statistically significant. Change in OHIP-EDENT score showed greater improvement in the silicone group and the difference between arms was statistically significant. Given negligible QALY gains and low level of resource use, results must be treated with caution. It is difficult to make robust claims about the comparative cost-effectiveness. CLINICAL SIGNIFICANCE: Silicone impressions for complete dentures improve patients' quality of life (OHIP-EDENT score). The extra cost of silicone impressions is £30 per patient. Dentists, patients and health care funders need to consider the clinical and financial value of silicone impressions. Different patients, different dentists, different health funders will have individual perceptions and judgements. ISRCTN01528038. NIHR-RfPB grant PB-PG-0408-16300. This article forms part of a project for which the author (TPH) won the Senior Clinical Unilever Hatton Award of the International Assocation for Dental Research, Capetown, South Africa, June 2014.

A randomised controlled trial of complete denture impression materials.

OBJECTIVES: There is continuing demand for non-implant prosthodontic treatment and yet there is a paucity of high quality Randomised Controlled Trial (RCT) evidence for best practice. The aim of this research was to provide evidence for best practice in prosthodontic impressions by comparing two impression materials in a double-blind, randomised, crossover, controlled, clinical trial. METHODS: Eighty-five patients were recruited, using published eligibility criteria, to the trial at Leeds Dental Institute, UK. Each patient received two sets of dentures; made using either alginate or silicone impressions. Randomisations determined the order of assessment and order of impressions. The primary outcome was patient blinded preference for unadjusted dentures. Secondary outcomes were patient preference for the adjusted dentures, rating of comfort, stability and chewing efficiency, experience of each impression, and an OHIP-EDENT questionnaire. RESULTS: Seventy-eight (91.8%) patients completed the primary assessment. 53(67.9%) patients preferred dentures made from silicone impressions while 14(17.9%) preferred alginate impressions. 4(5.1%) patients found both dentures equally satisfactory and 7 (9.0%) found both equally unsatisfactory. There was a 50% difference in preference rates (in favour of silicone) (95%CI 32.7-67.3%, p<0.0001). CONCLUSION: There is significant evidence that dentures made from silicone impressions were preferred by patients. CLINICAL SIGNIFICANCE: Given the strength of the clinical findings within this paper, dentists should consider choosing silicone rather than alginate as their material of choice for secondary impressions for complete dentures. TRIAL REGISTRATION: ISRCTN 01528038. This article forms part of a project for which the author (TPH) won the Senior Clinical Unilever Hatton Award of the International Assocation for Dental Research, Capetown, South Africa, June 2014.