14 research outputs found
Contamination in trials of educational interventions
Objectives: To consider the effects of contamination on the magnitude and statistical significance (or precision) of the estimated effect of an educational intervention, to investigate the mechanisms of contamination, and to consider how contamination can be avoided. Data sources: Major electronic databases were searched up to May 2005. Methods: An exploratory literature search was conducted. The results of trials included in previous relevant systematic reviews were then analysed to see whether studies that avoided contamination resulted in larger effect estimates than those that did not. Experts’ opinions were elicited about factors more or less likely to lead to contamination. We simulated contamination processes to compare contamination biases between cluster and individually randomised trials. Statistical adjustment was made for contamination using Complier Average Causal Effect analytic methods, using published and simulated data. The bias and power of cluster and individually randomised trials were compared, as were Complier Average Causal Effect, intention-to-treat and per protocol methods of analysis. Results: Few relevant studies quantified contamination. Experts largely agreed on where contamination was more or less likely. Simulation of contamination processes showed that, with various combinations of timing, intensity and baseline dependence of contamination, cluster randomised trials might produce biases greater than or similar to those of individually randomised trials. Complier Average Causal Effect analyses produced results that were less biased than intention-to-treat or per protocol analyses. They also showed that individually randomised trials would in most situations be more powerful than cluster randomised trials despite contamination. Conclusions: The probability, nature and process of contamination should be considered when designing and analysing controlled trials of educational interventions in health. Cluster randomisation may or may not be appropriate and should not be uncritically assumed always to be a solution. Complier Average Causal Effect models are an appropriate way to adjust for contamination if it can be measured. When conducting such trials in future, it is a priority to report the extent, nature and effects of contamination.We are grateful to the National Health Service Research and Development National Coordinating Centre for Research Methodology for funding this research
The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set
Background
Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables.
Methods
Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set.
Results
Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001).
Conclusions
The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy
Effectiveness and cost-effectiveness of salicylic acid and cryotherapy for cutaneous warts: an economic decision model
Objectives: To estimate the costs of commonly used
treatments for cutaneous warts, as well as their health
benefits and risk. To create an economic decision model
to evaluate the cost-effectiveness of these treatments,
and, as a result, assess whether a randomised controlled
trial (RCT) would be feasible and cost-effective.
Data sources: Focus groups, structured interviews
and observation of practice. Postal survey sent to 723
patients. A recently updated Cochrane systematic
review and published cost and prescribing data.
Review methods: Primary and secondary data
collection methods were used to inform the
development of an economic decision model. Data from
the postal survey provided estimates of the
effectiveness of wart treatments in a primary care
setting. These estimates were compared with outcomes
reported in the Cochrane review of wart treatment,
which were largely obtained from RCTs conducted in
secondary care. A decision model was developed
including a variety of over-the-counter (OTC) and GPprescribed
treatments. The model simulated 10,000
patients and adopted a societal perspective.
Results: OTC treatments were used by a substantial
number of patients (57%) before attending the GP
surgery. By far the most commonly used OTC
preparation was salicylic acid (SA). The results of the
economic model suggested that of the treatments
prescribed by a GP, the most cost-effective treatment
was SA, with an incremental cost-effectiveness ratio
(ICER) of 2.20 £/% cured. The ICERs for cryotherapy
varied widely (from 1.95 to 7.06 £/% cured) depending
on the frequency of applications and the mode of
delivery. The most cost-effective mode of delivery was
through nurse-led cryotherapy clinics (ICER =
1.95 £/% cured) and this could be a cost-effective
alternative to GP-prescribed SA. Overall, the OTC
therapies were the most cost-effective treatment
options. ICERs ranged from 0.22 £/% cured for OTC
duct tape and 0.76 £/% cured for OTC cryotherapy to
1.12 £/% cured for OTC SA. However, evidence in
support of OTC duct tape and OTC cryotherapy is
very limited. Side-effects were commonly reported for
both SA and cryotherapy, particularly a burning
sensation, pain and blistering.
Conclusions: Cryotherapy delivered by a doctor is an
expensive option for the treatment of warts in primary
care. Alternative options such as GP-prescribed SA and
nurse-led cryotherapy clinics provide more costeffective
alternatives, but are still expensive compared
with self-treatment. Given the minor nature of most
cutaneous warts, coupled with the fact that the
majority spontaneously resolve in time, it may be
concluded that a shift towards self-treatment is
warranted. Although both duct tape and OTC
cryotherapy appear promising new self-treatment
options from both a cost and an effectiveness
perspective, more research is required to confirm the
efficacy of these two methods of wart treatment. If
these treatments are shown to be as cost-effective as
or more cost-effective than conventional treatments,
then a shift in service delivery away from primary care
towards more OTC treatment is likely. A public
awareness campaign would be useful to educate
patients about the self-limiting nature of warts and the
possible alternative OTC treatment options available.
Two future RCTs are recommended for consideration:
a trial of SA compared with nurse-led cryotherapy in
primary care, and a trial of home treatments. Greater
understanding of the efficacy of these home treatments
will give doctors a wider choice of treatment options,
and may help to reduce the overall demand for
cryotherapy in primary care
Effectiveness and cost-effectiveness of salicylic acid and cryotherapy for cutaneous warts: an economic decision model
Objectives: To estimate the costs of commonly used
treatments for cutaneous warts, as well as their health
benefits and risk. To create an economic decision model
to evaluate the cost-effectiveness of these treatments,
and, as a result, assess whether a randomised controlled
trial (RCT) would be feasible and cost-effective.
Data sources: Focus groups, structured interviews
and observation of practice. Postal survey sent to 723
patients. A recently updated Cochrane systematic
review and published cost and prescribing data.
Review methods: Primary and secondary data
collection methods were used to inform the
development of an economic decision model. Data from
the postal survey provided estimates of the
effectiveness of wart treatments in a primary care
setting. These estimates were compared with outcomes
reported in the Cochrane review of wart treatment,
which were largely obtained from RCTs conducted in
secondary care. A decision model was developed
including a variety of over-the-counter (OTC) and GPprescribed
treatments. The model simulated 10,000
patients and adopted a societal perspective.
Results: OTC treatments were used by a substantial
number of patients (57%) before attending the GP
surgery. By far the most commonly used OTC
preparation was salicylic acid (SA). The results of the
economic model suggested that of the treatments
prescribed by a GP, the most cost-effective treatment
was SA, with an incremental cost-effectiveness ratio
(ICER) of 2.20 £/% cured. The ICERs for cryotherapy
varied widely (from 1.95 to 7.06 £/% cured) depending
on the frequency of applications and the mode of
delivery. The most cost-effective mode of delivery was
through nurse-led cryotherapy clinics (ICER =
1.95 £/% cured) and this could be a cost-effective
alternative to GP-prescribed SA. Overall, the OTC
therapies were the most cost-effective treatment
options. ICERs ranged from 0.22 £/% cured for OTC
duct tape and 0.76 £/% cured for OTC cryotherapy to
1.12 £/% cured for OTC SA. However, evidence in
support of OTC duct tape and OTC cryotherapy is
very limited. Side-effects were commonly reported for
both SA and cryotherapy, particularly a burning
sensation, pain and blistering.
Conclusions: Cryotherapy delivered by a doctor is an
expensive option for the treatment of warts in primary
care. Alternative options such as GP-prescribed SA and
nurse-led cryotherapy clinics provide more costeffective
alternatives, but are still expensive compared
with self-treatment. Given the minor nature of most
cutaneous warts, coupled with the fact that the
majority spontaneously resolve in time, it may be
concluded that a shift towards self-treatment is
warranted. Although both duct tape and OTC
cryotherapy appear promising new self-treatment
options from both a cost and an effectiveness
perspective, more research is required to confirm the
efficacy of these two methods of wart treatment. If
these treatments are shown to be as cost-effective as
or more cost-effective than conventional treatments,
then a shift in service delivery away from primary care
towards more OTC treatment is likely. A public\ud
awareness campaign would be useful to educate
patients about the self-limiting nature of warts and the
possible alternative OTC treatment options available.
Two future RCTs are recommended for consideration:
a trial of SA compared with nurse-led cryotherapy in
primary care, and a trial of home treatments. Greater
understanding of the efficacy of these home treatments
will give doctors a wider choice of treatment options,
and may help to reduce the overall demand for
cryotherapy in primary care
Treatment of peripheral neuropathies.
There are three general approaches to treatment of peripheral neuropathy. First, an attempt should be made to reverse the pathophysiological process if its nature can be elucidated. Second, nerve metabolism can be stimulated and regeneration encouraged. Third, even if the neuropathy itself cannot be improved, symptomatic therapy can be employed. This review outlines the options available for each approach
Predicting the difficult laparoscopic cholecystectomy: development and validation of a pre-operative risk score using an objective operative difficulty grading system
Background:
The prediction of a difficult cholecystectomy has traditionally been based on certain pre-operative clinical and imaging factors. Most of the previous literature reported small patient cohorts and have not used an objective measure of operative difficulty. The aim of this study was to develop a pre-operative score to predict difficult cholecystectomy, as defined by a validated intra-operative difficulty grading scale.
Method:
Two cohorts from prospectively maintained databases of patients who underwent laparoscopic cholecystectomy were analysed: the CholeS Study (8755 patients) and a single surgeon series (4089 patients). Factors potentially predictive of difficulty were correlated to the Nassar intra-operative difficulty scale. A multivariable binary logistic regression analysis was then used to identify factors that were independently associated with difficult laparoscopic cholecystectomy, defined as operative difficulty grades 3 to 5. The resulting model was then converted to a risk score, and validated on both internal and external datasets.
Result:
Increasing age and ASA classification, male gender, diagnosis of CBD stone or cholecystitis, thick-walled gallbladders, CBD dilation, use of pre-operative ERCP and non-elective operations were found to be significant independent predictors of difficult cases. A risk score based on these factors returned an area under the ROC curve of 0.789 (95% CI 0.773–0.806, p < 0.001) on external validation, with 11.0% versus 80.0% of patients classified as low versus high risk having difficult surgeries.
Conclusion:
We have developed and validated a pre-operative scoring system that uses easily available pre-operative variables to predict difficult laparoscopic cholecystectomies. This scoring system should assist in patient selection for day case surgery, optimising pre-operative surgical planning (e.g. allocation of the procedure to a suitably trained surgeon) and counselling patients during the consent process. The score could also be used to risk adjust outcomes in future research