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Surgical treatments for men with benign prostatic enlargement: cost-effectiveness study |
Armstrong N, Vale L, Deverill M, Nabi G, McClinton S, N'Dow J, Pickard R |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary This study examined the cost-effectiveness of alternative surgical strategies for men with lower urinary tract symptoms suggestive of benign prostate enlargement. The strategy of initial ablation with transurethral diathermy vaporisation followed by holmium laser enucleation for those men who experienced treatment failure or subsequent symptom relapse was cost-effective from the perspective of the National Health Service. The study was based on valid methodology and the authors’ conclusions appear to be robust, despite some limitations in the available data. Type of economic evaluation Study objective The objective was to examine the cost-effectiveness of several surgical strategies for men with lower urinary tract symptoms suggestive of benign prostate enlargement and no existing relevant complications. Interventions The four surgical prostate treatments were transurethral resection (TUR), transurethral microwave thermotherapy (TUMT), transurethral diathermy vaporisation (TUDV), and holmium laser enucleation (HLE). Potassium titanyl phosphate (KTP) laser vaporisation was also considered as a substitute for TUDV.
An additional 19 combinations of these strategies were considered, according to the following rules, which were derived from experts’ opinions: the order of treatments was always from less to more invasive; minimally invasive treatments could be repeated only once; tissue ablative and HLE procedures could not be repeated because of the effect on the remaining prostate tissue (ablative) and near total removal (HLE); and TUR could only be repeated after confirmation of an obstruction of the bladder outlet and only once. Methods Analytical approach:This economic evaluation was based on a Markov model with a 10-year time horizon. The authors stated that the perspective of the UK National Health Service (NHS) was taken.
Effectiveness data:The clinical data on treatment effect came both from a systematic review of the literature and an individual level data set. The authors reported some information about the source for each model parameter. Transition probabilities were mainly derived from a published meta-analysis, the methods of which were not reported. Expert opinion was also used in a few cases. The key clinical input was the probability of remission with each of the surgical options.
Monetary benefit and utility valuations:The utility estimates were derived from previous studies, that used time trade-off and standard gamble techniques, and were adjusted for total symptom score and for the presence of incontinence.
Measure of benefit:Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at an annual rate of 3.5%.
Cost data:The economic analysis included only the hospital costs associated with each procedure and the costs of short-term complications. These were mainly estimated using NHS reference costs with the addition of appropriate costs for extra equipment, that were derived from UK based manufacturers or distributors. The resource use was based on official rates or experts’ opinions. All costs were in UK pounds sterling (£) for the year 2006. Those incurred after the first year were discounted at an annual rate of 3.5%.
Analysis of uncertainty:A probabilistic sensitivity analysis was carried out using a Monte Carlo simulation that assigned probability distributions to the model inputs to generate mean estimates of costs, benefits, and cost-utility ratios. Deterministic one-way sensitivity analyses were also performed on the discount rate, the lifetime horizon, the single cohort design, the relative risk of re-operation, the need for urodynamic investigations after relapse after diathermy or laser vaporisation, and the inclusion of the results from studies performed outside the UK. The expected value of perfect information was also calculated. Results The reference strategy, namely TUR, repeated once if necessary, was dominated because there was at least one alternative procedure with lower costs and greater benefits. All strategies starting with TUMT were dominated, as were those that contained KTP laser vaporisation. A direct comparison between the alternative strategies and TUR, repeated if necessary, produced similar results.
When the non-dominated strategies were considered, the expected costs for the cohort of 25,000 men were £380,775,000 with TUDV, £400,550,000 with HLE, £413,713,000 with TUDV plus HLE, and £418,264,000 with TUDV plus TUR repeated once if necessary. The QALYs were 917,082 with TUDV, 919,656 with HLE, 921,041 with TUDV plus HLE, and 921,091 with TUDV plus TUR repeated once if necessary. The incremental cost per QALY gained over the next more expensive strategy was £7,682 with HLE, £9,505 with TUDV plus HLE, and £90,576 with TUDV plus TUR repeated once if necessary.
The strategy of TUDV plus HLE was the most cost-effective, with a probability of being cost-effective of 0.85 at a willingness to pay threshold of £20,000 per QALY gained.
The deterministic sensitivity analysis showed that these base-case findings were robust. The calculation of the expected value of perfect information suggested an upper limit of £5.3 million should be spent on further research to give worthwhile benefit. Authors' conclusions The authors concluded that a strategy of initial ablation with TUDV followed by HLE for those men who experienced treatment failure or subsequent symptom relapse was cost-effective from the perspective of the UK NHS. CRD commentary Interventions:The authors provided a justification for their choice of the comparators. TUR was recommended for men who had not benefited from behavioural or drug treatment as it offered a relatively high chance of benefit at a low risk of re-treatment. The newer minimally invasive technologies improved symptoms, but had a higher rate of re-treatment. These comparators were identified on the basis of current practice, a previous study evaluating the evidence for effectiveness, and commercial availability. A clinical expert group determined the sequences of strategies. The authors stated that initially more strategies were included, but were later excluded due to a lack of available reliable data.
Effectiveness/benefits:Details on the literature review, to identify relevant sources of data, were not provided. A meta-analysis of published studies was carried out to combine the primary estimates, but no information on the methods and conduct of this approach was given. The authors reported some aspects of the derivation of the key clinical inputs and highlighted the uncertainty around the estimation of some data, as a limitation of this analysis, but they pointed out that their sensitivity analysis showed that their findings were robust and showed the minimal impact of these uncertain inputs on the outcomes. QALYs are a validated benefit measure appropriate to capturing the impact of the interventions on quality of life and survival. They are generalisable and allow cross-disease comparisons.
Costs:The analysis of costs reflected the perspective in terms of cost categories and the sources used, but a breakdown of the cost items was not given. For most items, the unit costs and resource quantities were not reported separately. The majority of costs were presented as macro-categories, which are consistent with the use of NHS costs. The price year, use of discounting, and assumptions required were reported.
Analysis and results:The costs and benefits were appropriately synthesised using an incremental approach, which was appropriate, to rule out dominated strategies and to generate a ranking of optimal procedures. Given the large number of strategies, the findings were presented only for the non-dominated ones. The issue of uncertainty was extensively addressed in the sensitivity analysis, which used both a probabilistic and a deterministic approach. The details of the probabilistic approach (i.e. types of distributions and other assumptions) were described. The results of all the sensitivity analyses were clearly presented and discussed. The justification for the time horizon was that 10 years was the period over which the population would be likely to seek active treatment and for which current technologies would remain relevant. The authors noted that their analysis reflected the UK health care setting and might not be transferable to other health care systems.
Concluding remarks:The study was based on valid methodology and the authors’ conclusions appear to be robust, despite some limitations in the available data.
Note: as the authors have pointed out, further details of the methodology, and results of the systematic review of effectiveness can be found in the two preceding BMJ papers and in the HTA monograph (see first three references in 'Other Publications of Related Interest' below). Funding Funded by the Health Technology Assessment Programme. Bibliographic details Armstrong N, Vale L, Deverill M, Nabi G, McClinton S, N'Dow J, Pickard R. Surgical treatments for men with benign prostatic enlargement: cost-effectiveness study. BMJ 2009; 338: b1288 Other publications of related interest Lourenco T, Pickard R, Vale L, et al. Minimally invasive therapies for the treatment of benign prostatic enlargement – a systematic review of randomised controlled trials. BMJ 2008; 337: a1662.
Lourenco T, Pickard R, Vale L, et al. Alternative approaches to endoscopic ablation for benign enlargement of the prostate: systematic review of randomised controlled trials. BMJ 2008, 337: a449.
Lourenco T, Armstrong N, N’Dow J, et al. Systematic review and economic modelling of effectiveness and cost utility of surgical treatments for men with benign prostatic enlargement. Health Technol Assess 2008;12:1-516.
Norby B, Nielsen HV, Frimodt-Moller PC. Cost-effectiveness of new treatments for benign prostatic hyperplasia: results of a randomised trial comparing the short-term cost-effectiveness of transurethral interstitial laser coagulation of the prostate, transurethral microwave thermotherapy and standard transurethral resection or incision of the prostate. Scand J Urol Nephrol 2002;36:286-95.
Stovsky MD, Griffiths RI, Duff SB. A clinical outcomes and cost analysis comparing photoselective vaporization of the prostate to alternative minimally invasive therapies and transurethral prostate resection for the treatment of benign prostatic hyperplasia. J Urol 2006;176:1500-6. Indexing Status Subject indexing assigned by NLM MeSH Aged; Aged, 80 and over; Catheter Ablation /economics; Cost-Benefit Analysis; Health Status; Humans; Laser Coagulation /economics; Male; Markov Chains; Microwaves /therapeutic use; Middle Aged; Prostatic Hyperplasia /economics /mortality /surgery; Prostatism /surgery; Quality-Adjusted Life Years; Risk Factors; Transurethral Resection of Prostate /economics AccessionNumber 22009101385 Date bibliographic record published 20/05/2009 Date abstract record published 22/07/2009 |
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