dimensions (Table 9) consider important aspects of the evidence supporting a particular intervention and include three main domains: strength of the evidence, size of the effect and relevance of the evidence. The first domain is derived directly from the literature identified as informing a particular intervention. The last two require expert clinical input as part of its determination. Table : Evidence dimensions Type of evidence Definition Strength of the evidence Level Quality Statistical precision The study design used, as an indicator of the degree to which bias has been eliminated by design.* The methods used by investigators to minimise bias within a study design. The p-value or, alternatively, the precision of the estimate of the effect. It reflects the degree of certainty about the existence of a true effect. Size of effect The distance of the estimate from the ‘null’ value and the inclusion of only clinically important effects in the confidence interval. Relevance of evidence The usefulness of the evidence in clinical practice, particularly the appropriateness of the outcome measures used. Strength of the evidence The sub-domains (level, quality and statistical precision) are collectively a measure of the strength of the evidence. The ‘level of evidence’ reflects the effectiveness of a study design to answer a particular research question. Effectiveness is based on the probability that the design of the study has reduced or eliminated the impact of bias on the results. The NHMRC evidence hierarchy provides a ranking of various study designs (‘levels of evidence’) by the type of research question being addressed (Table 10). trial trial
Eltabey et al(2010) HoLEP: 40 TURP: 40 RCT Patients with BOO caused by BHP, with related voiding symptoms, prostate size between 30–100 g , who had not responded to pharmacologic therapy, with AUA symptom score ≥12 and Qmax ≤15ml/s. Outcomes reported at 1, 6 and 12 months post-surgery. HoLEP (with tissue morcellation) compared to TURP. Safety outcomes: blood transfusion urethral stricture incontinence. Effectiveness outcomes: peak flow AUA symptom scores PVR prostate volume Cost-related outcomes: length of operation length of catheterisation length of hospital stay Mavuduru et al (2009) HoLEP: 15 TURP: 15 RCT Patients eligible for surgery for symptomatic BPH Outcomes at 3 months and 9 months post-surgery. (morcellation was only used in one patient) compared to TURP. Safety outcomes: transfusion capsular perforations urethral stricture incontinence Effectiveness outcomes: IPSS symptom scores PVR prostate volume) Cost-related outcomes: length of operation length of catheterisation BOO = Bladder outlet obstruction; PVR=post-void residual volume; AUA Urological Association score; Qmax=peak urinary flow rate. Quality assessment The two additional new studies identified in the updated literature search relevant to the comparison between HoLEP and TURP had an unclear risk of bias. While sequence generation was undertaken by a computer generated table, allocation concealment was not described. No details were given regarding blinding of patients, personnel or outcomes assessors, although this is not unusual in surgery trials (McCulloch et al 2002). It is unlikely however that lack of blinding will have a significant impact on the reported results as the majority of the primary measures of effectiveness are functional outcomes. Follow-up of patients (attribution bias) was generally not well reported. Approach to assessing HoLEP in comparison to OP
Assumptions on results of meta-analysis the length of hospital stay for treatment (without adverse events) for HoLEP, TURP and OP is two, three and five days respectively. It was assumed that the clinical and other management of patients with BPH up to the time of procedure, as well as post-operative management are equivalent. Based on this assumption, hospital costs for HoLEP procedures were derived based on equivalent TURP costs but adjusted for lengths of stay. For HoLEP treatment, adverse events associated with the procedure, longer-term complications and re-treatment rates were calculated by multiplying the relative risk of experiencing these events by the associated rates for TURP or OP that were derived from the meta-analysis of data. From the published literature it was not possible to determine if a given patient experienced more than one short-term adverse event following treatment. As a result, rates of these events were derived by summing the rates presented in the meta-analysis. As the events and patient numbers that were summed are not necessarily mutually exclusive this may result in an overall over-estimation of rates. Therefore, the overall figures presented for adverse events represent a ‘worst case’ treatment scenario. Adverse events associated with treatment (HoLEP or TURP) would be treated on an basis and result in additional length of hospital stay of two days. Adverse events associated with OP would be treated and resolved within the five day treatment time frame for this intervention. Treatment for longer-term incontinence would include either behavioural interventions, including education programs and lifestyle modifications, or pharmacologic therapy using oxybutynin 5mg twice daily (or equivalent). Treatment for urethral stricture would be performed as an in-patient procedure and undertaken by either urethrotomy or dilation. Patients would not undergo any upon failure of initial urethral stricture treatment. The utility associated with urethral stricture is the same as that for long-term incontinence. Transition probabilities. Rates of short-term adverse events, longer-term side effects and re-treatment associated with TURP were derived from the meta-analysis and are shown in Table 20. All rates were transformed into probability values for use in the model using the formula: P=1-e-rt Where P is the probability that an event will occur; e is the base of the natural logarithm; r is the rate; and t is time.
Rieken et al 2010 Switzerland Databases searched: Medline. Time period of search: Approx. 2005-2009 (the article indicates that data were based on a MEDLINE search conducted “over the past 4 years”; the article was received for publication on July 28, 2009.) Comparators: HoLEP vs. TURP and OP. Outcomes: safety, effectiveness. Quality: Low Explicit review questions: No Explicit & appropriate eligibility criteria: No Explicit & comprehensive search strategy: No Quality of included studies appraised: No Methods of study appraisal reproducible: No. Heterogeneity between studies assessed: N/A. Summary of main results clear and appropriate: Yes (NB: Levels of evidence were assessed, however, the quality of evidence was NOT assessed.) Tan et al 2007 China Databases searched: Medline, Embase and The Cochrane Library. Time period of search: 1990–2007. Comparators: HoLEP versus TURP Outcomes: Safety, effectiveness, cost-effectiveness Quality: Fair Explicit review questions: Yes Explicit & appropriate eligibility criteria: Yes Explicit & comprehensive search strategy: No Quality of included studies appraised: Yes Methods of study appraisal reproducible: Yes. Heterogeneity between studies assessed: Yes Summary of main results clear and appropriate: No (NB: Has no PICO or actual explicit review questions, but does provide very inclusion criteria (page 1202))