L McKenzie

University of Aberdeen, Aberdeen, Scotland, United Kingdom

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Publications (13)47.89 Total impact

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    ABSTRACT: Haemorrhoidal disease is a common condition causing considerable distress to individuals and significant cost to healthcare services. This paper explored the cost-effectiveness of stapled haemorrhoidopexy (SH) compared with the non-surgical intervention, rubber band ligation (RBL), for grade II symptomatic circumferential haemorrhoids. An economic evaluation alongside a randomized controlled trial conducted between October 2002 and February 2005. Adults were recruited and randomized to either SH or RBL. The same surgeon performed all procedures and investigators were blinded until analyses were completed. Primary outcomes measured at 52 weeks were cumulative costs to the NHS, clinical diagnosis of recurrence and quality adjusted life years (QALYs). Sixty symptomatic men and women with confirmed clinical diagnosis of grade II symptomatic haemorrhoids were randomized. Loss to follow-up was up to 10% at 52 weeks. The mean cost for SH was greater than RBL (mean difference: 1483 pounds, 95% CI: 1339-1676); disease recurrence was lower (OR = 0.18, 95% CI: 0.03-0.86); and there was no evidence of a statistically significant difference in QALYs (-0.014, 95% CI: -0.076 to 0.051). SH was associated with a modest incremental cost per recurrence avoided at 12 months follow-up (4945 pounds). Based on current data, it was considered highly unlikely to be cost-effective in terms of incremental cost per QALY. There is insufficient evidence about the cost-effectiveness of SH for grade II haemorrhoids to recommend its routine use in place of RBL. Further information is needed from larger trials with a longer-term follow-up to inform subsequent economic evaluation.
    Full-text · Article · May 2009 · Colorectal Disease
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    R Flin · S Yule · L McKenzie · S Paterson-Brown · N Maran
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    ABSTRACT: A survey was undertaken to assess surgical team members' attitudes to safety and teamwork in the operating theatre. The Operating Room Management Attitudes Questionnaire (ORMAQ) measures attitudes to leadership, teamwork, stress and fatigue and error. A version of the ORMAQ was distributed to surgical teams in 17 hospitals in Scotland. A total of 352 responses were analysed, 138 from consultant surgeons, 93 from trainee surgeons and 121 from theatre nurses. Respondents generally demonstrated positive attitudes to behaviours associated with effective teamwork and safety. Attitudes indicating a belief in personal invulnerability to stress and fatigue were evident in both nurses and surgeons. Consultant surgeons had more positive views on the quality of surgical leadership and communication in theatre than trainees and theatre nurses. While the ubiquity of human error was well recognised, attitudes to error management strategies (incident reporting, procedural compliance) suggest that they may not be fully functioning across hospitals. While theatre staff placed a clear priority on patient safety against other business objectives (e.g. waiting lists, cost cutting), not all of them felt that this was endorsed by their hospital management. Attitude surveys can provide useful diagnostic information relating to behaviour and safety in surgical units. Discrepancies were found between the views of consultants compared with trainees and nurses, in relation to leadership and teamwork. While attitudes to safety were generally positive, there were several areas where theatre staff did not seem to appreciate the impact of psychological factors on technical performance.
    Preview · Article · Jul 2006 · The surgeon: journal of the Royal Colleges of Surgeons of Edinburgh and Ireland
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    ABSTRACT: To assess the effectiveness and cost-effectiveness of HealOzone (CurOzone USA Inc., Ontario, Canada) for the management of pit and fissure caries, and root caries. The complete HealOzone procedure involves the direct application of ozone gas to the caries lesion on the tooth surface, the use of a remineralising solution immediately after application of ozone and the supply of a 'patient kit', which consists of toothpaste, oral rinse and oral spray all containing fluoride. Electronic databases up to May 2004 (except Conference Papers Index, which were searched up to May 2002). A systematic review of the effectiveness of HealOzone for the management of tooth decay was carried out. A systematic review of existing economic evaluations of ozone for dental caries was also planned but no suitable studies were identified. The economic evaluation included in the industry submission was critically appraised and summarised. A Markov model was constructed to explore possible cost-effectiveness aspects of HealOzone in addition to current management of dental caries. Five full-text reports and five studies published as abstracts met the inclusion criteria. The five full-text reports consisted of two randomised controlled trials (RCTs) assessing the use of HealOzone for the management of primary root caries and two doctoral theses of three unpublished randomised trials assessing the use of HealOzone for the management of occlusal caries. Of the abstracts, four assessed the effects of HealOzone for the management of occlusal caries and one the effects of HealOzone for the management of root caries. Overall, the quality of the studies was modest, with many important methodological aspects not reported (e.g. concealment of allocation, blinding procedures, compliance of patients with home treatment). In particular, there were some concerns about the choice of statistical analyses. In most of the full-text studies analyses were undertaken at lesion level, ignoring the clustering of lesions within patients. The nature of the methodological concerns was sufficient to raise doubts about the validity of the included studies' findings. A quantitative synthesis of results was deemed inappropriate. On the whole, there is not enough evidence from published RCTs on which to judge the effectiveness of ozone for the management of both occlusal and root caries. The perspective adopted for the study was that of the NHS and Personal Social Services. The analysis, carried out over a 5-year period, indicated that treatment using current management plus HealOzone cost more than current management alone for non-cavitated pit and fissure caries (40.49 pounds versus 24.78 pounds), but cost less for non-cavitated root caries ( 14.63 pounds versus 21.45 pounds). Given the limitations of the calculations these figures should be regarded as illustrative, not definitive. It was not possible to measure health benefits in terms of quality-adjusted life-years, due to uncertainties around the evidence of clinical effectiveness, and to the fact that the adverse events avoided are transient (e.g. pain from injection of local anaesthetic, fear of the drill). One-way sensitivity analysis was applied to the model. However, owing to the limitations of the economic analysis, this should be regarded as merely speculative. For non-cavitated pit and fissure caries, the HealOzone option was always more expensive than current management when the probability of cure using the HealOzone option was 70% or lower. For non-cavitated root caries the costs of the HealOzone comparator were lower than those of current management only when cure rates from HealOzone were at least 80%. The costs of current management were higher than those of the HealOzone option when the cure rate for current management was 40% or lower. One-way sensitivity analysis was also performed using similar NHS Statement of Dental Remuneration codes to those that are used in the industry submission. This did not alter the results for non-cavitated pit fissure caries as the discounted net present value of current management remained lower than that of the HealOzone comparator ( 22.65 pounds versus 33.39 pounds). Any treatment that preserves teeth and avoids fillings is welcome. However, the current evidence base for HealOzone is insufficient to conclude that it is a cost-effective addition to the management and treatment of occlusal and root caries. To make a decision on whether HealOzone is a cost-effective alternative to current preventive methods for the management of dental caries, further research into its clinical effectiveness is required. Independent RCTs of the effectiveness and cost-effectiveness of HealOzone for the management of occlusal caries and root caries need to be properly conducted with adequate design, outcome measures and methods for statistical analyses.
    Preview · Article · Jun 2006 · Health technology assessment (Winchester, England)
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    Hilary Pinnock · Lynda McKenzie · David Price · Aziz Sheikh
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    ABSTRACT: Only about a third of people with asthma attend an annual review. Clinicians need to identify cost-effective ways to improve access and ensure regular review. To compare the cost-effectiveness of nurse-led telephone with face-to-face asthma reviews. Cost-effectiveness analysis based on a 3-month randomised controlled trial. Four general practices in England. Adults due an asthma review were randomised to telephone or face-to-face consultations. Trial nurses recorded proportion reviewed, duration of consultation, and abortive calls/missed appointments. Data on use of healthcare resources were extracted from GP records. Cost-effectiveness was assessed from the health service perspective; sensitivity analyses were based on proportion reviewed and duration of consultation. A total of 278 people with asthma were randomised to surgery (n = 141) or telephone (n = 137) review. Onehundred-and-one (74%) of those with asthma in the telephone group were reviewed versus 68 (48%) in the surgery group (P <0.001). Telephone consultations were significantly shorter (mean duration telephone = 11.19 minutes [standard deviation {SD} = 4.79] versus surgery = 21.87 minutes [SD = 6.85], P <0.001). Total respiratory healthcare costs per patient over 3 months were similar (telephone = pounds sterling 64.49 [SD = 73.33] versus surgery = pounds sterling 59.48 [SD = 66.02], P = 0.55). Total costs of providing 101 telephone versus 68 face-to-face asthma reviews were also similar (telephone = pounds sterling 725.84 versus surgery = pounds sterling 755.70), but mean cost per consultation achieved was lower in the telephone arm (telephone = pounds sterling 7.19 [SD = 2.49] versus surgery = pounds sterling 11.11 [SD = 3.50]; mean difference = - pounds sterling 3.92 [95% confidence interval = - pounds sterling 4.84 to pounds sterling 3.01], P <0.001). Telephone consultations enable a greater proportion of asthma patients to be reviewed at no additional cost to the health service. This mode of delivering care improves access and reduces cost per consultation achieved.
    Full-text · Article · Mar 2005 · British Journal of General Practice

  • No preview · Article · Jan 2005
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    ABSTRACT: To assess the effectiveness and cost-effectiveness of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction (MI). Major electronic databases. Two reviewers independently extracted data and assessed study quality. A decision tree model was used to model the diagnosis decision and a Markov model was developed for the management of patients with suspected coronary artery disease. Costs for the treatments and interventions within strategies were derived from the literature and expressed in 2001-02 pounds sterling. Quality-adjusted life-year (QALY) weights for the different Markov model states were also obtained from the literature. Twenty-one diagnostic and 46 prognostic studies were included, plus two studies comparing SPECT with electrocardiography (ECG)-gated SPECT and one study comparing SPECT with attenuation-corrected SPECT. The diagnostic values of SPECT were generally higher than those of stress ECG, indicating that SPECT provided a better diagnostic performance. SPECT also provided higher positive and lower negative likelihood ratios than stress ECG but heterogeneity was evident among studies. The subgroup of studies including patients with previous MI tended to report a better diagnostic performance for SPECT than stress ECG, but there were too few studies to assess this reliably. The extent and size of the perfusion defect, and whether reversible or fixed, were important factors in predicting future cardiac events such as cardiac death or non-fatal MI. SPECT may be able to identify lower risk patients for whom coronary angiography (CA) might be avoided. Normal SPECT scans were associated with a benign prognosis and the option of medical rather than invasive management. Four studies of patients post-MI reported SPECT to be valuable in stratifying patients into at-risk groups for further cardiac events. The two studies comparing SPECT with ECG-gated SPECT, one diagnostic and the other prognostic, found in favour of gated SPECT. The study comparing SPECT with attenuation-corrected SPECT reported the latter to be more accurate. The systematic review of economic evaluations indicated that strategies involving SPECT were likely either to be dominant or to produce more QALYs at an acceptable cost. There was less agreement about which of the strategies involving SPECT was optimal. The model suggested that, for low prevalence, the incremental cost per unit of output (true positives diagnosed, accurate diagnosis, QALY) for the move from stress ECG-SPECT-CA and from stress ECG-CA to SPECT-CA might be considered worthwhile. Even after allowing for different values for sensitivity or specificity, the least costly and least effective strategy was stress ECG-SPECT-CA. The sensitivity analysis suggested that the cost-effectiveness of SPECT-CA improved if it was assumed that SPECT results allowed for the adoption of a management strategy without recourse to CA. As the time horizon reduced, the incremental cost per QALY increased (as the cost of initial diagnosis and treatment were not offset by survival and quality of life gains). There was a considerable variability in terms of measurement of outcomes, management, setting and patient characteristics, however the direction of evidence tended to favour SPECT in terms of test sensitivity, although these conclusions are based on a relatively small number of diagnostic studies. SPECT, in a variety of settings and patient populations, provided valuable independent and incremental prognostic information to that provided by stress ECG and/or CA that helped to risk-stratify patients and influence the way in which their condition was managed. However, all of the prognostic studies were observational studies and may be biased by unknown confounding factors. Although the ECG-gated and attenuation-corrected SPECT findings seem promising, it is difficult to draw conclusions from so few studies. Further research is needed on the effectiveness and cost-effectiveness, diagnostically and prognostically, of (a) gated and attenuation-corrected SPECT compared with standard SPECT, (b) standard SPECT compared with stress echocardiography and (c) the uncertainty surrounding the results presented in the cost-effectiveness analysis.
    Full-text · Article · Aug 2004 · Health technology assessment (Winchester, England)
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    ABSTRACT: To evaluate the effectiveness and efficiency of a tailored multifaceted strategy, delivered by a national clinical effectiveness programme, to implement a guideline on induced abortion. Cluster randomised controlled trial. All 26 hospital gynaecology units in Scotland providing induced abortion care. Following the identification of barriers to guideline implementation, intervention units received a package comprising audit and feedback, unit educational meetings, dissemination of structured case records and promotion of a patient information booklet. Control units received printed guideline summaries alone. Compliance with five key guideline recommendations (primary outcomes) and compliance with other recommendations, patient satisfaction and costs of the implementation strategy (secondary outcomes). No effect was observed for any key recommendation: appointment with a gynaecologist within five days of referral (odds ratio 0.89; 95% confidence interval 0.50 to 1.58); ascertainment of cervical cytology history (0.93; 0.36 to 2.40); antibiotic prophylaxis or screening for lower genital tract infection (1.70; 0.71 to 5.99); use of misoprostol as an alternative to gemeprost (1.00; 0.27 to 1.77); and offer of contraceptive supplies at discharge (1.11; 0.48 to 2.53). Median pre-intervention compliance was near optimal for antibiotic prophylaxis and misoprostol use. No intervention benefit was observed for any secondary outcome. The intervention costs an average of pound 2607 per gynaecology unit. The tailored multifaceted strategy was ineffective. This was possibly attributable to high pre-intervention compliance and the limited impact of the strategy on factors outside the perceived control of clinical staff.
    Full-text · Article · Aug 2004 · BJOG An International Journal of Obstetrics & Gynaecology
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    L McKenzie · L Vale · S Stearns · K McCormack
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    ABSTRACT: This paper explores the cost utility of metal-on-metal hip resurfacing arthroplasty (MOM) as an alternative intervention to total hip replacement or 'watchful waiting' for patients with advanced hip disease. Early implant failure among younger and more active elderly patients can mean that the use of total hip replacement (THR) is delayed, with patients managed through 'watchful waiting', a combination of pain control and other non-surgical interventions. Information on costs is combined with evidence on effectiveness from a systematic review in a Markov model in order to estimate the incremental cost per quality adjusted life year (QALY) of MOM relative to THR and 'watchful waiting'.
    Full-text · Article · Feb 2003 · The European Journal of Health Economics
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    ABSTRACT: Changes to the present age policy of cervical screening are currently under consideration. We conducted a retrospective matched case-control study and cost analysis study to identify risk factors for the development of an abnormal smear after age 50 and to determine the impact of age-restricted cervical screening on the annual cost of the screening program. All women (229) from an 11-year birth cohort who developed an abnormal smear at age 50 or over were age-matched for two controls with negative smears. Routine screening smears taken between age 48 and 52 were tested for human papillomavirus (HPV) subtypes 16 and 18. Epidemiologic data were collected by postal questionnaire. Changes in costs under a policy of HPV testing and age-restricted screening were assessed. We found that HPV 16 status was the only independently significant risk factor for abnormal cytology after age 50 with an odds ratio of 10.26 (95% CI 1.25-84.11). A policy of early withdrawal from screening at age 50 on the basis of HPV testing would produce net cost savings. These findings suggest that HPV testing could be a valuable means of identifying the small proportion of women still at risk after 50, and of releasing health care resources.
    No preview · Article · Nov 2002 · International Journal of Gynecological Cancer
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    ABSTRACT: There is still debate over the benefit of self-management programmes for adults with asthma. A brief self-management programme given during a hospital admission for acute asthma was tested to determine whether it would reduce readmission. A randomised controlled trial was performed in 280 adult patients with acute asthma admitted over 29 months. Patients on the self-management programme (SMP) received 40-60 minutes of education supporting a written self-management plan. Control patients received standard care (SC). One month after discharge SMP patients were more likely than SC patients to report no daytime wheeze (OR 2.6, 95% CI 1.5 to 5.3), no night disturbance (OR 2.0, 95% CI 1.2 to 3.5), and no activity limitation (OR 1.5, 95% CI 0.9 to 2.7). Over 12 months 17% of SMP patients were re-admitted compared with 27% of SC patients (OR 0.5, 95% CI 0.3 to 1.0). Among first admission patients, OR readmission (SMP v SC) was 0.2 (95% CI 0.1 to 0.7), p<0.01. For patients with a previous admission, OR readmission was 0.8 (95% CI 0.4 to 1.6), p=0.6. SMP patients were more likely than SC patients to be prescribed inhaled steroids at discharge (99% v 92%, p=0.03), oral steroids (98% v 90%, p=0.06), and to have hospital follow up (98% v 84%, p<0.01) but adjustment for these differences did not diminish the effect of the self-management programme. A brief self-management programme during hospital admission reduced post discharge morbidity and readmission for adult asthma patients. The benefit of the programme may have been greater for patients admitted for the first time. The programme also had a small but significant effect on medical management at discharge.
    Preview · Article · Oct 2002 · Thorax
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    L Vale · L Wyness · K McCormack · L McKenzie · M Brazzelli · S C Stearns

    Full-text · Article · Feb 2002 · Health technology assessment (Winchester, England)
  • Lynda McKenzie · John Cairns · Liesl Osman
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    ABSTRACT: This paper reports on an application of discrete choice modelling to the measurement of patient preferences over asthma symptoms. A sample of patients with moderate to severe asthma was asked to choose between a series of pairs of scenarios characterised by different combinations of asthma symptoms. Their responses were analysed using a random effects ordered probit model. The results implied that patients weighted some symptoms more highly than others. Discrete choice modelling proved to be a useful approach for developing preference based outcome measures, although the results show how, in contexts where preferences over health care outcomes based on symptoms or some measure of health status are involved, a conventional linear additive model may not always be suitable.
    No preview · Article · Oct 2001 · Health Policy
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    ABSTRACT: Quality of life measures are increasingly important in evaluating outcomes in asthma. If some asthma symptoms are more troublesome to patients than others, this may affect their contribution to outcome measures. This study was designed to assess the relative importance of common symptoms in adults with asthma. A postal survey using conjoint analysis was performed in 272 adults attending hospital outpatient clinics with moderately severe asthma. Patients were asked to chose between "symptom scenarios" offering different combinations of levels of five common asthma symptoms over one week. Two versions of the questionnaire were used with identical scenarios presenting symptoms in different orders. Different patients answered the two versions. Regression analysis was used to calculate symptom weights for daytime cough, breathlessness, wheeze and chest tightness, and sleep disturbance. Symptom order, percentage predicted peak expiratory flow (PEF), and symptoms in the week before the survey did not influence the choice of scenario. In both questionnaires patients were more likely to choose scenarios with low levels of cough and breathlessness than low sleep disturbance, wheeze or chest tightness. Regression weights for cough (-0.52) and breathlessness (-0.49) were twice those of wheeze (-0.25), chest tightness (-0.27), and sleep disturbance (-0.25). For 12% of patients cough dominated patient preferences, regardless of all other symptoms. Age was inversely related to weight given by patients to breathlessness. The prominence of cough among other asthma symptoms was unexpected. Daytime cough and breathlessness had greater impact for patients than wheeze or sleep disturbance. Age influenced symptom burden, with younger patients giving greater weight to breathlessness than older patients. Conjoint analysis appears to be a useful method for establishing the relative importance of common symptoms.
    Full-text · Article · Mar 2001 · Thorax