The appraisal of public health interventions: an overview.

BACKGROUND: The approach currently used to appraise public health interventions is close to that of health technology appraisal for drugs. This approach is not appropriate for many public health interventions, however, when extremely small individual level benefits are delivered to extremely large populations. In many such situations, randomized controlled trials with sufficient size and power to determine individual level effects are impractical. Such interventions may be cost-effective, even in the absence of traditional evidence to demonstrate this. METHODS: We outline an alternative approach based on decision theory. We apply it to cases where prior beliefs are sufficiently strong and well grounded to allow decision-makers to assume the direction of change of the intervention's outcome, within the context of a transparent and deliberative decision-making process. Decision theory also assumes that decision-makers are risk neutral, implying that they should make decisions based on an intervention's mean cost-effectiveness, and should therefore disregard variance except when deciding to wait for more information. However, they must allow for biases. RESULTS: A framework is presented which has the potential to achieve large health gains at no additional cost. CONCLUSIONS: This analysis provides a rigorous theoretical framework for decision-makers in public health. The implied paradigm shift also applies to some clinically based areas.

Clinical decision guidelines for NHS cosmetic surgery: analysis of current limitations and recommendations for future development.

Because of increasing demand for publicly funded elective cosmetic surgery, clinical decision guidelines have been developed to select those patients who should receive it. The aims of this study were to identify: the main characteristics of such guidelines; whether and how they influence clinical decision making; and ways in which they should be improved. UK health authorities were asked for their current guidelines for elective cosmetic surgery and, in a single plastic surgery unit, we examined the impact of its guidelines by observing consultations and interviewing surgeons and managers. Of 115 authorities approached, 32 reported using guidelines and provided sufficient information for analysis. Guidelines mostly concerned arbitrary sets of cosmetic procedures and lacked reference to an evidence base. They allowed surgery for specified anatomical, functional or symptomatic reasons, but these indications varied between guidelines. Most guidelines also permitted surgery 'exceptionally' for psychological reasons. The guidelines that were studied in detail did not appreciably influence surgeons' decisions, which reflected criteria that were not cited in the guidelines, including cost of the procedure and whether patients sought restoration or improvement of their appearance. Decision guidelines in this area have several limitations. Future guidelines should: include all cosmetic procedures; be informed by a broad range of evidence; and, arguably, include several nonclinical criteria that currently inform surgeons' decision-making.

Reproducibility of exhaled nitric oxide measurements in healthy and asthmatic adults and children.

Airway inflammation in asthma is not measured routinely in clinical practice. Fractional exhaled nitric oxide (FE(NO)), a marker of airway inflammation, is increasingly used as an outcome measure in asthma intervention studies and yet the reproducibility of FE(NO) measurements is unknown. The reproducibility, day-to-day, diurnal variation and perception of standardised FE(NO) measurements were examined in 59 subjects (40 children aged 7-13 yrs and 19 adults aged 18-60 yrs), both healthy (n=30) and with mild (n = 29) asthma. FE(NO) was measured on five consecutive days (four measurements on the same day) for adults and twice on the same day for children. The coefficient of reproducibility expressed as the mean pooled standard deviation (n = 59, 675 estimations) was 2.11 parts per billion (ppb) and intraclass correlation coefficient was 0.99 in both children and adults. FE(NO) was significantly higher in asthma subjects (32.3 ppb) than in healthy subjects (16.3 ppb). There was no diurnal or day-to-day variation, or a learning effect, as the result of FE(NO) measurements were identical at results of the beginning and at the end of the study. It was concluded that fractional exhaled nitric oxide measurements are simple, reproducible, free from diurnal and day-to-day variation, and acceptable by both healthy and asthmatic adults and children, as a part of their routine visit to a physician.

Relationship between exhaled nitric oxide and mucosal eosinophilic inflammation in mild to moderately severe asthma.

BACKGROUND: Exhaled levels of nitric oxide (NO) are raised in asthma but the relationship between exhaled NO levels and a direct measure of airway inflammation has not been investigated in asthmatic patients treated with inhaled steroids. METHODS: The relationship between exhaled NO levels, clinical measures of asthma control, and direct markers of airway inflammation were studied in patients with asthma treated with and without inhaled corticosteroids. Thirty two asthmatic patients (16 not using inhaled steroids and 16 using inhaled beclomethasone dipropionate, 400-1000 microg/day) were monitored with respect to measures of asthma control including lung function, symptom scores, medication usage, and variability of peak expiratory flow (PEF) for one month. Measurements of exhaled NO and fibreoptic bronchoscopy were performed at the end of the monitoring period. Bronchial mucosal biopsy specimens were stained with an anti-MBP antibody for quantification of eosinophils. RESULTS: There was no significant difference in lung function, symptom scores, or medication usage between the two groups, but there was a significant difference in PEF variability (8.7 (1.2)% in steroid naive patients versus 13.6 (1.9)% in steroid treated patients, p<0.05) and exhaled NO levels (9.9 (3.5) ppb in steroid naive patients versus 13.6 (2.0) ppb in steroid treated patients, p<0.05). There was no correlation between exhaled NO and mucosal eosinophils, or between NO and conventional measures of asthma control. There was a significant correlation between mucosal eosinophils and lung function (r = -0.43, p<0.05). CONCLUSIONS: Exhaled NO levels do not reflect airway mucosal eosinophilia and these markers reflect different aspects of airway inflammation. The clinical usefulness of exhaled NO needs to be determined in prospective longitudinal studies.

Randomised controlled trial of a synthetic triglyceride milk formula for preterm infants.

AIMS: To test whether use of infant formula containing synthetic structured triglycerides results in: (i) increased palmitate absorption; (ii) increased total fat absorption; (iii) reduction in calcium soap formation in the gut; and hence (iv) increased calcium absorption. METHODS: A randomised study was made of 24 infants comparing three formulas, one containing the synthetic fat Betapol with 74% of palmitate in the 2-position, which was substantially higher than in the two comparison diets (8.4% and 28%). The hypothesised outcomes were tested using balance studies, detailed chemical analysis of stool specimens and dual calcium isotope tracers (44calcium orally and 46calcium intravenously). RESULTS: Three of the four hypotheses were confirmed: use of a formula rich in 2-position palmitate (i) improved palmitate (16:0) and also (18:0) absorption; (ii) reduced the formation of insoluble calcium soaps in the stool; and (iii) improved calcium absorption, determined by the dual tracer technique from 42 (SE 3)% to 57 (7)%. CONCLUSION: Synthetic triglycerides that mimic the stereoisometric structure of those in breast milk may have a valuable role in the design of formulas used for preterm infants in neonatal intensive care units.

An exploration of midwives' attitudes to research and perceived barriers to research utilisation.

OBJECTIVE: To explore midwives' views about research and their perceived barriers to research utilisation. SETTING: Thirty-two midwives from four midwifery units in the north west of England. The units ranged in size from a small district unit (52 midwives, and 1200 deliveries per annum), to a large regional centre (290 midwives, 6500 deliveries per annum). METHODS: Midwives' opinions concerning research were explored using focus group interviews; within the interviews midwives were asked to discuss how they viewed the relevance of research to midwifery care, the constraints which they felt prevented them from delivering research-based care and existing and potential methods of disseminating research. FINDINGS: There was a consensus among the midwives that they aspired to deliver research-based care. However, there are clearly a number of barriers preventing this. Research was poorly accessible to most midwives, both in terms of its physical location and complexity. Furthermore, midwives felt they lacked the knowledge and skills to appraise research, and lacked the confidence to judge when research should be implemented. CONCLUSIONS: The current trend to demedicalise childbirth demands that midwives become proficient users of research. However, the means of disseminating research findings to midwives in the north west of England does not meet their needs.