Benefits, harms and costs of screening mammography in women 70 years and over: a systematic review

OBJECTIVE

To assess the (i) benefits, (ii) harms and (iii) costs of continuing mammographic screening for women 70 years and over.

DATA SOURCES AND SYNTHESIS

(i) We conducted a MEDLINE search (1966 - July 2000) for decision-analytic models estimating life-expectancy gains from screening in older women. The five studies meeting the inclusion criteria were critically appraised using standard criteria. We estimated relative benefit from each model's estimate of effectiveness of screening in older women relative to that in women aged 50-69 years using the same model. (ii) With data from BreastScreen Queensland, we constructed balance sheets of the consequences of screening for women in 10-year age groups (40-49 to 80-89 years), and (iii) we used a validated model to estimate the marginal cost-effectiveness of extending screening to women 70 years and over.

RESULTS

For women aged 70-79 years, the relative benefit was estimated as 40%-72%, and 18%-62% with adjustment for the impact of screening on quality of life. For women over 80 years the relative benefit was about a third, and with quality-of-life adjustment only 14%, that in women aged 50-69 years. (ii) Of 10,000 Australian women participating in ongoing screening, about 400 are recalled for further testing, and, depending on age, about 70-112 undergo biopsy and about 19-80 cancers are detected. (iii) Cost-effectiveness estimates for extending the upper age limit for mammographic screening from 69 to 79 years range from $8119 to $27 751 per quality-adjusted life-year saved, which compares favourably with extending screening to women aged 40-49 years (estimated at between $24,000 and $65,000 per life-year saved).

CONCLUSIONS

Women 70 years and over, in consultation with their healthcare providers, may want to decide for themselves whether to continue mammographic screening. Decision-support materials are needed for women in this age group.

Feasibility of an evidence-based literature search service for general practitioners

OBJECTIVE

To test the feasibility of an evidence-based clinical literature search service to help answer general practitioners' (GPs') clinical questions.

DESIGN

Two search services supplied GPs who submitted questions with the best available empirical evidence to answer these questions. The GPs provided feedback on the value of the service, and concordance of answers from the two search services was assessed.

SETTING

Two literature search services (Queensland and Victoria), operating for nine months from February 1999.

MAIN OUTCOME MEASURES

Use of the service; time taken to locate answers; availability of evidence; value of the service to GPs; and consistency of answers from the two services.

RESULTS

58 GPs asked 160 questions (29 asked one, 11 asked five or more). The questions concerned treatment (65%), aetiology (17%), prognosis (13%), and diagnosis (5%). Answering a question took a mean of 3 hours 32 minutes of personnel time (95% CI, 2.67-3.97); nine questions took longer than 10 hours each to answer, the longest taking 23 hours 30 minutes. Evidence of suitable quality to provide a sound answer was available for 126 (79%) questions. Feedback data for 84 (53%) questions, provided by 42 GPs, showed that they appreciated the service, and asking the questions changed clinical care. There were many minor differences between the answers from the two centres, and substantial differences in the evidence found for 4/14 questions. However, conclusions reached were largely similar, with no or only minor differences for all questions.

CONCLUSIONS

It is feasible to provide a literature search service, but further assessment is needed to establish its cost effectiveness.

Ways of using evidence-based medicine in general practice

General practitioners wanting to practise evidence-based medicine (EBM) are constrained by time factors and the great diversity of clinical problems they deal with. They need experience in knowing what questions to ask, in locating and evaluating the evidence, and in applying it. Conventional searching for the best evidence can be achieved in daily general practice. Sometimes the search can be performed during the consultation, but more often it can be done later and the patient can return for the "result". Case-based journal clubs provide a supportive environment for GPs to work together to find the best evidence at regular meetings. An evidence-based literature search service is being piloted to enhance decision-making for individual patients. A central facility provides the search and interprets the evidence in relation to individual cases. A request form and a "results" format make the service akin to pathology testing or imaging. Using EBM in general practice appears feasible. Major difficulties still exist before it can be practised by all GPs, but it has the potential to change the way doctors update their knowledge.

Outcomes of a randomized controlled trial of a clinical pharmacy intervention in 52 nursing homes

AIMS

To evaluate whether a year long clinical pharmacy program involving development of professional relationships, nurse education on medication issues, and individualized medication reviews could change drug use, mortality and morbidity in nursing home residents.

METHODS

A cluster randomised controlled trial, where an intervention home was matched to three control homes, was used to examine the effect of the clinical pharmacy intervention on resident outcomes. The study involved 905 residents in 13 intervention nursing homes and 2325 residents in 39 control nursing homes in south-east Queensland and north-east New South Wales, Australia. The outcome measures were: continuous drug use data from government prescription subsidy claims, cross-sectional drug use data on prescribed and administered medications, deaths and morbidity indices (hospitalization rates, adverse events and disability indices).

RESULTS

This intervention resulted in a reduction in drug use with no change in morbidity indices or survival. Differences in nursing home characteristics, as defined by cluster analysis with SUDAAN, negated intervention-related apparent significant improvements in survival. The use of benzodiazepines, nonsteroidal anti-inflammatory drugs, laxatives, histamine H2-receptor antagonists and antacids was significantly reduced in the intervention group, whereas the use of digoxin and diuretics remained similar to controls. Overall, drug use in the intervention group was reduced by 14.8% relative to the controls, equivalent to an annual prescription saving of A64 dollars per resident (approximately 25 pound sterling).

CONCLUSIONS

This intervention improved nursing home resident outcomes related to changes in drug use and drug-related expenditure. The continuing divergence in both drug use and survival at the end of the study suggests that the difference would have been more significant in a larger and longer study, and even more so using additional instruments specific for measuring outcomes related to changes in drug use.

Managing ADHD in general practice. N of 1 trials can help!

OBJECTIVE

To pilot single patient trials designed to improve decision making about stimulant use for attention deficit hyperactivity disorder (ADHD) in general practice.

METHOD

Patients previously stabilised on dexamphetamine were enrolled from a general practice. Each undertook a six week same patient randomised, double blind, placebo controlled crossover comparison of dexamphetamine with placebo for ADHD. Rating scales were completed weekly by self, parent and teacher.

RESULTS

Three of the four patients were clear responders to dexamphetamine (including a noncompleter, as his results still demonstrated a clear response). The results were clinically useful in each case. Management was confirmed for three patients and changed for one (who ceased dexamphetamine).

DISCUSSION

Prescribing stimulant medications only to children with diagnosed ADHD and who are found to respond, limits use of these worrisome drugs to those who will respond, and minimises their use in those who will not benefit.

N of 1 trials. Practical tools for medication management

BACKGROUND

In single patient (n of 1) trials, a patient acts as his or her own control in a study comparing the effectiveness of a drug with placebo or another drug. The aim of a single patient trial (SPT) is to identify the best treatment for the individual patient, formalising a 'trial of treatment' by using blinding and multiple crossover periods.

OBJECTIVE

We have successfully piloted SPTs for osteoarthritis and attention deficit hyperactivity disorder, and several others are currently being piloted. Barriers encountered include: obtaining identical placebos, ethical approval for individual SPTs, standardising doses, determining length of treatment periods, patient withdrawals and cost of the SPTs.

DISCUSSION

Only prescribing medications if an individual has been shown to be a responder can greatly benefit general practitioners, patients and the healthcare system. We have established the infrastructure necessary to offer a single patient trial service to GPs and patients anywhere in Australia. This has the potential to revolutionise prescribing for certain chronic conditions.

Preliminary experiences with a single-patient trials service in general practice

OBJECTIVE

To pilot a single-patient trials (SPTs) service in general practice, designed to improve decision-making about long-term medications for chronic conditions.

DESIGN

12-week within-patient, randomised, double-blind, placebo-controlled, crossover comparison of ibuprofen with paracetamol for osteoarthritis, involving three pairs of two-week treatment periods for each participating patient.

SETTING AND PATIENTS

Patients attending an academic general practice with a clinical diagnosis of osteoarthritis, with pain of at least a month's duration severe enough to warrant consideration of long-term non-steroidal anti-inflammatory drug (NSAID) use.

MAIN OUTCOME MEASURES

Pain and stiffness; measures of overall arthritis compared with previous fortnight; preference for NSAID at the end of each two-week treatment period; use of escape analgesia; side effects; and management changes as a result of the SPTs.

RESULTS

Eight of 14 patients completed SPTs. One was a clear responder to NSAIDs, five were non-responders, and two were indefinite. Of the five who were using NSAIDs' before the SPT, two continued and three ceased using them. Clinically useful information assisted decision-making for all eight participants. Medication management changed for six.

CONCLUSIONS

Single-patient trials can be successfully implemented in general practice and might be a valuable method for GPs to identify patients who respond to medication for chronic stable conditions such as osteoarthritis, in which individual response to medication is variable.

A comparison of standard gamble, time trade-off, and adjusted time trade-off scores

OBJECTIVE

To adjust patients' time trade-off (TTO) scores using information on their utility functions for survival time to derive a measure of health state utility equivalent to the standard gamble (SG).

METHODS

A sample of 199 cardiovascular patients were asked three TTO and SG questions (to assess their own health state), and three certainty equivalent questions (to assess their utility function for survival time) in an interview.

RESULTS

Patient's utility functions for time were increasingly concave, but being unable to model this successfully, a constant function with an averaged level of concavity was used. The raw TTO scores were significantly higher than SG scores, while the adjusted TTO scores were equivalent to the SG.

CONCLUSIONS

Raw time trade-off scores will give biased estimates of health state utility when patients' utility functions for time are not linear, but these can be adjusted to yield true utilities. The constant proportional risk-posture assumption of the conventional QALY model, on which previous attempts to adjust time trade-offs have been based, was not supported by the data.