Best Evidence Topics

Survey (including pre-test probabilities)

Odegard E, Rossow I.
Alcohol and non-fatal Drug Overdoses
European Addiction Research
  • Submitted by:Jenifer Barrie - Student
  • Institution:University of Manchester
  • Date submitted:12th July 2005
Before CA, i rated this paper: 7/10
1 Objectives and hypotheses
1.1 Are the objectives of the study clearly stated?
  Yes in the abstract and introduction.
Aims are to assess to what extent alcohol is a factor in non fatal overdose.
2 Design
2.1 Is the study design suitable for the objectives
  Yes, ambulance records were studied.
2.2 Who / what was studied?
  3838 cases of drug-related emergencies with a non fatal outcome constituting 1943 different persons. Ambulance records were studied.
2.3 Was this the right sample to answer the objectives?
  Yes, the samle size was large and only patients with suspected opiate overdose were studied.
2.4 Did the subject represent the full spectrum of the population of interest?
  Demographics resembled those from several previous studies.
2.5 Is the study large enough to achieve its objectives? Have sample size estimates been performed?
  No mention of sample size estimates.
2.6 Were all subjects accounted for?
2.7 Were all appropriate outcomes considered?
  No reports of adverse events after naloxone administration or those patients who had to be hospitalised.
Some patients were awoken without naloxone and there is no definative diagnosis of opiate overdose by toxicological analysis.
2.8 Has ethical approval been obtained if appropriate?
  No mention of ethical approval or informed consent.
2.9 What measures were made to contact non-responders?
  100% as all data sheets were completed on ambulance callouts by paramedic staff.
2.10 What was the response rate?
  see above
3 Measurement and observation
3.1 Is it clear what was measured, how it was measured and what the outcomes were?
  In data and methods. Data registered; date, time, address, name, date of birth, clinical status, type of substance consumed and intervention.
3.2 Are the measurements valid?
  Although alcohol intake was reported the amount was not.
3.3 Are the measurements reliable?
  They rely on witness accounts or patient accounts for type of drug used, Patients may have poor recall after being unconscious and receiving treatment. In terms of intervention and clinical status as long as ambulance staff were accurate in their interpretation and recordings.
3.4 Are the measurements reproducible?
  Yes the survey could be carried out again on another group of patients.
4 Presentation of results
4.1 Are the basic data adequately described?
  Basic numbers aren't described but there are percentages stated in the findings.
4.2 Are the results presented clearly, objectively and in sufficient detail to enable readers to make their own judgement?
  There are three tables.These aren't particularly clear however.
1 shows how alcohol relates to respiration and consciousness. This is clear with numerical value and percentage.
2 shows sex and age of those who ingested alcohol with coefficient and standard error.
Table three shows analyses.
4.3 Are the results internally consistent, i.e. do the numbers add up properly?
  yes all numbers add up.
5 Analysis
5.1 Are the data suitable for analysis?
5.2 Are the methods appropriate to the data?
  Yes, cox regression models and kaplan-Meier estimations were used.
5.3 Are any statistics correctly performed and interpreted?
  yes, cox regression showed that alcohol intake at first overdose was a risk for recurrent overdoses.
6 Discussion
6.1 Are the results discussed in relation to existing knowledge on the subject and study objectives?
  Yes the discussion refers to other appropriate studies.
6.2 Is the discussion biased?
  No because it includes studies where there have been conflicting results. There is no descripton of the problems with the study but these are described in the methods.
6.3 Can the results be generalised?
  Yes but it would be beneficial to have fatal overdoses included.
7 Interpretation
7.1 Are the authors' conclusions justified by the data?
  Yes for the demographic data, it does state however that alcohol leads to an increased risk of fatal outcome and the percentages are not significantly higher for those who have taken alcohol.
7.2 What level of evidence has this paper presented? (using CEBM levels)
  level 3, survey.
7.3 Does this paper help me answer my problem?
  It shows the prevalence of alcohol in fatal overdose, but doesn't indicate if it is the cause of a worse outcome or indeed its relationship to a fatal outcome.
After CA, i rated this paper: 5/10
8 Implementation
8.1 Can any necessary change be implemented in practice?
  An increasing awareness of concomitant use of alcohol and how to prevent this.
8.2 What aids to implementation exist?
  Community drug workers and health professionals such as general practitioners giving advice about not mixing heroin and alcohol and having alcohol detox programmes simultaneously with methadone maintenance.
8.3 What barriers to implementation exist?
  Many addicts will not be in contact with health professionals and resources may not be available to detox patients addicted to both alcohol and heroin.