Research Methods in Community Medicine

Surveys, Epidemiological Research, Programme Evaluation, Clinical Trials

Joseph Abramson, Z. H. Abramson

• Publisher: Wiley
• Year: 2011
• ISBN:
  9781119964162
• Edition: 6
• Topic: Medicine
• Subtopic: Pharmacology

• A simple and systematic guide to the planning and performance of investigations concerned with health and disease and with health care
• Offers researchers help in choosing a topic and to think about shaping objectives and ideas and to link these with the appropriate choice of method
• Fully updated with new sections on the use of the Web and computer programmes freely available in the planning, performance or analysis of studies

1

First Steps

The purpose of most investigations in community medicine, and in the health field generally, is the collection of information that will provide a basis for action, whether immediately or in the long run. The investigator perceives a problem that requires solution, decides that a particular study will contribute to this end, and embarks upon the study. Sound planning – and maybe a smile or two from Lady Luck – will ensure that the findings will be useful, and possibly even of wide scientific interest. Only if the problem has neither theoretical nor practical significance and the findings serve no end but self-gratification may sound planning be unnecessary.

Before planning can start, a problem must be identified. It has been said that ‘if necessity is the mother of invention, the awareness of problems is the mother of research’.¹ The investigator’s interest in the problem may arise from a concern with practical matters or from intellectual curiosity, from an intuitive ‘hunch’ or from careful reasoning, from personal experience or from that of others. Inspiration often comes from reading, not only about the topic in which the investigator is interested, but also about related topics. An idea for a study on alcoholism may arise from the results of studies on smoking (conceptually related to alcoholism, in that it is also an addiction) or delinquency (both it and alcoholism being, at least in certain cultures, forms of socially deviant behaviour).

While the main purpose is to collect information that will contribute to the solution of a problem, investigations may also have an educational function and may be carried out for this purpose. A survey can stimulate public interest in a particular topic (the interviewer is asked: ‘Why are you asking me these questions?’), and can be a means of stimulating public action. A community self-survey, carried out by participant members of the community, may be set up as a means to community action; such a survey may collect useful information, although it is seldom very accurate or sophisticated.

This chapter deals with the purpose of the investigation, reviewing the literature, ethical aspects, and the formulation of the study topic.

First Steps

• Clarifying the purpose
• Reviewing the literature
• Ethical considerations
• Formulating the topic

Clarifying the Purpose

The first step then, before the study is planned, is to clarify its purpose: the ‘why’ of the study. (We are not speaking here of the researcher’s psychological motivations – a quest for prestige, promotion, the gratifications of problem-solving, etc. which may or may not be at a conscious level.) Is it ‘pure’ or ‘basic’ research with no immediate practical applications in health care, or is it ‘applied’ research? Is the purpose to obtain information that will be a basis for a decision on the utilization of resources, or is it to identify persons who are at special risk of contracting a specific disease in order that preventive action may be taken; or to add to existing knowledge by throwing light on (say) a specific aspect of aetiology; or to stimulate the public’s interest in a topic of relevance to its health? If an evaluative study of health care is contemplated, is the motive a concern with the welfare of the people who are served by a specific practice, health centre or hospital, or is it to see whether a specific treatment or kind of health programme is good enough to be applied in other places also?

The reason for embarking on the study should be clear to the investigator. In most cases it will in fact be so from the outset, but sometimes the formulation of the problem to be solved may be less easy. In either instance, if an application is made for facilities or funds for the study it will be necessary to describe this purpose in some detail, so as to justify the performance of the study. The researcher will need to review previous work on the subject, describe the present state of knowledge, and explain the significance of the proposed investigation. This is the ‘case for action’.

Preconceived ideas introduce a possibility of biased findings, and an honest self-examination is always desirable to clarify the purposes. If the reason for studying a health service is that the investigator thinks it is atrocious and wants to collect data that will condemn it, extra-special care should be taken to ensure objectivity in the collection and interpretation of information. In such a case, the researcher would be well advised to ‘bend over backwards’ and consciously set out to seek information to the credit of the service. Regrettably, not all evaluative studies are honest.²

To emphasize the importance of the study purpose, and maybe to make it clearer, let us restate it in the words of three other writers:

The preliminary questions when planning a study are:

1. What is the question?

2. What will be done with the answer?³

Do not: say that you will try to formulate a good subject.

Do: tell what you want to accomplish with the subject.⁴

Discover the ‘latent objective’ of a project. The latent objective is the meaning of the research for the researcher, and gives away his or her secret hopes of what (s)he will achieve. To detect this latent objective, it is often fruitful to ‘begin at the end.’ How will the world be changed after the research is published?⁵

Reviewing the Literature

The published experiences and thoughts of others may not only indicate the presence and nature of the research problem, but may be of great help in all aspects of planning and in the interpretation of the study findings. At the outset of the study the investigator should be or should become acquainted with the important relevant literature, and should continue with directed reading throughout. References should be filed in an organized way, manually or in a computerized database.⁶ It is of limited use to wait until a report has to be written, and then read and cite (or only cite) a long list of publications to impress the reader with one’s erudition – a procedure that may defeat its own ends, since it is often quite apparent that the papers and books listed in the extensive bibliography have had no impact on the investigation.

Papers should be read with a healthy scepticism; in Francis Bacon’s words, ‘Read not to contradict and confute, not to believe and take for granted … but to weigh and consider’.⁷ Several guides to critical reading are available.⁸ Remember that studies that have negative or uninteresting findings are less likely to be published than those with striking findings.⁹

If the title and abstract suggest that the paper may be of interest, then you should appraise the methods used in the study (which requires the kind of familiarity with research methods and their pitfalls that this book attempts to impart), assess the accuracy of the findings, judge whether the inferences are valid, and decide whether the study has relevance to your own needs and interests. Do not expect any study to be completely convincing, and do not reject a study because it is not completely convincing; avoid ‘I am an epidemiologist’ bias (repudiation of any study containing any flaw in its design, analysis or interpretation) and other forms of what has been called ‘reader bias’.¹⁰

Search engines such as Google Scholar, and the increasing tendency to provide free access on the Internet to the full text of publications, have made it very much easier to find relevant literature. Google Scholar not only finds publications, it also finds subsequent publications that have cited them, and related publications, and it provides links to local library catalogues.

But, at the same time, the explosive growth in published material in recent years means that a computer search may find so many references (and so many of them irrelevant) that sifting them can be a demanding chore, to the extent that one may be misguidedly tempted to rely only on review articles, or on the abstracts provided by most databases, instead of tracking papers down and reading them.

Conducting a computer search in such a way that you get what you want – and don’t get what you don’t want – is not always easy. It is particularly difficult to get all of what you want. Investigators who wish to perform a systematic review of all previous published researches on a particular topic, for example, may be well advised to enlist the help of a librarian. A biomedical librarian advises the use of regular Google as well as Google Scholar if hard-to-find government or conference papers are sought, and also advises use of PubMed and other databases if the aim is an exhaustive search.¹¹ Most users find Google Scholar easy to use and very helpful – the answer to a maiden’s prayer – but its coverage (in its present incarnation) is incomplete,¹² and in terms of accuracy, thoroughness, and up-to-dateness it falls short of PubMed, which provides access to over 16 million citations, mainly from MedLine, back to the 1950s. The way to use PubMed is explained on the website (http://?www.ncbi.nlm.nih.gov/entrez), and it is easy to use if requirements are simple; but otherwise, it has been said, ‘If you enjoy puzzles, MedLine is great fun’.¹³ A user-friendly simplified interface, SLIM, is now available.¹⁴

Ethical Considerations

Before embarking on a study the investigator should be convinced that it is ethically justifiable, and that it can be done in an ethical way. Ethical questions arise in both experimental and nonexperimental studies.

There is an obvious ethical problem whenever an experiment to test the benefits or hazards of a treatment is contemplated. However beneficial the trial may turn out to be for humanity at large, some subjects may be harmed either by the experimental treatment or by its being withheld. There is also an ethical problem in not performing a clinical trial, since this may lead to the introduction or continued use of an ineffective or hazardous treatment. ‘Where the value of a treatment, new or old, is doubtful, there may be a higher moral obligation to test it critically than to continue to prescribe it year-in-year-out with the support merely of custom or wishful thinking.’¹⁵ But, it has been pointed out, ‘this ethical imperative can only be maintained if, and to the extent that, it is possible to conduct controlled trials in an ethically justifiable way’.¹⁶ The heinous medical experiments conducted on helpless victims by Nazi physicians in the first part of the 20th century should never be forgotten.¹⁷

For an experimental study to be ethical, the subjects should be aware that they are to participate in an experiment, should know how their treatment will be decided and what the possible consequences are, should be told that they may withdraw from the trial at any time, and should freely give their informed consent. These requirements are not always easily accepted in clinical settings, and they are sometimes circumvented by medical investigators who feel that they have a right to decide their patient’s treatment. Studies have shown that patients (especially poorly educated ones) who sign consent forms are often ignorant of the most basic facts. Special problems concerning consent may arise in cluster-randomized trials,¹⁸ where clusters of people (e.g. the patients in different family practices) are randomly allocated to treatment or control groups (see p. 351), or where a total community is exposed to an experimental procedure or programme, or when experiments (such as trials of new vaccines) are performed in developing countries.¹⁹

Ethical objections to clinical trials are reduced if there is genuine uncertainty about the value of the treatment tested or the relative value of the treatments compared (equipoise) – for some investigators, it is sufficient that there is genuine uncertainty in the health profession as a whole, whatever their own views – and if controls are given the best established treatment. ‘The essential feature of a controlled trial is that it must be ethically possible to give each patient any of the treatments involved’.¹⁹

Decisions on the ethicality of trials may not be simple.²⁰ Bradford Hill has said that there is only one Golden Rule, namely ‘that one can make no generalization … the problem must be faced afresh with every proposed trial’.

The goals of the research should always be secondary to the wellbeing of the participants. The Helsinki declaration states:

Concern for the interests of the subject must always prevail over the interests of science and society … every patient – including those of a control group, if any – should be assured of the best proven diagnostic and therapeutic method.

But researchers sometimes argue that obtaining an answer to the research question is the primary ethical obligation, so that they then ‘find themselves slipping across a line that prohibits treating human subjects as means to an end. When that line is crossed, there is very little left to protect patients from a callous disregard of their welfare for the sake of research goals’.²¹ This has raised debates about possible ‘scientific imperialism’, characterized by the performance of trials, sometimes with lowered ethical standards, in countries that are unlikely to benefit from the findings: ‘Are poor people in developing countries being exploited in research for the benefit of patients in the developed world where subject recruitment to a randomized trial would be difficult?’²²

In 1997, a furore was aroused at the disclosure that, in developing countries, controls were receiving placebos in trials, sponsored by the USA, of regimens to prevent the transmission of human immunodeficiency virus (HIV) from mothers to their unborn children, although there was an effective treatment that had been recommended for all HIV-infected pregnant women in the USA and some other countries. A debate ensued, the main issue being whether the Helsinki declaration’s requirement that controls should be given the best current treatment was outweighed by the claims that a comparison with placebo was the best way of finding out whether the relatively cheap experimental regimens would be helpful in countries that cannot afford optimal care, and that the investigators were simply observing what would happen to the infants of the controls, who would anyway not have received treatment if there had been no study.

How well the trial is planned and performed is also important:

Scientifically unsound studies are unethical. It may be accepted as a maxim that a poorly or improperly designed study involving human subjects – one that could not possibly yield scientific facts (that is, reproducible observations) relevant to the question under study – is by definition unethical. When a study is in itself scientifically invalid, all other ethical considerations become irrelevant. There is no point in obtaining ‘informed consent’ to perform a useless study.²³

It is generally accepted that a study that is too small to provide clear results is ipso facto unethical. But it is has been argued that this is not necessarily so, since a larger sample size would impose the burden of participation on more subjects, without having a proportionate effect on the trial’s capacity to yield clear results.²⁴

Other ethical considerations may arise after the trial has started. If it is found to be in a subject’s interest to stop or modify the treatment, or to start treating a control subject, then there should be no hesitation in doing so. If there is reason to think that continuation of the trial may be harmful, then it should be stopped forthwith. For example, the first randomized controlled trial of the protective effect against HIV infection of the performance of circumcision of young men, conducted in Orange Farm, a region close to Johannesburg in South Africa, was stopped as soon as an interim analysis revealed that the incidence of HIV infection was much higher in the controls than in the circumcised group.²⁵

In nonexperimental studies²⁶ ethical problems are usually less acute, unless the study involves hazardous test procedures or intrusions on privacy. But here, too, there is a need for informed consent²⁷ if participants are required to answer questions, undergo tests that carry a risk (however small), or permit access to confidential records. The investigators should give an honest explanation of the purpose of the survey when enlisting subjects, and respondents should be told what their participation entails, and assured that they are free to refuse to answer questions or continue their participation. Pains should be taken to keep information confidential. Any promises made to participants, e.g. about anonymity or the provision of test results, should of course be kept.

Of particular importance is the question of what action should be taken if a survey reveals that participants would benefit from medical care or other intervention. In studies involving HIV antibody testing, subjects with positive results should obviously be notified, even if this affects the soundness of the study.²⁸

The notorious Tuskegee study in Alabama is a horrible illustration of an unethical survey.²⁹ It began in 1932, with the aim of throwing light on the effects of untreated syphilis. Some 400 untreated Black syphilitics (mostly poor and uneducated) were identified and then followed up; their course was compared with that of apparently syphilis-free age-matched controls. Treatment of syphilis was withheld. By 1938-1939 it was found that a number of the men had received sporadic treatment with arsenic or mercury, and a very few had had more intensive treatment. In the interests of science ‘fourteen young untreated syphilitics were added to the study to compensate for this’. Treatment was withheld even when penicillin was found to be effective and became easily available in the late 1940s and early 1950s. Participants received free benefits, such as free treatment (except for syphilis), free hot lunches, and free burial (after a free autopsy). By 1954 it was apparent that the life expectancy of the untreated men aged 25–50 was reduced by 17%. By 1963, 14 more men per 100 had died in the syphilitic group than in the control group...

Table of contents

• Cover
• Dedication
• Title page
• Copyright
• Preface
• 1: First Steps
• 2: Types of Investigation
• 3: Stages of an Investigation
• 4: Formulating the Objectives
• 5: The Objectives of Evaluative Studies
• 6: The Study Population
• 7: Control Groups
• 8: Sampling
• 9: Selecting Cases and Controls for Case-control Studies
• 10: The Variables
• 11: Defining the Variables
• 12: Definitions of Diseases
• 13: Scales of Measurement
• 14: Composite Scales
• 15: Methods of Collecting Data
• 16: Reliability
• 17: Validity
• 18: Interviews and Self-Administered Questionnaires
• 19: Constructing a Questionnaire
• 20: Surveying the Opinions of a Panel: Consensus Methods
• 21: The Use of Documentary Sources
• 22: Planning the Records
• 23: Planning the Handling of Data
• 24: Pretests and Other Preparations
• 25: Collecting the Data
• 26: Statistical Analysis
• 27: Interpreting the Findings
• 28: Making Sense of Associations
• 29: Application of the Study Findings
• 30: Writing a Report
• 31: Rapid Epidemiological Methods
• 32: Clinical Trials
• 33: Programme Trials
• 34: Community-Oriented Primary Care
• 35: Using the Web for Health Research
• Appendix A: Community appraisal: a checklist
• Appendix B: Random numbers
• Appendix C: Free computer programs
• Index