Epidemiology module of practical skills for mbbs student

1. Choosing the general domains or topic areas for focus
Relevance to health in the community:
Among conditions affecting lung health, the most frequent serious conditions in your region are (list them, be specific):

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What criteria did you use to select these conditions?

Is the list the same for other countries (or regions)?

Interests and experience of the research team; Relevance to the political and social imperatives
Are there specific research questions or topics of particular interest to you or your colleagues, or that you know are of particular interest to managers of health services or health spending in your region (list them):

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2. Narrowing the focus
Combining aspects from the two lists above, list (? in order of priority), several topics or research questions for protocol development.
Questions for the group to consider: What criteria will you use to decide what topics remain on the list? to decide the order of priority? (interest of participants - ? by vote, consensus; fundability; seriousness of the disease; frequency of the disease; prior experience of participants)

In previous courses, participants have found it useful to select 4 to 6 general topic areas that address different diseases (or health-related states), or that reflect differing types of study populations (eg. clinical topics, health service delivery issues, community or workplace studies, evaluation of treatments).

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   From general ‘topics’ to study questions and specific objectives
   

At some point in the study question development process, participants in previous courses have found it useful to fill in templates similar to the ones below for the study topics / questions identified (either after the initial brainstorming – to help narrow the focus, or after 4-6 topics have been chosen).

Studies of disease in populations (natural history, determinants, etc)

Disease or health-related state	Target population	Determinant(s) of interest	Feasible? Significance?	Intervention possible?	Most likely study design

Epidemiologic studies of clinical procedures, treatments, interventions, diagnostic tests

Procedure, intervention, etc	Patient group	Outcome to be assessed?	Feasible? Significance?	Implementation likely?	Experimental design possible?

Practical exercise

Study Design

The following are a group of selected abstracts of scientific articles on lung health published in recent years (slightly edited for purposes of this exercise). Each abstract describes a scientific study of an epidemiological nature, giving setting, objectives, design, results and conclusions.

Read each abstract and then define what type of study design is described in the abstract, using the enclosed standard form and taking into account the elements described in the preceding section.
In assessing the study design, first ask the question:

Was only one group (either a group of patients, or a group with a common experience/exposure) studied?
If the answer is no, ask:

Did the investigator choose which group an individual would be in or assign interventions to groups?
If the answer is no, ask:

When selecting the groups to be studied, did the investigator begin by selecting groups defined by the presence or absence of disease, or did the investigator select according to the presence or absence of a common factor or exposure?
If the answer is no, ask:

Was the presence of disease and of the factor or exposure thought to be associated with the disease measured at the same point in time?
The answers to these questions should allow you to correctly determine which type of study design the investigators have selected.

ABSTRACTS:

Study 1 - Short course chemotherapy for tuberculoma of the brain

Setting: Tuberculosis Research Centre, Madras, India

Objective: The efficacy of a short-course regimen in the treatment of brain tuberculoma and computerized tomography scan appearance before, during and after antituberculosis treatment was studied.

Design: Patients aged over 5 years with tuberculoma of the brain diagnosed by CT scan were randomly allocated to one of the following 2 regimens:

Regimen 1: rifampicin, isoniazid and pyrazinamide daily for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months;

Regimen 2: rifampicin, isoniazid and pyrazinamide thrice-weekly for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months.

The patients were followed intensively for 2 years from the start of treatment

Results: Of the 108 patients analysed (regimen 1: 56, regimen 2: 52), at the end of treatment clinical status was normal in 91% in regimen 1 and 88% in regimen 2. Of the 91 patients with scan assessments, CT scan lesions disappeared at 24 months in 77% of 47 patients in regimen 1 and 80% of 44 in regimen 2, and in both groups 88% of the patients were clinically normal. None had relapses requiring treatment.

Conclusions: Short-course regimens of 9 months’ duration are effective in the treatment of tuberculoma of the brain; clinical recovery was faster than scan clearance.